Atlas Of Otology And Surgery Paparella 3q4f3l

Editor

Marcos V. Goycoolea, M.D., M.S., Ph.D. M i n n e s o t a Ear, H e a d & N e c k Clinic Minneapolis, Minnesota

Co-Editors

Michael M. Paparella, M.D. Minnesota Ear, Mead & Neck Clinic Minnesota

Rick L. Nissen, M.D. M i n n e s o t a E a r , H e a d & N e c k Clinic Minneapolis, Minnesota

ATLAS OF

Otologic Surgery 1989 W.B. SAUNDERS COMPANY Harcourt Brace Jovanovirh, I n c . Philadrlphia ' lôndon / Toronto Montreal ' Svdnev ' Tokyo

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s a u n company . Brace Jovanovich. Inc. | . f u r t ^ Center dependence Square Wesl u

hiuTdelphia. PA 19106

Library of Congress Catag-in-Publication

PURO CHILE ES TU CIELO AZULADO

Data

PURAS

Alias o f o t o l o g i c s u r g e r y . Bibliography: p. I

R F 2 9 5 . G 6 9 1989

6I7.8TO9

W, II. Saunders Stall l.iz Schweber

«ludiría Manager: "iiiscr/ul Etlitor: ^í'iJíiir.

lull I'reslnn lorn Cihhons

Melissa Walter

isfmlim GonnfiiM/or: 'IT Dtffitr. l''wr¡

as

Waller Verbilski

Michelle Maloncy

William Cole

°< Otologic Surgen'

INIOJ

(I-72H- -2J37-

^19H9 by W. B. Saunders Company. Copyright under the Uniform Copyright Conven Simultan. oiisly published in Canada. All rights reserved This hook is protected bv 'Vrighl No part ol it niay be reproduced, stored in a retrieval system, or transmitted in any itterT y _ e a n s . electronic, mechanical, photocopving, recording, or otherwise, without n,.r ' ", " 'rom the publisher. Made in the United Stales of America Library of "8«SS catalog card number N8-1HW9. an

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CRUZAN

TAMBIÉN

(from the Chilean national anthem)

ISBN 0 - 7 2 1 6 - 2 3 3 7 - 9

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A TI. DULCE PATRIA

Ear—Surgery—Aliases. I. P a p a r e l l a , M i c h a e l M. 11 N i s s e n , Kick I.. III. T i t l e . [ D N L M : 1. E a r surgery- aliases. W V 1 7 G 7 2 4 a |

nor:

BRISAS

Y ESE CAMPO DE FLORES BORDADO ES LA COPIA FELIZ DEL EDEN . . .

Govcoolea, Marcos V.

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Contributors G w e n n Afton, M . S . Medical Illustrator, M i n n e s o t a Ear, H e a d and N e c k Clinic and Beck Visual Communications,

Minneapolis,

Minnesota.

M a r c o s V . Goycoolea, M . D . , M . S . , P h . D . Minnesota Ear, H e a d and N e c k Clinic. Otology Consultant, Chilean Military Hospital and Audia Chile, Santiago, Chile.

Peter Hilger, M . D . , M . S . Assistant Professor,

Department of Otolaryngology,

University of Minnesota.

Staff Physician, St. Paul R a m s e y Medical Center, St. Paul, M i n n e s o t a .

T i m o t h y K. J u n g , M . D . , P h . D . Associate Professor,

Division of Otolaryngology and Head and Neck Surgery,

L o m a Linda University, L o m a Linda, California.

Sherry Lamey Head

technologist,

Otopathology Laboratory,



Alan J . Nissen, M . D . California Ear Institute, Palo Alto, California. Clinical Instructor, Stanford University,

Palo Alto, California.

Rick L. Nissen, M . D . M i n n e s o t a Ear,

Head and Neck Clinic.

Michael M. Paparella, M . D . M i n n e s o t a Ear, and

Head and Neck Clinic. Chairman Emeritus, Clinical Professor,

Director of the Otopathology Laboratory,



Donald Robertson, P h . D . Associate Professor,

D e p a r t m e n t of O t o l a r y n g o l o g y a n d D e p a r t m e n t of Cell

Biology and Neuroanatomy, University of Minnesota.

Kurt Schellhas, M . D . D i r e c t o r o f N e u r o - I m a g i n g , C e n t e r for D i a g n o s t i c I m a g i n g , S t .

Louis Park,

Minnesota.

V

vi

Contributors

Robert Smith,

Chief Resident,

M.D.


Motto


Edward W. Szachowicz, M . D . , Ph.D. Assistant Professor,



Staff Physician, St. Paul R a m s e y Medical Center, St. Paul, M i n n e s o t a .

Learn to learn from everything you do and everybody around you.

•

Key Words Anatomy Function Pathogenesis Research Open

mind

Common Dedication

sense

Preface This book is written primarily for physicians in training (residents). It is my aim to make it a dialogue with you, the residents, beginning with the preface itself. T h e origin of this book goes back to my first year of residency in Otolaryngology. Although m a n y good texts w e r e available, 1 felt that I needed a book that went back to basics in clear and understandable language, and that would provide me with the essential concepts from which to start. It s e e m e d to me that a complicated organ such as the ear could be made, at least at that stage, a little simpler (not simple). O v e r time 1 h a v e been thinking of different aspects that 1 felt to be important and useful for this purpose, and 1 asked the different contributors to do the s a l * . Accordingly, we have tried to create a book that emphasizes the basics, rather than o n e that s h o w s our methods. In the s a m e context, this atlas is only intended to complement other texts on the subject. Because this is primarily a conceptual atlas, we have m a d e no attempt to provide detailed discussions of evaluations and indications; such discussions are provided by the works cited in the list of selected references. This list also includes publications that describe essential concepts of a n a t o m y a n d function. Because of the extent of these subjects, the works available number in the thousands; we apologize to, those authors w h o s e important publications are not cited owing to lack of space and request their understanding. We are a w a r e that this first edition will need improvements. It is our h o p e that these will c o m e from your criticisms and suggestions. There are a number of thoughts and general philosophies that 1 believe a r e useful. 1 do not expect you to agree with them but to be exposed to t h e m and think. S o m e of them will make sense, s o m e will not. 1 h o p e that s o m e of the latter will make sense to you in, time. T h e techniques described in "this book are intended to s h o w different a p p r o a c h e s based on the knowledge of anatomy, function, and pathology. They are oriented m o r e toward a w a y of thinking than toward a d o g m a of doing, in the expectation that the surgeon will think of each surgical procedure as a distinct and different act. It is my hope that this will allow the surgeon to vary an a p p r o a c h according to need> habit, or ability at a specific time. 1 believe that there is no single best technique for otologic surgery; in order to achieve a safe and efficient result, different surgeons might select different but equally valid approaches. It is easy to be rigid; it is e v e n successful, on the whole. It is harder to tailor your a p p r o a c h case by case since this requires an overall concept. In the long run, however, it is much m o r e rewarding. Research a n d knowledge of a n a t o m y and pathogenesis permit proper changes and improvem e n t s . Ear surgery can be what you want it to be. If it is to be developed into an art, knowledge, creativity, dynamism, and an open mind, together with c o m m o n sense, a r e essential. As in any discipline, there are basic principles; h o w e v e r , they should be regarded not as rigid rules but rather as underlying philosophies. An essential point to be ed is that the aim of surgery is to solve problems. Patients c o m e to you for you to solve their problem, not for the surgery itself. In the same context, solving a problem does not m e a n applying formulas or fitting patients into treatment classifications. Classifica-

xi

1

XU

Preface

tions and formulas a r e nothing more than c o m m o n sense put on paper—use them as a tool, do not be "ruled by t h e m . " This may s e e m like a subtle concept but it makes all the difference in the world. The difference between operating and solving a problem is like the difference between ing a cloth over a table and cleaning the table. A n o t h e r important concept implied here is what I call the concept of "intent." F o r all actions that are to be translated into an efficient result, there must be the intention of obtaining such a result. This involves the rational use of y o u r senses. W h e n you look through the operating microscope y o u must s e e , observe, analyze, and use the information obtained. This is quite different from "glancing." You must know what you are looking at (based on a n a t o m y ) and the most likely possibilities and alternatives that can be found (based on pathogenesis). It is also essential to understand that surgery is in the mind and the heart and not primarily in the hand. Good hands are important, but they are not enough. A mechanical task can be performed brilliantly by a moron if it is done over and o v e r again in the s a m e fashion. The art of surgery lies as much in the choices as in the act itself, and also in the postoperative care. T h e medical act begins with the first clinical visit and ends when the problem is solved. It is always tempting to simplify o u r lives with what is "usual" and "customary." If you are in pursuit of excellence, avoid this temptation. A c o m m o n attitude of residents (we have all been residents and I have not forgotten the experience) is to proceed as the "books say" or the "journal s a y s . " Books and journals (including this one) do not say anything; they present what different authors believe. Although important and valuable, this information should be treated as a reference, not as d o g m a . On patient evaluation: Despite the fact that the a m o u n t of information available and the precision of laboratory studies have had a great impact on today's medicine, the essential process of evaluation remains u n c h a n g e d . Regardless of the facilities available, the patient's history and examination are as critical as ever. Provided that they are done properly, a diagnosis is reached most of the time based on history and examination alone. For children, the parents (usually the mother) a r e crucial in providing information. Regardless of a mother's background, she is the one w h o spent the night with the sick child a n d provided food, clothing, cleansing, and so on. The mother will not tell you what to diagnose and do, but she will provide important clues for the diagnosis, and at times for treatment. Again, our role is to listen respectfully and learn; then, using our knowledge, diagnose and if possible tench. Laboratory studies confirm impressions, provide documented objective evidence, and rule out or detect problems or lesions not detectable otherwise. Much can be said about this; suffice it to mention that laboratory studies are ordered with specific questions in mind, and should not be ordered if the results are not oriented toward an action to be taken. On the procedure of choice: Apart from strict physiopathology, there are other factors to consider in deciding what benefits an individual most. W h a t is good for s o m e may not be good for others. A procedure that requires frequent checkups might not benefit somebody w h o cannot be checked periodically. People and circumstances vary and so should your solutions. Although it is our duty to c h a n g e attitudes for the better, it is c o m m o n sense to accept that some things cannot be changed. On the risks of surgery: it is important to reiterate that it is the patient w h o takes the risk, not the surgeon. H o w warranted a specific risk is will depend on the patient's situation and needs, and calls for c o m m o n sense on the part of the surgeon. A surgeon should be conservative. Although "everybody has something that can be operated upon," the surgeon's role is to assess

Preface

XIII

if the operation is indicated and really helpful. Conservatism should be a product both of knowledge a n d of profound respect for an individual w h o has trusted you; it should not c o m e from ignorance or inability to perform what is needed. As for doing what other surgeons do successfully, again, their experience should be seen as background and reference a n d not as d o g m a . It is fine to imitate others a n d this should be done by all m e a n s , provided that what is imitated is understood, agreed u p o n , and applicable to your patients. It is important to evaluate a n d rationalize what the leading surgeons do; behind each of the true leading surgeons are m a n y hours of study and hard work. Question positively their m e t h o d s and rationale. Ask yourself what is intended by a specific m e t h o d and w h y . Is it reasonable? Is it the best way? "Trendy" procedures and "state of the art" instruments also require thorough knowledge a n d understanding. They usually have good reasons behind them; you must understand and agree with those reasons. If all you need to do is kill a fly, u s e a 50-cent fly swatter; do not buy a $ 5 0 , 0 0 0 electronic fly killer because it is "state of the a r t . " Trends c o m e and trends g o . U s e c o m m o n sense when investing. Otologic surgery, like medicine itself, is a never-ending learning process. Y o u are never too good to learn from everybody else. Seeking advice is a sign not of weakness but of maturity. Learn to use your senses; observe a n d listen to other surgeons and specialists, the operating team, your patients, and others. Learn positively from those w h o want to help you and from those w h o want to harm or use you. Learn to'Jearn from everything you do and everybody a r o u n d you. Each surgical cas< is different. W h e n placing pressure-equalizing tubes, study the ear canals a n d their contents, the tympanic m e m b r a n e , the middle ear m u c o s a , characteristics of the effusion, and so on. Relate them to o n e another, to the laboratory studies, and to the clinical history. This simple process will enrich you a n d you will learn what you never thought you would. A difficult task is to learn how to accept reality and our lack of true knowledge. As hard as it is to deal with success, it is h a r d e r and d e m a n d s more stamina to deal with failure. Complications and unwanted results do h a p p e n , e v e n if you seemingly have done y o u r job properly. Objective self-assessment and complete revision of the subject should follow every failure, even .if it " w a s bound to h a p p e n . " Y o u m a y easily forget 2 0 0 successful stapedectomies and never forget one case of hearing loss d u e to a reparative granuloma. Y o u must also learn to accept that in m a n y cases in otology, surgery d o e s not t u r n back the disease process, and that different individuals have different responses to similar surgical procedures and different healing capabilities. F r o m this standpoint alone, the results of tympanoplasty m a y vary from 60% to 100%. A 60% success in a population with .poor nutritional background can be better than 90% in one with optimal nutrition. Percentages are relative; your o w n and those of others should be analyzed in their full context. There are m a n y o t h e r points and ideas that 1 would, have liked to discuss here. Some of them are discussed in the text. U A few w o r d s on the contributors to this atlas: Gwenn Afton, the illustrator, has an MS in Medical Illustration from the Medical College of Georgia. I had the privilege of writing the temporal bone dissection manual that she illustrated as her master's thesis. At the time s h e not only performed such dissections herself but requested direct supervision and explanations. In spite of her being by far the youngest m e m b e r of this team, her professionalism, dedication, interest, and talents are what 1 would have expected from an experienced and famed medical illustrator. I worked directly with her on each and every drawing (in all chapters) in this atlas. However, it must be mentioned that the designs for Chapter 1 (Pertinent A n a t o m y ) w e r e selected by Donald Robertson; for the discussions of n e u r o -

xiv

Preface

otology (in C h a p t e r s 5, 17, 18, and 19) by Rick Nissen; and for C h a p t e r 14 (Lasers in Otologic Surgery) by Alan Nissen. We have been asked to lend m a n y of the illustrations (only those designed by G w e n n and m e ) to Michael Paparella for the otology v o l u m e of his forthcoming text. 1 have no doubt that with the appearance of this atlas we are also witnessing the e m e r g e n c e of an artist w h o will be a significant contributor to medical illustration in the coming years. Timothy Jung is my former fellow resident at Minnesota. Tim oriented his research toward biochemistry of the ear and has remained working in this area while practicing primarily clinical otolaryngology. He has contributed directly to the discussions of the Thiersch graft (in Chapter 7) and mastoid obliteration and surgery for complications of suppurative otitis media (in Chapter 1 0 ) , and is wholly responsible for Chapter 8 (External Ear Canal Procedures). His clinical and surgical experience, coupled with his a p p r o a c h toward e a r disease based on a n a t o m y and pathogenesis, m a d e him a natural contributor to this book. Sherry L a m e y has headed the Otopathology Laboratory at the University of Minnesota for 20 years. She is, in my opinion, directly responsible for transforming this laboratory into one of the best, if not the best, of its kind in the world. M a n y generations of residents (including mine) and research fellows have benefited from h e r knowledge and expertise. The histology and histopathology slides in this atlas, as well as C h a p t e r 4 (Temporal Bone Removal), are a l l products of her work. In order to include a solid discussion of the use of lasers in otologic surgery ( C h a p t e r 14), we asked Alan Nissen to be a contributor. Alan trained at the University of Nebraska and took a postdoctoral fellowship with Dr. Michael Glasscock in Tennessee. He is currently a member of the California Ear Institute in Palo Alto, where he has developed expertise in the use of lasers. Rick Nissen is a m e m b e r of our team at the Minnesota Ear Head and Neck Clinic, where he directs the Neuro-otology division. Rick did his residency •it the University of Nebraska and hail his postdoctoral training in N e u r o otology at the House Ear Institute in Los Angeles, lie started as a contributor tn this atlas, but his interest, efficiencv, and understanding of the spirit of the h o o k were such that he also b e c a m e a co-editor of the chapters dealing wholly or in part with ncuro-otologv (Chapters 5, 17, IK. and 19). This section is the product of his work. Michael PaparWI.i was Professor and Chairman of flu' Department ol Olobryngologv at the L'nivcrsitv ot Minnesota for 17 ve.IRS. Under h i s leadership, the department became one ol the primarv otologv centers in the world, both clinically and in research. H i s contributions to our specialty in the last two decades have been a m o n g the most significant by any single individual, a n d his n a m e has a well-deserved place of honor in the historv of otology. In addition, he had the vision and openness to train specialists from all over the world. The results of his teachings and philosophies are becoming more evident every year as his former students gradually reach the highest academic positions both in the United States and abroad. After his retirement as active c h a i r m a n , he developed the Minnesota Ear, Head and Neck Clinic. Clinically m o r e active 'han ever, he has continued doing research as Clinical Professor and Director of t h e Otopathology Laboratory at the University of Minnesota. 1 originally trained with him in Minnesota and have reed him at the Minnesota E a r , H e a d and Neck Clinic. W h e n 1 c a m e from Chile to train with him, he opened ' h e doors of the department a n d of his friendship to m e . He has undoubtedly h a d a direct influence on my training; at the same time, he has trained m a n y °f the contributors to this work. It was a privilege for me to have Michael as a » editor of this atlas. c

Preface

4

XV

Donald Robertson h a s headed the a n a t o m y course for medical a n d g r a d u a t e students in the Department of Cell Biology and N e u r o a n a t o m y (formerly Department of A n a t o m y ) , and the yearly course in Head and Neck A n a t o m y for otolaryngology residents for 17 y e a r s at the University of Minnesota. Having been his student both as a resident a n d as a g r a d u a t e in a n a t o m y , 1 h a v e appreciated the value of his experience and his teaching. It has been a privilege for me to have him contribute C h a p t e r 1 (Pertinent A n a t o m y ) . Kurt Schellhas has contributed C h a p t e r 3 (Pertinent Concepts in High Resolution Temporal Bone Imaging). Kurt went to medical school, did his residency, and took his neuroradiology fellowship at the University of Minnesota. His experience with and clarification of concepts in diagnostic imaging in otology have been instrumental in this short but conceptual chapter. C h a p t e r 20 (Plastic Surgery of the Pinna) w a s written by Ed Szachowicz, Peter Hilger, and Robert Smith. Ed and Peter trained in Otolaryngology u n d e r Michael Paparella. Ed had postdoctoral training in Plastic Surgery with Drs. William Wright and Russell Kridel in H o u s t o n and Dr. Clyde Litton in Washington, DC. Peter had his postdoctoral training in Plastic Surgery at H a r v a r d Medical School and Massachusetts E y e and E a r Infirmary u n d e r Dr. Richard Webster. Robert is currently a Chief Resident at the Department of Otolaryngology at the University of Minnesota. O t h e r contributors to this atlas a r e Dr. H a m m e d Sajjadi, formerly a Fellow in our clinic ( 1 9 8 6 - 1 9 8 7 ) , w h o assisted with Chapter 6 (Operating R o o m Principles and General C o n c e p t s ) , and Drs. Michael Morris and Richard F o x , currently otology Fellows, w h o served as reviewers and critics. Professor A. Rosales from Santa Cruz, Bolivia, provided me with the diagrams and design of his consistently successful piston wire prosthesis. David Muchow took the scanning electron micrograph of the stapes used on the cover, and Jodi Nielsen, the radiology and vestibular technologist and medical photographer at the Minnesota E a r , Head and Neck C.inic, took the photographs in C h a p t e r 6. The "patients" in this chapter are my children M a r c o s and Hortensia, and t h e nurse is Joanne Eplev, RN, head nurse at our institution. Kay E m e r y typed a n d edited the manuscript and J o y c e Hansen assisted in typing. Gail E. M o w e n assisted Alan Nissen with his chapter. The contributions of grants N « . 5P-50-NS-14538 from the National Institute of Neurological and C o m m u n i c a ' i v e Disorders and No. NS-19433-04 from the Deafness Research Foundation, as well as a grant from the 3M C o m p a n y of Minnesota, a r c acknowledged. A final note: The opinions in this preface, as well as the selection of t h e dedication, key words, and motto, are my o w n and do not necessarily represent the opinions and choices of the contributors to this atlas. M a r c o s V.

G o y c o o l e a , M.D.

? i

SECTION I

Contents

Basic Anatomic Concepts

C H A P T E R 1 Pertinent A n a t o m y '. Donald Robertson, Ph.D. CHAPTER 2 Marcos V.

Pertinent Histology Goycooha M.D., M . S . , r

1

3

23 Ph.D.

CHAPTER 3 Kurt

Pertinent C o n c e p t s in High Resolution Temporal Bone Imaging Sdwtlhas, M.D.

S E C T I O N II

Temporal Bone Dissection

28

37

C H A P T E R 4 Temporal Bone Removal Marcos V. Goycooiea, M.D., M.S., Ph.D. Sherry Lamcy

39

C H A P T E R 5 Surgical Procedures Marcos V. Goycoolea, M.D., MS.^Ph.D. Kick L. Nisscrt, M.D.

44

S E C T I O N III

99

General Principle
CHAPTER 6 Marcoa V.

Operating R o o m Principles a n d General C o n c e p t s Goycootca, M.D.. M.S.? Ph.D

CHAPTER 7

Surgical Approaches to the External Ear Canal and Middle Ear j Goycaalea, M.D., M.S., Ph.D. Jung, M.D., Ph.D.

Marcos Timothy

V. K.

101

121

S E C T I O N IV

Specific Surgical Approaches

147

CHAPTER 8 Timothy K.

External Ear Canal Procedures Jung, M.D., Ph.D.

149

CHAPTER 9 Marcos V.

Congenital Atresia Goycooka M.D., M . S . ,

159

r

Ph.D.

C H A P T E R 10 Surgical Procedures in Different Forms of Otitis Media Marcos V. Goycoolea, M.D., M.'g., Ph.D. Timothy K. Jung, M.D., Ph.D.

. . . 164

xvii

XVlii

Contents

CHAPTER 11 Exploratory T y m p a n o t o m y Marcos V. Guycoofoi, M.D., M . S . , Ph.D.

210

CHAPTER 12 Tympanoplasty Marcos V. Coycoolea, M.D., M.S.,

218 Ph.D.

CHAPTER 13 Surgery for Stapes Fixation Marcos V. Coycoolea, M.D., M.S., Ph.D.

247

CHAPTER 14 Lasers in Otologic Surgery Alan }. Nissen, M.D.

272

CHAPTER 15 Marcos

V.

Surgical Approach for Bone Conduction Hearing Devices Coycoolea, M.D., M.S., Ph.D.

...

281

CHAPTER 16 Surgical A p p r o a c h e s for Cochlear Implants Marcos V. Cm/coolea, M.D., M.S., Ph.D.

286

CHAPTER 17 Surgery for Incapacitating Peripheral Vertigo Marcus V. Coycoolea, M.D.. M.S., Ph.D. Rick l. Nisse«, M.D.

297

CHAPTER 18 Infratemporal Facial Nerve Surgery Marius V. Govorita. M.D., M.S., Ph.D. Rnk L. Nissen, M.D.

315

CHAPTER 19 T u m o r s of the Middle and Inner Ear Marius V. Coycoolea, M.D.. M.S., Ph.D. Rick L. Nissen. M.D.

325

CHAPTER 20 Plastic Surgery of the Pinna Peter Hilter, M.D., M.S. M v r f Smith, M . D . l.tlward W. Szachowicz. M.D.. Ph.D.

339

SECTION V

359

K

U

>

Selected References

363

SECTION I Basic Anatomic Concepts

CHAPTER 1 Pertinent Anatomy For descriptive three

parts:

auricle,

(1)

purposes

the e a r is divided into

the external

ear,

consisting of the

the external acoustic meatus, and

the t y m -

after birth, and the alteration in form as it d e v e l o p s brings

about

a

shift

in

the

depth

of

(he

external

m e a t u s a s well a s i n t h e o r i e n t a t i o n o f t h e t y m p a n i c

panic m e m b r a n e ; (2) the middle e a r ( t y m p a n i c cavity)

membrane.

a n d the associated ossicles a n d muscles; a n d (3) the

that

inner ear, containing the o r g a n s of equilibration a n d

growth,

hearing.

anterior and posterior crura extend

is

In t h e n e w b o r n it is a slight b o n e ring

imperfect small

superiorly.

projections of

With

bone

subsequent

arising

from

its

into the l u m e n

of the ring, eventually fusing to divide the a n n u l u s into the and a

The External Ear

superiorly located acoustic

small,

meatus

interiorly situated a p e r t u r e .

proper

Although

the latter usually closes with continued d e v e l o p m e n t , it m a y on occasion persist to form w h a t is designated t h e foramen o f Huschke.

Bony Features and Relationships

the T h e b o n y c o m p o n e n t s of the e x t e r n a l e a r (Fig.

portion,

forming

a

small,

superi-

orly located part of the bony external auditory m e a t u s a n d the anterolateral portion of the mastoid process. E x t e n d i n g laterally a n d anteriorly

from the inferior

part of the s q u a m o u s portion of the temporal b o n e is

the

anterior with

zygomatic root

process,

extends

which

has

medially

the articular tubercle;

lo

three

roots.

become

The

confluent

t h e medial root f o r m s t h e

p o s t e r i o r wall of the m a n d i b u l a r fossa; a n d

t h e pos-

terior root c u r v e s s l i g h t l y d o w n w a r d o n t o t h e m a s t o i d process.

This

root

bears

the

small

( o f H e n l e ) o n its d o r s a l e x t r e m i t y . portion

of

the

external

acoustic

suprameatal

spine

tympanic

tion of

following: squamous

located

discon-

notch

(of

Rivinus).

Posteriorly the t y m p a n i c ring forms, in c o n j u n c -

1¬

1 ) a r e all p a r t o f t h e t e m p o r a l b o n e . T h e y i n c l u d e t h e 1. T h e

T h e superiorly

t i n u i t y i n t h e t y m p a n i c r i n g p e r s i s t s i n t o a d u l t life a s

with

both

the

mastoid

tympanic

sutures

the squamous and process,

the

(frequently

petrous portions

tympanomastoid a n d designated

petro-

collectively

the t y m p a n o m a s t o i d s u t u r e ) . Anteriorly the ring p a r ticipates

in

petrotympanic

the

formation

sutures.

It

is

in

of

the

the

squamotympanic a n d

latter suture

that

the foramen transmitting the c h o r d a tympani nerve (the

iter c h o r d a e

anterius)

is

found.

It should

be

a p p r e c i a t e d t h a t t h e t y m p a n i c ring, w i t h its g r o w t h , f o r m s a p o r t i o n of the p o s t e r i o r wall of the m a n d i b ular fossa. 3.

T h e p e t r o u s portion,

forming t h e tip a n d

poste-

rior portion of the mastoid process.

Hence, the upper meatus

is

located

between the middle a n d posterior roots. T h e crest of

The Auricle

the posterior root and the postcrosuperior portion of t h e b o n y m e a t u s a r e j o i n e d b y a n i m a g i n a r y line t o form

the

suprameatal

triangle,

marking

the

site

of

access to the a n t r u m of the middle ear.

T h e auricular c o m p o n e n t of the external ear cons i s t s o f a s i n g l e c a r t i l a g i n o u s p l a t e w i t h its c o v e r i n g

bony

skin. T h i s cartilage f r a m e w o r k is responsible for t h e

m e a t u s . T h e g r e a t e s t part o f this c o m p o n e n t d e v e l o p s

s h a p e o f t h e a u r i c l e , a n d d e t e r m i n e s all o f t h e v a r i o u s

2. T h e

tympanic portion,

forming

most

of

the

Pertinent A n a t o m y 4

Pertinent A n a t o m y

F1CURE

1-2.

A, Major relationships of the auricular cartilage. External acoustic meatus.

Mastoid air cells

I t I

FIGURE 1 - 1 . Bum

l ' o m p n n c n N i>l

tin- cvlt-rn.il r.ir

Prominences a n d depressions seen on the e a r , with he exception of the lobule. In addition to the features that are superficially hscemible, the cartilage plate contains other features hat become evident upon removal of overlying skin, "riese include the following (Fig. 1-2/1): 1- The spine of the helix, projecting anteriorly from helix, near the c m s . 2 The tail of the helix (cauda helix), the terminal W i o n of the helix, located at the posteroinferior r g i n of the auricle. 3 The isthmus, the point of continuity between auricular a n d meatal cartilages, located imme'ely posterior to the entrance of the external mean e

n a

1e

la

Js.

+. The lermmai incisure, between the isthmus and the tragal lamina of the auricular cartilage. Its inferior extremity is the opening of the external meatus. Superiorly it is marked by the anterior incisure. The auricle is attached to the side of the head by the following features: 1. Its continuity with the cartilaginous portion of the external acoustic meatus. 2. The skin covering the ear and continuing onto the skull. The skin of the auricle is tightly bound to the perichondrium of the lateral aspect of the ear but is s o m e w h a t freer on the medial surface. There is very little fat in the subcutaneous tissue of the ear. Except in the tragal a n d antitragal regions, the hair of the auricle is rudimentary. Sebaceous

B

£


Pertinent A n a t o m y g l a n d s are present on both surfaces and are part i c u l a r l y n u m e r o u s in the concha and triangular fossa.

3 Three extrinsic ligaments. T h e s e include: A. The anterior ligament, extending from the zygoma to the helix and the tragus.

¡ 3 . The superior ligament, extending from the superior margin of the bony meatus to the spine of the helix. C. The posterior ligament, extending from the mastoid process to the concha of the auricle, i. Muscles, consisting of the following: A An extrinsic g r o u p , formed of three small musc l e s (anterior, superior, and posterior) belonging to the facial g r o u p of muscles and supplied by the facial nerve. B. An intrinsic g r o u p of six small muscles, which are extremely variable in their development and have no functional significance in h u m a n s .

The External Acoustic Meatus The external acoustic meatus is a bony-cartilagious c a n a l extending from the concha of the auricle 5 the tympanic membrane. In its adult configuration d e s c r i b e s a slight S-shape, with the lateral cartilaglous portion s o m e w h a t concave anteriorly and inTOirly and t h e medial bony portion slightly concave o s t e r i o r l y and superiorly. Owing to the obliquity of le tympanic membrane, the posterosuperior wall of le m e a t u s is slightly shorter than the anteroinferior •all (approximately 25 mm and 31 m m , respectively), lightly more than half of the external meatus is ntirely bony (medially), with the anterior wall, floor, nd lower posterior wall formed by the tympanic ortion of the temporal bone. Its roof and the upper art of t h e posterior wall are formed by the squamous ortion. The cartilaginous (lateral) portion of the external e a t u s forms a trough-shaped structure that is open i p e r i o r l y and posteriorly. This canal is completed ' h e latter quadrants by the squamous portion of e temporal bone. In addition to being slightly >™ed, it is s o m e w h a t broader in its lateral aspect " e r e it makes up approximately two thirds of the rcumference of the meatus. Medially it makes up " g h l y one third of the meatal wall. At its lateral •tremity the cartilage of the meatus is continuous ' " i that of the auricle through the isthmus; mediy. it articulates with the bony portion of the meaT h e anterior wall is characterized by the presence " fissures (incisures of the cartilaginous m e a t u s 5

h v

or fissures of Santorini), which assist in imparting a limited mobility to the auricle. The major relationships of the meatus are the following (Fig. 1 - 2 B ) : 1. Anteriorly and laterally, the parotid gland. T h e more medial and anterior relationships include the mandibular fossa a n d the condyle of the mandible. 2. Inferiorly, the parotid gland. 3. Superiorly and medially, the epitympanic recess of the middle ear. 4. Posteriorly, the mastoid air cells. The skin lining the external m e a t u s is continuous with that of the auricle, and also forms the external layer of the tympanic membrane. It varies considerably in thickness, being m u c h heavier in the cartilaginous portion of the meatus w h e r e there is a population of large sebaceous glands and numerous fine hairs. The skin of the bony meatus, which is m u c h thinner, is firmly b o u n d to t h e periosteum of the underlying bone and contains a rather sparse p o p u lation of glands and hair cells, located predominately on the superoposterior wall.

7

Mallear prominence

Umbo Ant. mallear told

Para flaccida

P o s t , m a l l e a r told

FIGURE

1-3.

A, Tympanic membrane. B, Vascular supply of the tympanic membrane.

The Tympanic Membrane The tympanic m e m b r a n e (Fig. 1-3/1) is a thin, elliptically shaped m e m b r a n e situated between the medial end of the external meatus and the middle ear cavity. Its vertical axis measures approximately 9 to 10 mm; its horizontal axis measures approximately 8 to 9 m m . In its final adult position the tympanic m e m b r a n e slopes medially from superior to inferior and from posterior to anterior, so that its external (meatal) surface faces somewhat inferiorly and anterolaterally. In the newborn the membrane is situated much more horizontally, but gradually shifts to the adult position with development of the tympanic portion of the temporal bone. The major features of the tympanic membrane, as viewed from the lateral aspect, include the following: 1. T h e umlw, which is the center of the slight lateral concavity. It marks the point of attachment of the tip of the manubrium of the malleus.

2. The malleal stria, extending superiorly and slightly anteriorly from the umbo. It is formed by the manubrium of the malleus. The stria and a perpendicular line extending through the umbo divide the m e m b r a n e into quadrants (anterosuperior, anteroinferior, posterosuperior, and posteroinferior). 3. The mallear prominence, marking the attachment of the lateral process of the malleus to the membrane. Extending from the prominence in anteroinferior and

posteroinferior directions a r e , respectively, the ante-

approximately 0.1 mm thick (combined). These in-

rior and posterior mallear folds.

clude: », 1. An outer cutaneous layer of thin skin, which is continuous with the skin of the external meatus.

4. The purs fensa, that portion of the m e m b r a n e lying below the mallear prominence and the mallear folds and making up the greatest part of the m e m brane. 5. The purs flaccida, that portion of the m e m b r a n e lying above the mallear prominence and the mallear folds. It is n a m e d for its characteristic laxity. Structurally, the m e m b r a n e consists of three layers

2. A middle layer of connective tissue consisting of the following: A. The radiate fibrous layer, m a d e up of fibers radiating peripherally from the u m b o a n d m a nubrium of the malleus. B. T h e circular fibrous layer, m a d e up of concen-

g

;

Pertinent A n a t o m y trically arranged fibers that are most prominent peripherally, w h e r e they thicken to form a fibrocartilage ring or annulus, attaching the m e m b r a n e to the tympanic sulcus of the temporal bone.

3

An inner layer of mucous m e m b r a n e continuous with that of the middle e a r cavity.

Vascular

Supply of the

External Ear

T h e arteries of the external ear originate from s e v e r a l sources. T h e auricle has an abundant blood supply, which is derived primarily from the posterior auricular branch of the external carotid artery a n d the auricular rami arising from the superficial temporal a r t e r y . These are shared by the meatus, which also r e c e i v e s the deep auricular branch of the maxillary artery. T h i s artery es through the parotid gland to enter e i t h e r the cartilaginous or bony part of the meatus. T h e tympanic m e m b r a n e is supplied on both its lateral and medial surfaces. Laterally, the deep auricular artery forms a small peripheral vascular ring from which small branches radiate onto the memb r a n e . Superiorly, a large vessel, the external descending artery, arises from the vascular ring to descend to the region of the umbo, with a course more or less parallel to the manubrium (Fig. 1-3B). Internally, a s e c o n d peripheral vascular ring is formed primarily

by the stylomastoid branch of the posterior auricular artery and t h e anterior tympanic branch of the maxillary artery. The largest of the vessels arising from this inner

vascular ring is the internal descending artery, which descends on the inner surface of the m e m b r a n e in a course parallel to that of its external counterpart. T h e venous channels draining the structures of Ihe external ear roughly correspond to the arteries of supply. Those draining the auricle and the external

postbranchial region. For this reason, both the cranial; n e r v e s supplying the branchial arches (V, VII, IX, I a n d X) and the cervical nerves m a y be represented; by sensory c o m p o n e n t s . Although there is consid ! erable variation, the approximate sensory D I S T R I B U T ; Hon is as follows (Fig. 1-4): .^


9

i

1. T h e cervical plexus of nerves ( C 2 - 3 ) , via t h e ' great auricular n e r v e , supplies most of the lateral' surface of the auricle (except for the upper anterior '. portion). T h e lesser occipital nerve from the plexus supplies much of the medial surface of the auricle. 2. The mandibular division of the trigeminal n e r v e , via its auriculotemporal branch, supplies the u p p e r anterior portion of the auricle, the u p p e r and ' anterior walls of the external meatus, and the u p p e r L anterior part of the lateral surface of the tympanic membrane. '

3. The auricular branch of the vagus supplies ap¬ 1

proximately half of the external meatus and lateral surface of the tympanic membrane. Although this nerve is typically described as being of vagal origin, it should be appreciated that branches of VII and IX.! may it and contribute to the sensory innervation , of the external ear. It is impossible to differentiate ! between the distribution of the components; clinical I studies of herpes zoster indicate that all three may, participate. !

FIGURE 1 - 4 . Innervation of the external ear.

t

T h e distribution of nerves supplying the t y m p a n i c , ! m e m b r a n e is very much like that of the arteries— ' small, peripheral contributions supplying the mar-, gins of the m e m b r a n e while the primary nerves^ descend from the superior aspect of the m e m b r a n e a n d parallel the course of the external descending artery, tending to lie slightly posterior to the vessel. The pars tensa of the membrane is not particularly well supplied with sensory nerves; in contrast, t h e pars flaccida has an extremely rich innervation. > I

The Middle Ear

meatus are the anterior auricular tributaries of the superficial temporal veins and the auricular tributaries the posterior auricular vein. Drainage of the tymP " c m e m b r a n e is both external (via vessels c o m "nicating with veins of the external meatus) and "iternal (via branches paralleling the arteries).

Morphology

\

of

a r

m

innervation of the External Ear

The external ear is a region of transition between originally overlying the branchial area and the

ln

i i

T h e middle e a r , or tympanic cavity, is an irregu-l larly shaped c h a m b e r lying within the temporal bone, i bounded laterally by the squamous and t y m p a n i c ) portions and medially by the petrous portion. Itsgreatest dimensions are in the anteroposterior and j vertical planes, which measure approximately 15 mm . each, while the transverse diameter (between the I medial and lateral walls) varies with location and i ranges from 2 to 6 m m . It is not a confined s p a c e but c o m m u n i c a t e s anteriorly with the nasopharynx i

through the auditory tube a n d posteriorly with the mastoid a n t r u m and air cells. T h e middle e a r c a n be divided into the tympanic cavity proper, which is that portion situated medial to

the tympanic membrane, and the epitympanic recess, the upward extension of the tympanic cavity proper above the level of the tympanic membrane. T h e lateral wall (membranous wall) of the middle ear is formed for the most part by the tympanic m e m b r a n e . Superiorly, within the epitympanic recess this wall is formed by a plate of bone (the scufwrn) derived from the s q u a m o u s portion of the

temporal bone. The head of the malletfe and the body and short process of the incus lie in the epitympanic recess. The roof (tegmental wall) of the middle ear consists of a thin plate of b o n e , the legmen tympani, which separates the epitympanic recess from the cranial cavity. It is traversed by the petrosquamous suture, which persists into adult life in approximately 50% of the population, a n d by small foramina that transmit nerves a n d arteries. The j'oor (jugular wall) is a very narrow, irregular surface lying slightly below the level of the m e a t u s ,

10


and is formed by a plate of bone separating the cavity f r o m the bulb of the internal jugular vein. If the bulb of the vein is small, the floor may be as much as 8 to 10 mm thick a n d may contain hyporympanic air cells. In contrast, a large bulb may cause the floor to b u l g e u p w a r d into the middle ear. In such cases the floor m a y be imperfect, and the vessel a n d cavity are separated only by the mucosa of the middle ear. The anterior wall (carotid wall) is a very thin, bony septum separating the middle e a r from the carotid c a n a l . Perforations in the plate allow the transmission of nerves a n d vessels from the canal to the middle e a r . Above this is the site of the opening of the

semicanal for the tensor tympani muscle, and immediately inferior to this is the tympanic ostium of the auditory tube, through which the middle ear communicates with the nasopharynx.

The posterior wall (mastoid wall) (Fig. 1-5A) is somewhat triangular, with the narrowest portion s i t u a t e d inferiorly where it is related to a number of tympanic air cells. Superiorly, at the level of the epitympanic recess, the posterior wall is deficient a n d forms the aditus, through which the middle ear communicates with the mastoid antrum. Salient feat u r e s of the posterior wall include the following: 1. The pyramidal eminence, located just below the aditus. At the apex of the eminence is a small a p e r t u r e that transmits the tendon of the stapedius muscle.

2. The iter chordae tympani posterior, a small foram e n immediately lateral to the pyramidal eminence. Through this foramen the chorda tympani nerve e n t e r s the middle e a r . 3. T h e posterior sinus, a small fossa just above the p y r a m i d a l eminence. 4. The fossa of the incus, situated just above the p o s t e r i o r sinus. This marks the point of attachment of t h e posterior ligament of the incus. T h e medial wall (labyrinthine wall), which separates t h e middle ear cavity from the inner e a r , is the m o s t complex of the middle ear boundaries. Its major features are s h o w n in Figure 1-5B: 1. The promontory, a slight elevation formed by ' h e basal turn of the cochlea of the inner ear. Extending inferiorly and posteriorly from the promontory is a slight ridge, the subioiium. More superiorly, r u n n i n g from the posterior aspect of the promontory t o w a r d the. pyramidal eminence, is a second ridge, ' h e ponticulus. The subiculum and, the ponticulus c r e a t e three small depressions on the posterior part t h e medial wall. of

2 T h e fossula fenestrae cochleae (cochlear fossa or round window niche), which is posteroinferior to the Promontory. The lowest of the three depressions of e medial wall, it is b o u n d e d superiorly by the l h

subiculum and is the site of the cochlear window (round window), in which the secondary tympav.c membrane (round window m e m b r a n e ) resides, lie round window and associated membrane may or m a y not be visible, depending upon the size a."id configuration- of the promontory and subiculum.

3. The tympanic sinus, occupying the midc ie depression formed by the subiculum and ponticuf is at the junction of the posterior and medial walls. T> ie extent of the sinus is variable; it may extend fir enough into the petrous portion of the temporal bone to bring it into close relationship to the a m p l 1lary end of the posterior semicircular canal and tl e posterior end of the lateral canal.

4. The fossula fenestrae vestibuli (fossa of the oVil window or "stapes niche"), lying in the superk r depression above the ponticulus. It contains the vestibular (oval) window, w h i c h is closed by the footplate of the stapes and the associated a n n u k r ligament. 5. A slight bony ridge, the prominence of the latere I semicircular canal, which lies high on the posterior aspect of the medial wall in the region of the aditu;. and marks the anterior end of that c o m p o n e n t of the inner ear. ,

6. The prominence of the facial canal, lying above thr\ posterior edge of the promontory a n d the oval win-' d o w , immediately below and parallel to the prominence of the lateral semicircular canal. It runs almost horizontally across the posterior half of the medial wall, then turns to enter the posterior wall. T h e facial n e r v e courses through this canal. 7. The cocWfnri/orm process, located anterosuperiorly on the medial wall. It represents the curved end of the bony semicanal of the tensor tympani muscle.

The

Ossicles

The ossicles form an articulated bony chain that I extends across the middle ear and connects the tympanic membrane with the vestibular window. This chain acts as a bent lever to convert the vibrations of the tympanic m e m b r a n e into intensified thrusts of the stapes against the perilymph. Developmentally, the ossicles arise from three different sources. The first branchial arch of the embryo (mandibular a r c h ) gives rise to the head of the malleus and the long and short process of the incus; the second arch (facial a r c h ) , to the long process of the incus and the stapes. The anterior process of the malleus develops independent of the branchial arches as a m e m b r a n o u s bone.

Pertinent A n a t o m y The major features of t h e malleus include the allowing (Fig. U6A): I A relatively large and h e a v y head lying within the epitympanic recess, which bears on its surface a small facet for articulation with the incus. > A short, s o m e w h a t constricted neck from which three processes arise, including: A. The long and prominent manubrium, the largest of the mallear processes. It is attached to the tympanic membrane and in turn is the site of insertion of the tensor tympani muscle. B. T h e lateral process, which creates t h e mallear prominence of the tympanic m e m b r a n e .

C. The anterior (long) process, a long and delicate bony projection in the fetal malleus. In the adult it is a small bony stump that is the site of attachment of t h e anterior ligament of the malleus. The malleus is s u s p e n d e d by three small ligaments

Fig 1-6B), which include the anterior mallear liganent, extending from the anterior process to the

vmpanosquamous fissure; the superior mallear liganent, extending from the top of the head to the roof

jf the epitympanic recess; and the lateral mallear igament, which runs from the lateral process to the •nargin of the tympanic notch. Also associated with the malleus is the tensor ympani muscle. This muscle arises from the cartilagnous part of the auditory tube, t h e adjacent spheloid bone, and the semicanal situated directly above •he osseous portion of the auditory tube. Its tendon )f insertion es through the cochleariform proc!ss, turns sharply lateral, and inserts on the manu>rium of the malleus, close to the neck. The muscle icts to draw the manubrium medially, tensing the ympanic m e m b r a n e , and thus serves a protective Hinction. T h e tensor tympani is innervated by a 'ranch of the mandibular division of the trigeminal lerve.

The mews (Fig. 1 - 6 C ) is characterized by the following features: '•• A relatively large body that is deeply indented anteriorly to form an articular facet. •• Two bone processes. These include: A The sliort process, which extends posteriorly from the body. B. The slender long process, extending inferiorly from the body and paralleling the manubrium of the malleus. On the medial side of the very distal extremity of the long process is the small lenticular process, through which the incus articulates with the stapes. Like the malleus, the incus is s u s p e n d e d by small 5'irnents (Fig. I - 6 D ) . These are t h e posterior ligament, " h acts to hold the short process in the fossa of K

the incus, a n d the superior ligament, which extends '< from the body to the roof of the epitympanic recess.'; T h e stapes (Fig. l - 6 £ ) consists of the following: 1. A small, cylindrical head, which articulates with the lenticular process of the incusT * 2. T w o crura (anterior and posterior), which extend from the head. The anterior c m s is s o m e w h a t shorter and straighter than the posterior. 1

3. A thin base (footplate), a flattened plate of b o n e . attached on its end to t h e distal extremities of thec r u r a . It fits into the vestibular window a n d , like thatt structure, has a straight inferior border and a curved^ superior border. The ligamentous of the stapes is t h r o u g h ; the elastic annular ligament, which attaches to t h e ) margins of the footplate and the vestibular w i n d o w and allows m o v e m e n t of the stapes. Such m o v e m e n t is greatest at the anterior end and upper border of the footplate and very slight posteroinferiorly. It has been stated that loud tones c h a n g e the normal pattern of m o v e m e n t to a rocking motion; this would result in a net d e c r e a s e in the displacement of perilymph, thereby protecting the inner e a r . This c h a n g e presumably is brought about by contraction of the stapedius muscle (Fig. 1 - 6 F ) , which inserts onto t h e posterior crus. As mentioned above, this muscle serves a protective function by preventing excessive excursion of the footplate; it does not m o v e the ossicle unless the ossicular chain is broken. It is innervated by a branch of the seventh nerve. The ts of the ossicular chain are true synovial (diarthrodial) ts with characteristic articular c a p sules. There are t w o such ts within the chain. T h e first is the incudomalleal, between the head of the malleus and the body of the incus. This is a relatively lax t that allows the m o v e m e n t of the incus to lag behind that of the malleus; as a result, the amplitude of the m o v e m e n t of the bony process of the incus is less than that of the manubrium. The second t is the incudostapedial, between the lenticular process of the incus and the head of the stapes.

The Auditory (Pharyngotympanic or Eustachian) Tube

T h e auditory tube extends from its tympanic ostium within the anterior wall of the middle ear cavity to its pharyngeal ostium within the nasopharynx. The latter is situated just posterior to the dorsal end of the inferior nasal concha. In the adult the tube is between 30 and 40 mm in length, a n d has a slight S-shaped configuration as it es obliquely d o w n -

14

Pertinent Anatomy


w a r d , medial, and anterior from the middle ear to t h e pharynx. The tympanic ostium is roughly 25 mm higher than the pharyngeal ostium in the adult. There are s o m e basic and significant morphologic differences between the auditory tube of the child a n d that of the adult; in the child the tube is shorter a n d relatively wider and more horizontally situated. Structurally, the auditory tube consists of both cartilaginous a n d bony c o m p o n e n t s . The bony portion makes up approximately two thirds of the tube; jt is widest at the tympanic orifice and gradually narrows throughout its length, with its anterior extremity (the isthmus) the most constricted portion of t h e entire tube. In its course the bony tube is lateral to the carotid canal, superior to the jugular fossa. The cartilaginous portion of the tube extends from t h e isthumus to the nasopharynx. It is not totally cartilaginous, however; its lower lateral and inferior w a l l s consist of fibrous connective tissue overlying t h e tensor and levator veli palatini muscles. The lumen of the auditory tube, in the resting state, is a closed, slitlike cavity. The pharyngeal end of the tube strongly resists age of air from the pharynx to the middle ear. age from the tympanic cavity to the pharynx is much easier.

The Mucosal Lining of the Middle Ear

The tympanic cavity is lined throughout hv a thin, transparent, vascular membrane that is continuous w i t h that of the auditory tube anteriorlv and the tympanic antrum and mastoid cells posteriorly. The membrane is tightly bound to the periosteum and a l s o invests the ossicles and their associated ligaments. In reflecting Irom the walls ol the cavitv to the ossicles and their ligaments, the mucous lining forms various folds and pouches; the most important of these a r e the superior vouch (Prussak's pouch), situated medial to the pars flaccida of the tympanic

membrane, and the anterior and posterior vouches (of Troltsch), which are related to the anterior and posterior mallear ligaments respectively.

Vascular Elements Middle Ear

of the

The middle e a r receives blood via a number of small arteries (Fig. 1 - 7 , 4 , 6 ) , which with one excep-

15

tion are derived from the external carotid c its branches. They include;

1. T h e anterior tympanic, a branch of the maxillary artery. It is distributed to the anterior part oi the cavity, including the medial surface of the tympanic membrane, and enters the middle ear by parsing through the petrotympanic fissure.

2. T h e stylomastoid branch of either the posterior auricular or occipital artery. This artery e n t e r s the facial canal and gives rise to the posterior lyn panic artery, which then enters the middle ear in c o r r o a n y with the chorda tympani nerve.

3. The inferior tympanic artery, derived frorii the ascending pharyngeal branch of the external carotid. It accompanies the tympanic branch of nerv? IX through the tympanic canaliculus to gain the middle ear cavity.

4. The superficial petrosal and superior tympanic^ arteries, which are both branches of the middle mr ningeal artery. T h e former runs through the facial canal for a short distance, then pierces the tegmen tym, >ani to enter the middle ear; the latter enters through the petrosquamous fissure. 5 . The atroficutympitmc arteries arise from the i t t e r nal carotid as it es through the carotid canal; and enter the middle ear by ing through the thin bony lamina separating the carotid canal from the middle ear. The veins of the middle ear parallel the arteries. TUey are tributary to the superior petrosal dural sinus m e t the pterygoid plexus of veins.

Nerves of the Middle Ear ( R R .

\\

U

The major nerve of the middle ear is the lumpttmc 1'iathh vt the gU^>ophan,nytvl iicnr (Jarobson's nerve}. Arising (rom the inferior ganglion of the parent trunk, the tvnipanic nerve enters the tvmpanic catnaliculus through a small foramen located on the crest of the thin plate of bone separating the j u g u h r foramen and the external orifice of the carotid c a m I. O n c e in the middle ear, the nerve forms the tympanic plexus within the mucosa overlying the promontor /. There are two modalities represented in the tympanic nerve/plexus. The greatest portion of the fibers a e sensory; these are distributed to the mucosa of t i e middle e a r , the mastoid air cells, and the audito'y tube. The remaining fibers are parasympathetic and have no function in the middle ear. Instead, they e m e r g e from the upper border of the plexus to pierce the tegmen tympani and run forward on the floor of

FIGURE 1-7 A-B, Arteries of the middle ear.

Sup. tympanic

Petrosal

\d



17

I*

Greater petrosal

Geniculate ganglion

of the middle ear to these a r e a s , a basic appreciation of the location a n d extent of pneumatized areas is desirable. Since the mastoid process develops from both petrous and s q u a m o u s portions of the temporal bone, there is a sutural line between the two c o m ponents that normally is obliterated with growth. Occasionally, however, a heavy plate of bone persists between the two portions, forming what has been designated [Corner's septum or the "false bottom." The existence of this septum c a n cause confusion in surgical a p p r o a c h e s through the mastoid process. T h e mastoid process is rather consistently pneumatized (80%), the process usually being completed by the third or fourth year. T h e r e is, h o w e v e r , considerable variation both in its extent a n d in the arrangement of the air cells. Because of this variation, several types are described, including the pneumatized, in which the entire process is occupied by air cells; the diploic, in which the process is occupied by bpne m a r r o w instead of air cells; the mixed type, consisting of a combination of the pneumatized a n d diploic types; a n d the sclerotic or nonpneumatized/ nondiploic process. Owing to the considerable variation in the extent and location of the mastoid cells, several terminologies have been used. T h e position of the sigmoid sinus in the posterior cranial fossa will influence markedly the position or occurrence of all types.

FIGURE 1-8. Nerves of the middle ear.

Caroticotympanic

the middle cranial fossa as the lesser petrosal nerve; ultimately they leave the skull to run with the auriculotemporal branch of V3 and supplv the parotid gland.

1 he middle ear receives sympathetic fibers derived from the internal carotid plexus. These fibers, which n t e r the middle ear along with the caroticotympanic a r t e r i e s , are primarily associated with the vessels of we cavity and have a vasoconstrictive effect. T h e chorda tympani branch of t h e facial nerve enters he middle ear through the iter chordae posterius. P a s s e s forward and down between the manubrium ' *e malleus and the long process of the incus, n e n leaves the cavity by ing through the petrotympanic suture. T h e chorda tympani has no func°n in the middle ear. It contains both parasympaJ l i c fibers supplying the submandibular and ' "lingual glands a n d taste fibers for the anterior t h . r d s of the tongue. After leaving the middle e

0

ear it s the lingual branch of V3 to be distributed with that nerve. Although they do not enter the middle ear, the nerves to the muscles associated with the ossicles must be mentioned since they are vital to normal function. The nerve to the stapedius muscle is a branch of the facial nerve, and arises from the parent trunk as it descends through the vertical portion of the osseous facial canal. The nerve to the tensor tympani is a branch of the mandibular division of the trigeminal nerve.

Pneumatization of the Temporal Bone The temporal bone exhibits varying degrees of pneumatization. Because of the intimate relationship

Mastoid air cells may invade adjacent areas of the temporal bone. Some of the more frequent extensions form the hy\iotympanic cells, which lie in the plate of bone separating the middle ear cavity from the jugular bulb, a n d the epitympanic cells, which are extensions into the roof of the middle ear. T h e latter g r o u p may be extensive e n o u g h to include cells that will invade the root of the zygomatic arch a n d the squam o u s portion of the temporal bone. T h e petrous apex of the temporal bone (i.e., that part of the petrous portion anterior to the labyrinth) may also be pneumatized, particularly by outgrowths from the tympanic cavity. These cells, the petrous apex cells, are necessarily related to the auditory tube and the carotid canal.

The Facial Nerve in the Temporal Bone

After traversing the internal acoustic meatus a n d ing through the lateral end of that structure, the facial nerve enters the bony facial canal (fallopian canal). This canal continues laterally for a short

distance a n d brings the facial nerve to just above the base of the cochlea, w h e r e it makes a s h a r p turn (the external genii) to run posteriorly. The g e n u is also the site of the. geniculate ganglion of the nerve, which contains the cell bodies of the nerve's sensory c o m ponents. T h e genu and the ganglion are anterolateral to the superior semicircular canal a n d between the vestibule of the inner e a r and the cochlea, a n d c a n be easily localized from the middle ear as a point situated just medial to the tip of the cochleariform process. Continuing posteriorly with a slight inferolateral inclination, the bony canal forms the prominence of the facial canal on the medial wall of the middle ear. This prominence may be large enough to partially cover the oval window and the base of the stapes. T h e lateral wall of the canal in this part is extremely thin a n d m a y be dehiscent. Behind the base of the pyramidal eminence the canal makes a broad turn to descend vertically and somewhat laterally through the mastoid process. In this descending or vertical portion the nerve may have a slight anterior concavity. Relative to the exterior of the skull, the canal normally lies d e e p to the sutural groove between the tympanic and mastoid portions of the temporal bone. It should be ed that there m a y be marked deviation from this "normal" position, in which case the canal is usually situated more posteriorly. In its course from the brainstem through the facial canal the facial nerve is supplied with blood by small arteries derived from the anteroinferior cerebellar branch of 4 h e basilar artery, the stylomastoid or occipital branches of the external carotid, and the petrosal arteries. T h e r e are apparently no anastomoses b e t i e e n the labyrinthine blood supply a n d these arteries, which seem to anastomose freely with one a n o t h e r . Insufficiency of the vascular supply to the facial nerve, from whatever cause, is regarded by s o m e as one of the primary causes of Bell's palsy.

The Inner Ear T h e inner ear containing the essential cochlear and vestibular mechanisms, lies within the petrous portion of the temporal bone. T h e labyrinth of the inner ear is surrounded by the bony otic capsule, which is a unique structure for several reasons. It is formed from 14 separate centers of ossification that fuse, leaving no sutural lines. These centers, though formed from cartilage, retain no areas of chondral growth. In addition, the bone of the capsule retains its fetal character, that is, typical haversian systems

18

Pertinent A n a t o m y Pertinent A n a t o m y anterior canal and the superior crus of the posterior canal unite to form a single crus. The canals h a v e very definite planes of orientation. The anterior is situated in the vertical plane at an angle of 45 degrees with respect to the sagittal plane of the skull, the posterior crura being m o r e medial. The posterior canal is also in the vertical plane, at 45 degrees with respect to the sagittal plane of the skull (that is, at 90 degrees with respect to the plane of the anterior canal). The lateral canal forms an angle of approximately 30 degrees with the horizontal plane, its anterior end being highest, and is situated in the angle between the anterior and posterior canals. 3. The cochlea, a cone-shaped, hollow, bony spiral of about two and three quarters turns with a relatively broad base and a pointed apex or cupula. Its base lies against the anteromedial surface of the vestibule and the lateral end of the internal auditory meatus. Part of the basal turn of the cochlea forms the promontory of the middle ear. • From its base the axis of the cochlea is directed anterolaterals/ and slightly u p w a r d . The central bony core of the cochlea is the modiolus, through which nerves and vessels travel to attain the structures of the cochlea. From the outer surface of the modiolus the osseous spiral lamina projects into the cavity of the cochlea, partially subdividing the duct. It terminates at the cupular end of the cochlea by projecting slightly beyond the apex of the modiolus. This projecting bony process of the lamina is the hamulus.

never develop. Finally, the capsule's maximum dimensions are attained by the fifth week of intrauterine life. The labyrinth of the inner ear is divided into osseous a n d m e m b r a n o u s c o m p o n e n t s . The osseous labyrinth, a system of bony canals within the otic capsule, consists of three parts: 1. The vestibule, which forms the central portion of the labyrinth; it is a relatively large, ovoid space approximately 4 mm in diameter. Its characteristic features include the following: A. The elliptical recess, located on the floor of the vestibule. It receives the anterior end of the utricular portion of the m e m b r a n o u s labyrinth. B. The spherical recess, located anterior and slightly inferior to the elliptical recess. It is the site of the saccular portion of the membranous labyrinth.

C. The •vestibular whitlow, of the vestibule.

within

the

lateral

w,.ll

D. Small orifices for the age of nerves to the vestibular portion of the inner ear. These a e found on the medial wall and adjacent flo-•, where the vestibule abuts on the lateral e r d of the internal acoustic meatus. 2.

The semicircular canals, which are continuous with the vestibule. The anterior (superior) canal forms the arcuate eminence on the bonv floor of the middle cranial fossa. The posterior'canal has no externally located landmarks associated with if. Ihe lateral canal, as mentioned above, creates ,i prominence in the region of the aditus of th.middle ear. All of the semicircular canals com municate with the vestibule through both of theicrura. There are only five openings into the ves tibule, however, since the posterior crus of th.

By convention, and for ease of reference and description, the cochlea is described as if it were sitting on its base with the apex pointing directly up. Viewed in this orientation, it can be seen that the spiral lamina is initiating the division of the cochlear duct into an upper chamber, the scala vestibuli, and a lower chamber, the scala tympani. Only the scala vestibuli communicates with the vestibule of the inner ear; it also communicates with the scala tympani at the apex of the duct. The scala tympani ends blindly at the round window (secondary tympanic m e m b r a n e ) of the middle ear. T h e osseous labyrinth is not a closed chamber; there are several areas of communication with the exterior. These include the following: 1. The vestibular aqueduct, extending through the otic capsule from the vestibule to the posterior cranial fossa. Its cranial end lies lateral to the internal acoustic meatus on the posterior surface of the petrous portion of the temporal bone, where it is usually overlaid by a scale of b o n e . This a q u e d u c t transmits the endolymphatic duct and an accompanying vein.

19

2. The cochlear aqueduct, which begins in the scala tympani of the basal coil of the cochlea near the round window. This small canal terminates on the inferior surface of the petrous pyramid, between the jugular fossa and the external orifice of the carotid canal. In the human it is not patent, being filled with connective tissue. 3. The oval window, which is closed by the footplate of the stapes and the associated annular ligament. 4. T h e round window, closed by the secondary tympanic m e m b r a n e . 5. The fissula ante fenestram and the fossula post fenestram, small clefts related to the vestibular wind o w of the lateral wall. The fissula ante fenestram usually extends completely through the bony lateral wall of the vestibule, while the fossula does so in only about 25% of all individuals. Both normally are filled with connective tissue. The fissula is important because of its predilection for otosclerotic bone formation. 6. The orifices of the nerves and vessels attaining the inner ear. Lining the entire osseous labyrinth is a layer of periosteum or endosteum, which is continuous with the periosteum of the cranium through the various apertures and lies in close apposition to the walls of the osseous labyrinth. T h e areas of modification that merit further description occur within the cochlea. At the free edge of the osseous spiral lamina the endosteum is thickened to form the limbus, which then divides into vestibular and tympanic lips separated by a groove, the internal spiral sulcus. The vestibular lip is confluent with the vestibular membrane. The tympanic lip extends from the edge of the osseous spiral lamina across the lumen of the cochlea to the opposing peripheral wall, forming the fibrous basilar membrane. It attaches peripherally to the crest of the spiral ligament, which in turn is an area of thickened, modified endosteum overlying the lateral wall of the cochlea. While the basilar m e m brane divides the lumen of the cochlea, it d o e s not extend all the way to the cupula but terminates just before it, leaving a small area of communication termed the helicotrenm between the scala vestibuli and the scala tympani. The membranous labyrinth is a system of delicate, epithelium-lined channels surrounded by connective tissue a n d lying within the osseous labyrinth (Fig. 1 - 9 ) . Like its osseous counterpart, the m e m b r a n o u s labyrinth has vestibular, semicircular, and cochlear c o m p o n e n t s that c o m m u n i c a t e with one another. The m e m b r a n o u s labyrinth exhibits certain general features: 1. Its luminal capacity is much less than that of the osseous labyrinth.

pO



''• 1. The m e m b r a n o u s labyrinth tends to be placed peripherally within the osseous labyrinth; it is surjounded by the perilymphatic space (and perilymph). In most locations this space is traversed by n u m e r o u s (Jelicate trabeculae extending from the endosteum to £e m e m b r a n o u s labyrinth. The exception to this is in the cochlea, where the trabeculae are very much (educed or absent.

is the most highly modified. Situated within the bony cochlea, where it lies upon the upper surface of the basilar m e m b r a n e , it is a triangular duct extending, the full length of the basilar membrane (but not to the apex of the cochlea). Basally it is continuous with the saccule through the ductus reuniens. The three basic structural c o m p o n e n t s of the cochlear due include the following:

3. The membranous labyrinth contains the recepj p t s for hearing and equilibration.

1. The vestibular membrane, which forms the roo, of the cochlear duct and separates the endolymphatic space of the duct from the perilymphatic space oi the scala vestibuli. It is an extremely thin m e m b r a n e (approximately 0 . 0 0 3 m m ) .

4. It is a self-contained system with no patent communication with other areas. 5 . The lymph.

membranous

labyrinth

contains

endo-

Individual Components of the Membranous Labyrinth

The vestibular portion of the m e m b r a n o u s labyrinth is characterized by two large dilatations, the Hfricfe and saccule. The utricle, located in the posterior portion of the osseous vestibule, receives the crura of the three membranous semicircular canals. F r o m its anterior end arises the minute utricular duct through which it communicates with both the endolymphatic duct and the saccule. Situated within the utricle on its floor and lower lateral wall is the macula, one of the receptor sites of the vestibular system. The saccule is located anteromedial to the utricle within the osseous vestibule. F r o m its posterior aspect arises the small saccular duct that is continuous with the utricular duct (hence, utriculosaccular) and the endolymphatic duct. Anteriorly the saccule is continuous with the cochlear duct through the extremely small ductus reuniens. The saccule has a macula located on its lateral wall. The endolymphatic duct arises from the union of the utricular and saccular ducts and es through the vestibular aqueduct to terminate in a blind dilatation, the endolymphatic sac, within a dural cleft on the medial surface of the petrous portion of the temporal bone. Within the sac are extensive folds of epithelium with cores of vascular connective tissue, which would seem to indicate that this particular site is the region "'greatest physiologic activitv. The membranous semicircular canals conform closely to the configuration of their osseous counterparts. At the anterior ends of the anterior and lateral canals n d at the posterior (inferior) end of the posterior canal are prominent dilatations or ampullae, which house the receptor sites (cristae).

a

The cochlear portion of the m e m b r a n o u s labyrinth

2. The lateral wall, consisting of the sfrin vascularis, a highly vascular region situated on the inner surface of the spiral ligament. As its n a m e implies, it is characterized by its highly vascular nature and is generally believed to be the source of endolymph. 3. The floor, consisting of the organ of Corti, which is the sensory organ for hearing.

The Sensory Receptors of the Inner Ear

Within the vestibular portion of the inner ear the receptors consist of the following: 1. The cristae, located within the ampullae of thr m e m b r a n o u s semicircular canals. They consist oi thickened epithelium containing neuroepithelial hai; cells. Overlying the epithelium and extending to the opposite wall of the ampulla is the gelatinous cupula. The cilia of the hair cells project into the base of the cupula. 2. The maculae, which are located in the utricle and saccule and have similar structures. The hair cells of the neuroepithelium are stiff, nonmotile projections embedded in an overlying gelatinous m e m brane, the statoconic or otolithic membrane. This m e m brane is unique in that it contains n u m e r o u s crystals termed otoliths. The sensory portion of the cochlear duct, the organ of Corti or spiral organ, has the same basic structure as the cristae and maculae. It lies upon the basilar membrane and consists of ing cells and hair colls overlaid by a gelatinous tectorial membrane. The ing cells are of several different types; however, all contain fibrils within their cytoplasm, and their free edges form a reticular membrane against which the tectorial m e m b r a n e rests. The most important of the ing cells are the phalangeal cells, arranged in a single inner row, and an outer group consisting of three to five rows depending on the

level of the cochlea under consideration, there being more rows apically than basally. The inner row is associated with a single row of hair cells, while the outer group has phalangeal cells alternating with rows of hair cells. Between the inner and outer group of phalangeal cells is an intercellular space extending the entire length of the spiral organ and termed the tunnel, inner tunnel, or canal of Corti. It is bounded by special ing cells designated the inner and outer pillars (Corti's rods). Together the pillars and the canal form Corti's arch. Peripheral to the phalangeal cells are other ive elements, the tall cells of Hensen and the shorter, more peripherally located cells of Claudius. The hair cells of the spiral organ have numerous "hairs" projecting from their reticular surface (40 to 100 per cell). The innermost of these cells are long and are thought to be the least sensitive to sound. In contrast, the outer hair cells are short, being wedged between the apical portions of the phalangeal cells.

Vascular Supply of the Inner Ear

The primary source of blood to the inner ear is the Inbi/riiiHiine (internal auditory) artery. While this vessel is usually described as originating from the basilar artery, it probably arises more frequently from the anterior inferior cerebellar artery. In addition, it may be duplicated by terminal branches that arise independently to enter the internal acoustic meatus. In its course the labyrinthine artery accompanies nerves VII and VIII through the internal acoustic meatus. Its main branches run in the endosteum of the labyrinth, and small branches traverse the trab e c u l e to gain the m e m b r a n o u s labyrinth. Apparently there are no functional anastomoses between these two areas of distribution. The most c o m m o n first branch of the labyrinthine artery is that which is distributed to the utricle, part of the saccule, and the anterior e n d s of the anterior and lateral semicircular canals. This branch has been called both the anterior vestibular and vestibular artery. When there is an apparent doubling of the labyrinthine artery, it is this branch that most frequently arises independently. The other two c o m m o n branches of the labyrinthine artery are the vestibulocochlear (posterior vestibular) artery, which is distributed to the saccule, the posterior semicircular canal and parts of the anterior and lateral canals, part of the utricle, and the entire basal coil of the cochlea; and the cochlear nrlcry, which is distributed to the remaining portion of the cochlea. There is consider-

21

able variation in the pattern of branching of the labyrinthine artery. Any one of the normal branches may be missing or may arise via a c o m m o n trunk with a n o t h e r branch. Descriptions of the venous drainage of the inner ear conflict. In all probability most are accurate, reflecting a considerable but normal variation. The described patterns include the following: 1. A vein of the vestibular aqueduct, draining most of the semicircular canals and emptying into either the sigmoid or the inferior petrosal dural sinus. 2. A vein of the cochlear aqueduct, draining the entire cochlea and vestibule. It runs in a long canal paralleling the cochlear aqueduct to enter the superior bulb of the internal jugular vein or the inferior petrosal dural sinus. 3. A labyrinthine vein, which seems to be inconsistent. W h e n present, it drains the apical and middle coils of the cochlea and traverses the internal acoustic meatus to become tributary to the inferior petrosal dural sinus.

Nerves of the Inner Ear Before describing the innervation of the inner ear we will consider the fundus of the internal acoustic meatus. The fundus is divided into superior and inferior portions by a horizontal bony ridge termed the transverse crest. Located posteriorly within the smaller superior depression are a number of small foramina that transmit the nerves to the utricle and the ampullae of the anterior and lateral semicircular canals. This is the superior vestibular area. Anteriorly within the u p p e r depression is a relatively large foramen that transmits the facial nerve. In the larger inferior depression, immediately u n d e r the posterior end of the transverse crest, is the inferior vestibular area, which contains small foramina transmitting the nerves to the saccule. Below and slightly posterior to the inferior vestibular area is the foramen singulare, through wiiich nerves to gain the ampulla of the posterior semicircular duct. Anteriorly the inferior depression is occupied by the foraminiferous spiral tract, a series of minute foramina arranged in spiral fashion that appose the base of the cochlea and the modiolus. At the center of the spiral is the somewhat larger orifice of the modiolar canal. The nerve of the inner ear is the vestibulocochlear (statoacoustic, acoustic, or auditory) nerve. Functionally, it consists of two divisions: 1. The vestibular division, containing fibers arising from the vestibular ganglion, a sensory ganglion situated at the lateral end of the internal acoustic meatus.

22


These sensory fibers form the superior and inferior vestibular n e w s . T h e superior vestibular nerve supplies the ampullae of the anterior and lateral semicircular canals plus the maculae of the utricle and saccule. Hence, it is this nerve that enters the inner ear through the superior vestibular area of the fundus of the meatus. The inferior vestibular nerve supplies the ampulla of the posterior semicircular canal and the macula of the saccule. It is associated with the inferior vestibular area and the foramen singulare of the meatal fundus. 2. The cochlear division, consisting of fibers arising from the spiral ganglion, which is situated in the coils of the modiolus at the base of the osseous spiral

lamina. These fibers through the lamina to gain the organ of Corti. Within the internal meatus these fibers are associated with the foraminiferous spiral tract and orifice of the modiolar canal. Associated with the nerves of the inner e a r is the bundle of Oort, a small number of efferent fibers arising from the superior olive of the brainstem. These fibers run from the brainstem to the inner ear within the inferior vestibular nerve, then ovet to the cochlear nerve. Although it is a s s u m e d that these fibers are distributed primarily to the cochlea, where they may play a part in some sort of mechanism, their exact function has yet t•;• be determined.

CHAPTER 2 Pertinent Histology This short chapter presents four photomicrographs of horizontal temporal bone sections at different levels. The sole purpose is to provide a general orientation in of temporal bone anatomy; these sections are useful in achieving the three-dimensional visualization necessary for temporal bone surgery. A detailed description of horizontal temporal bone sections is beyond the purpose of this atlas. The horizontal sections are also to be used as references for

the pertinent! histopathologic slides described in this book, which* for practical reasons are included in their specific chapters rather than grouped together here. W h e n describing horizontal sections of temporal bones, "superior" m e a n s cephalad; "inferior" is caudad; "anterior" is ventral; "posterior" is dorsal; "lateral" is toward the external ear canal; and "medial" is away from' the external ear canal.

24

Pertinent 1 listology Pertinent Histology

25

FIGURE 2 - 2 FIGURE 2 - 1 This section is in the area of the epitvmpamim It is important to that the middle car cavitv extends superiorly above the tympanic m e m b r a n e It is at this level that the malleus can be laterally fixed (not shown in this section). The wide communication between the middle e a r a n d mastoid can be observed as can the close proximity of the incus and horizontal (lateral) semicircular canal to the aditus and antrum At this high level the tensor tympani occupies the anterior wall and is in close proximity to the facial nerve (FN), which is surrounded by a thin plate of bone that is sometimes dehiscent. It is also important

to recognize the thinness of the bone plate separating the vestibule from the internal auditory canal (pnrall'c' «r,vw>). I his must be kept in mind when doing ./abyrinthcctomy, since it is very easy to accidentally create a fistula with subsequent cerebrospinal fluir leak during this procedure. Note in these sectionthe air space that exists in the normal mastoid cavity c o m p a r e d with that in temporal bones with otitr media (see Chapter 1 0 ) . At this higher level, the nerves of the internal auditory canal are the facial nerve anteriorly and the superior division of the vestibular nerve posteriorly.

This section is at the level of the stapes footplate, which is bound to the oval window by the annular ligament. The short distance from the footplate to the contents of the vestibule (utricle and saccule) should be noted. There is very little room ( 1 . 5 to 2 . 0 m m ) to work with a Hough hoe (or similar instrument) when removing the footplate without touching vestibular structures. At this level the FN is located posterior to the oval window; dehiscence (sometimes bulging) is not u n c o m m o n at this site. This should be ed when working in this area. This section also provides guidance for placing tubes in the superior quadrants of the tympanic m e m b r a n e . The risk of damaging the incus or leaving it directly exposed to the exterior by placing a tube

in the posterior superior quadrant is obvious in this section; the safe placement in the anterosuperior quadrant is more evident in Figure 2 - 3 . The tendon of the tensor tympani can be observed inserting^laterally over the anteromedial surface of the manubrium of the malleus. It is here that the tendon of the tensor tympani is sectioned (when this procedure is needed). The body of the incus is reduced in diameter at this level to form the body of the descending long crus (long process of the incus). The posterior incudal ligament can be observed as it attaches at the fossa of the incus (fossa incudis). At this level the nerves of the internal auditory canal are the cochlear nerve anteriorly and the inferior division jf the vestibular nerve posteriorly.

26

Pertinent Histology

Pertinent Histology

27

FIGURE 2-3 FIGURE 2-4 I n this section the e x t e r n a l e a r c a n a l a n d t y m p a n i c

ship

between

the

posterior

s e m i c i r c u h r canal

™H

At

this

lower

level

in

the

mesotympanum

the

p r o m o n t o r y is clearly apparent, as is the t y m p a n i c m e m b r a n e i n its full h o r i z o n t a l e x t e n t . T h i s s e c t i o n provides t h e thin p l a t e of b o n e t h a t s e p a r a t e s b o J s t r u c t u r e s An i m p o r t a n t f e a t u r e in this section is the relation-

m i c o ^ r X"^

Xet °

*

a

clear

image

of

the

middle

ear

space

a n t e r i o r l y a n d p o s t e r i o r l y for p l a c e m e n t of t u b e s in the

inferior

quadrants.

The

sinus

tympani

can

be

o b s e r v e d a n d t h e difficulty of c l e a n s i n g it a d e q u a t e l y if it is i n v o l v e d with c h r o n i c d i s e a s e c a n be s e e n . In these

four

figures

the

thinness of the

mucoperios-

t e u m s h o u W b e n o t e d a s a r e f e r e n c e for c o m p a r i s o n with the p a t h o l o g i c slides s h o w n in specific c h a p t e r s .

Pertinent Concepts in High Resolution Temporal B o n e Imaging

29

CHAPTER 3 Pertinent Concepts in High Resolution Temporal Bone Imaging FIGURE 3 - 1 . Normal temporal bone (1.5 mm thick axial LI images, w ?°oo;

Computed Tomography and Magnetic Resonance Imaging

High resolution computed t h e field

a

u

M

„„

o

r n

. | ) . The geniculate l l „ , head (lane curved arrow) and incus body

c a n a l ( i a £ )

,,|

m a

v e s i i b u

e ( o p e n a

m

w

P

studied with C T , but MR is the procedure of choice for e v a l u a t i o n o f i n t e r n a l a u d i t o r y canal m a s s l e s i o n s .

tomography (CT) and

magnetic resonance (MR) imaging have dramatically enhanced

, •

handle of malleus (curved arme); normal mastoid air cells Mule arrows).

Vascular Ultrasound for Atherosclerosis Screening

of temporal bone imaging. Thin

section axial a n d coronal C T p r o v i d e s detailed v i e w s of the ossicles, bony labyrinth, cochlea, and mastoid air cells (Figs. 3 - 1 t o 3 - 5 A ) . M R p r o v i d e s s u p e r i o r soft

tissue

contrast

resolution

over

CT

and

often

e l i m i n a t e s t h e n e e d for i n v a s i v e p r o c e d u r e s s u c h as arteriography 5B

to 3-9).

and

pneumocisternography

(Figs.

3-

T h e multiplanar characteristics of MR

p e r m i t d e m o n s t r a t i o n o f s o f t t i s s u e a n a t o m y i n anydesired plane of projection, and imaging parameters may

be

section tures

adjusted CT is

need

to

to

fit

each

recommended be viewed

in

particular

case.

whenever bony detail.

Thin struc-

Temporal bone

injuries, developmental anomalies, otosclerosis, and i n f l a m m a t o r y middle ear or mastoid lesions are best

High

resolution

r e a l - t i m e d u p l e x u l t r a s o u n d witrf.

D o p p l e r a n d spectral analysis is a

useful a n d cost-

e f f e c t i v e s c r e e n i n g p r o c e d u r e for cervical c a r o t i d atherosclerosis.

Real-time

ultrasound

provides

direct

visualization of the cervical carotid arteries (Figs. 3¬ 10, 3-11). D o p p l e r a n d s p e c t r a l a n a l y s i s d e f i n e f l o w patterns and

velocity.

These noninvasive screening

procedures are easily performed common complaints headedness,"

such as

upon patients with

"dizziness"

precluding the need

or "light-

for a r t e r i o g r a p h y

in most circumstances. MR shows immense promise for n o n i n v a s i v e s t u d y o f t h e i n t r a c r a n i a l v e s s e l s ( s e e Fig. 3 - 7 8 , C).

FIGURE 3-2. , , „ Mondini deformity in a child with congenital deafness. The deformed cochlea (arrow) is globular in configuration and is continuous with the deformed vestibule fourni rtrnite). Note an operative defect (ic/iilc imam) from previous exploratory surgery.

J

Pertinent C o n c e p t s in High Resolution

Tempora] B o n e Jmoging

Pertinent Concepts in High Resolution Temporal B o n e imaging

31

FIGURE 3 - 5 . Intraconalicular acoustic schwannoma shown with coronal CT (A) and MRt (R) A, There is marked expansion of the ny;ht internal auditory canal (arrow). 8, Expansile mass Cornue) is isointense with brain
Pertinent Concepts in High Resolution Temporal Bone Imaging

33

FIGURH y-b. Paraganglioma ol the temporal hone demonstrated with carotid arteriography Oronlal pru)eclion). An intense tumor blush (forge arrow*) is mh-ii within the temporal bone on this common carotid injection \'o
FICIUKL Cholesterol granuloma ol the medial petrous ,ipe\ (surgically i n f i r m i ' I). A, /!. Axial 3 mm thick images ( I R - 21100, TH = 2(1 [A\ and KO [8]) demonstrate a complex, signal-intense mass (arrow) \sCi(hin the medial petrous apex. Noie considerable hypointenv." material within the flmcKonlainmg mass in R. C, Coronair-mm image demonstrates the signal-intense mass < forge arrow) d lorming the left internal auditorv ânal «umU arww) from below (TR - 800, TH = 20).

y-lCURl: 3 - 7 Non-chrum.iMin paraganglioma (chemodecloma, of jugular Niramen cj using tinnitus, hearing low ,ind paresis <,il cranial ne » e > l(! to 12 -\. Axial '-mm thiik nn.iî shows si^n-il-intense i. -is> tltu^c iiHivci hi uiti-roiuedial tmiptM.il 'rone ( I K 2>lHl, 1. 10}. iff,C-i-shows normal cmhlear .u|iieduet. n\ C. Cor nal im.i^cs show hvpoinlense i,t-s i .iMiybf \chitr inrow*) i itli ociluded internal jugular vein
n

Pertinent Concepts in

High

Résolution Temporal

Bone Imaging

Pertinent Concepts in High Resolution Temporal B o n e Imaging

35

FIGURE .1-10. A longitudinal ultrasound imam' ol' the carotid bifurcation (10 MHz transducer). An irregular, calcific plaque (open arrow) at the origin of the internal carotid artery (ICA) causes moderate narrowing of the proxim.il vessel lumen. Normal external carotid artery (ECA). Note the acoustic shadow (arrow) caused by calcium within the plaque.

I IGL'Kl. ^ I I Advanced carotid atherosclerosis with internal carotid artery (ICA) stenosis. A lan;e, circumferential calcific plaque (lumws) causes stenosis o( the »proximal internal carotid artery. Normal external carotid artery (ECA). Note the acou.stic shadow (lur^c ¡\rrow) from heavilv calcified plaque.

SECTION II Temporal Bone Dissection

CHAPTER 4 Temporal Bone Removal Knowledge of the human temporal bone is essential for the study of anatomy, histology, and pathology, and for the practice of microscopic surgical dissection. This knowledge helps provide a solid basis for medical and surgical treatment, and allows rational innovations and progress. It is useful for the surgeon to learn how to remove a temporal bone adequately. The specimen removed should contain the external auditory canal, middle ear, mastoid, inner ear structures, and surrounding petrous pyramid.

Technique T he cal\ ariuni is opened and (ho brain K exposed. I he brain is then removed, care being taken to section cranial nerves Vll and VIII sharplv at the surface of the internal auditorv meatus (I ig. 4 - M ) . Thus the nerve trunks remain with the temporal bom- specimen. 1 he two most c o m m o n methods of removal arc (1) the block method and (2) the bone plug method

Block Method (Fig. 4 - 1 B ) A motor-driven saw or, preferably, a Strvker saw* (rocker-type oscillating saw) is used. Four saw cuts are made. The first (1) is made at a right angle, as close to the apex of the petrous bone as the regional anatomy will allow. If the cut is made further anterior the eustachian tube can be removed. The second cut (2) is made parallel to the first, through the mastoid "Available frnm Ihr Orthopedic Fnime Comp.inv, K.il.im.i/uo. MI.

process and as close to the lateral wall as possible. The third cut (3) is made approximately 2.5 cm anterior and parallel to the petrous ridge in the floor of the middle cranial fossa. It includes the bony external ear canal. The fourth cut (4) is made in the horizontal plane, close to the floor of the posterior cranial fossa. This undermining cut severs the bone from its inferior attachments. The temporal bone is still not loose, and great care must be taken to avoid fracturing it. A "lion-jawed" forceps is used to grasp the specimen, and the remaining bony connections are loosened by a gentle rocking motion that will free the specimen for further dissection. A sharp chisel, knife, or scissors is used to cut the remaining ligamentous, fibrous, and bony attachments. Whether the temporal bone is removed by the block method or the bone plug method, the carotid artcrv should be ligated and a suture placed in the external auditorv canal to prevent anv leakage of fluid

Bone Plug Method (Schuknecht's) This technique requires the use of a specially designed oscillating bone plug saw attached to the conventional Stryker apparatus. The procedure is simple and provides an adequate specimen. For the adult skuli, a 1.5-in diameter saw adjusted to a depth of 1.5 in is used; a 1-in diameter saw adjusted to a depth of 1 in is used for smaller skulls. The saw should be centered over the arcuate eminence (superior semicircular canal prominence or the superior surface) (Fig. 4 - 2 / 1 ) and directed to the floor of the middle cranial fossa. The skull is held by an assistant, and a stream of water is directed at the

40

Temporal Bone Removal

Temporal Bone Removal

41

42

Temporal Bone Removal Temporal Bone Removal blade for lubrication (Fig. 4 - 2 S ) . Cutting is completed when a loss of resistance is felt, indicating penetration through the base of the skull. An improved cutting action is obtained by slight rotation of the saw. The plug is then grasped with the "lion-jawed" forceps (Fig. 4—2C), and the bone is rotated, permitting visualization of the internal carotid artery on its inferior surface. The artery is ligated. Additional attachments are sectioned with a knife, scissors, or osteotome. Fresh temporal bones can be wrapped in watersealed cotton or placed in Teflon bags; the air is expelled and the bones are frozen. This helps to preserve the soft tissues for later use.

General Setup and Equipment A temporal bone dissection station (Fig. 4 - 3 ) should be arranged to simulate actual operating room conditions as closely as possible. Essential items of equipment include a proper table, a comfortable chair, an operating microscope, a motor-driven drill or other otologic drill, suction apparatus, an assortment of otologic instruments, and a temporal bone holder. A list of suggested instruments appears below. In general, two types of temporal bone holders

43

are most commonly used: one that embeds and fixes the temporal bone in a medium such as plaster of Paris, and another that secures the temporal bone specimen with specially designed screw holders, allowing study of all surfaces and relationships of the bone during dissection.

List of instruments and Materials Operating microscope Whirlybird Drill with a set of Small alligator forceps Fenestrometer cutting burs Scalpel Bulb syringe 4-0 silk (mounted on Suction curved needle) Suction tips No. 1 and 0.05-mm stainless steel No. 5 wire Stapes curets Silastic sheeting Straight canal knife Gel foam Sickle knife TORP, PORP, PE tube t knife Scissors (small plastic) Straight pick Ossicle holder Stapes bending die Measuring rod Hough hoe Residents with imagination can obviate many of these instruments and ma terials by adapting broken instruments and selecting similar, cheaper materials than those suggested

Surgical Procedures

45

CHAPTER 5 Surgical Procedures Highlights

T h e guidelines in this c h a p t e r have b e e n designed for t h e practical p u r p o s e o f b e i n g r e a d a n d f o l l o w e d as

the

dissection

serve as a

proceeds.

They

dialogue between

are

intended

the instructor and

surgeon dissecting the temporal b o n e .

Aims,

to the

lights, pitfalls, pertinent a n a t o m y , and surgical s t e p s

2. Drill u n d e r direct vision, a v o i d i n g " h o l e s " (crili evenly).

are d i s c u s s e d during the dissection in an attempt to simulate a rational procedure. The

authors

encourage

3. W h e n in d o u b t , identify l a n d m a r k s a n d us • i, mastoid

dissection

of

temporal

p r o g r a m s o r for o t o l a r y n g o l o g i s t s w h o

wish to practice specific techniques.

curet.

4. D e v e l o p a gradual, step-by-step procedure.

b o n e s a s a n e s s e n t i a l p r e r e q u i s i t e for o t o l o g i c t r a i n i n g in residency

5. Think

anatomically

and

t h r e e - d i m e n s i o n a iv.

L o o k for s t r u c t u r e s ; d o n o t " f i n d t h e m . "

This practice,

6. K e e p anatomic aberrations in

mind (high

moid sinus, anterior sigmoid sinus, Korner's septum,

essential

etc.).

developing

rational

and

not

merely

Mastoid tip

s.g-

plus a k n o w l e d g e of a n a t o m y a n d histopathology, is for

Spine of Henle

r

1 . U s e t h e m i c r o s c o p e a t all t i m e s .

high-

imitative m e a n s of surgical treatment. T h e succession of procedures has been organized for t h e

fullest

temporal

utilization of the b o n e s .

bones

are

needed

for

full

Four "wet"

completion

Pitfalls

of

these guidelines. When dissection temporal

describing or discussing a procedure, line

"superior"

(cephalad);

temporal

means

"inferior"

is

bone

toward

the

toward

the

1. Failing to identify the a n t r u m . A. Korner's

m a s t o i d tip ( c a u d a d ) , " a n t e r i o r " is t o w a r d the external a u d i t o r y canal (ventral); " p o s t e r i o r " is a w a v from the e x t e r n a l a u d i t o r y c a n a l (dorsal); " l a t e r a l " is to-

septum.

B. Insufficient t h i n n i n g of the t e g m e n a n d / o r p

s-

terior o s s e o u s canal.

mastoid

3 . I n j u r i n g t h e facial n e r v e b y g o i n g

is a w a y from the mastoid cortex (deep). 4.

A.

Deep to the horizontal semicircular canal.

13.

T o o far a n t e r i o r i n t h e d i g a s t r i c r i d g e .

D i s l o c a t i n g t h e i n c u s by drilling blindly into t" ,e antrum

area.

Surgical Steps

surface line

(cortex)

(linea

tip inferiorly.

in

its e n t i r e t y

temporalis) Identify

from

superiorly

to

the

future

the

trum. Y o u r superior limit is the t e g m e n m a s t o i d e u m

the posterior aspect

posterior to the o s s e o u s canal. R e v i e w the imaginary

if adequate access to the antrum is intended.

lines

posterior c a n a l wall s h o u l d be t h i n n e d d o w n as well

the

mastoid

the temporal line and

antrum,

that is,

be-

spine of Henle (fossa

maintaining the integrity of the posterior canal.

5-1).

Place the tem-

anatomic location

for s u r g e r v ) .

Visualize and s t u n '

middle cranial

for t h e s a m e p u r p o s e .

fossa.

Thin

the

tegmen The

A g a i n , drilling s h o u l d remain

mastoidea or M a c e w e n ' s triangle). Imagine the inner

e v e n a t all t i m e s , n o t s t r a i g h t b u t o r i e n t e d a n t e r i o r l y

structures

toward

Initiate A s s e s s External Aliatomi/ ( F i g .

s u p e r i o r to w h i c h lies the

d o w n , b e i n g careful to k e e p it intact; this is important

that overlie

of the

an-

the suprameatal spine (spine of Henle) immediately

of the

mastoid

cavity

in

a

three-dimen-

Drilling

(Use

Large

Burs,

Sauccrize).

izing

in

an

even

fashion,

beginning

at

the

nose of our imaginary patient.

O u r an-

t e r o s u p e r i o r limit is the root of the z y g o m a t i c proc-

sional fashion and trace your surgical plan.

poral b o n e in s u r g i c a l p o s i t i o n ( s i m u l a t i n g its n o r m il

(level of t e m p o r a l line),

the

dura

Employ-

ing the m i c r o s c o p e , u s e a large b u r a n d start s a u c e r E x e n t e r a t i o n ( r e m o v a l ) o f all m a s t o i d air c e l l s w h i l e

landmarks to orient yourself toward

of the o s s e o u s canal anteriorly. Note the presence of

tween

Simple Mastoidectomy Aim

lateral

temporal

2. Injuring a high sigmoid s i n u s .

ward the mastoid cortex (superficial); and " m e d i a l "

the

the

fossa

ess.

This

should

be

opened

without

opening

the

epitympanum. Identify

the

Lateral you

will

Sinus

(Sigmoid

encounter

Sinus). the

In

drilling

m a s t o i d e a until air cells a p p e a r (Fig. 5 - 2 A ) . M a k e a

posteriorly

sigmoid

wide cortical removal, including thinning of the pos-

(lateral s i n u s ) (Fig. 5 - 2 B ) . It is identified in surgery

terior canal. As you go deeper, k e e p thinking of your

b y its b l u i s h c o l o r a n d

s m o o t h b o n y plate.

sinus

(In

this

46

Surgical P r o c e d u r e s Surgical P r o c e d u r e s

47

d i s s e c t i o n w e a r e l o o k i n g for t h e s m o o t h b o n y p l a t e . )

(and s h o r t p r o c e s s of t h e incus) inferolaterally to the

T h e s e c h a r a c t e r i s t i c s a r e t h e best g u i d e s t o t h e sig-

a n t r u m a n d the horizontal canal, the e p i t y m p a n u m ,

m o i d sinus. A c h a n g e in the s o u n d of the b u r s is a

a n d a l s o t h e e x t e r n a l g e n u o f t h e facial n e r v e , w h i c h

helpful hint but d o e s not suffice as a g u i d e ; visuali-

is medial to the horizontal semicircular canal.

zation

far

surgery.

outweighs

It

must be

sinus d o e s not high

(lateral)

U s i n g a f e n e s t r o m e t e r , m e a s u r e an i m a g i n a r y tri-

that the sigmoid

a n g l e 1 0 m m f r o m t h e tip o f t h e s h o r t p r o c e s s o f t h e

uniform a n a t o m y ; it can be

incus or fossa incudis, along the axis of the horizontal

(medial'deep).

semicircular canal (30 degrees from the tegmen), and

in

ed

have a or

bone

sensation

low

temporal

The

surgeon

s h o u l d b e c a u t i o u s w i t h t h e u s e o f t h e drill.

Interi-

o r l y , t o w a r d t h e m a s t o i d tip, t h e a i r cells a r e t o b e

from

the

fossa

degrees from

12

mm

the

tegmen.

incudis

at

an

This area

angle

of

45

identifies a n d

superiorly.

isolates t h e hard angle (containing the posterior semi-

L i t t l e b y little, a t y p i c a l k i d n e y - s h a p e d m a s t o i d c a v i t y

c i r c u l a r c a n a l ) (Fig. 5 - 3 C ) . I m m e d i a t e l y inferior to it

becomes

a n d a n t e r i o r to the s i g m o i d (lateral sinus) is the plate

drilled

evenly

counter

the

level

of drilling

evident.

Identify medially

with

Korncr's

Septum

mid

(deeper down), a

thick

impression of

plate

having

Kórner's septum,

a

Antrum.

In

occasionally

of

bone

reached solid

that

proceeding one m a y en-

may

give

the antrum.

plate that

the

This

is

represents the

fusion of the s q u a m o u s and p e t r o u s portions of the temporal

bone.

When

in

doubt,

go

back

to

of b o n e that overlies the d u r a of the posterior cranial fossa, by

Now

the

lateral

sinus

(sigmoid

sinus),

tegmen,

and

semicircular canals. T h i s triangle identifies the location of t h e p o s t e r i o r cranial fossa.

your

p r e v i o u s l y identified l a n d m a r k s a n d s t r u c t u r e s , ver-

w h e r e the endolymphatic sac is found.

identify T r a u t m a n n ' s triangle (Fig. 5 - 3 D ) , b o r d e r e d

The

facial

nerve

is

identified

but

not

unroofed.

W e will c o m e b a c k t o i t f u r t h e r i n t h e d i s s e c t i o n . T h e

ify y o u r l o c a t i o n , a n d i m a g i n e t h e b o n e t h r e e - d i m e n -

s i m p l e m a s t o i d e c t o m y i s n o w c o m p l e t e d , t h a t is, all

sionally along with the suspected area of the a n t r u m .

air

Using mastoid curet, curet superiorly and posteriorly

petrous

until identifying t h e " t r u e a n t r u m . " T h e a n t r u m i s

l a n d m a r k s , triangles, and angles.

posterosuperior

to

the

osseous

canal.

A

cells

have apex).

been

removed

Reidentify

all

(except

those

anatomic

in

the

structures,

common

e r r o r i s t o g o t o o far b e l o w t h e t e m p o r a l line o w i n g to lack of thinning of the plate. An i m p o r t a n t guideline is that the a n t r u m s h o u l d be r e a c h e d or e n t e r e d from

above if d a m a g e is to be avoided.

antrum

is

identified,

avoid

uncovering

Endolymphatic Sac Surgery

O n c e the the

identilv the horizontal semicircular canal,

incus;

which

is

Aim

o n e of the m o s t i m p o r t a n t l a n d m a r k s . At that point, vim k n o w that vou a r c definitely in the a n t r u m a n d that v o u a r c s u p e r i o r to t h e lacial n e r v e .

K you are

To

identilv

u n a b l e t o s e c t h e i n c u s , w o r k . i n t e r i o r l y just i n f e r i o r

overlving

to t h e d u r a ol t h e t c g m c i i , tins is t h e widest d i s t a n c e

fossa.

between Identify

and

expose

dura

mater

the of

endolymphatic

the

sac

posterior cranial

the ossicles anil c p i l v m p a n u n i . ami

fV/mr

the

Snmluntl

Angle,

Hard

Angle,

and racial , \ V i w ( F i g . 3 - 3 ) . Drill p o s t e r i o r l y , t h i n n i n g the

the

sigmoid

sinus,

and

between

the sinus and

Highlights and Surgical Steps

the

t e g m e n plate until they m e e t in a s h a r p a n g l e (sinod u r a l a n g l e or Citelli's a n g l e ) . teriorly

toward

the

mastoid

C o n t i n u e drilling intip,

exenterating

cells

from the digastric ridge area. K e e p in m i n d that the facial n e r v e a n d its p o i n t o f e x i t f r o m t h e s t y l o m a s t o i d foramen

are

immediately

ridge. At this point,

anterior

to

the

digastric

w e a r e left w i t h a n i n t a c t a r e a

in the so-called " h a r d a n g l e " (an area c o n t a i n i n g the posterior semicircular canal in the plate that overlies t h e p o s t e r i o r c r a n i a l fossa, a n d a n unidentified facial l-'IGURK 5-2.

nerve). It is i m p o r t a n t to remain a b o v e the area of the horizontal semicircular canal. T h e location of the h o r i z o n t a l c a n a l a l l o w s e x p o s u r e o f the fossa i n c u d i s

1. C o m p l e t e simple m a s t o i d e c t o m y (already performed). 2 . Dril' t o , but n o t b e l o w , t h e d o m e o f t h e h o r i zontal semicircular canal. 3. Identify, p r e s e r v e , a n d m e a s u r e the hard a n g l e containing the posterior semicircular canal. 4. Identify

the

position of the sigmoid

sinus a n d

its r e l a t i o n s h i p t o T r a u t m a n n ' s t r i a n g l e . 5. Decompress

the

lateral

sinus

and

dissect

the

i n f r a l a b y r i n t h i n e cell t r a c t . 6 . I n c i s e t h e e n d o l y m p h a t i c s a c , p r o b e its l u m e n , a n d p l a c e Silastic s h e e t i n g .

46

Surgical l'rocedures Surgical Procedures

Pitfalls 1. Skeletonizing or damaging the posterior semicircular canal. 2. Insufficient unroofing of the dural plate. 3. Failing to identify the endolymphatic sac and its lumen. 4. Damaging the incus. 5. Depositing debris in the middle ear. 6. Lateral sinus bleeding.

Procedure In endolymphatic sac surgery, the authors advocate a thorough simple mastoidectomy (which has already been done). In our dissection, we have already identified the bone plate overlying the posterior cranial fossa d u r a . Redefine Trautmann's triangle, identify the hard bone containing the posterior semicircular canal, and measure the distances again (Fig. 5 - 4 B ) : 10 mm from the tip of the short process of the incus or fossa incudis, along the axis of the horizontal semicircular canal (30 degrees from the tegmen); 12 mm from the fossa incudis at an angle of 45 degrees from the tegmen. Drill into the infralabyrinthine cell tract to help expose the sac location. Pav special attention to the position of the sigmoid sinus. On occasion it partially overlies the dural plate, reducing the size of Trautmann's triangle. The plate is thinned down to eggshell thickness, then gently elevated and separated from the underlying dura with a duckbill elevator. The sac is identifiable as a thickened white area of the dura over the thin surrounding dura (Fig. 5 - 5 ) . The posterior semicircular canal shoud not be thinned or skeletonized. Drilling is done immediately inferior to this area. The sac c o m e s toward the dura from the direction of the posterior semicircular canal. If the lateral sinus is in such a position that it tends to partially cover the dura or make access to it difficult, first recheck the position of the bone; the "head" might be bent too far forward. If the sinus is still prominent after repositioning of the "head," it should be decompressed by removing part of its bony covering facing the dura. Infralabyrinthine cells might have to be drilled (leading toward the jugular bulb). The sac is incised gently with a sickle knife and the lumen probed with a Whirlybird. HC;UKL 5-1.

49

Facial Recess Approach, Posterior Tympanotomy Aim Removal of air cells immediately lateral to the facial nerve at the external genu (facial recess collection of air cells).

Highlights 1. Define the landmarks clearly. 2. Thin the posterior canal wall. 3. Drill parallel to facial nerve fibers. 4. If fhe approach is troublesome, combine transmastoid and transcanal visualization.

PitfaVs 1. 2. 3. 4.

Damaging the facial nerve. Perforating the bony external ear canal. Perforating the tympanic membrane. Those of a simple mastoidectomy.

Procedure Define your landmarks (Fig. 5 - 6 / 4 ) . The external genu of the facial nerve is medial; the fossa incudis is superior. Thin the posterior canal wall. Identify the facial nerve by its pearly white color underneath the thin layer of bone. The bone is still too thick; thin it down very carefully by drilling parallel to the direction of the facial nerve fibers (Fig. 5 - 6 8 ) . Small cutting burs should be used since the recess is quite small. Inferiorly, identify the chorda tympani (which is to be preserved) as it leaves the facial nerve in an anterosuperior direction; it then takes a lateral direction toward the annulus (Fig. 5-7A). On occasion, the facial recess is quite small and the procedure difficult. Rather than insisting on taking unnecessary risks, use a combined transcanal-transmastoid a p proach. Text

continued

on

nage

54

5U

Surgical Procedures Surgical Procedures Horizontal canal

HGUKI. n

4

i IGURI:

51

Surgical

Procedures

Surgical Procedures

Horizontal facial nerve

FIGURI; 5 li FIGURE 5-:

53

Surgical Procedures 54

Surgical Procedures Once

the

recess

is

opened,

the

landmarks

Procedure

are

reidentified: t h e e x t e r n a l g e n u o f t h e facial n e r v e i s medial;

the

fossa

incudis

is

superior;

the

chorda

tympani is inferolateral and posterior; a n d the tympanic m e m b r a n e is anterolateral.

At this point in the dissection, for t h e

N o w observe the following structures (Fig. 5 - 7 B ) ;

procedure has been done.

inserting

the

electrode

through

the m a i n drilling Y o u a r e l=ft w i t h

the

round

vindow

t h e h o r i z o n t a l p o r t i o n o f the facial n e r v e , the lentic-

a n d drilling a seat for t h e internal r e c e i v e r p o s t e r o -

ular p r o c e s s of the incus, the i n c u d o s t a p e d i a l t,

superior to the mastoid cavity. Locate a p o s

the capitulum of the

the internal receiver; it should be immediately pos-

don.

Next

identify

stapes,

the

and

the stapedial

promontory,

and

ten-

inferome-

dially the round w i n d o w niche.

terior

to

the

posterior

limit of the drilled

;

i o n for

Mastoid

c a v i t y , w i t h its a n t e r i o r ( t o w a r d the e a r c a n a l ) b o r d e r no

further

than

where

the

border of the im: ginary

pinna (auricle) w o u l d be if it w e r e p u s h e d pc sterior (that is, i m m e d i a t e l y posterior to the posterior oorder

Cochlear Implant (Facial Recess Approach)

of the pinna). Superiorly,

the border should not be

a b o v e the s u p e r i o r b o r d e r of the p i n n a . Drill a sent, using as a guideline the circumference of the internal receiver of your practice electrode (Fig.

Aim

practice e l e c t r o d e is

not available,

5-8).

If a

drill a s e a t into

w h i c h a n i c k e l - s i z e d c o i n w o u l d fit.

Drilling can be

d o n e carefully with a regular bur, or it can be d o n e To place an electrode into the cochlea by sliding it through

the r o u n d w i n d o w . ( W e will d e a l o n l y with

intracochlear trodes

that

electrode are

placed

placement far

into

the

and

with

interior

elecof

the

with either a butterfly bur or a bur specially d e s g n e d by o n e of the cochlear implant manufacturers

[f a

screw

drill

type of internal

receiver

is to be

used,

f o u r h o l e s i n t h e c o r r e s p o n d i n g o p e n i n g s o f the b a s e of the pedestal to a m a x i m u m depth of 2 m m .

cochlea.)

R e g a r d l e s s of the type of internal receiver, with a s m a l l b u r drill t w o s m a l l h o l e s i m m e d i a t e l y s u p e r i o r

Highlights

and scat,

inferior to the that

is,

two

location holes

ol

your alreadv dilled

superiorlv

and

two

holes

inferiorly (Fig. 5 - 9 / 1 ) . Bring the small holes together 1. F.nsure g o o d visualization eia an a d e q u a t e l.uial 2. Clearlv round

identilv

window

vcrv

carefully,

then

o p e n i n g s (I ig. 5

recess approach. the

round

window

niche and

l

2-0

silk

through

thes-

' / i ) ; t h i s u ill h e u s e d t o crus*. o v e r

the interna! r e c e i \ o i a m i seat it in place. Do mil plate \ our internal r e c e i v e r vol.

membrane.

Our attention electrode

is

now

turned

hack

to

the a. live

A g a i n , \ i s u , i h / c t h e r o u n d w i n d o w I-P

he.

II v i s u a l i z a t i o n is n o t , u l e . | u , i t o a t r . m s c a n a I a p p - - >a. h

Pitfalls

tan he n u d e dow imhe

\ c i i l v the o p e n i n g o t the r o u n d win-

On occasion, it is nccess.irv or use.; I to

g e n t l v drill the . i n t e r i o r b o r d e r ol the n i c h e (I i ;. 51.

[ h o s e o f t h e facial r e c e s s a p p r o a c h itself.

2. Inadequate visualization of the round with

the electrode unable

to be ed

y(').

window,

beyond

the

hook.

I his will p r o v i d e a slightly larger o p e n i n g ". th

b e t e r v i s u a l i z a t i o n , a n d a t t h e s a m e t i m e will pr. a "straight s h o t " at the cochlea,

icnt

skipping the ' o o k

p o r t i o n that s o m e t i m e s is difficult to b y p a s s . P o s (ion the electrode in the o p e n i n g of the w i n d o w a n d

hen

g e n t l y p u s h it in, u s i n g a b l u n t pick or w i r e g u i c e or

Surgical Steps

o n e of the special e l e c t r o d e g u i d e s p r o v i d e d by implant manufacturers (Fig. 5 - 1 0 ) .

1. T h o s e

of

a

simple

mastoidectomy

and

recess approach.

facial

the

If there is s u n e

resistance, it is likelv that the electrode is c a u g h

up

in the h o o k . Retract the electrode gently and tr

to

r o t a t e it, w h i l e i m a g i n i n g t h e d i r e c t i o n o f t h e c o c h - e a .

2. P r e p a r e a s e a t for t h e i n t e r n a l r e c e i v e r .

O n t h e left, for e x a m p l e , t u r n g e n t l y t o w a r d t h e r ' ? h t

3. Insert the intracochlear electrode.

( c l o c k w i s e ) ; o n t h e r i g h t , t u r n g e n t l y t o w a r d t h e 'eft

7V.v( tvntiiiiicd on p a e e 59

FIGURE 5-8

55

56

Surgical I' rocedures

Surgical Procedures

Scala tympani

( '"

:'

"

A

A ~Iectrode In scala tympani

B 15mm

Facial nerve

o

'. <'-'

Round window niche

/'SIrf,'/'h.e'\

~11,1

' .

B

FIGURE 0- J(J

57

Surgical Procedures (counterclockwise). Place the electrode and then secure the internal receiver with either screws or sutures (Fig. 5 - 1 1 ) .

Transmastoid Facial Nerve Decompression Highlights and pitfalls are discussed in the text.

Surgical Steps 1. Those of a simple mastoidectomy. 2. Identify the different segments of the nerve, and skeletonize the fallopian canal.

facial

3. Fracture and remove any bony covering. 4. Open the sheath of the facial canal.

Procedure In the course of the complete simple mastoidectomy, the vertical portion and external genu of the facial nerve were fairly well delineated. For practical surgical purposes the facial nerve can be divided into three segments: (1) that within the internal auditory canal; (2) the tympanic segment (horizontal/middle ear); and (3) the vertical segment (mastoid). We will deal now with the vertical and horizontal segments, in that order.

HCLÌRK 5-11

From the external genu, the nerve proceeds vertically to the stylomastoid foramen at the level of the anterior edge of the digastric ridge (Fig. 5 - 1 2 ) . It is important to visualize its anatomy and, if possible, c o m p a r e it with cither bones, since there is considerable variation. The nerve is lateral to the horizontal canal; however, it may have a posterior projection at the genu, lending itself to potential damage. It is useful to visualize the nerve anterior to the digastric ridge and to appreciate how lateral it becomes as it reaches the mastoid tip. Its tympanic or middle ear segment appears in the region of the cochleariform process at the geniculate ganglion, then runs posteriorly towards the oval window (stapes) to a point just inferior and usually medial (deep) to the horizontal semicircular canal. The vertical segment can be dissected from the

59

level of the fossa incudis or from the digastric ridge. From the ridge it can be followed superiorly to the external genu; however, this is not a reliable landmark. Although this approach is perfectly acceptable, the authors tend to follow nerves peripherally rather than centrally, which seems both safer and simpler. After visualization of the genu, the canal is skeletonized all the way down to the stylomastoid foramen. Drilling is done in strokes parallel to the direction of the nerve (superior to inferior or vice versa). Exposure of the tympanic segment is helped by enlarging the aditus ad antrum. This dissection, plus enlargement of the facial recess approach, allows visualization anteriorly toward the cochleariform process. Visualize the segment at the level of the oval window and the pyramidal eminence. This is a very useful image to keep in mind. If necessary, adequate 'isualization can be obtained by a combined approach. Visualize the tympanic segment through the canal. It is also possible to obtain adequate visualization by removing the incus (Fig. 5 - 1 3 A ) . Before disarticulating the incus, try to drill under it without damaging or dislocating it, using the smallest possible burs. Now try to remove and replace the incus. If drilling toward the geniculate ganglion was incomplete, drill now without the incus in place. (The incus should be left in place for use in the next procedure; however, practice placing and replacing the incus to become familiar with its normal anatomic position.) Once the entire facial canal has been thinned to eggshell consistency, fracture it with a pick and lift the bone fragments gently with a Whirlybird without using the facial nerve as a fulcrum (Fig. 5 1 3 8 ) . The sheath is then opened with a sharp sickle knife (Fig. 5 - 1 3 C ) .

Canalplasty (Fig. 5-14) Aim

I

Enlargement of the bony canal and visualization of the enhre fibrous and bony annulus.

Pitfalls Excessive drilling of the anterior wall and entrance into the temporomandibular t space.

60

Surgical Procedures

['IGL'Ri: 5- 12

62

Surgical Procedures Surgical Procedures

Procedure

Procedure

Ant. canal wall

Tympanic membrane

Using a large bur, drill the canal wall evenly until visualization of the entire fibrous annulus is achieved (Fig. 5 - 1 4 A ) . Do not drill in one spot, but "sweep" the bur gently with even pressure and go one step at a time. (Skin procedures will not be dealt with, since the skin is thick, tight, and difficult to elevate adequately for these purposes in harvested temporal bones.)

Underlay Graft of the Tympanic Membrane

A

Aim

Post, canal wall

I Anterosuperior quadrant

Placement of a graft under the tympanic membrane, covering all edges of the perforation.

Procedure Visualize the t v m p a n i c m e m b r a n e . four q u a d r a n t s (Fig. a n d a sickle knife,

5-14R).

Using a

m a k e a central

Imagine it in straight

pick

perforation (Fig.

3 - 1 5 / 1 ) . Fill t h e m i d d l e e a r s p a c e w i t h C i e l f o a m ( F i g . 5-15/t).

Obtain

a

e x c e e d s the size ol

piece

of

fascia

(or

paper)

that

the perloration bv at least 10'.;.

Scarifv the u n d c r s u r f a c c of the t v m p a n i c m e m b r a n e around

the

63

perloration,

using a

Hough

p l a c e t h e graft o v e r t h e p e r f o r a t i o n a n d medially bv using the H o u g h hoe (Fig.

hoe.

Now

Remove the "graft," the entire tympanic membrane, and the Gelfoam filling the cavity. Now visualize the cavity and what is found beneath the different quadrants (see Fig. 5 - 1 4 B ) . Familiarize yourself with the anatomy. Mobilize the temporal bone and learn what areas can be seen best at different angles. Palpate the ossicles with a blunt pick, and observe the round window niche area, the opening of the eustachian tube, the stapedial tendon, and other features. C o m p a r e the views of the middle ear cavity with the transcanal and posterior tympanotomy approaches. The incus is already loose. Clip the distalmost portion of the long process of the incus ("necrosis of the lenticular process") (Fig. 5 - 1 6 A ) . Since the mastoidectomy has been done already, remove a piece of "cortical bone" posterior to the mastoid cavity opening. Using a small bur, delineate a square of bone and remove it. Shape this piece of bone in order to restore continuity. Drill a small acetabulum for the head of the stapes and a groove for the remaining long process of the incus (Fig 5 - 1 6 B - E ) . Remove the entire incus. Restoration of ossicular continuity in this case can be achieved in a number of w a y s (Fig. 5 - 1 7 ) . We will use a sculptured incus, a sculptured cortical bone and, if available, a partial ossicular replacement prosthesis (PORP). Clip the short process of the incus and drill an acetabulum in the remaining long process, for fitting over the head of the stapes. Then drill a groove over the remaining body for fitting under the malleus. Now try to sculpture a piece of cortical bone in this same shape. Avoid of the incus graft with the promontory. Try a PORP as well, if available.

position it

5-15C

D).

Ossiculoplasty (Incus Procedures)

Intact Bridge Mastoidectomy (IBM), Modified Radical Mastoidectomy, and Radical Mastoidectomy

B

Aim Restoration of ossicular chain continuity (in this case, where incus problems are the cause of the loss). FIGURI: s-14

Aims Exteriorization of the disease process within the epitympanum, antrum, and mastoid to the meatus.

64


65

Surgical Procedures The IBM is a version of modified radical mastoidectomy with bridge preservation, allowing tympanoplasty repairs.

Highlights

1. Enlarging the anterior canal wall without opening the temporomandibular t, and visualizing the entire fibrous and bony annulus. 2. Large meatoplasty is crucial for the success of the procedure.

Pitfalls

1. Incomplete removal of the posterior meatal wall.. 2. Poor meatoplasty.

Surgical

67

Intact Bridge M a s t o i d e c t o m y The "bridge" is the most medial portion of the posterosuperior meatal wall; it is literally the bridge that crosses the attic toward the tegmental area. It has both anterior and posterior buttresses. The anterior buttress is the superior portion where the posterior bony canal meets the tegmen. The posterior buttress is the inferior portion where the posterior bony canal meets the floor of the external auditory canal, lateral to the facial nerve. Drill the anterior canal wall, enlarging it until clearly visualizing the entire fibrous and bony annulus but without entering the temporomandibular t space (Fig. 5-18/1). Lower the posterior canal wall, leaving the bridge intact (Fig. 5 - 1 8 B ) . Normally the facial recess is not drilled open, but in our bone this has already been done. Visualize and section the tensor tympanic tendon (this maneuver lateralizes the manubrium) (Fig. 5 - 1 8 C ) . At this point in a clinical case, you would place a tube in the tympanic membrane remnant and perform an ossiculoplasty, place a graft, and obliterate the aditus with either periosteum or cartilage.

Steps Modified Radical M a s t o i d e c t o m y

1. Meatoplasty. 2. Canalplasty. 3. Saucerize the mastoid circumferentially. 4. Enlarge the aditus and sculpture the bridge to widen the m e s o t y m p a n u m . 5. Remove all disease. 6. Preserve when possible the anterior tympanic membrane and manubrium. 7. Use a ventilation tube. 8. Ossiculoplasty, tympanoplasty. 9. Obliterate the aditus with periosteum or cartilage. 10. Obliterate the mastoid (usually not necessary). 11. Thiersch graft (at the primary procedure or 34 weeks postoperatively).

Procedure

IMC.URI-: 5 1?.

These procedures involve removal of the posterior meatal wall. The original Bondy modified radical mastoidectomy implies this step; however, in the Bondy procedure the middle ear cavity is not entered. Both the IBM and the modified radical mastoidectomy imply entering the middle ear.

For practical purposes, a modified radical mastoidectomy has already been performed, except that the bridge is still intact. Removing the bridge will complete the modified radical mastoidectomy. There a r e two approaches for the modified radical mastoidectomy: the "inside-out" or atticotomy approach, a n t the "outside-in" or atticoantrotomy approach. We have already performed, step by step, an outside-in approach in this bone. In our next bone, which will be used for middle ear dissection, the inside-out modified radical mastoidectomy approach will be used. Drilling is started in the epitympanum and followed posteriorly into the antrum. In doing this, the bridge is removed. The antrum is identified, as well as the d o m e of the horizontal canal (Fig. 5 - 1 9 A ) . With this landmark under direct vision, mastoidectomy is performed and the posterior bony wall is lowered to the level of the facial ridge (Fig. 5 - 1 9 B ) . This method is easier and safer than the outside-in approach in a sclerotic mastoid.

Radical M a s t o i d e c t o m y (Fig. 5 - 2 0 ) The purpose of this procedure is to create an exteriorized cavity that includes the mastoid, antrum,

68

Surgical Procedures Surgical

FIGURE 5-19.

Procedures

Surgical Procedures epitympanum,

and

mesotympanum,

epithelialized

cavity

meatus.

procedure

The

leus a n d

continuous

incus while

leaving

with

the

a

dry

external

involves

removing the

mal-

leaving the

s t a p e s intact.

The

wall thinned; both of t h e s e p r o c e d u r e s h a v e a l r e a d y been performed. found

in

the to

associated dissection

Petrous Drainage

the with

and

promontory. the

carotid

areas in

to the eustachian

tegmen

the

tube orifice

T h e s e cells a r e closely mastoideum;

m u s t be d o n e very carefully.

therefore,

The authors

p r e f e r to u s e s m a l l c u r e t s at this level.

Aim

Labyrinthectomy (Transmastoid Labyrinthine Dissection)

Exenteration while

T h e cells o f the a n t e r i o r tract a r e

"peritubal"

b o n y wall just medial anterior

m u c o s a of the m i d d l e e a r is r e m o v e d as well.

71

(removal)

maintaining

the

of petrous

integrity

of

apex the

air

cells

inner

ear

Aim

structures. The petrous apex (petrous pyramid) has two major g r o u p s o f air cells,

the anterior and

the

posterior.

T h e p o s t e r i o r g r o u p ( F i g . 5 - 2 1 4 ) i n c l u d e s cell t r a c t s superior,

posterior,

and

inferior to the s e m i c i r c u l a r

c a n a l s ; the a n t e r i o r g r o u p (Fig. tracts in

the superomedial aspect of the eustachian

tube'orifice, w h e r e the carotid artery is located. o r d e r to

Complete removal of the semicircular canals and soft t i s s u e of t h e v e s t i b u l e

5 - 2 1 6 ) i n c l u d e s cell

reach

t h e s e a n t e r i o r cell

tracts,

a

In

radical

mastoidectomy (described above) must be done.

Highlights

Hy-

p o t y m p a n i c air cells also a r e p r e s e n t a d j a c e n t to t h e round

window

X.

niche.

The

thinned 2.

Posterior Cell Tract

sinodural

angle

must

be

completely

for a d e q u a t e e x p o s u r e o f t h e v e s t i b u l e .

T h e t e g m e n m u s t b e t h i n n e d for a d e q u a t e vis-

ualization

of the superior aspect of the semicircular

canals. F o r this dissection, skeletonization of the s i g m o i d s i n u s , t h e p o s t e r i o r f o s s a d u r a , a n d t h e facial n e r v e is

required.

This

has already

been

done.

O u r next

step is to earcfullv skeletonize the semicircular canals (Fig.

5-2IC).

U s e s m a l l b u r s (."1-0 o r 4 - 0 s i z e ) .

areas or tracts, should arch ol

be looked

which lor.

mav

or mav

T h e first

not

Four

be present,

tract is t h r o u g h the

the superior semicircular canal

I he s e c o n d

tract is a n t e r o s u p e r i o r to the semicire ular c.tnal, leadi n g i n t o t h e s t i p r a c o c h l e a r a i r c e l l s \ isvialize t h i s t r a c t a n d its r e l a t i o n s h i p t o t h e facial n e r v e . T h e t h i r d t r a c t is posterior to the superior canal and runs between the

tegmen

mastoideum

and

m e m b r a n o u s labyrinth t o w a r d canal.

common

crus

Procedure

of

the

T h e t h r e e s e m i c i r c u l a r c a n a l s a r e s k e l e t o n i z e d until t h e m e m b r a n o u s l a b v r i n t h i s visible t h r o u g h t h e b o n e a s a t h i n b l u e line ( F i g . 5 - 2 2 , 4 ) . N o t e t h e r e l a t i o n s h i p o f t h e facial n e r v e t o t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l (Fig. 5 - 2 2 / i ) . F e n e s t r a t e the horizontal canal. U n r o o f the

posterior and

semicircular canal. canal

until

.t

anterior

portions

of the

superior

Follow the superior semicircular

reaches

its

common

crus

with

the

the internal auditory

posterior semicircular canal. T h e arcuate artery pen-

Do not e x p o s e the c o m m o n c r u s — t h i s is to be

etrates the h a r d labyrinth in the center of the arch of

d o n e later.

T h e intention here is to obtain a better

the superior semicircular canal.

Go back to the su-

visualization of this a n a t o m i c relationship. T h e fourth

perior semicircular canal,

o r r e t r o l a b y r i n t h i n e cell t r a c t i s i n f e r i o r t o t h e p o s t e -

tibular n e r v e , a n d follow it into the internal a u d i t o r y

rior semicircular canal, medial to the vertical s e g m e n t

meatus

o f t h e facial n e r v e , a n d s u p e r i o r t o t h e j u g u l a r b u l b .

N o w identify the e n d o l y m p h a t i c d u c t as it e n t e r s the

(Fig.

5-22C).

identify

Visualize

the

the

p o s t e r o s u p e r i o r end of the vestibule.

superior ves-

common

crus.

V e r i f y its p r e s -

e n c e a n d its d i r e c t i o n t o w a r d t h e e n d o l y m p h a t i c s a c ;

Anterior Cell Tract

this is a useful a n a t o m i c relationship to k e e p in m i n d , since this a r e a is not visualized in e n d o l y m p h a t i c s a c

A

radical

mastoidectomy

The tegmen should

has already

been

done.

be skeletonized and the anterior

e n h a n c e m e n t procedures. Bone is n o w r e m o v e d from

72

Surgical Procedures

FIGURE 5 21 FIGURE 5-22.

74


t h e floor o f t h e v e s t i b u l e w h e r e the inferior v e s t i b u l a r nerve is e n c o u n t e r e d . Follow the c o m m o n crus anteriorly into the vestibule.

O p e n i t w i d e l y a n d try t o identify t h e m e m -

brane of the utricle and saccule. Notice the relationships and and

distances between the footplate,

utricle.

Now

skeletonize

the

round

saccule window'

since

two

additional

observations can

be

ma le

in

t h i s a r e a . F i r s t , drill c a r e f u l l y at t h e i n f e r i o r n. ,rgin of the round w i n d o w and identify the singular n e r v e ( F i g . 5 - 2 3 / 1 ) . S e c o n d , drill t h i s a r e a a n d i d e n t i f y t h e h o o k of the basal turn of the cochlea (Fig

a n a t o m y in order to see the direction in which the

H o u g h h o e (Fig. 5 - 2 6 D ) . Using the wire bending die

electrode should be pointed and the amount of bone

0.005

that should be drilled to b y p a s s the hook.

thesis as described in Figure 5 - 2 7 . Place it over the

V i s u a l i z e its

stainless

steel

and

Gelfoam,

make

the

pros-

long process of the incus and gently crimp—not too

5-/3B)

tightly,

C o c h l e a r electrodes m a y be obstructed in this area w h e n being inserted into the cochlea.

75

not too l o o s e l y — a l l o w i n g it s o m e mobility

since excessive tightness might result in necrosis of

Middle Ear Dissection

the long process of the incus. M a k e a Teflon piston (Rosales technique) as described in Figure 5 - 2 8 . Place this piston prosthesis o v e r the long process of the

Procedure

i n c u s a n d g e n t l y c r i m p it. Now

T h i s procedure is started with

a

new wet bone.

S k i n p r o c e d u r e s will not be dealt with s i n c e the skin is t h i c k , tight, a n d difficult to e l e v a t e a d e q u a t e l y for these purposes.

Singular nerve

Identify the walls of the ear canal.

Visualize the t y m p a n i c m e m b r a n e ; imagine it in four Round

window

quadrants (Fig. 5 - 2 4 / \ ) . M a k e o p e n i n g s in the anterosuperior, anteroinferior, osuperior quadrants. panic

membrane

posteroinferior, and poster-

Now and

gently

elevate

identify

the

the

tym-

areas

and

structures b e n e a t h the four o p e n i n g s . Visualize w h a t

remove

prosthesis

of

the

incus.

stainless

steel

Try

to

wire

make and

a

longer

Gelfoam

to

e x t e n d from the m a l l e u s to the oval w i n d o w (Fig. 52 9 ) . U s e t h e i n c u s t o m a k e a strut for u s e b e t w e e n the malleus and the stapes. Section the short process o f t h e i n c u s a n d drill a n a c e t a b u l u m o v e r t h e b o d y s o t h a t i t w i l l fit u n d e r t h e m a l l e u s . U s e a s m a l l g r a f t to cover the oval w i n d o w . At this point, with the use of a curet or very small bur,

c u r e t o r drill

the attic in order to perform an

atticotomy. Use a Whirlybird to probe the antrum.

is found beneath the posterosuperior quadrant opening.

N o w bend the tvmpanic m e m b r a n e forward; if

i t i s t o o b r i t t l e , r e m o v e it. V i s u a l i z e t h e m i d d l e e a r (Fig. 5 - 2 4 B ) . Palpate the ossicles, J a c o b s o n ' s nerve, the

round

window

niche area,

and

the opening of

the eustachian tube, and identify the tensor tympani.

Cochlear Implant (Mastoidotomy-Tympanotomy Approach)

R e m o v e the skin, leaving the a n n u l u s intact. Identify t h e t y m p a n o s q u a m o u s s u t u r e s u p e r i o r l y a n d t h e t y m p a n o m a s t o i d suture posteriorly. B e t w e e n the su-

Aim

tures is the vascular strip. Identify the anterior wall a n d carefullv drill

the anterior b o n v overhang with-

out

temporomandibular

entering

the

t

space.

E n l a r g e the canal until the entire t v m p a n i c m e m b r a n e

To place an electrode into the cochlea by sliding it through

the

round

window.

a n n u l u s is clearlv visualized (Fig. 5 - 2 4 C ) . C o c h l e a ( b a s a l turn)

U s i n g a large stapes curet, curet the s c u t u m from superior

to

inferior,

thus

avoiding

injurv

to

the


ossicles (Fig. 5 - 2 5 ) . Visualize the stapedial t e n d o n . M a k e sure it is clearlv in sight. At this point y o u are r e a d y for a s t a p e d e c t o m y .

Instead of sectioning the

1. Achieve good

s t a p e d i a l t e n d o n ( w h i c h can be d o n e , as w e l l ) , try to

and round

window

lift i t a l o n g w i t h i t s p e r i o s t e u m w i t h t h e i n c u d o s t a -

(Lempert 1 incision).

visualization of the middle ear n i c h e via a n e n d a u r a l a p p r o a c h

pedial t knife, leaving it attached to the perios-

2. Perform an atticotomy.

t e u m of the long process of the incus (Fig. 5 - 2 6 / 4 ) .

3. R e m o v e the incus.

This is not a

simple procedure.

Using the incudo-

stapedial t knife, separate the t very gently. Fracture the footplate in the m i d d l e with a straight pick (Fig. 5 - 2 6 B ) . Mobilize the stapes, using superiorto-inferior and

inferior-to-superior

movements,

and

4 . E x p o s e t h e m a s t o i d c o r t e x a n d drill a m a s t o i d o t o m y (Lempert II incision). 5. P e r f o r m a s m a l l p o s t a u r i c u l a r i n c i s i o n a n d drill a seat for t h e internal receiver. 6.

Tunnel

the

electrode

from

the

postauricular

r e m o v e it, h o o k i n g t h e j o i n t k n i f e t o t h e a r e a i m m e -

incision .o the m a s t o i d o t o m y into the antrum, middle

diately inferior to the capitulum (Fig.

ear, and round w i n d o w niche.

5-26C).

The

r e m a i n i n g f o o t p l a t e p o r t i o n s a r e lifted g e n t l y w i t h a

7. S e c u r e the internal receiver in place. Text

continued

on

ptigc

82

Surgical Procedures

Tympanosquamous suture

B

FIGURE 5-24 FIGURE 5-25

77

Ib

Suq~ical

Surhica! l'rocl'durl'S

Gelfoam

-ff-......--.--, 0.005 stajnJess steel wire

A

t--- 4 mm ---l A

B

B

Foolplate

c

D

FIGURE o-B

Malleus to oval window

Procedures

79

80

Surgical

Surgical Procedures

FIC'.URl-' 5-28. FIGURE 5-24

Procedures

Surgical Procedures

82

Surgical Procedures

Procedure

below and

behind

the nerve, and the ampu;e of the

horizontal canal inferiorly beneath the nervt (Fig. 53 3 / 1 , B ) . In this p r o c e s s , the utricle is d e s t o y e d as This

procedure

exposing

both

implies

the

middle

an ear

endaural and

approach,

mastoid

cortex.

well. It is important to stay within the b o n y and

to

destroy

only

the

"membranous

.onl'ines

lab/rinth."

O n c e the round w i n d o w niche is clearly exposed and

I m m e d i a t e l y inferior to the vestibule is the internal

defined, an atticotomy (Fig. 5 - 3 0 A ) is done and the

auditory

incus

T h e facial n e r v e also c a n b e i n j u r e d . T o c o m p e t e ' h e

is

removed.

A

small

mastoidotomy

is

per-

canal,

w h e r e the b o n y plate is quite thin.

f o r m e d ( F i g . 5 - 3 0 C ) . T h i s o p e n i n g will a l l o w p a s s a g e

procedure,

of

a n d rotind w i n d o w s , e x p o s i n g the beginning

the

electrode

into

the

middle

ear

through

the

a n t r u m (Fig. 5 - 3 0 E ) . T h e receiver is placed as in the

basal

posterior

drilling c a n

tympanotomy

approach;

however,

only

a

small postauricular incision is needed, and the electrode

is

tunneled

anteriorly

toward

the

mastoidot-

omy.

the

promontory

of the cochlea (Fig. be d o n e

at

this

and

5-33C).

point

for

Kie

oval

of the

Additional

purposes

of

orientation to the cochlear anatomy. Placing aa elect r o d e via t h e b a s a l t u r n c a n g i v e t h e s u r g e o n a

:learer

g r a s p o f t h i s p r o c e d u r e a n d its a n a t o m i c l o c a l o n .

S i n c e this is a t e m p o r a l b o n e d i s s e c t i o n , an a t t e m p t can

turn

drill

be

made

to

place

the

receiver,

performing

a

m a s t o i d o t o m y and p a s s i n g the electrode through the

A t this p o i n t , a n i n s i d e - o u t m o d i f i e d radica'. m a s toidectomy

a n t r u m and into the round w i n d o w (Fig. 5 - 3 1 ) . T h e incus

must

be

removed

(which

has

already

been

(atticotomy)

can

be

performed,

, s

de-

scribed earlier in this chapter. After this procedure,

it will be p o s s i b l e to r e p e a t

s o m e o f t h e o p e r a t i v e p r o c e d u r e s d o n e w i t h t h e first

d o n e ) . A m a s t o i d o t o m y is the creation of an o p e n i n g

wet bone.

in

a r e r e c o m m e n d e d : o n e for t h e m i d d l e fossa a p p r o a c h

the

fossa

mastoidea

without

performing a

com-

plete cortical m a s t o i d e c t o m y . T h e b o n e is drilled in the direction of the a n t r u m by area

directly

ascertain

the

through

the

location

of

middle the

is

not

opening

precisely a cortical

should

be

large

o p e n i n g is d a n g e r o u s .

ear.

antrum,

can be u s e d for d i r e c t p r o b i n g . omv

visualizing In a

order

next

procedures

two

wet

bones

a n d o n e for t h e r e m a i n i n g a p p r o a c h e s .

to

Whirlybird

mastoidectomy, a

the

the attic

E v e n if a mastoidot-

enough;

For

blind,

the

Retrolabyrinthine Approach to the Cerebellopontine Angle

small

T h e m a s t o i d o t o m y itself is a

Aim

useful e x p l o r a t o r y tool for the a n t r u m w h e n b l o c k a g e is s u s p e c t e d or i m p r o v e d aeration of the middle ear is

desired.

Insertion

of

the

electrode

round w i n d o w is the s a m e as in

through

the

the posterior tym-

p a n o t o m y approach; the electrode is ed through

To obtain

surgical access to the cerebellopontine

angle and preserve integrity of the labyrinth.

the o p e n i n g into the c o c h l e a .

Highlights

Transcanal Lahyrinthectomy

1. C o m p l e t e r e m o v a l of b o n e up

Procedure

to the posterior

semicircular canal. 2. Skeletonization and mobilization of the sigr oid sinus to allow posterior retraction.

Visualize the m i d d l e e a r cavity (Fig. 5 - 3 2 ) . Identify the

oval

and

round

windows

well a s t h e facial n e r v e .

and

promontory,

as

Hie p u r p o s e of this proce-

3. Complete the

dure is to destroy the labyrinth. T h e stapes footplate has been removed,

and

t h e vestibule containing the

removal

of bone

from

the

postctci

f o s s a d u r a , s i n o d u r a l a n g l e , a n d p o s t e r i o r portio•> t f tegmen.

4 . R e m o v a l o f b o n e o v e r t h e p o s t e r i o r f o s s a d ira posterior to the sigmoid sinus.

saccule and utricle is e x p o s e d . Bv the use of a h o o k

B e f o r e b e g i n n i n g this a p p r o a c h , a small s e g m

o r H o u g h h o e , the s a c c u l e c a n b e d e s t r o y e d (Fig. 5 -

ot IV tubing or red rubber catheter should be plated

33A).

in

Using

this

same

route,

the

ampule

of

the

the

internal

auditory

canal

to

simulate

nt

c r a r i.il

superior semicircular canal can be reached above and

n e r v e s VII a n d V I I I . B o n e w a x o r g l u e will h o l d i t i n

i n front o f t h e facial n e r v e , t h a t o f t h e p o s t e r i o r c a n a l

position.

FIGURE 5 - W

surgical

Procedures Surgical Procedures

85

Horizontal canal ampule

Common crus

Procedure

from

the

sinus

completely thinned T h e initial s t e p i n t h e r e t r o l a b y r i n t h i n e a p p r o a c h is

a

thorough

simple

mastoidectomy

as

blunt

if so

removed

to eggshell

desired. with

the

Bone

can

be

diamond

thickness and

either

drill

a

instrument.

Following mobilization of the sigmoid sinus,

described

or

removed with

ever

posterior semicircular canal is essential, as this is the

angle

ir-

anterior limit of the dissection a n d e x p o s u r e .

fragile in p r e p a r e d b o n e , a n d care m u s t be taken not

it

is

in

this

important

chapter.

to

Clear

remove

identification

bone

up

to

of

the

Hence,

the

canal.

to

tear

the

posterior

removed it.

It

is

in

fossa

the

same

important

to

dura way.

and

the

bone

earlier

sinodural

Dura

is that

very the

removal of

superior petrosal sinus runs in the sinodural angle;

b o n e i n the i n f r a l a b y r i n t h i n e cell tract. T h e s i g m o i d

b l e e d i n g in this area m u s t be p r e v e n t e d . R e m o v a l of

s i n u s is s k e l e t o n i z e d a n d m o b i l i z e d , if this has not

bone

already been completed. T h e authors prefer to leave

canal. Exposure is e n h a n c e d with bone removal con-

Exposure also is enhanced by adequate

an island of b o n e on the sinus (Bill's island) to protect it from accidental rupture with a shaft of the b u r or during retraction; b o n e can be completely

removed

is

continued

up

to the posterior semicircular

tinued a short distance into the tegmen. It s h o u l d be r e m e m b e r e d that the posterior fossa dura m u s t also be exposed

posterior to the sigmoid

86

Surgical Procedures

Surgical Procedures sinus to allow for better retraction. This is usually not possible in temporal bone specimens, as this bone is needed to hold bone in position. Following decompression of the dura and sinus, the dura is opened with a sickle knife and Malis scissors. The incision lines are depicted in Figure 534/1. The lateral incision parallels the sigmoid sinus, running from superior to inferior, and runs just lateral to the endolymphatic sac in its inferior aspect. The second incision runs from lateral to medial and parallels the superior petrosal sinus. The dura is hinged at the posterior semicircular canal; the dura flap is draped over the canal. With retraction of the cerebellum (not present in specimen) and angling of the microscope anteriorly, good visualization of the cerebellopontine angle and cranial nerves V, VII, VIII, IX, X, and XI is afforded (Fig. 5 - 3 4 B ) . For this demonstration, identification of the internal auditory canal marker should be accomplished.

Translabyrinthine Approach to the Internal Auditory Canal Aim To expose and open the internal auditory canal and identify the four cranial nerves contained within.

Higliliglits 1. Complete mastoidectomy and labyrinthectomy. 2. Identifying and outlining the internal auditorv canal. 3. Opening into the internal auditorv canal; identifying Bill's bar and the transverse crest. 4. Identifying the superior and inferior vestibular nerves, the cochlear nerve, and the facial nerve.

Procedure The initial step in the translabyrinthine approach is the complete mastoidectomy and labyrinthectomy (described earlier). To help in later identification of the superior vestibular nerve, the medial wall of the ampulla of the semicircular canal is often preserved.

87

It is helpful to visualize the internal auditory canal as it traverses the temporal bone. Several points should be ed. The internal auditory canal, as it runs anterior to posterior, starts a w a y from the dissection; hence, at the posterior fossa dura it will be deeper or more medial than at the vestibule. There is a c o m m o n wall between the vestibule and internal auditory canal. In other words, the medial wall of the vestibule represents the lateral wall of the internal auditory canal. A reference for the direction in which the canal runs is from the external genu to the sinodural angle. Bone removal is continued medially following the labyrinthectomy. Again, it is important to that the canal becomes m o r e medial (or deeper) as it approaches the posterior fossa dura. As the canal is approached a dark blue color will be seen, as in the blue lining of any hollow structure. Diamond burs are used at this point to decrease the risk of damage to important structures. It is important to skeletonize the internal auditory canal 180 degrees to allow adequate exposure and prevent bony overhangs. Superiorly, the middle fossa dura is identified and followed medially. A thin layer of bone is left over the internal auditory canal. The "trench" that is developed extends from the facial nerve anteriorly to the posterior fossa dura posteriorly. It is important to that the superior petrosal sinus runs posterior superiorly in the sinodural angle; careful bone removal is required here. The inferior border of the internal auditory canal is now delineated. It is extremely important to be aware of and alert for the jugular bulb as soon as the posterior semicircular canal is removed in the labyrinthectomy. While usually positioned low in the mastoid tip, the bulb may present as high as the posterior semicircular canal (Fig. 5 - 3 5 / 1 ) . Again, the internal auditory canal has a blue lining, and a trench is developed inferior to the canal. The inferior margin of this canal will be the jugular bulb. It is safest to begin at the posterior fossa junction and proceed medially and anteriorly. As the incision continues anteriorly, a small white discoloration in the bone will appear. This represents the cochlear aqueduct, which is an important landmark. E x t r e m e diligence is needed to identify this structure. Cerebrospinal fluid often is released when the aqueduct is entered. Anterior to this lie cranial nerves IX, X, .and XI. Again, bone should be removed for 180 degrees around the internal auditory canal. The bone overlying the canal is thinned to eggshell thickness; it can then be carefully cracked with a blunt instrument and removed in one piece. The dura is best opened inferiorly to protect the facial nerve.

Surgical

Procedures

FIGURE 5-35.



3. T r a n s p o s i t i o n of t h e facial n e r v e posterior ",.

To locate the various nerves in the internal audit o r y c a n a l , t h e facial n e r v e m u s t first b e i d e n t i f i e d a s it r u n s t h r o u g h its labyrinthine c o u r s e (Fig. 5 - 3 5 B ) . W i t h t h e u s e o f s m a l l d i a m o n d b u r s , t h e facial n e r v e can be skeletonized (blue-lined) from the area of the

4 . R e m o v a l o f t h e f a l l o p i a n c a n a l a t all t u r n s o f the cochlea. 5. A n t e r i o r limit b e c o m e s the internal carotic.

ar-

tery.

s u p e r i o r s e m i c i r c u l a r c a n a l a m p u l l a t o t h e first g e n u . Again, a trench can be developed b e t w e e n the nerve and tegmen. T h e superior semicircular canal ampulla helps

to

identify the

superior vestibular

nerve;

Procedure

its

medial wall represents the last r e m a i n i n g b o n e o v e r the s u p e r i o r v e s t i b u l a r n e r v e at its t e r m i n a t i o n in t h e ampulla.

Upon

removal

of this

vestibular nerve is identified. used

to

perforate

bone

separating

nerves. hook

Bill's

facial

A

1-mm

which

sion

h o o k can be

bellopontine

the

complete

of the translabyrinthine approach angle.

Again,

mastoidectomy

the

and

to the

initial

ete-

steps

a e

a

labyrinthectomy

as

described earlier. T h e internal auditory canal is then o u t l i n e d , a n d the facial n e r v e is identified as it e n t e r s

be

superior

ridge of vestibular

never

and

is

T h e t r a n s c o c h l e a r a p p r o a c h is an a n t e r i o r e; le-i-

the superior

T o p r e v e n t d a m a g e t o the facial n e r v e , the

should

the

bar,

bone,

inserted

into

the

fallopian

the labyrinthine s e g m e n t of the fallopian canal.

This

canal. The superior vestibular nerve is then avulsed

is found by using the ampulla of the superior semi-

(Fig. 5 - 3 6 A ) . After proper identification of Bill's bar,

c i r c u l a r c a n a l a s a l a n d m a r k f o r t h e s u p e r i o r ve< f i b -

it is safe to r e m o v e e v e r y t h i n g lateral to this ridge of

ular n e r v e . W i t h a small d i a m o n d bur, the t e g m e a is

bone.

followed medially in this area to d e v e l o p the s u p e i o r

Next, the transverse crest should be identified. A bony

prominence

vestibular and auditorv

lies

inferior

facial

nerves,

into

superior

canal

Immediately

that

inferior

to

the

it

to

divides

and

the

a s p e c t o f t h e i n t e r n a l a u d i t o r y c a n a l . T h e facial n e r v e

superior

w i l l b e b l u e - l i n e d a s i t l e a v e s t h e i n t e r n a l a u d i t >ry

the internal

c a n a l a n d b e g i n s its c o u r s e in the l a b v r i n t h i n e 'I'g-

inferior

portions.

transverse crest

is

the

inferior vestibular nerve. M e d i a l to this lies the c o c h lear nerve (Fig. 5 - 3 6 6 ) . T h i s c o m p l e t e s the e x p o s u r e and identification of the internal auditorv canal.

m e n t of the fallopian canal (Fig. 5 - 3 7 / 1 ) . The facial

next

step

nerve

from

internal

is

to

the

auditory

completely

stylomastoid

canal.

o p e n i n g is m a d e (Fig.

An

skeletonize

he

foramen

he

extended

5-37B).

to

facial

recess

After adequate th n-

ning of the posterior external auditory canal, a cutt; ig or d i a m o n d bur is used to enlarge an area i m m e d i -

Transcochlear Approach to the Skull Bone

ately inferor to t h e fossa i n c u d i s a n d lateral to 1 \e tacial nerve at the b e g i n n i n g of its m a s t o i d s e g m e t t. It is i m p o r t a n t to u s e as l a r g e a drill as p o s s i b l e prevent

tunneling and

facial r e c e s s ,

Aim

poor visualization.

In

a

o

tr e

care must be taken not to disrupt tEe

c h o r d a t y m p a n i (lateral limit) and the t v m p a n i c m e m brane.

These

approach To gain access to the cerebellopontine angle medial to the p o r u s acusticus and/or anterior to the brainstem.

A c c e s s to this area is limited with a c o n v e n -

tional

suboccipital

brainstem;

in

limited

the

by

the

approach

by the cerebellum a n d

translabyrinthine

facial

nerve

in

the

approach tympanum

it

is

and

mastoid.

more

so

swiftlv.

middle ear, and

structures that

After

the

separated.

attic.

The

through

to

will

dissection the

be

The

the

incus

recess fossa

be

opening

incudostapedial

facial

removed

mav

is

made

t

is

removed

is then

incudus

is

this

into

the

visualized

through

enlarged

and

in

accomplished

th•!

superior!

inferiorly

to

r

th '

level of the floor of the t y m p a n u m . T h e external auditory canal is then removed will' a r o n g e u r to i m p r o v e v i s u a l i z a t i o n of the facial n e r v e T h e anterior

Highlights

middle

fossa

transition plished. 1. Complete mastoidectomy and labvrinthectomv.

then

2 . M o b i l i z a t i o n o f t h e facial n e r v e w i t h i n t h e entire

bone.

fallopian canal.

to

buttress tegmen the

is drilled and

to

floor of the

The chorda

completely tympani

as

a

tympanum

W i t h the d i a m o n d drill,

skeletonized

t h e l e v e l o f th'.

inferiorly

has

the

within

facial the

already

smootl

is accomnerve tempore

been

sacri-

ficed. W h e n the b o n e h a s b e e n completely r e m o v e d ,

FIGURE 5-36

92

Surgical Procedures Surgical Procedures the greater superficial petrosal nerve is cut at its origin from the geniculate ganglion (Fig. 5 - 3 7 C ) . This frees the facial nerve from all a t t a c h m e n t s in the temporal bone. It is then carefully reflected posteriorly out of its bony bed. Any remaining tympanic m e m b r a n e is now rem o v e d , as well as any skin remaining on the anterior part of the external auditory canal. The anterior external auditory canal and any bony overhang are drilled to the level of the temporomandibular t. The stapes is also removed at this point. Starting with the basal coil, the cochlea is completely drilled out, as well as the remnant of the fallopian canal (Fig. 5 - 3 8 B ) . (It is good practice to follow the cochlea's coils to gain a better understanding of its anato m y . ) Bone removal is carried forward to the septum that lies between the internal carotid artery a n d anterior wall of the basal coil. The internal carotid artery can be blue-lined with the diamond drill, m u c h as the jugular bulb is blue-lined in the translabyrinthine approach. Interiorly, bone removal extends to the inferior petrosal sinus and jugular bulb. Superiorly, the superior petrosal sinus and tegmen are followed medially to Meckel's c a v e (Fig. 5 - 3 8 C ) . Medially, removal of bone continues to the lateral clivus. W h e n bone removal has been completed, a large window covered by dura (bounded superiorly by the superior petrosal sinus and interiorly by the jugular bulb and inferior petrosal sinus, with its apex just below Meckel's cave and the internal carotid artery located anteriorly) is created into the skull bone. If the dura is still intact, this window can be opened posterior to the internal auditory canal and extended as far forward as needed for exposure. Cuts m a y run medially, anteriorly, and parallel to the superior petrosal sinus and jugular bulb. In an actual procedure, the dural defect is packed with abdominal fat and the external ear canal is sewn shut to prevent postoperative leakage of cerebrospinal fluid.

Middle Fossa Approach to the Internal Auditory Canal

Aim To expose the floor of the middle cranial fossa and identify the structures contained within, including the cochlea, arcuate eminence, and contents of the internal auditory canal.

93

Highlights 1. To d e c o m p r e s s the labyrinthine segment of the facial nerve or remove facial nerve lesions. 2. To r e m o v e small intracanalicular acoustic tumors in art attempt to preserve residual hearing. 3. To rupair large defects of the tegmen and dura that have Resulted in cerebrospinal fluid leaks. 4. To section the superior and inferior vestibular nerves and retain hearing.

Procedure W h e n practicing this approach in the laboratory, placement of the bone within the bone cup is important. Imagine a patient lying supine with the head turned to one side; the surgeon sits at the head of the patient and looks down on the middle cranial fossa floor through the craniotomy opening (described earlier). H e n c e , the bone needs to be placed in the bone cup so that the surgeon looks directly down upon the floor of the middle fossa (Fig. 53 9 / 1 ) . If the dura is still intact, it should be stripped from the exposed floor. As the dura is being elevated, the middle meningeal artery will be found anteriorly as it exits from the foramen spinosum. This represents the anterior limit of an adequate exposure. After all the dura has been removed, the floor should be studied. Laterally, where the floor rises to the pars squamosa, the tegmen overlies the aerated mastoid and; the epitympanum. The eustachian tube (covered by thin bone) is located anterior to the e p i t y m p i n u m . Posteriorly, the floor of the middle fossa d r o p s into the posterior fossa. Along this ridge runs the superior petrosal sinus within the reflected dura. Approximately" 1 cm medial to the middle meningeal artery lies the greater superficial petrosal nerve, which runs in a posterior to anterior direction as it leaves the geniculate ganglion. This nerve is an important landmark; it can be followed back to find the geniculate ganglion and the facial nerve. In approximately 5% of cases the geniculate ganglion will not be covered by bone. Another important landmark is the arcuate eminence of the superior semicircular canal; usually an obvious feature, it may occasionally be indistinct. It is medial to the aerated bone of the mastoid and epitympanum, and a p p e a r s as a rounded prominence. It must be ed that every temporal bone will have its own unique middle fossa topography; no consistent landmark

Surgical Procedures

Surgical Procedures

FIGURE 5-38.

FIGURE 5-39.

96

Surgical Procedures Surgical Procedures can be relied upon. Familiarity with the middle fossa is accomplished only with repeated inspection and dissection. The major landmarks of the middle fossa have now been identified, including the middle meningeal artery, the greater superficial petrosal nerve with its facial hiatus, and the arcuate eminence. Dissection begins with positive identification of the facial nerve. The greater superficial petrosal nerve is followed back to the facial hiatus, where it enters and s the geniculate ganglion. With a large diam o n d bur and suction irrigation to avoid heat generation and bone dust accumulation, the thin bone overlying the geniculate ganglion is removed (Fig. 5 - 3 9 B ) . Here the facial nerve turns slightly posterior and inferior as it runs into its tympanic course. The epitympanum may be opened to expose the head of the malleus, tensor tympani, and cochleariform process. The cochleariform process is the limit to which the facial nerve can be adequately decompressed by this, approach. Following this, the labyrinthine segment of the facial nerve is exposed; this is a very short segment running from the geniculate ganglion to the lateral end of the internal auditory canal. Care must be taken not to enter the ampulla of the semicircular canal, which lies only a few millimeters posterior, or the cochlea, only a few millimeters anterior. This segment of the facial nerve courses almost parallel to the plane of the semicircular canal. A diamond bur is needed to work in this limited space. Bone is removed medially following the course of the facial nerve, which runs in a posterior and inferior (deeper) direction. When the posterior fossa

Incus

|

Facial nerve

In' vestibular nerve

FIGURE 5-10.

97

is reached (medially), the exposure can be widened because the semicircular canal courses posteriorly and the dissection at this point is medial to the cochlea. As the edge of the posterior fossa is reached, that the superior petrosal sinus lies in this dural reflection. At this point obtain wide exposure of the internal auditory canal. By carefully removing the final eggshell thinness of bone, the contents of the canal may be identified. The facial nerve occupies the anterosuperior compartment, with the superior vestibular nerve immediately behind in the posterosuperior aspect (Fig. 5 - 3 9 C ) . At the lateral end of the canal is Bill's bar, the ridge of bone separating these two nerves. Here the superior vestibular nerve runs to the ampulla of the semicircular canal. Immediately below the facial nerve lies the cochlear nerve, and the inferior vestibular nerve lies beneath the superior vestibular nerve. These represent the anteroinferior and posteroinferior c o m p a r t m e n t s respectively. For the sake of completeness, the following structures should be found and followed in their courses. This will help to further the understanding of temporal bone anatomy in a three-dimensional view (Fig. 5 - 4 0 ) . Slightly lateral to the greater superior petrosal, the eustachian tube runs medially from the middle ear cavity to the nasopharynx. Upon dissection of the eustachian tube, the carotid artery may be found on the inferomedial floor of the tube; it courses horizontally from the middle ear to the cavernous sinus. The semicircular canal and cochlea should be entered and followed to gain a clear understanding of their positions within the temporal bone.

SECTION III i

General Principles and Approaches

CHAPTER 6 Operating Room Principles and General Concepts Evaluation All patients should have a complete history obtained and be given a physical examination. Although proper surgical indications and adequate laboratory studies are essential, their discussion is beyond the scope of this chapter. A complete assessment of the patient's general conditions, as well as of the otologic problem itself, is to be made. It should be ed that the ear is not an isolated organ; it interrelates anatomically and functionally with other organs and systems—for example, the nasopharynx and nasal cavity—that must be evaluated in detail. The local conditions of the ear, including the skin of the pinna, the ear canal, middle ear mucosa, and so forth, must be improved as much as possible before surgery. An otologic evaluation includes a number of basic tests in addition to the history and physical examination. A recent complete audiogram that includes pure tones and speech discrimination is essential. Equally important is confirmation of the results by the surgeon, utilizing tuning forks. Radiologic studies include conventional mastoid x-rays ed by tomograms, computed tomographic scans, magnetic resonance, and other imaging modalities, depending on specific needs such as in cases of retrocochlear lesions, complications of otitis media, and congenital atresia. Specific indications of such studies will not be discussed here except to mention that conventional x-rays remain valuable

and essential in many cases, providing information on mastoid aeration, the position of the sigmoid sinus, a n c other details. X-rays must be available in the o p e r a f n g room. A number of additional tests are used, su< "i as BAER (brainstem auditory evoked responses;, electrocochleography, promontory stimulation, and others, the indications for which are outside the scope of this atlas. The essential concept in this section is that the patient must be evaluated from a general as well as a local standpoint, and that tests serve the purpose of screening, ruling out, or confirming specific questions in the mind of the surgeon. They are not a "routine blanket ordered according to trends," n o r are they intended to replace c o m m o n sense and clinical acuity.

Patient Consent As important as informed consent is from a legal standpoint, it is much more important in that it provides the patient with information. It is essential that the patient (or his or her parents) be aware of the rationale for and purpose of the surgical procedure. Is tlje aim reconstruction of the ossicular chain? Is it eradication of disease? What are the chances of success and the risks involved? A well-informed patient is the best guarantee of success. I.iformation on the postoperative course and care is also essential and should be provided by the surgeon. Commercially printed instructions are very

Operating Room Principles and General Concepts 102

Operating Room Principles and General C o n c e p t s

helpful; however, they do not approach the usefulness of instructions printed by the surgeon.

Anesthesia Most otologic procedures can be performed under local anesthesia, with or without sedation. The decision will depend on the specific case and the surgeon's judgment and c o m m o n sense. It should be ed that a general anesthetic usually carries a small risk, at times comparable with that of local procedures under sedation. If a local anesthetic is to be used, it is important to know the innervation of the area to be anesthetized. (See the chapters on anatomy and general surgical approaches.) Different agents are utilized; the a u t h o r s usually use lidocaine (Xylocaine) 1% with 1:100,000 epinephrine in both local and general anesthesia cases, since epinephrine exerts a vasoconstrictive effect essential for microscopic surgery. The m a x i m u m safe dose of lidocaine is 3 mg/kg without epinephrine and 7 mg/kg with epinephrine. In cases of myringotomies and tubes, iontophoretic anesthesia is a useful method in the office. It is based on a battery-operated unit (iontophoretic applicator) that generates a constant direct current, allowing ion transfer of a local anesthetic (placed in the ear canal) into the ear canal and tympanic membranes. Because it does not require an injection it is verv well accepted by s o m e patients.

Antibiotics The use of antibiotics is a controversial a b j e c t that will not be dwelled upon here. The a u t h o r ; use t h e m prophylactically when there is a risk that n f e i tion will extend into the inner ear or intracrajiially, c o m p r o m i s e the survival of a graft or reconstructive procedure, or spread locally—for example, 6 ths auricular cartilage. When antibiotics are used; it is immediately before, during, and after the operation. In chronically draining ears the authors tend to star' antibiotic therapy several days prior to the p r o c e d u r e Use of antibiotics does not mean that strict aseptic techniques are disregarded; they are used only when t h e r e are additional risks in spite of a flawless .echnique that includes asepsis, meticulous hemoslasis, and gentleness with tissues.

FIGURE 6-2.

Equipment and Procedures The operating table must be comfortable but dard enough to allow for resuscitation p r o c e d u r e ; if needed. It should be easily adjustable so that it can be raised or lowered or the patient placed in a Trendelenburg or reverse Trendelenburg position (Figs, 6 - 1 , 6 - 2 ) . The headpiece should be separable in order to change the position of the patient's head independently from the rest of the table (Fig. f - 3 ) .

At times a simple "donut" will suffice; in general,

Preparation of the Skin

however, a Juers head holder is m o r e useful, allowing adjustments in angulation of the head as needed (Figs. 6 - 4 , 6 - 5 ) . The patient's head should be taped to the head holder (which in turn is taped to the head of the table) and moved with the holder as a unit (Fig. 6 - 6 ) . The patient lies supine with the head turned a n d lowered in order to bring the external auditorv canal, which has a bonv orientation that is d o w n w a r d and forward, into a nearly vertical posi-

The skin is prepared after shaving the hair. Shaving of the hair is done with a dry razor blade at the time of surgery, avoiding any lacerations of the skin. Enough ,:air is shaved to provide a clean operative field For i postauricular approach the authors shave an area of approximately 2 . 5 cm. If a large flap is to be raisec. (for example, for a postauricular cochlear implant)'more hair is shaved. For an endaural ap-

tion.

F1GURE 6 - 3 . A headpiece that can be separated from the table is useful.

104

Operating R o o m Principles a n d General C o n c e p t s Operating R o o m Principles and General C o n c e p t s

FIGURES 6-4, 6-5. A Jucrs head holder allows neuverahilitv.

FIGURE 6-6. The patient's head is taped to the head holder.

p r o a c h 0 . 5 cm of hair superiorly along the superior

bility.

helix

will

i n o r d e r t o a l l o w t h e s u r g e o n ' s l e g s t o fit c o m f o r t a h )

such

as

suffice.

A

germicidal

povidone-iodine

phene (pHisoHex)

soap

(Betadine)

is used.

or

and

solution

hexachloro-

The "hanging drapes" are clamped togeth ; :

u n d e r the h e a d o f t h e table w i t h o u t i n t e r f e r e n c e .

W h i c h e v e r a g e n t is se-

solution w i p e d d r y before sterile d r a p e s a r e applied. is cleansed

with

a

solution

such

as

Foreign Body Reaction

h y d r o g e n peroxide or irrigated with saline, or both. T h e o p e r a t i v e field i s i s o l a t e d w i t h s t e r i l e d r a p e s , avoiding excessive bulk that would c o m p r o m i s e m o -

tory reactions that are potentially harmful. good

habit

towel to

to

keep

a

sterile

solution

and

It is a a

moist

rinse a n d clean the surgical gloves before

initiating s u r g e r y . T h e scrub n u r s e s h o u l d h a v e o n

lected, the s c r u b s h o u l d be for ten m i n u t e s a n d the The ear canal

105

Particles contained thesis, or surgical

in

gloves

(powder),

a

pro:;

instruments can cause inflamma

the

surgeon

does

not

inform

him

or

m o m e n t of injection of epinephrine, the head of the patient,

her

of

the

mobilization of

elevation of the operative

table, or o t h e r p r o c e d u r e s . T h e s a m e rules a p p l y in

his or h e r table a c o n t a i n e r with saline in o r d e r to

principle for t h e circulating a n d s c r u b n u r s e s . T h e

clean

the instruments and prosthesis prior to use.

precept of this chapter is that in surgery, t e a m w o r k

I n s t r u m e n t s should be rinsed meticulously after the

yields better results than " w o n d e r m a n " o r " w o n d e r

u s e of sterilizing c h e m i c a l s ,

woman"

since these can be v e r y

d a m a g i n g to tissues.

alone.

The authors' positioning of the team and instruments in t i e operating r o o m is s h o w n in Figure 67. T h e s c r u b n u r s e is at the right of the s u r g e o n a n d

Positioning of the Surgical Team

the

assistant

is

at

the

left.

Other surgeons

prefer

different s e t u p s . T h e best position is o n e that p r o vides the i i o s t c o m f o r t a n d efficiency to a particular T h e surgeon position,

m u s t be in a c o m f o r t a b l e a n d

with both

feet o n

the

floor,

and

stable

with

team.

the

back s u p p o r t e d by a chair that can be m o v e d easily (by

the

surgeon)

while

patient m u s t be placed

retaining

its

position.

so that the surgeon

Instruments

The

is not

bent or forced into uncomfortable positions. This is usually

achieved

by

positioning

the

head

of

the

The

operating

microscope

obviously

must

be

binoc-

o p e r a t i n g table virtually o v e r the s u r g e o n ' s lap, with

ular with a focal l e n g t h of at least 20 c m . T h e a u t h o r s

the

prefer to use the 2 5 - c m length; it provides a r a n g e of

surgeon

capable

of

"comfortably

writing

on

a

desk" while looking through the microscope. T h e surgical successful

team

surgical

is

of t h e

utmost

procedure

magnification from 6 X A

16 X

com-

light

importance.

represents

the

the

most

(either

bulb

or

used.

fiberoptic),

and

the

good good

n u r s e m u s t be familiar with the different k n o b s that

matter how

surgeon

with

requires

and

No

the

it

handling

circulating nurses.

Both

Along

bined efforts of a t e a m of s u r g e o n s , anesthesiologists, scrub and

ability.

to 40 X , w i t h 6 x , 10 x , a n d

commonly

scrub

skilled t h e s u r g e o n , his or h e r w o r k is not possible

provide maneuverability. T h e authors prefer to use

without

an

a

safely

and

adequately

anesthetized

or

angled

eyepiece

that

provides

an

angle

of

45

s e d a t e d p a t i e n t ; n o m a t t e r h o w skilled t h e a n e s t h e -

degrees a n d allows a m o r e comfortable h e a d position

s i o l o g i s t , a d e q u a t e a n e s t h e s i a will n o t b e p o s s i b l e i f

for t h e s u r g e o n (Fig. 6 - 8 ) .

Operating R o o m Principles and General C o n c e p t s

107

a full range of motion (Figs. 6 - 9 , 6 - 1 0 ) . In the c a s e of the OPM1-1 the "longer leg" of the pedestal should point toward the patient's shoulder on the operated side. The side viewer (teaching lens) is placed at the I left side; if possible a video c a m e r a is attached. This allows the operating team to be a w a r e of the proced u r e , anticipate the use of instruments, and even maintain a permanent record of the operation. A suitable sterile d r a p e of either cloth or disposable plastic must be used (Fig. 6 - 1 1 ) . For insertion of PE tubes, rubber handles for focusing and magnification are useful. If they are not available, a sterile towel will suffice. A variety of drills are commercially available. A high-speed drill should suffice, provided that it is a durable instrument capable of withstanding continuous use. At least t w o drills should be available in the operating room. The drill handles should be light and easy to manipulate; the instrument should have several speeds, including reverse and forward. Control by a foot pedal is preferable since handle-controlled drills tend to h a v e m o r e vibration. The reverse speed is useful for saucerizing small bleeding points in the mastoid and bony e a r canal. It is also important that both the surgeon and scrub nurse should be able to assemble and operate the drill. Different metal burs, usually made out of tungsten or steel, are available. Rounded burs work best for otology; they can be of six or eight teeth. In general, burs with m o r e teeth accumulate m o r e debris and are less effective; however, a bur full of debris is useful in areas requiring gentle work, and is similar in this regard to a diamond bur (a metal bur coated with diamond p o w d e r ) . Burs must be sharp; dulling leads to overheating. The authors favor burs with regular shafts over those with special hooks, which in practice limit ;(he surgeon to particular brands; the m o r e universal the drill, the better. Sizes of burs vary according'to need (discussed in specific chapters). The "suction irrigation" feature is c o m m o n l y used today. Drills with continuous irrigation (variable FIGURE 6 - 8 . flow) are available, and are useful in avoiding drilling The eyepiece angles (IF A microscope. over "dry bone," which promotes overheating and necrosis. The authors prefer to use intermittent irrigation with a bulb syringe to provide moisture as In spite of the many theoretical advantages of fully needed, thus avoiding the visual distortion that oca u t o m a t e d microscopes (except for their price), the curs with "underwater drilling." Again, the purpose classic Zeiss OPM1-1 or one of its equivalents (for is to avoid heating and necrosis of bone; that is best e x a m p l e , Vasconcellos) allows better maneuverability achieved in a m a n n e r that is efficient for the surgeon. and is less c u m b e r s o m e to operate in ear surgery. Good suction is essential. The tubing should be Again, this is a matter of preference; the point is flexible, soft but not collapsible, and not too rigid, m a d e because it is not unusual for the "starting so that it is easy to handle. A No. 5 suction tip is surgeon in practice" to be talked into buying a fully used for cleansing the ear canal, a No. 20 for raising a u t o m a t e d , "state of the a r t " piece of equipment. flaps and for middle ear work, and a N o . 24 for work T h e position of the microscope is essential. The in the oval window. The authors prefer fenestrated a r m s should be at a 90-degree angle, which permits urnmiit

I

Operating R o o m Principles and General C o n c e p t s

109

FIGURE 6 - 1 1 . A disposable sterile plastic drape has been used with this microscope, which has a video camera attached.

handles, which allow control of the degree of suction;

Instruments bearing the e n d o r s e m e n t of a particular

some surgeons prefer to control the d e g r e e of suction

surgeon

with a

c o n s i d e r e d for acquisition; h o w e v e r ,

foot c o n t r o l .

For drilling, larger suction tips

provide a

sense of security and

should be

they represent

are u s e d ( N o . 7 to N o . 9 F r e n c h ) . A s y r i n g e for f o r c e d

the p r e f e r e n c e of that s u r g e o n a n d m a y not n e c e s -

irrigation, as well as a wire to clean the s u c t i o n tip,

sarily m e e t y o u r n e e d s .

should be available.

Small

sponges or cotton

balls

Operating room cards d e s c r i b i n g t h e i n s t r u m e n t s

s h o u l d b e u s e d a t t h e s u c t i o n tip w h e n w o r k i n g o v e r

and

grafts o r p r o s t h e s e s that c a n b e l o o s e n e d o r d i s l o d g e d

dures

by the suction.

j o b s easier a n d m o r e effective. Ear i n s t r u m e n t s pref-

since

it

is a

( C o t t o n m u s t n o t b e left i n t h e e a r

guarantee

of

infection.)

The authors'

materials

erably

should are

required

for different surgical

be available.

placed

in

a

They

rack

make

and

proce-

the

nurses'

numbered

in

the

usual i n s t r u m e n t s e t u p is s h o w n in Figures 6 - 1 2 a n d

order in

6-13.

straight canal knife. N o . 2 curved canal knife, No. 3

S t a n d a r d c a u t e r y u n i t s will not b e d e s c r i b e d ; suffice it

to

mention

m o n o p o l a r unit,

duckbill elevator, and so on. If the scrub and circut e e " b e l i e v e s t h a t n u r s e s c a n b e " j a c k s o f all t r a d e s , " it is

( b e s i d e their

units

should

be

and clipped to the drapes, allow

easy

handling

but

both the suction

adequately

positioned

with sufficient length to short

enough

to

prevent

contamination if the units are d r o p p e d (Fig. 6 - 1 4 ) . A

variety

of

1

lating nurses rotate or the operating r o o m " c o m m i t -

routinely

a bipolar unit s h o u l d be available, cautery

No.

for c a s e s o f a c o u s t i c n e u r o m a

the authors

o r i n w h i c h w o r k i s t o b e d o n e n e a r t h e facial n e r v e and

they are used—for example,

use a

that

but

which

instrument

sets

are

commercially

useful

plasticized,

to

print

the

names

numbers) and

describing

operating

instruments table a

'sterilizable" card listing the n a m e s a n d

positions of instruments and cards

of the

to place on the

room

the

materials. In addition,

position

should

be

of

taped

the to

team the

in

wall

the in

a

clearly visib'e place.

available. S i n c e the p u r p o s e of this atlas is descriptive and

not

promotional,

the

authors'

specific

prefer-

e n c e s are not listed; t h e y will b e s e n t u p o n r e q u e s t . It is important to acquire quality i n s t r u m e n t s , partic-

Record of Operation

ularly for w o r k i n s i d e t h e e a r . A p p a r e n t s a v i n g s f r o m buying cheaper but poorly m a d e instruments can be illusory.

Instruments arc designed

poses and should be

for specific

pur-

purchased with them in mind.

As

important

as

describing

describing what was found,

what

was

done

is

preferablv with a draw-

Operating Room'Principles and General C o n c e p t s

111

FIGURE 6 - 1 4 . Suction tip and cautery "hanging" in the operating field. They are not left in this position during surgery; this figure simply shows that if clipped correctly, the suction tip and cautery will not become contaminated if they fall.

i

ing. Problem areas should be noted; such records are useful in evaluating prospective causes and factors in both failures and successful results. A stamped or printed drawing or diagram in the operative description is useful. Packing techniques are described in specific sections and will not be discussed here. Illustrations of h o w to apply an oval eye pad (Figs. 6 - 1 5 to 6 - 1 7 ) and a mastoid dressing (Figs. 6 - 1 8 to 6 - 3 0 ) are included, as well as two photographs showing the application of ointment with a rubber-tipped syringe (Figs. 6 - 3 1 , 6 - 3 2 ) .

Surgical

Time $

It is i m p o r t a n t to develop surgical techniques and habits that fellow a systematic and efficient use of time, but c o m p l e t e n e s s and thoroughness are equally essential. In^ measuring success, results have more weight than speed. W o u l d y o u prefer to be operated on by a s # g e o n w h o is rushing to "finish the schedule" of by one w h o is more concerned about finishing o n l y when his or her purposes of helping you have be;?n surgically achieved? I

FIGURES 6 - 1 5 to 6-17. Placement of an ova] eye pad

Operating Room Principles and General Concepts Operating Room Principles and General Concepts

113

114

Operating Room Principles and General Concepts


FIGURE 6-20.

FIGURE 6-22.

FIGURE 6-23. FIGURE 6-21.

-------.-----~--

115


117

118

Operating R o o m Principles and Genera! C o n c e p t s

Operating Roojn Principles and General C o n c e p t s i

119

Operating Room Principles and General C o n c e p t s

FIGURE

6-32.

CHAPTER 7 Surgical Approaches to the External Ear Canal and Middle Ear This chapter describes basic general principles underlying the possible alternative approaches to the external ear canal and middle ear. It is obvious that the approach selected will depend upon the type of procedure planned, the needs of exposure, and the surgeon's preference or ability. Specific approaches are described in the chapters in Section IV; however, since these basic principles apply partly or totally in those approaches, they are described separately here in order to avoid repetition. Three alternative approaches are available to gain access to the external ear canal and middle ear: the transcanal, the endaural, and the postauricular (Fig. 7 - 1 ) . In all three approaches, all surgical steps are equally important and should be done methodically and carefully, from preparing the patient, draping, and positioning, to applying the last piece of tape to the dressing. Meticulous care should be observed. The procedure is not finished when the flaps are repositioned; it is finished when the ear is healed. All steps, including postoperative care, are essential for proper healing.

Transcanal Approach Highlights 1. Adequate visualization. 2. Completion of incisions (all the way through).

3. Elevation of an intact flap. 4. Entrance into the middle ear beneath the annulus. 5. Meticulous anatomic repositioning of the flap. 6. Careful packing.

Pitfalls 1. tion. 2. 3. 4. 5. 6.

Operating in a small space without visualizaTearing the flap or tympanic membrane. Suctioning the flap. Making superficial incisions. Entering the middle ear above the annulus. Selecting an inadequate approach.

Inspection

and

Cleansing

O n c e the patient has been adequately positioned and the ear has been sterilely prepared and draped, the canal and tympanic membrane are inspected with an ear speculum. An oval, anteriorly beveled, nonreflecting speculum of the largest possible size is used. Too small a speculum provides inadequate vision and is too loose; too large a speculum causes folds in the ear canal that obstruct vision and macerate the skin. The correct size allows satisfactory vision and sufficient tightness to allow bimanual exploration.

Surgical A p p r o a c h e s to the External Ear Canal and Middle Ear Surgical Approaches to the External Ear Canal and Middle Ear The narrowest portion of the external ear canal is medial to the junction of the bony and cartilaginous canal; it is at this point that placement of the speculum is critical. The canal is carefully cleansed with ring curets, suction (No. 5), or both. The skin and tympanic membrane are carefully visualized, and the size of the canal is appreciated. This visualization is very important, since the surgeon should first think in of anatomy. W h a t e v e r needs to be done in the middle ear is done best with adequate exposure. Again, positioning of the patient and the surgeon plus adequate angulation of the arm of the microscope are essential. It is a good idea to gently irrigate the canal (with either saline or alcohol).

Injection of Local Anesthetic Injection of the anesthetic is a skill to be mastered by all means. It is a crucial step that decides if the procedure will be done in a clean, dry field or in a field obstructed by blood and offering inadequate vision. A local anesthetic with vasoconstrictor is used, usually lidocaine 2% with 1:100,000 epinephrine. Alternative anesthetic agents (owing to allergies, desire for a longer-lasting effect, or other reasons) or different concentrations of epinephrine are acceptable, but maximum doses must be kept in mind in order to avoid toxicity or cardiovascular effects, or both. A syringe affording ease of injection (for example, Carpule) is preferred. A 27- or 30gauge needle is used. A nasal speculum is used for initial injections into the four quadrants of the cartilaginous canal (Fig. 7 - 2 A ) . The bevel of the needle is placed parallel to the surface of the underlying cartilage (or bone), and injection is done very slowly in order to avoid blebs. (If a small bleb is formed, it can be punctured with a needle.) With slow injection under direct vision infiltration and blanching of the skin can be clearly noted; thus the necessary a m o u n t of anesthetic can be easily decided. With the aid of an ear speculum, additional injections are done, if needed, into the bony canal under direct vision until blanching of the skin is observed. The skin of the osseous canal is thinner than that of the cartilaginous portion; it is usually simpler and safer to inject into the cartilaginous portion, allowing the injected solution to "dissect its way toward the annulus." On occasion, under local anesthesia a facial paralysis becomes evident at this point. This denotes a dehiscent facial nerve, which should completely recover.

123

Incisions With the speculum tightly in the canal and the surgeon working with two hands, the incisions are m a d e . A Paparella No. 1 straight canal knife or sickle knife is used for the first incision at 12 o'clock in a direction straight toward the surgeon (Fig. 7 - 2 B ) . A second incision is m a d e at 6 o'clock, curving toward the vertical incision; this curved incision can be made with a curved canal knife. The length of the flap (distally from the annulus to the horizontal incision) may vary, as well as the location of the vertical incision. In a routine stapedectomy a 6-mm flap should suffice, whereas in a more extensive exploration with a small atticotomy, or if extensive bony canal is to be removed, an 8-mm flap might be necessary. If the canal is wide, a large flap extending even to the cartilaginous canal can be used, since folding it anteriorly will not obscure vision or result in a tight space with no room to work. The length of the flap is then determined by m e a n s of exposure and size of the canal. If attic disease or fixation of the head of the malleus is suspected, a wider flap is elevated, and the vertical incision is m a d e at the 1 or 3 o'clock position in order to provide a flap of sufficient size to cover the defect easily. If more extensive surgery is anticipated, an endaural incision is used. When making the incision, the underlying bone should be "felt" with an instrument, even to the point of producing a sound, to make certain that the skin is completely sectioned. The junction of the skin with the annulus, at 12 or 3 o'clock, is usually thicker and richer in connective tissue. Complete sectioning of this area is very important; a Bellucci scissors is very helpful for this purpose. No attempt to lift flaps or gain entrance into the middle ear should be made until the incisions are completed and the skin flaps are free.

Elevation

of Flaps

With the skin edges free, the surgeon takes his or her finger off the hole of the suction tube and holds the speculum and suction in the left hand (for a right-handed surgeon) (Fig. 7 - 2 C ) . This helpful technique is not difficult to master, and with an adequately s h e d speculum obviates the need for a speculum holder. The latter is a useful instrument, the most widely used design being the classic Shea

Surgical Approaches to the External Ear Canal and Middle E a r speculum holder; other designs are modifications incorporating surgeons' various preferences. With the use of a flat elevator, preferably a duckbill or large curved canal knife, the skin is gently separated from the underlying bone (Fig. 7 - 2 D ) . Special care must be observed when a prominent tympanomastoid suture is present; simply lifting the skin will cause tears in the flap. A smaller sharp instrument (for example, a No. 1 straight knife or sickle knife) is helpful in releasing connective tissue attachments. Separation must be slow and careful in order to preserve the flap intact. The suction tip (finger off the hole) is used behind (posterior to) the elevator. The skin is elevated evenly, avoiding tunneling, and the flap is elevated until it reaches the annulus. At this point, greater magnification may be used (for example, 16 x) in the microscope. All bleeding must be controlled, and entrance to the middle ear should be "dry." A No. 20 suction tip is preferred for the middle ear. Small sources of bleeding can be stopped using "Adrenalin tape." Occasionally cautery is needed; however, it is preferable to avoid any edema or necrosis, such as that caused by cauterization, in these thin flaps.

FIGURE 7-2.

The middle ear is entered beneath the annulus with a duckbill or curved canal knife (Fig. 7 - 2 E ) . If there is adequate visualization, the site of entrance is not crucial; in general, however, it is preferable to enter interiorly toward the round window rather than toward the ossicles. O n c e the annulus is separated, a d r u m h e a d elevator is introduced and the annulus is gently lifted by a sweeping motion from 6 to 12 o'clock through the whole extent of the exposed annulus. The chorda tympani should be gently and carefully moved out of the field of vision; if this would stretch it, the best course is simply to cut it with a Bellucci scissors (Fig. 7-3A, B). In cases in which adhesions or thickened mucoperiosteum obscure visualization of the middle ear structure, it is imperative to enter the middle ear cautiously and systematically. Avoiding d a m a g e , particularly to ossicles (or their remnants) or an exposed facial nerve, is crucial. The cavity is entered inferiorly, where the round window niche area is found; from there the surgeon works toward the ossicles. If they are still obscured, or if the a n a t o m y is (or seems) distorted, a small atticotomy is done. The head of the malleus and body of the incus (which usually are present even if extensive ossicular erosion has occurred) are identified, and the dissection is started from this point. (Beware of the tensor tympani area, where the facia] nerve might be dehiscent.) The chorda tympani can also serve as a guide to follow. Whatever the choice, thickened tissue should not be removed blindly.

125

Exposure of the Middle Ear The middle ear is visualized and the mucosa as well as the different anatomic structures are identified before any planned procedure is begun (Fig. 73C). Methodical evaluation of the cavity is good practice. This includes evaluation of ossicular mobility, which is done by mobilizing the long process of the malleus with a d r u m h e a d elevator or t knife (Fig. 7 - 3 D ) , followed by palpation of the incus and stapes (Fig. 7 - 3 E ) . Testing the mobility of the stapes includes the footplate, not the head alone. If m o r e complete exposure of the oval window is needed, the posterior canal wall should be curetted. The tip of the curet should always be in view. A sharp curet that is as large as possible should be utilized. An angled curet is used to remove the bone of the posterior canal, including the area of the scutum. In general, it is better to curet from 12 to 6 o'clock in order to avoid accidental dislocation of ossicles. The curet should not be used in a perpendicular fashion. Special time should be dedicated to completely removing bone fragments, which if left in the middle ear stimulate localized tissue reaction and make the cavity prone to infection. Again, for good visualization it is important to position the patient appropriately, with the surgeon and microscope in the correct position as well.

Closure Upon completion of middle ear work (procedures are described in specific chapters), the flaps are repositioned. At the same time, they are carefully cleansed, fraed of debris with thin suction tips, a t knife, or both, and examined for tears. The tympanic membrane also is examined for small punctures or lacerations; if any are present, their edges are closely approximated, and small pieces of Gelfoam are used to cover them. The paramount consideration, requiring great care, is anatomic position. The fact that flaps shrink initially must be taken into .

Revisions Ideally, previous reports should be available. Revisions shoi'ld be approached as a "box of surprises" from beginning to end. The main points to keep in

Surgical A p p r o a c h e s to the External Ear Canal and Middle E a r Surgical Approaches to the External Ear Canal and Middle Ear mind are that flaps are quite thin and tear easily, and that bony defects of the ear canal are to be expected. Careful incisions and elevation are used. Adhesions are c o m m o n and should be sectioned carefully and sharply in order to avoid tears. Repositioning of the flaps should be carefully done and anatomically adequate; adequate packing is of the utmost importance as well.

Packing

FIGURE 7-3.

Alternatives to packing exist, depending upon the particular case and the surgeon's preference. They are all satisfactory and will work if done correctly. Different materials can be utilized; if used properly, m o s t of them suffice. Excessive pressure must be avoided. Antibiotic or steroid ointments or solutions, or both, are useful in preventing localized inflammation and infection. Only the most c o m m o n packing techniques will be mentioned. 1. A basket is fashioned from surgical rayon or Owen's silk strips moistened with antibiotic or steroid ointment. Cotton soaked in antibiotic solution fills the space, and the silk is used as a rosebud packing. A 1/2-in gauze pack with antibiotic ointment is placed in the lateral third of the canal (Fig. 7 - 4 A C). This type of packing provides adequate pressure to keep the flaps flat, but not enough to d a m a g e them. It should be removed at intervals of one week for the gauze and two weeks for the rosebud; if left for a longer period granulation tissue invades the silk, making it difficult if not impossible to remove it by simply pulling. 2. The canal is filled with Gelfoam soaked in antibiotic solution. It is placed initially in layers, with Gelfoam strips covering all areas of incision. The lateral aspect of the canal can be filled with ointment, or a piece of sterile cotton can be placed (Fig. 7 - 4 D ) . The disadvantage of this method is that it takes a long time for the Gelfoam to c o m e out spontaneously; thus removal must be done very carefully in order to avoid flap disruption. Gelfoam promotes granulation. This type of packing m a y require the use of otic drops or ointments. 3. The canal is filled with an antibiotic ointment as the sole packing, and a piece of cotton is placed in the meatus (Fig. 7 - 4 E ) . This method of packing requires perfect approximation of intact flaps. 4. The incisions are completely covered with compressed, dry Gelfoam in strips, and a flat, round piece of Gelfoam is placed over the tympanic m e m brane. Ointment is then inserted into the canal through a syringe with an 18-gauge needle (Fig. 7-

127

4 F ) . Gelfoam provides some stimulation for granulation, favors healing, and discourages maceration of the skin flaps.

Canalplasty in Exploratory Tympanotomy If the canal is small or "tight" owing to thick skin or anterior "bony overhang that prevents satisfactory visualization despite adequate approach and positioning, a canalplasty becomes a very useful procedure (Fig. 7 - 5 ) .

Highlights 1. Before performing a canalplasty: A. E n s u r e that the approach is the best one. B. E n s u r e that the positioning of the patient and surgeon is adequate. 2. Use curets as needed. 3. Protect the anterior w i n d o w shade flap. 4. Drill the anterior wall carefully. 5. Carefully remove all debris.

Pitfalls 1. Drilling the skin flaps. 2. Exposing the temporomandibular t capsule anteriorly. 3. Inadequately removing bone dust and debris, which leads to inflammation and infection.

Procedure An anesthetic and vasoconstrictors are injected into the anterior wall. The purpose is to expose the bony canal and safely r e m o v e as much bone as needed for adequate exposure. This can be accomplished with an "anterior window shade" with a horizontal c o m p o n e n t and two vertical limbs; the vertical limbs preferably should not involve the vascular strip. The horizontal incision can be m a d e medially or laterally—that is, immediately above the annulus or at the bony cartilaginous junction. In the medial horizontal incision, the skin is gently elevated laterally as a flap with a duckbill elevator or curved

Surgical Approaches to the External Ear Canal and Middle Ear

Surgical A p p r o a c h e s to the External Ear Canal and Middle Ear

FIGURE 7-4.

F I G U R E 7-5.

130



canal knife, and gently rolled anteriorly (Fig. 7 - 5 A , B,). This skin is very thin and tears easily; thus lifting must be done carefully. In the lateral horizontal incision, a flap is developed inferiorly until it reaches the annulus (Fig. 7 - 5 C , D). Before drilling, the surgeon must ensure that the flaps are safely flattened in order to avoid drilling them. It is a good idea to cover them with a strip of O w e n ' s silk for added protection; if the flaps are touched by the drill bit, the silk will be trapped. A drill bit large enough to be safe but small enough to leave room for drilling should be used; it can be supplemented with curets as needed. Proper use of curets should be learned; they are safe and very effective. Enough bone should be removed to permit visualization of the anterior annulus. Care must be taken to avoid entering the temporomandibular t anteriorly. If the temporomandibular t is entered despite these precautions, a small defect may be created that is extracapsular; if this is the case, no particular coverage is needed except for the flap. In obtaining satisfactory visualization of the entire annulus, it should be ed that adequate positioning of the patient's head, and of the surgeon, will avoid unnecessary drilling. Exposure of posterior mastoid cells is not a major problem; they should be adequately covered with the skin flap. O n c e the entire bone work has been done, time should be allotted for complete removal of bone fragments in order to prevent local tissue reaction and possible infection. The flaps are completely elevated posteriorly; the anterior flap ("window shade") is anatomically repositioned and all bleeding vessels are controlled (Fig. 7 - 5 E ) . Then, and only then, can the middle ear be entered.

Endaural Approach Highlights 1. Same as with the transcanal approach. 2. Control bleeding before entering the middle ear. 3. Position the two-prong retractors properly and carefully.

Pitfalls 1. Same as with the transcanal approach. 2. Exposing or damaging the helix with a Lempert 11 incision.

3. Inadequately packing and positioning the flap i, resulting in adhesions or stenosis. The endaural approach can be used for an exploratory t y m p a n o t o m y , a tympanoplasty, and a mastoidectomy, and is particularly useful and safe (or revision surgery. It is useful, as well, for "tigr^" canals and canals with thick skin. This a p p r o a c a utilizes different sizes of incisions according to n e e c , varying from a minimal to a large Lempert II incision (described below). It is insufficient for large mastoid cavities and does not provide a good view of the anterior annulus unless a canalplasty is done. Position, inspection, and cleansing are done as i i transcanal procedures. Injection of local anesthefcc with vasoconstrictors is similar as well, except thct additional injections are made between the tragus and helix (at the incisura) and immediately antericr to the helix (Fig. 7 - 6 A ) . The endaural approac l avoids the use of an ear speculum and provides a direct view of the middle ear.

Incisions For purposes of exposure, it is best to use a curved nasal speculum. Incisions are made with a scalp-'l. The first incision (Lempert I) is made semicircumferentially between 6 and 12 o'clock on the poster or wall at the bony cartilaginous junction (Fig. 7 - 6 >')• This incision must extend down to the bone. T >.e second incision (Lempert 11) runs between the trag JS and helix and incisura; care must be taken not 'O expose or cut the helix. The extension of this incisi >n depends upon the degree of exposure needed, varying from a few millimeters (for an exploratory tympanotomy) to a full 3 . 4 cm (for a mastoidectom ). This incision is made in the ear. Caution must ie exercised not to deepen it immediately after going through the subcutaneous tissue, since branches' :>f the superficial temporal artery and vein are prese it in this area; too deep a cut also may section t ' i e temporal fascia, which might be needed for grafting purposes. It is important to completely section the connective tissue and to expose the bony canal at t! ie level of the incisura, allowing more space. Snv 11 bleeding vessels are cauterized. The remaining posterior canal skin (cartilaginous portion) is preserved and gently elevated with a small periosteal e l e v a t e , leaving the whole posterior bony canal clearly e ;posed (Fig. 7 - 6 C ) . On occasion, a small free sk'n graft can be taken safely from this area. Two tw..prong retractors are used for exposure. It is useful o position them at right angles to each other, one 1

FIGURE 7 - 6 .

131

130



canal knife, and gently rolled anteriorly (Fig. 7 - 5 / 4 , B,). This skin is very thin and tears easily; thus lifting must be d o n e carefully. In the lateral horizontal incision, a flap is developed inferiorly until it reaches the annulus (Fig. 7 - 5 C , D). Before drilling, the surgeon must e n s u r e that the flaps are safely flattened in order to avoid drilling them. It is a good idea to cover them with a strip of Owen's silk for added protection; if the flaps are touched by the drill bit, the silk will be trapped. A drill bit large enough to be safe but small enough to leave room for drilling should be used; it can be supplemented with curets as needed. Proper use of curets should be learned; they are safe and very effective. Enough bone should be removed to permit visualization of the anterior annulus. Care must be taken to avoid entering the temporomandibular t anteriorly. If the temporomandibular t is entered despite these precautions, a small defect may be created that is extracapsular; if this is the case, no particular coverage is needed except for the flap. In obtaining satisfactory visualization of the entire annulus, it should be ed that adequate positioning of the patient's head, and of the surgeon, will avoid unnecessary drilling. Exposure of posterior mastoid cells is not a major problem; they should be adequately covered with the skin flap. O n c e the entire bone work has been done, time should be allotted for complete removal of bone fragments in order to prevent local tissue reaction and possible infection. The flaps are completely elevated posteriorly; the anterior flap ("window shade") is anatomically repositioned and all bleeding vessels are controlled (Fig. 7 - 5 E ) . Then, and only then, can the middle ear be entered.

Endaural Approach Highlights 1. Same as with the transcanal approach. 2. Control bleeding before entering the middle ear. 3. Position the two-prong retractors properly and carefully.

Pitfalls 1. Same as with the transcanal approach. 2. Exposing or damaging the helix with a Lempert II incision.

3. Inadequately packing and positioning the flap i, resulting in adhesions or stenosis. The endaural approach can be used for an exploratory tympanotomy, a tympanoplasty, and a mastoidectomy, and is particularly useful and safe tor revision surgery. It is useful, as well, for "tigHj?" canals and canals with thick skin. This a p p r o a c a utilizes different sizes of incisions according to n e e c , varying from a minimal to a large Lempert II incision (described below). It is insufficient for large mastoid cavities and does not provide a good view of the anterior annulus unless a canalplasty is done. Position, inspection, and cleansing are done as :i transcanal procedures. Injection of local anesthetic with vasoconstrictors is similar as well, except thct additional injections are m a d e between the tragus and helix (at the incisura) and immediately antericr to the helix (Fig. . 7 - 6 / 4 ) . The endaural approac 1 avoids the use of an ear speculum and provides a direct view of the middle ear.

Incisions For purposes of exposure, it is best to use a curved nasal speculum. Incisions are m a d e with a scalp.'l. The first incision (Lempert 1) is made semicircumforentially between 6 and 12 o'clock on the poster or wall at the bony cartilaginous junction (Fig. 7 - 6 i). This incision must extend down to the bone. T le second incision (Lempert 11) runs between the trag js and helix and incisura; care must be taken not ro expose or cut the helix. The extension of this incisi >n depends upon the degree of exposure needed, varying from a few millimeters (for an exploratory tympanotomy) to a full 3 / 4 cm (for a mastoidectonv ). This incision is made in the ear. Caution must te exercised not to deepen it immediately after going through the subcutaneous tissue, since branches'of the superficial temporal artery and vein are presc it in this area; too deep a cut also may section t'ie temporal fascia, which might be needed for grafting purposes. It is important to completely section the connective tissue and to expose the bony canal at tlie level of the incisura, allowing more space. Srmll bleeding vessels are cauterized. The remaining posterior canal skin (cartilaginous portion) is preserved and gently elevated with a small periosteal e l e v a t e , leaving the whole posterior bony canal clearly e:posed (Fig. 7 - 6 C ) . On occasion, a small free skm graft can be taken safely from this area. Two twuprong retractors are used for exposure. It is useful o position them at right angles to each other, one

FIGURE 7 - 6 .

132


pointing cephalad (superiorly) and the other caudad (posteriorly); this provides better exposure and stability and is less inconvenient for the surgeon. Temporal fascia is harvested at this point (discussed in Chapter 12) and all bleeding vessels are controlled. With the scalpel, incisions can be m a d e at 6 and 1 or 2 o'clock (Fig. 7 - 6 D ) . These incisions allow for easier development of the flap; however, the flap can be elevated without the incisions. The flap is elevated in the same manner as in a transcanal incision. The same principles and technique also apply for a canalplasty.

Closure The flap is repositioned anatomically; particular attention is paid to repositioning the skin, which must cover the cartilaginous canal. Subcutaneous tissues are approximated with interrupted absorbable sutures (for example, 3 - 0 chromic catgut). Approximation does not need to be very tight at the incisura. Skin is approximated with absorbable 4 - 0 silk or nylon sutures. The first skin suture should be at the incisura; as in other ear incisions, there is remarkably good healing in this area. Packing is done as in transcanal procedures for the bony canal; however, it is best to use 1/2-in g a u z e impregnated with antibiotic or steroid ointment in the lateral third (cartilaginous canal), followed by a mastoid dressing. The gauze and the skin sutures are removed one week after the procedure. At this time the authors usually fill the space with antibiotic ointment for one additional week.

Postauricular Approach Highlights 1. S a m e proaches.

as

for

transcanal

and

endaural

ap-

2. The postauricular incision should be made plane by plane. 3. The canal should be reached in the "avascular" plane. 4. Cleansing of all debris should be done carefully.

Pitfalls 1. Tearing of the canal with the three-prong retractors.

2. Inadequately wound infection.

Surgical Approaches to the External Ear Canal and Middle Ear cleansing

debris,

learing

to

The postauricular approach can be used for an exploratory t y m p a n o t o m y , a tympanoplasty, and a mastoidectomy. It provides a good view of he anterior rim of the annulus, unless there is a prr^ ninent bony o v e r h a n g or a "tight" canal; h o w e v ^ iti is useful for dealing with these t w o problems as we I. Position, inspection, and cleansing are done in transcanal and endaural procedures; however, patient preparation and shaving of hair is different (see Chapter 6 ) . Injection of a local anesthetic is similar to the transcanal procedure, as far as the a n a l is concerned; however, a postauricular injection s necessary in the whole area w h e r e the incision i< to be m a d e , as well as in the posterior aspect of the canal from behind. It is useful to lift the auricle, 7ull it forward, and inject posteriorly, while feeling the tip of the needle and the flow of anesthetic and vasoconstrictors with the index finger placed in th* meatus of the canal; this maneuver ensures arVquate injection.

Incisions The classic incision is m a d e 3/4 cm behind the posterior sulcus, with the inferior end dev ating posteriorly. In children, the incision is higr and posterior with the inferior limb far posterioi since the facial nerve can be very superficial in its exit at the stylomastoid foramen (because of lack of development of the mastoid tip). For cosmetic pu poses the incision can be made in the crease itself, I ut the cosmetic advantage is relative; this location lends itself to minor healing problems, small epic ermal cysts, and so on. An additional incision that an be made is the posterosuperior ( P o r t m a n n ) , whu h is a compromise between the posterior incision at d the anterosuperior ( H e r m a n n ) incision. (In spite of its good exposure, the latter is not used because -i m a y lead to necrosis of the helix.) The posterosu ?erior incision provides excellent exposure.

Procedure

The Incision is m a d e with a scalpel and deepened perpendicularly through subcutaneous tissues without advancing too far. The purpose is to read i the musculo-aponeurotic or "avascular" plane. C a i t e r " can be used for bleeding vessels. If the planet ar<'

developed carefully, large branches of the posterior auricular artery usually will not be sectioned; if this does occur, it is best to tie them with a nonabsorbable suture. Many surgeons use cutting cautery in the skin, which is effective in of surgical time and dryness of the field. However, this must be weighed against the disadvantage of skin healing secondary to a cutting cautery burn. If the right plane is reached, the auricle is pulled anteriorly (forward) and the cartilaginous canal is identified, as well as the spine of Henle. (At this point the temporal fascia can be harvested; this is discussed in C h a p t e r 12.) O n c e this is done, the connective tissue plane behind the cartilaginous canal can be developed sharply and safely. All bleeding vessels, if there are any, should be controlled. Elevating the plane toward the zygomatic root gains room to mobilize the auricle forward (anteriorly) easily (Fig. 7 - 7 A ) . A circumferential incision is made at the bony cartilaginous junction posteriorly, as in ' the endaural procedure. (We are discussing exploratory approaches alone; other types of flaps for other purposes—for example, Korner's—will be dealt with later.) A piece of twill tape ed gently through the incision ensures that the skin of the meatus posteriorly is not torn when using a retractor, and at the same time serves to keep this flap out of the field of vision (Fig. 7 - 7 B ) . With the use of a three-prong Wullstein retractor, the auricle (pinna) is gently pulled anteriorly with the posterior cartilaginous canal, protected by the twill tape (Fig. 7 - 7 C ) . Care must be taken not to tear this skin and cartilage. If a Wullstein retractor is not large enough, a modified Schuknecht three-prong retractor is used. (This is usually necessary in a mastoidectomy but u n c o m m o n in exploratory procedures.) From this point on, the same procedure is followed as in endaural or transcanal incisions. Closure is preceded by careful removal of debris. The packing of the bony canal is similar to that in other approaches; the lateral aspect of the canal (cartilaginous) is packed as in the endaural approach. Postauricular closure is done with interrupted absorbable sutures for subcutaneous tissues (for example, 3-0 chromic catgut). This layer should be approximated carefully; otherwise, the pinna may lack adequate subcutaneous and show a tendency to project anteriorly. Skin is approximated with interrupted, nonabsorbable silk or nylon. Some surgeons close the skin with 4-0 catgut sutures; although this method may be adequate, the authors do not use it. A mastoid dressing is applied. Removal of sutures and packing is done as in the endaural approach.

133

Simple Mastoidectomy as a Surgical Approach A simple mastoidectomy is described here as a general surgical a p p r o a c h for different procedures; it is discussed as a specific procedure in Chapter 5. Mastoid procedures for chronic otitis are described separately in Chapter 10.

Aim Exenteration (removal) of all mastoid air cells while maintaining the integrity of the posterior canal.

Highlights 1. Skin incision is performed with the scalpel perpendicular to the skin. 2. Incision should be deepened in layers. 3. Careful elevation of intact periosteum should be done. 4. Retractors must be adequately positioned. 5. Complete exposure of landmarks is important. 6. Carefully close in layers.

Pitfalls 1. 2. 3. 4.

Tearing of the skin of the posterior ear canal. Inadequate exposure. Injuring a high sigmoid sinus. Injuring the facial nerve by going: A. Deep to the horizontal semicircular canal. B. Too far anterior in the digastric ridge. 5. Dislocating the incus by drilling blindly into the antrum area. 6. Exposing the dura mater. 7. Drilling the semicircular canals.

Positioning, patient preparation and draping, and injection have already been discussed. As described in previous chapters, a classic postauricular incision will be used, starting at the level of the linea temporalis and following the contour of the external meatus to turn posteroinferiorly at the level of the mastoid tip.

Surgical Approaches to the External Ear Canal and Middle E a r

Incision and Exposure

Intraoperative

135

Complications

or Problems Before initiating postauricular work, it is a good idea to place a piece of sterile cotton in the canal in order to avoid accumulation of debris and bone dust. T h e incision is m a d e in layers with a scalpel held perpendicularly to the skin. Subcutaneous vessels are cauterized. A plane between the musculo-aponeurotic layer a n d connective tissue is reached by sharp dissection, a n d developed. It is possible in this plane to avoid damaging branches of the posterior auricular artery; if d a m a g e does occur, it is better to ligate than to cauterize them. T h e periosteum is identified a n d sectioned, following the c o n t o u r of the external e a r canal. Vertical incisions at 45-degree angles are m a d e at 6 and 12 o'clock (toward the linea temporalis and toward the mastoid tip) (Fig. 7-SA). The intact periosteum is elevated carefully, using periosteal elevators. This is important for closure, since re-establishing the perio s t e u m in position will avoid a marked postauricular depression. As soon as the periosteum is elevated, the landmarks become apparent. It is useful to expose the root of the zygoma; this provides better mobility when positioning the retractors. T w o three-prong retractors are positioned at right angles to one another (Fig. 7 - 8 C ) . Specific surgical steps are described in Chapter 5 (pages 4 5 - 4 7 ) . The discussion here will focus on closure and treatment of intraoperative complications.

Closure

FIGURE 7-7.

Careful washing and thorough removal of all debris a n d bone dust are of the utmost importance in order to prevent postoperative inflammation a n d infection. The retractors are r e m o v e d , and the periosteal flap is repositioned and secured to the posterior canal by nonabsorbable sutures, (f the flap is intact and the approximation is adequate, marked postauricular depression will be avoided. Subcutaneous tissues are approximated with layers of interrupted absorbable sutures (for example, 3-0 or 2-0 chromic catgut), and skin with interrupted nonabsorbable sutures (for example, 4-0 silk or nylon), making sure that the skin and subcutaneous sutures do not overlap. A mastoid dressing is then applied.

1. Facial nerve trauma. 2. Exposure of the dura mater. 3. Drilling of the semicircular canals. 4. Damage to the sigmoid sinus. 5. Dislocation of the incus.

Facial Nerve Trauma. Inadvertent exposure of the facial nerve sheath does not necessarily imply injury to the nerve and requires no treatment. H o w e v e r , if the nerve itself is injured in its course through the fallopian canal, it should be opened for several mil-

limeters to ensure continuity. The nerve sheath should not be opened unless discontinuity of nerve fibers is suspected. Opening of the sheath might allow ingrowth of fibrous tissue, which can compromise nerve regeneration, if discontinuity of fibers exists, they should be apposed cleanly to each other. If the injury is severe and includes maceration, the nerve should be sharply a n d cleanly incised and an endto-end anastomosis performed (see C h a p t e r 18). If the traumatized segment is too broad, nerve grafting should be done. Exposed nerve fibers should be covered in order to avoid ingrowth of fibrous tissue.

They should not be covered with fascia, since fascia provides such ingrowth; materials that discourage fibrous tissbe ingrowth (for example, thin sheets of gold foil) should be used. Facial paralysis that is evident immediately postoperatively may be c a u s e d by intraoperative injury, the effect of local anesthesia, or pressure from packing on a dehiscent nerve. Paralysis from such sources necessitates immediate re-exploration unless the surgeon is certain there is no facial nerve d a m a g e , in which case packing and pressure should be released. Steroids can be argued against, but in this case the authors believe their use m a y be beneficial. Delayed facial paralysis (developing after the patient has recovered without paralysis) requires loosening of the packing and should be treated as Bell's palsy. Exposure of the Dura Mater. Exposure of the dura mater during mastoidectomy can happen at the tegmen (middle cranial fossa dura) and at the posterior cranial fossa dura. Without penetration or rupture of the dura itself, it is of no significance except as a reflection of poor technique. If the dura is torn a cerebrospinal fluid leak will result, with subsequent potential for infection. Small leaks in the middle cranial fossa often cease spontaneously because of the abundant arachnoid that is present. A small piece

Surgical Approaches to the External Ear Canal and Middle Ear of fascia can be used for coverage, after it is ascertained that the surrounding dura is intact. (Remove a few millimeters in each direction.) The fascia can be tucked in place. Larger defects can be closed by using cartilage or bone lateral to the fascia, or both. Intraoperative and postoperative antibiotics are used as in all other complications involving areas or structures beyond the confines of the mastoid or middle ear cavity. Antibiotics that cross the blood-brain barrier should be used; this is an important but frequently overlooked point. Posterior cranial fossa dura has less arachnoid, and leaks there are occasionally quite profuse. As soon as the leak occurs, a large piece of Gelfoam or twill tape is placed over the defect and finger pressure is applied. This is followed by tissue grafting with temporal muscle medially and fascia laterally. The cavity is then covered with large pieces of Gelfoam, and, if necessary, filled u n d e r pressure. If the flow continues, an indwelling lumbar catheter rhay. be placed in order to diminish the cerebrospinal fluid pressure for several days.

FIGURE 7-8.

Drilling of the Semicircular Canals. Damage occurs most commonly at the d o m e of the lateral (horizontal) semicircular canal and occasionally at the posterior semicircular canal w h e n exposing Trautmann's triangle. If the d a m a g e is recognized before injury to the m e m b r a n o u s labyrinth occurs, sealing the fistula with Gelfoam or tissue graft may prevent serious sequelae. Damage to the m e m b r a n o u s labyrinth results in an irreversible disturbance in hearing and balance, except on rare occasions in which previous involvement of the labyrinth has allowed its compartmentalization. Damage to the Sigmoul Sinus. The best way to deal with this problem, as with all other complications, is to avoid it. This can be achieved bv having a good set of preoperative mastoid films that provide information on the location of the sigmoid sinus (for example, "high-lateral," "low-medial," "anterior," e t c . ) , and by developing the mastoidectomy step by step. Ear surgery is not for "racing surgeons." Laceration of the sigmoid sinus results in profuse h e m o r r h a g e . A similar problem can occur with a dehiscent jugular bulb in the h y p o t y m p a n u m . Bleeding can often be stopped by immediate, firm, application of large pieces of Gelfoam and twill tape and by finger pressure, followed by application of oxidized cellulose (oxycel). This in turn is covered by pieces of Gelfoam and fascia if needed. At the end of the procedure, extradural h e m a t o m a should be ruled out. Dislocation of the Incus. This complication entails exploratory t y m p a n o t o m y and repositioning of the

137

incus in its normal anatomic position (see Chapter 11).

Posterior Tympanotomy (Facial Recess) as a Surgical Approach The posterior t y m p a n o t o m y (facial recess) procedure is included here as a general surgical approach for different purposes; aim, highlights, pitfalls, and procedure are described in Chapter 5. Specific indications are discussed in pertinent preceding chapters. Closure is exactly the same as in a simple mastoidectomy. Management of complications also is identical except for those inherent in this specific a p proach.

Intraoperative Complications or Problems Inherent in This Approach 1. Damage to the tympanic membrane. 2. Perforation of the bony external ear canal. Damage» to the tympanic membrane implies a transcanal exploration. The borders of a small tear are cleansed and approximated anatomically and covered with Gelfoam. A larger defect necessitates a graft (to be discussed in Chapter 12). Small perforations of the posterior wall of the bony external ear canal are not significant and need no repair except for adequate coverage with skin flap. Major defects may require posterior wall reconstruction.

Mastoidotomy as a Surgical Approach Aim Visualizing the a n t r u m and establishing (or reestablishing) communication between the mastoid and middle ear cavities. The highlights, pitfalls, technique, and complications of a mastoidotomy are essentially those of a cortical mastoidectomy (see C h a p t e r 5), but the a m o u n t of bone removed is much less. This proce-

Surgical Approaches to the External Ear Canal and Middle 138


dure is performed using a postauricular or endaural approach. Drilling is done in the fossa mastoidea toward the a n t r u m . W h e t h e r the purpose is to rem o v e tissue blockage, improve aeration to the middle ear, or introduce an electrode into the middle ear, the opening should be large enough to allow visualization of the antrum.

2. Effect meticulous hemostasis. 3. Thin the skin flap. 4. Excise conchal cartilage (the cornerstone of meatoplasty). 5. Drill underlying bone (if necessary). 6. Use sutures to keep the meatus open. > 7. Cover all open areas. 8. Postoperative care must be adequate and s e quent. 1

Meatoplasty Pitfalls Meatoplasty is discussed in this chapter as a general concept owing to its practical and often crucial importance in otologic procedures. The meatus consists of skin, subcutaneous tissue, cartilage, and underlying bone. It is essential to consider all of these structures in a meatoplasty; adequate treatment of the soft tissues combined with insufficient attention to the underlying cartilage or bony meatus, or both, might result in an inadequate meatoplasty. Meatoplasty is essential for obtaining a good surgical result in tympanomastoid surgery and in tympanoplasty (when indicated and usually associated with canalplasty). Large canals do not need a meatoplasty. The procedure is used for small canal entrances (openings), whether congenital or acquired (by disease or by surgery). A normal-sized meatus allows for proper aeration and self-cleansing of the canal, and adequate sound conduction. The procedures described here (exemplified for practical purposes in open- and closed-cavity tympano-mastoidectomy) apply in principle to other surgical cases as well. With the understanding that a postauricular and an endaural approach can be used interchangeably, a postauricular approach is described in the meatoplasty for an open-cavity tympano-mastoidectomy, and an endaural approach for a closed-cavity tympano-mastoidectomy. The development of a Korner's flap will be described in the former, as well.

Aim

Highlights 1. Maintain continuity and integrity of the skin flap.

Complications

t. Leaving skin flap with a thin base. 2. Tearing of skin flap. 3. Excessive bleeding. 4. Leaving open areas with granulation formation. 5. Displacing a flap. 6 . Perichondritis. 7. Meatal stenosis.

tissie

M e a t o p l a s t y in O p e n - c a v i t y Tympano-mastoidectomy Since a meatoplasty can cause some bleeding, i can be deferred until the middle ear and mastoic work is completed, grafts are placed, and the dista third of the canal is packed. Meticulous hemostasi: should be exercised. In an open-cavity mastoide': tomv, a Korner's flap is quite useful in providing skin coverage for the newlv created mastoid cavity. The flap is developed by making vertical incisions in the skin of the external auditorv canal at 6 and l' . o'clock with a straight canal knife. They are connected by a horizontal incision made with a curved canal knife at 5 mm from the tympanic annulus (Fig". 7 - 9 A ) . 1 he vertical incisions are then extended to the conchal bowl (Fig. 7 - 9 8 ) . It is important to keep the base of the flap wide at the conchal bowl level. Th«( subcutaneous tissue of the flap is generally quite thick. It can be thinned carefully with a sharp scissors or scalpel, avoiding d a m a g e to the overlying skir 1

(Fig.

To provide a well-epithelialized meatus that is wide enough to aerate the ear canal and allow proper sound conduction and self-cleansing.

and

7-9C).

An opening is considered adequate when (hi surgeon's index finger can be introduced easily into the meatus. For practical purposes, a meatus canno< be made "too wide"; there is always a tendency toward reduction in size (narrowing). In order to keep the meatus open and provide better apposition of tissues for healing, two permanent sutures can be placed, bringing together the subcutaneous layer with the posterior margin of the postauricular incision (Fig. 7 - 9 D ) . It is important to prevent postop-

FIGURE 7 - 9 .

140



erative stenosis by controlling formation of granulation tissue. Clean edges of the flap and good skin coverage of the mastoid bowl are of paramount importance. A Thiersch graft can be performed during the primary procedure for these purposes, or after three weeks if open areas with granulation tissue are present; this should be necessary only occasionally. (See the discussion of the Thiersch graft in this chapter.) A steroid-saturated, firm pack is applied and left in place for two weeks; upon its removal, all granulations (if a n y ) are curetted and/or cauterized, and a steroid-antibiotic ointment is applied. Frequent and meticulous postoperative care is bask to successful healing in meatoplasty and in mastoid cavities in general. An additional point: If a Korner's flap is not used in a postauricular approach, a horizontal incision can be made in the bony cartilaginous junction with two vertical incisions at 6 and 12 o'clock, creating a rectangular flap (Fig. 7 - 9 E ) . With this flap, the basic principles described above apply equally. Other types of flaps can be used according to need, such as a vertical incision, an inverted T, or an inverted Y (Fig. 7 - 9 F ) . Regardless of the flap used, the important point is to provide adequate skin coverage for the newly created surface area, ft is crucial to that the meatus also comprises cartilage and bone; that the flap is an important part, but only a part, of the meatoplasty. Despite a flap that is beautifullv designed "on paper," an inadequate meatoplasty may result because of lack of attention to the underlying subcutaneous tissues, cartilage, or bonv meatus.

M e a t o p l a s t y in Closed-cavity Tympano-mastoidectomv An endaural Lempert I incision is made at a level approximately 7 mm below the mastoid cortex level. A Lempert II incision is made that is large enough to it the surgeon's forefinger freely. The bonv canal, especially the posterior bony canal, is enlarged; conchal cartilage is then removed by carefully everting the conchal skin and using a sharp scissors or scalpel (Fig. 7 - 1 0 ) . Packing, suturing, and postoperative care are identical to those for an open-cavity mastoidectomy.

Management of Pitfalls and Complications A torn skin flap or a flap with poor vascularity due to a thin base may not survive; however, a thin

flap may, behaving for all practical purposes as i skin graft. Lack of flap survival necessitates surgicrl debridement and a Thiersch graft. Excessive bleedin ; may lead to infection or a p p e a r a n c e of granulation tissue, or both; if bleeding occurs underneath th'-' flap, the flap may become medially displaced. An "organized clot" often leads to fibrosis, calling fo • careful elevation of the flap, meticulous hemostasia.. debridement, and tight packing. Fibrosis also can occur when using a tight packing, but there will be no secondary problems, provided that the packing is removed at the proper time (no longer than twe weeks afterward). Management of open areas witl granulation tissue has already been described. On occasion, especially when an infected mastoid h. 'j been dealt with, a perichondritis might occur, cha'acterized by e d e m a , induration, and pain over tr ^ entire pinna. In early stages, the possibility of allergy to the antibiotic ointment or solution must be consic ered. These signs (misnamed "cellulitis") requir • change of antibiotic solution, systemic antibiotic?, daily (at least twice) soaks with Burow's solution cany astringent solution, and application of packing saturated with antibiotic steroid solution. If t l y s y m p t o m s progress (which they rarelv do), debride ment, drainage, and placement of drains m a y be needed. Cultures should be obtained, if possible.

141

Cartilage

If general principles, including adequate follow .'• up, are not observed, meatal stenosis requiring i revision may occur. The meatal skin is carefulh elevated, the underlying bone (which usually dis plays new bone formation, bony spicules, ridges and so on) widelv drilled or curetted, and a largf meatus developed. that for practical pur poses a meatus cannot be made too large, only too small.

RGURE 7-10.

Highlights

Operative

Procedure

Thiersch Graft

Granulation tissue may develop in the mastoid cavity after canal-wall-down mastoidectomy. Drainage may persist from granulation tissue until the entire mastoid cavity is epithelialized. A Thiersch graft is a thin skin graft that helps to epithelialize and eliminate drainage from the mastoid cavity.

1. R e m o v e infected granulation tissue. 2. Harvest thin skin from the upper medial a r m . 3. Cut the skin into proper sizes on Owen's silk. 4. C o v e r the entire non-epithelialized mastoid cavity surface with the skin graft.

Pitfalls Aim

1. Inadequately removing infected granulation tiste.

2. Harvesting too-thick skin. Placing a thin skin graft in the mastoid cavity in order to achieve complete epithelialization.

The procedure usually is carried out under local anesthesia. Local injection of 1% lidocaine with 1 : 1 0 0 , 0 0 0 epinephrine, combined with topical application of 4% cocaine solution soaked in 1/2-in gauze strip, provides adequate anesthesia.

Debridement of Granulation Tissue from M a s t o i d C a v i t y The mastoid cavity is irrigated with warm saline to remove any debris or m u c o p u s . Using c u p p e d forceps, ring c t r e t s , and suction tips, all infected granulation tissue and necrotic tissue is removed;

Surgical A p p r o a c h e s to the External Ea Surgical A p p r o a c h e s to the External Ear Canal and Middle Ear a n y thin, clean, r a w tissue over the bone is left intact (Fig. 7 - 1 1 / 4 ) . Hemostasis is obtained with 1:1000 topical epinephrine (Adrenalin) soaked in 1/2-in g a u z e strip.

Harvesting Thin Skin After the mastoid cavity is cleaned out and while hemostasis is being attained, thin skin is harvested from the medial u p p e r arm. Local anesthesia is obtained with 1% lidocaine with 1:100,000 epinephrine injection. The authors use a razor blade held in a clamp to harvest very thin strips of skin (Fig. 711B). In order to obtain a thin skin graft, the razor blade is pressed d o w n only by the weight of the instrument and a slicing motion is used. The area of the u p p e r arm w h e r e the skin is harvested is m a d e tight by pulling the lateral part of the a r m with the surgeon's free hand. A thin coat of mineral oil o v e r • the skin helps to harvest thin pieces of skin. The area of the mastoid cavity requiring a skin graft determines the a m o u n t of skin to be harvested; the d o n o r site is then dressed with scarlet red or X e r o form gauze dressing. The thin pieces of harvested skin are laid on a piece of O w e n ' s silk impregnated

FIGURE 7-11

FIGURE 7-12.

143

with gentamicin sulfate (Garamycin) ointment, and placed on an upside-down Petri dish (Fig. 7 - 1 1 C ) . E x t r e m e care should be taken to lay the skin on the Owen's silk with the shiny dermis side up. The skin and O w e n ' s silk are then cut into the proper size (usually about 0 . 5 c m ) with a sharp scissors.

S k i n Graft of M a s t o i d Cavity The gauze strips soaked in topical epinephrine solution aê r e m o v e d from the mastoid cavity. The pieces of skin and O w e n ' s silk are placed over the raw tissue|in the mastoid cavity with the dermis side d o w n (toward the bone) a n d the O w e n ' s silk up (Fig. 7 - 1 1 D ) . The entire nonepithelialized surface of the mastoid cavity is covered carefully; slight overlap of c o v e r a g e is acceptable. An eye patch dressing is then applied over the ear.

Postoperative Care The pieces of O w e n ' s silk a r e removed in two weeks. If the skin has taken well, drainage is ended a n d only routine c a r e of the mastoid cavity is required.

Surgical A p p r o a c h e s to the External Ear Canal and Middle Ear 144

145


Pertinent Histopathology FIGURE 7 - 1 2 This section at the level of the footplate shows a dehiscent a n d bulging facial nerve over the stapes crura (the most c o m m o n area of dehiscence). This photomicrograph serves as a reminder of the importance of thorough visualization before any drastic p r o c e d u r e s are performed. T h e facial nerve can be dehiscent in other areas as well, such as adjacent to

the tensor tympani, in the facial recess, and in the medial wall of the anterior epitympanic r< cess. A dehiscent nerve can result in facial paresis or paralysis in cases of acute otitis media, and represents a potential complication in otologic surgical procedures.

FIGURE 7 - 1 3 This section shows a focus of otosclerosis, but m o r e importantly a dehiscent carotid artery (parallel arrows). Although this is u n c o m m o n , there is a risk

in working vigorously and blindly in the eusiachian tube area since complications could be disastrous.

FIGURE 7 - 1 4 This section shows the presence of a persistent stapedial artery immediately medial to the footplate in a middle ear with thickened mucosa and a dehiscent facial nerve. This persistence (representing persistence of the embryonal hyoid artery) ts rare and

should not be confused with a normal small arterial branch that crosses the footplate. Adequate v.sualization and careful dissection are crucial w h e n exploring an ear with chronic disease.

SECTION IV Specific Surgical Approaches

CHAPTER 8 External Ear Canal Procedures Canalplasty A canalplasty is a procedure that normalizes the external auditory canal by removing abnormal bony growth such as exostosis, removing and replacing intractably infected skin of the canal, or enlarging and straightening a severely stenotic and tortuous canal. Meatoplasty m a y be done at the same time.

Aim To restore the normal width and contour of the external auditory canal and, sometimes, to replace diseased with healthy skin.

Surgical Steps 1. 2. 3. 4. 5.

Endaural or postauricular incision. Elevation of canal skin flap. Widening of the bony canal. Placing back the canal skin flaps or skin graft. Packing and closure.

Pitfalls 1. Exposing the temporomandibular t capsule anteriorly.

2. Opening into the mastoid air cells. 3. Damaging the tympanic membrane, ossicles, or skin flaps.

Operative Procedure The procedure usually is carried out under general anesthesia but can also be done under local anesthesia. In either case, local injection of 1% lidocaine with 1:100,000 epinephrine is made into the four quadrants of the external auditory canal. Either an endaural or postauricular approach can be used.

Exostosis Large exostoses can cause retention of cerumen, recurrent inflammation of the canal skin, and even conductive hearing loss. An endaural approach usually is adequate. A posterior skin flap is developed from the bony cartilaginous junction to the annulus of the tympanic m e m b r a n e (Fig. 8 - 1 A ) . The skin over the exostosis is elevated and preserved. W h e n the exostoses are too large to permit a canal incision, a separate incision is m a d e on the top of the exostoses paralleling the annulus of the tympanic membrane. Two skin flaps are developed over each exostosis, one laterally and the other medially based. W h e n the posterior bony canal with exostosis is exposed, the exostosis is drilled out with a cutting bur and diamond bur under continuous irrigation (Fig. 8 - 1 B ) . As the base of the exostosis is removed, the entire tympanic membrane can be visualized and

150

External Ear Canal Procedui External Ear Canal Procedures the canal skin flap becomes better defined. The annulus of the tympanic membrane is left intact, and the middle ear is not entered. The remaining bony canal wall is smoothed down until the canal has a normal, even contour. Any other exostoses in the canal are removed in a similar manner. This is usually easier because the canal is less crowded and the tympanic membrane is readily visible. For an exostosis in the anterior canal, a laterally based anterior "window-shade" flap can be developed starting from an area just lateral to the anterior half of the tympanic ring. W h e n drilling the anterior wall of the canal, care must be exercised not to enter the temporomandibular t. After all the exostoses are removed and the rest of the canal wall is smoothed down, the skin flaps are laid back (Fig. 8 - 1 C ) . The external auditory canal is packed with Gelfoam saturated in antibiotic solution and "wrung out"; Owen's silk strips and pieces of cotton packing (rosebud packing) also can be used. T h e lateral part of the canal and the meatus are packed with 1/2-in gauze strips saturated with antibiotic ointment. The incision is closed in layers and a mastoidectomy type of pressure dressing is applied.

Intractable External Otitis

FIGURE 8-1

This procedure is indicated when chronic external otitis is persistent despite aggressive medical treatment. Usually the canal is obliterated with swollen, thick canal skin. The operation is usually performed under general anesthesia. Local injection of 17c lidocaine with epinephrine helps hemostasis. A postauricular incision is m a d e for wide exposure. The cartilaginous canal is sectioned at the level of the mastoid cortex through the postauricular incision (Fig. 8 - 2 / 1 ) . An infected stenotic plug of canal skin is removed using an elevator and curets (Fig. 82 8 ) . The thin epithelial layer over the tympanic membrane is also carefully peeled off; this can be done concurrently with canal skin removal or separately. The utmost care must be taken to avoid perforating the tympanic membrane. If a small tear occurs the edges are approximated; for larger defects a fascia graft might be needed (see Chapter 12). The best treatment is prevention. The bony canal is enlarged with a cutting bur. The canal is drilled as much as possible until the entire tympanic membrane is visible; care must be exercised not to enter the temporomandibular t anteriorly and the mastoid air cells posteriorly. A meatoplasty is performed by removing the infected narrow meatus and conchal cartilage (Fig. 82C). The anterior cartilaginous canal skin up to the

151

tragus also can be removed if infected. The meatus should be large enough to it a forefinger. After the infected canal skin and the meatus are removed and the bony canal wall is smoothed down, a split-thickness patch of skin of 0.01-in thickness is harvested from the upper medial surface of the arm with a Daf'ilva d e r m a t o m e . It is better to err on the side of thinness when harvesting since thinner skin takes better than thicker skin. The harvested skin is laid on a wooden tongue blade and cut into two unequal pieces. The larger piece is laid out on the d r u m h e a d and covers from the anterior annulus to the entire posterior half of the canal; the smaller piece covers the rest of the anterior half of the canal (Fig. 8 - 2 D ) . A double packing method is used. The first packing places strips of Owen's silk and antibiotic-saturated cottons through the postauricular exposure. Gelfoam saturated in antibiotic solution and "wrung out" can be used instead of rosebud packing. After this packing is placed, the excess skin is folded over the pack and the postauricular incision is closed (Fig. 8 - 2 E ) . Under the operating microscope, the folded grafted skin is laid over anteriorly toward the tragus and posteriorly toward the concha. A n y excess skin can be trimmed off. The second pack is placed endaurally (Fig. 8 - 2 F ) . All raw bone is covered with skin graft, and a pressure dressing is applied over the ear. The packs are removed after two weeks. Crusting m a y occur for several weeks and requires meticulous removal and cleansing until definite healing is achieved.

S t e n o t i c Canal The external auditory canal may narrow owing to the presence of scar tissue without infection. This stenosis can cause conductive hearing loss and secondary ear canal cholesteatoma. The operative procedure is similar to that for exostosis. The posterior canal skin flap is developed from the bony cartilaginous junction to the annulus, from the 12 to the 6 o'clock position. The bony canal is smoothed off with a drill and the skin flap is laid back. Anteriorly a window-shade flap may be necessary. Packing, dressings, and postoperative care are the same as for exostosis.

Tumors of the External Auditory Canal The external auditory canal m a y be involved with benign or malignant tumors. The surgical treatment

152

External Ear Canal Procedures

External Ear Canal Procedi), of these tumors depends on the type and their location in the canal.

Anterior Canal Tumors If benign, the tumor with surround!^ canal wall skin is removed. The ' i o n ^ ^b"" extended up to the tragus and over th, m e m b r a n e b y denuding the epithelial k " " drumhead (Fig. 8 - 3 C ) . The bony canal i ^ " i d i d with a drill, arid a split-thickness skin gr^f j q „ j in thickness from the upper medial arm • ; is used to cover the exposed bone and the drumht, , 3D). S- *If the tumor is malignant, lymph^j. through Santorini's fissures into the " , feauriculsr nodes can be assumed. Adequate e x c i s i elude a superficial parotidectomy and t \ ! j j 'u~ anterior canal wall. If a CT scan shows ^ has extended anteriorly and medially, t ^ , should include the cartilaginous and b o ^ ant'e^'o canal wall, the anterior d r u m h e a d , the lobe of the parotid gland, and the conq . " ' mandible (Fig. 8 - 3 E ) . The facial nerve \ ° ™j whenever possible; if involved with h j . ^ . . included in the excision and repaired vv-^ _J graft. The canal defect is covered with a _ , . plit-thickness skin graft. e x c

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Aim

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To achieve complete removal of the tumor and restore a normal external auditory canal whenever possible.

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1. Biopsy of the tumor. 2. Complete removal of tumor with or without parotidectomy, mastoidectomy, or temporal bone resection. 3. Split-thickness skin graft. 4. Packing and closure.

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Posterior C a n a l T u m o r s 1. Inadequately excising a malignant tumor. 2. Delaying the diagnosis. 3. Causing unnecessary damage to the tympanic membrane, ossicles, or temporomandibular t. 4. Leaking of cerebrospinal fluid after temporal bone resection.

Benign tumors involving the c a r t i l a g i t \ rior canal can £e excised with a margin ( p . If the defect is large, a split-thickness skit\ , b e used. W h e n a tumor i s i n the posterior l " y closer to the tympanic membrane, wid^ aj-eas f posterior canal.skin with the epithelial l f y j ^ d r u m h e a d can'be removed and a s p l i t - t h u ; ^ graft is applied! The posterior canal can b 'j with a drill before the skin graft is applieq W h e n a malignant tumor is small a r ^ extended t o tfce d r u m h e a d , a complete j j . . radical mastoidectomy is done. If the t u r t | . ' . to the d r u m h e a d a radical mastoidectomy . tc i* L L . . . j • done. If a malignant tumor is extensive and l v l v e s he middle ear or mastoid, a subtotal or total bone resection may be necessary. " Qus

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Biopsy

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FIGURE 8 - 2 .

The location, size, and extent of a tumor in the external auditory canal should be thoroughly evaluated. If otalgia or bleeding is associated with the tumor, malignancy should be suspected. N e w imaging techniques such as c o m p u t e d tomography (CT) or magnetic resonance (MR) are helpful in defining the extent of the tumor. Biopsy should follow after a thorough examination under an operating microscope, and can be done under local anesthesia using a cup-biting forceps (Fig. 8-3/4). If the lesion is small and has not penetrated to the underlying bone, an excisional biopsy that includes removal of surrounding canal skin should be adequate (Fig. 8 - 3 B ) .

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Subtotal Resection of Temporal Bone The external auditory canal with s u r r o u r , ^ ^ and bone is removed, leaving the facial r » ^ j The incision is made anterior and p o s t e r , ^ auricle, with the inferior extension along tk, border of the sternocleidomastoid m u s c l p. 4A). The auricle is elevated superiorly, leav; m

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FIGURE 8-3. FIGURE 8 - 4 .

155

External Ear Canal Procedures 156


of tissue from the canal and meatus. A wide area of mastoid cortex is exposed, along with the parotid gland and the facial nerve as it exits from the stylomastoid foramen. Using the operating microscope and drill, the entire mastoid portion of the facial nerve is exposed. The bony canal is isolated and separated from surrounding structures. Anterosuperiorly, the bony buttress of the zygomatic process of the temporal bone is drilled d o w n . Anteriorly, the capsule of the temporomandibular t is separated from the canal wall. The malleus is removed along with the tympanic membrane; the incus may be left intact or removed, depending on the extent of the tumor. Drilling is continued just anterior to the facial nerve, as in the extended facial recess approach. Interiorly, the dissection is limited by the jugular bulb. The specimen is separated as drilling continues just above the bony annulus (Fig. 8 - 4 B ) . After the specimen is removed, the middle ear space and exposed dura are covered by a large temporal fascial graft (Fig. 8 - 4 C ) . The fascia is held in place by a rosebud or Gelfoam pack and the wound is closed.

Total Temporal Bone Resection After the incision is made, the auricle is elevated with the superiorly based flap. Wide areas of the zygomatic arch, the squamous portion of the temporal bone, and the mastoid are exposed by elevating the temporal muscle (Fig. 8 - 5 , 4 ) . The lower limb of the incision is m a d e and the parotid gland is exposed. The internal jugular vein is exposed by detaching the sternocleidomastoid muscle from the mastoid tip. The arch of the zygoma is removed and the middle fossa dura is exposed by drilling on the squamous portion of the temporal bone; this opening is en-

larged with a rongeur. Elevation of the dura roni the temporal bone allows the tumor to be evali ated for possible intracranial extension (Fig. 8 - 5 B ) . The head of the mandible is removed. If the turno. has invaded the anterior canal, a total parotidectoriy is done; the facial nerve is resected and the post*rior belly of the digastric muscle is severed (Fig. 8- 5C). The internal carotid artery is exposed with a Irill; during this p r o c e d u r e the bony eustachian tut e is transected (Fig. 8 - 5 D ) . The bone over the internal carotid artery is removed with the points of the artery's entrance into the foramen lacerum defining the anterior and superior limits of the resection i Fig. 8 - 6 / 1 ) . A mastoidectomy is performed, exposing the sigmoid sinus with a drill (Fig. 8 - 6 B ) . The speciraen is removed by fracturing the temporal bone thro igh the otic capsule with a chisel placed just p o s t e r i c to the internal carotid artery. H e m o r r h a g e is contro led with packing. The boundaries of the resection are the internal carotid artery anteriorly, the middle fossa dura superiorly, the posterior fossa dura and sigmoid sinus posteriorly, and the petrous apex medially (f ig. 8 - 6 C ) . The line of resection as seen from abo 'e, es through the petrous portion of the tempo'al bone just lateral to the internal auditory canal. If the tumor extends to the dura, the involved portion may have to be resected; if there is evidence of metastasis to the neck, a radical neck dissection may be necessary. The wound is closed after the defect is filled with temporal muscle and a large meatoplasty is done (Fig. 8 - 6 D ) . A split-thickness skin graft ov^r the temporal muscle will shorten the healing time. If the tumor extends to the auricle, the entire auricle and its surrounding skin are excised (Fig. 8 - 6 E ) . The defect is best covered with a myocutaneous flap fro n the greater pectoral muscle.

FIGURE 8 - 5 .

CHAPTER 9 Congenital Atresia Congenital aural atresia remains one of the most challenging (and rewarding) of all otologic problems. With the eventual incorporation of fully developed bone conduction aids, the indications for surgery may vary; it is essential, however, to have a clear understanding of the main surgical points and concepts. A full discussion of the subject would require a detailed review of embryology types and forms of atresia and their surgical indications and timing. This is outside the scope of this atlas. The basic requirements for undergoing surgery include: 1. Pneumatization of the mastoid. 2. Adequate cochlear function. 3. A cooperative patient with a ive family.

Surgical Technique Aims 1. To achieve a large meatus. 2. To achieve a self-cleansing mastoid cavity that can be easily visualized through the meatus. 3. To avoid post-operative stenosis. A large meatoplasty, skin grafting of the cavity, and close followup are important favorable factors.

Highlights FIGURE R-6.

1. The middle ear cavity is approached from the mastoid and not by drilling directly over the atretic canal. 2. In many patients the temporomandibular t

is posterior to the auricular remnant. This requires surgical incisions that allow final positioning of the ear canal anteriorly to the remnant, and of the remnant posteriorly to the temporomandibular t.

Procedure

The Z-plasty technique shown in Figure 9 - 2 A allows repositioning of the auricle posteriorly and of the ear canal anteriorly to the auricular remnant. When the Z-plasty is completed, self-retaining retractors are applied and the mastoid cortex is identified. This is a crucial point. It is essential to have a clear anatomic picture before initiating any drilling. The linea temporalis usually is identifiable; drilling is begun anterior to it. The absence of adequate landmarks can lead the surgeon to explore, and become lost in, the temporomandibular t space without finding the middle ear cavity. This potentially can result in transection of the facial nerve. Another important precept is that the atretic canal must not be drilled directly. Pneumatization of the mastoid is required because the essential procedure to be done is an open-cavity mastoidectomy, which allows safe drilling and identification of the facial nerve, lateral semicircular canal, and middle ear "from behind" (Fig. 9 - 1 ) . Drilling directly into the atretic plate carries a significant risk of damaging these structures. The atretic plate is removed carefully while the mastoid drilling is being done (Fig. 9 - 2 ) . A tympanic remnant may or may not be present, and the middle ear cavity may be quite small. Extreme care must be taken not to injure the ossicles, which may be wholly or partially present, fused, or absent. O n c e the ossicles have been identified, their mobility is assessed and reconstruction of the os-

Congenital Atresia

Congenital Atresia

FIGURE 9 - 1 FIGURE 9 - 2 .

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Congenital Atresia Congenital Atresia

163

FIGURE 9 - 4 .

sicular chain is planned accordingly (see Chapter 5 ) . The facial nerve not uncommonly is found to have an abnormal angulation in the second genu, making a turn of 60 degrees rather than 120 degrees (Fig. 93/1). This occurs because the nerve has a smaller middle ear cleft to encircle; therefore it makes a sharper angle (60 degrees) and exits inferiorly near the glenoid fossa, in a more lateral position. Once the mastoidectomy has been performed, the lateral semicircular canal and facial nerve identified, the middle ear cavity enlarged, and an ossiculoplasty done, grafting of the tympanic membrane is performed. Temporal fascia is placed over the reconstructed ossicles; the fascia must not be excessive, in order to avoid adhesions and lack of ossicular mobility (Fig. 9 - 3 D ) . The mastoid cavity itself either is left " r a w " for an eventual Thiersch graft or is grafted primarily at the same time. The cavity is packed as described in previous chapters, and the incisions are closed with appropriate sutures (Fig. 9 - 3 E , F ) . FIGURE 9 - 3 .

Once again it should be mentioned that a large meatus is very important; for practical purposes a meatus can almost never be made too large.

Pertinent Histopathology

FIGURE 9 - 4 A horizontal section of the temporal bone of an individual with congenital atresia and malformation of the auricle. Mondini's dysplasia also is present. The magnitude of compromise is severe. Absence of the incus, stapes, and oval window can be noted. The facial nerve also is absent; this can be seen only in the internal ear canal (not shown here), since the facial nerve does not course through the temporal bone.

Surgical Procedures in Different F o r m s of Otitis Media

CHAPTER 10 Surgical Procedures in Different Forms of Otitis Media

is absent, but the patient is symptomatic or the tympanic membrane is retracted, or both. A good and not u n c o m m o n example is that of airline pilots or attendants with eustachian tube dysfunction (or individuals subjected repeatedly to pressure c h a n g e s ) , w h o are otherwise asymptomatic. 3. Recurrent otitis media, even w h e n normal conditions exist between episodes. 4. A c u t e suppurative otitis media with a bulging or insufficiently perforated tympanic membrane; the patient is markedly symptomatic. (A myringotomy alone is performed.) 5. For diagnostic purposes in infants with fever of u n k n o w n origin. 6. To correct conductive hearing losses due to effusions. 7. A retracted tympanic m e m b r a n e before the stage of atelectasis. 8. With a tympanoplasty in patients with tubal dysfunction. •9. Otitis media with facial paresis or paralysis or other impending complications.

Instruments Clinical experience and laboratory studies indicate that middle ear effusions, far from being innocuous, are slightly delayed reflections of severe underlying histopathologic changes in the mucoperiosteum. They are part of a continuum in which s o m e forms of otitis lead to others, resulting in complications or sequelae. The immediate purpose of the surgical procedures described in this chapter primarily is to halt this process, and to help in the regression of middle ear histopathologic changes. The ultimate goal is to arrest the continuum medically, thus reserving surgery for the restoration of function rather than the mere eradication of active disease. This chapter begins with a description of a myringotomy and insertion of ventilation tubes. Because this seems on the surface to be the simplest of surgical procedures, it can be, a n d usually is, treated lightly by surgeons. The procedure is detailed purposely in excess in order to develop a "conscience" in surgeons about the significance and extreme importance of this "little operation," which has changed the course of otologic practice and helped to reduce significantly the number of major otologic procedures for complications or sequelae of otitis media. The chapter concludes with a scries of horizontal sections of temporal bones, highlighting the underlying changes in the mucoperiosteum that take place behind an apparently benign "middle ear fluid."

Myringotomy and Tubes

Myringotomy is an incision of the tympanic m e r i brane.

Aim

1. 2. 3. 4. 5. 6.

Set of aural specula. Suction tubes (5- , 20- , and 7-gauge). Myringotomy knife. Baby alligator forceps. Blunt pick (straight or angled). Small ring curet.

Procedure To substitute f o r the function of the eustachian tube—that is, to provide ventilation and drainage fi r the middle ear. By providing aeration to the middl ? ear space, the intent is to reverse the patholog' : changes of the middle ear mucosa and prevent subsequent complications or sequelae. A myringotomy also provides symptomatic improvement, confirms i diagnosis, and allows aspiration of middle ear fluid (which can also be diagnostic) and insertion of ventilation tubes.

Indications

1. Persistent effusion that has failed to respond tc adequate nonsurgical therapy. 2. A poorly ventilated middle ear even w h e n fluH \

First, inspect and visualize (this means to purposefully look and screen and not to glance casually) the ear canal. Cleanse the cerumen and epithelial debris very carefully; dry, crusty cerumen can be washed and loosened with saline or hydrogen peroxide. Abrupt cleansing can cause bleeding or small h e m a t o m a s in the ear canal. Insert the proper ear speculum (see Chapter 6) and carefully scrutinize the four quadrants of the tympanic m e m b r a n e (Fig. 1 0 1/1). Look for perforations, retraction, and retraction pockets, and for characteristics of the drum itself, such as myringosclerosis, monomeric areas, atrophic changes, evidence or suggestion of a dehiscent jugular bulb, evidence of a reddish mass in the anterior or anteroinferior areas (dehiscent carotid artery), or myringostapediopexy. Once it becomes a habit, this

165

inspection does not take time and can avoid a number of problems. Look first; do the preparatory work; then—and only then—proceed with the operation. Initially, a magnification of 6x will suffice. In general, the authors tend to use higher power, which provides a better view of sections of the membrane (once the area has been inspected and the site of incision selected).

Incisions The incision should not be made in the posterosuperior quadrant because of the underlying incudostapedial t and stapes, nor should it be made too close to the annulus because this favors early extrusion of the tube (unless that is the purpose). An incision should not be made in the presence of acute infection, again because of the risk of early extrusion (unless only drainage is intended). Epithelial migration can be considered for practical surgical purposes as radiating from the umbo. Migration is slowest in the anterosuperior quadrant, followed by the anteroinferior and posteroinferior. For this reason, the incidence of persistent perforation is higher in the anterosuperior quadrant. Since migration is not the only factor in extrusion of the tubes, the benefits of using this quadrant should be judged on a case-by-case basis. In addition, surgical repair of perforations in this quadrant is not so simple as in other quadrants. The surgeon must decide whether, in a particular case, a larger flange tube (for example, a Paparella No. 2) in the anteroinferior or posteroinferior quadrant would be more beneficial than a No. 1 tube in the anterosuperior quadrant. In the middle ear space, incisions should not be made in the umbo because of its close proximity to the promontory. The widest space available is the h y p o t y m p a n u m (Fig. 10-1B); this must be considered w h e n there is retraction of the tympanic membrane. In such a case, incisions in this area allow better drainage and more space, and carry less risk of middle ear structural d a m a g e . The length of the incision depends partly on the type of tube to be used; in general, it should be the same as the diameter of the inner flange of the tube. Too short an incision can precipitate tears when the tube is placed, especially in a weakened or atrophic membrane (Fig. 1 0 - 2 / 1 ) . Too long an incision might preclude a tight fit around the tube, allowing it to extrude or even fall into the middle ear cavity (Fig. 10-2B). Paparella-type tubes that have a small indentation in the inner flange can be placed through a small incision and rotated with baby alligator forceps or a blunt pick ("screwing motion").


FIGURE 10-1

FIGURE 10-2.

167

168

Surgical Procedures in Different Forms of Otitis Media

A sharp myringotomy knife should be used. Incisions can be made radially or circumferentially (Fig. 1U-1C). Circumferential incisions tend to accumulate more epithelial debris, leading to earlier extrusion of the tube. In cases of acute purulent otitis a wide circumferential (smile) incision is preferred, since drainage alone is the purpose and prompt closure is desired. In all other circumstances, a radial incision is preferred, since it sections fewer fibers, runs parallel to most of the blood vessels irrigating the m e m brane, and causes less scarring. The tip of the knife should be inserted just far enough to section the membrane; deeper incisions might damage the middle ear mucosa (Fig. 10-1D, £ ) . If there is localized bleeding (thicker membranes sometimes bleed) and blood obscures the incision, 'hydrogen peroxide or cotton saturated with epinephrine, or both, will control it.

Tubes Tubes should be placed in a normal area of the m e m b r a n e . Special care should be taken to avoid atrophic or monomeric areas. Myringosclerotic areas tear easily and tubes do not hold well. In contrast, tubes in normal areas that are surrounded by sclerotic plaques tend to stay in place for long periods. Before inserting the tube, as m u c h middle ear fluid as possible should be removed. Markedly retracted tympanic membranes tend to have small amounts of this serous fluid. A No. 5 suction tip can be used, placed barely through the incision while trying to avoid enlarging the incision or causing localized bleeding (Fig. 1 0 - 2 C ) . If the middle ear cavity is to be entered with a suction tip, the smaller No. 20 is preferable. Excessive suctioning can also cause mucosal bleeding. With thick mucoid effusions, a No. 5 suction tip may be insufficient. In some cases a baby alligator forceps, or a No. 7 suction tip placed immediately above (not through) the incision, can be useful (Fig. 10-2D). Occasionally a counterincision that allows air to enter the middle ear cavity while the fluid is suctioned is helpful. W h e n fluid is not completely removed by one incision, a small incision in a different quadrant may be more effective in removing loculated fluid than "fishing" in the middle ear cavity with a suction tip. Some authors consider counterincisions undesirable, but in the authors' experience a small incision consistently heals well. It is important to make a clean incision and to approximate the edges carefully. A small piece of Gelfoam saturated with a drop or two of blood can be used to cover the incision. In thick, cloudy mucoid effusions, a No. 2 tube is placed; this tube is also used

in infected effusions with facial palsy. Cultures also should be obtained in these cases. It is a good habit to visualize the middle ear mucosa through the incision. The canal, the tympanic membrane, and eveo. the middle ear cavity can be irrigated with salin»j antibiotic-steroid solutions, or hydrogen peroxide as needed. W h e n used in the middle ear cavity, antibiotic solutions should be neutral (not acid); < therwise there m a y be considerable postoperative pain (or intraoperative pain if local anesthesia is used). Ophthalmic drops are useful. Ototoxic antib.otics should be avoided.

Types of Tubes There are m a n y kinds of tubes of different she pes, sizes, and materials, ranging from " h o m e m a d e " polyethylene to Silastic, Teflon, or metal; some examples are s h o w n in Figure 1 0 - 2 E - G . The type of tube is less important than the rationale for using it. In of size and shape, three types can be considered: s h o r t - , m e d i u m - , and long-term. L-.mgth of stay depends partially on the type of tube (except for permanent tubes, which are described e l s e v h o r e in this chapter). Additional important factors - O c f e d considered include the quadrant of insertion, c.mcfP tions of the m e m b r a n e , and individual tympanic membrane migration, among others. The au hois have seen m a n y so-called long-term tubes leid to eventual perforations requiring t y m p a n o p l a s t y . ! has also been observed that shorter tubes with wide lumens tend to plug less and collect less epithelial debris than long-term tubes protruding from the tympanic m e m b r a n e . In general, however, i lost well-designed tubes work well if they are pror erly used. Cost of the tubes is also a factor. Variation * in price sometimes seem illogical. The authors I ave designed and used 18-karat gold tubes h a n d m a d ? in Chile that are 200% cheaper than the least expen .ive plastic tube.

Placement of the Tube With a baby alligator forceps, the tube is grasi •ed gently from its outer border or from a special ip. The incision should be clean and free of blood. The inner flange is laid sideways on the incision (proximal end) (Fig. 1 0 - 3 A ) . Sometimes it can be "popped" or "screwed" in with a gentle motion (Fig. 1 0 - 3 8 ) . Usually it can be laid over the proximal lip of the incision and then pushed in with a blunt pick, either by pressing it from its superior surface or by gently

FIGURE 10-3.

170


twisting it around (Fig. 1 0 - 3 C , D ) . O n c e the tube has been inserted, it is a good idea to rotate it to ensure that it is in position. O n c e it has been verified that the tube is in place, it is a good idea to place a No. 20 (or smaller if needed) suction tip through the opening of the tube (Fig. I 0 - 3 E ) . Any middle ear fluid or blood should be suctioned and a few drops of hydrogen peroxide left in place. Postoperatively, the authors tend to r e c o m m e n d neutral pH d r o p s for t w o or three d a y s to e n s u r e that patency is maintained. If there is any pain or discomfort with the drops, they are discontinued. If the fluid is cloudy or shows any signs of infection, do not hesitate to keep the patient on antibiotics (and culture the effusion). These apparently small details in technique can make a big difference in ventilation tube insertion.

Complications Potential As in most surgical procedures, the best treatment for complications is to prevent them. Excessive desire for speed is a potential surgical enemy, particularly harmful in tube insertion. Many unnecessary problems arise in training p r o g r a m s because this "simple procedure" is left to the most junior and inexperienced surgeons. It takes time to learn how to use an operating microscope propcrlv and to see all thai must be seen. Mutual coordination ami understand ing with the anesthesiologist are essential. I he resident should ask for help if his or her orientation and timing are inadequate; the anesthesiologist should understand that the purpose of the procedure is to protect the patient's ears, not the ancslhesiologist's hand.

Intraoperative 1. A small ear canal can make it difficult to visualize the whole tympanic membrane. Extreme care should be taken to avoid damaging the skin of the ear canal; bleeding will further obscure vision. A small ear speculum can be gently "screwed" in, and the speculum size gradually increased. 2. For lacerations, bleeding, or hematoma of the ear canal, carefully irrigate with hydrogen peroxide or apply small cotton balls saturated with epinephrine, or both. 3. Facial paralysis due to injection of local anesthetics is a temporary p h e n o m e n o n of no conse-

quence, but the surgeon annoying possibility.

Surgical Procedures in Different Forms of Otitis Media must be aware of ' lis

4. For bleeding from the incision, use hydrogen peroxide or cotton balls saturated with epinephrine, or both. 5. If an incision is too long, approximate the borders carefully; if necessary, place small pieces of Gelfoam saturated with a few drops of blood and select a different site for the incision. Large tears and tears in myringosclerotic areas may require a tympanoplasty. 6. For a too-deep incision causing mucosal bleeding, aspirate fluid and irrigate the middle ear w i h hydrogen peroxide or a few drops of epinephrine solution, or both. Use postoperative antibiotic-stero d drops. 7. If a tube has fallen into the middle ear c a v i t / , carefully recover it through the available incision or make a new incision if necessary. However, if it is lost in the cavity, if is better to leave it in or ( r a r e ! ' ) perform an exploratory t y m p a n o t o m y than to fich blindly for it. 8. If bleeding occurs because of d a m a g e to a jugular bulb occupying the h y p o t y m p a n u m (either in a high location or medial to the tympanic membrane), immediate packing should be done, initially with Gelfoam and then with tight gauze packing. The Gelfoam layer helps to avoid further bleeding w h e n removing the gauze pack. Do not panic, j. st pack. 4, Damage to the ossicular chain and d a m a g e ;o the facial nerve are uncommonly seen complicatio IS that reqtiire exploration; they are dealt with in e 1ferenl chapters. 1

Postoperative I Short-term: A. Inlccted ear drainage (purulent otorrhea) ir •.mediately after surgery usually means that , n infected middle ear effusion or silent otil S media was present. Antibiotics (orally and topically) should be used. The same t r e a t m e ' T should suffice for late purulent otorrhea. B. Forcing the footplate into the vestibule in CAST 5 of previous myringostapediopexy (either spor taneous or postsurgical) has been described The best treatment here, as for all other complications, is prevention; once it has occurred exploration is indicated. C. Otalgia usually occurs with acid otic d r o p s Neutral drops or ophthalmologic drops usualli suffice. The value of d r o p s should be assessed on a case-by-case basis. On occasion, the dis-

comfort is caused by the drops dripping into the nasopharynx. 2. Long-term: A. Epithelial debris or cerumen blocking the tube can be removed with a small hook under the microscope. It is a good idea to use otic drops and sometimes hydrogen peroxide to soften this debris before removal. Occasionally it dissolves by itself and can be gently suctioned. B. Treatment of a permanent perforation of the tympanic membrane varies. If the patient is a child with eustachian tube dysfunction and the perforation is clean and small, it m a y serve the purpose of a tube and should be observed carefully. If the perforation is larger or if the exposure of the mucosa requires further action, a tympanoplasty should be d o n e , and possibly a tube should be placed at another site in the tympanic m e m b r a n e . C. Skin migrating into the middle ear cavity via the tube opening is a rare event that requires middle ear exploration, removal of tympanic membrane edges around the tube, and tympanoplasty. On occasion, a congenital cholesteatoma appears as an apparent complication of tubes. Adequate preoperative radiologic evaluation and thorough middle ear exploration are crucial in such cases. D. Extrusion of the tubes may be followed by recurrence of the original problems. In some cases tubes must be reinserted In other cases, tubes are poorly tolerated or are extruded shortly alter insertion; these might require so-called "Iransmeatal p e r m a n e n t aeration tubes." The indications are relative and should be assessed on a case-bv-ease basis. Some surgeons utilize "permanent" tubes through the tympanic membrane; these have a high incidence ol persistent perforation requiring an eventual tympanoplasty. Transmeatal tubes are preferred, but the indication for their use also is relative. The authors do not use permanent tubes, preferring instead to reinsert a No. 2 tube in such cases. Because of their c o m m o n use, however, insertion of permanent tubes is described below.

171

Aim To place a tube beneath the annulus in the posteroinferior quadrant.

Technique

(Portmann)

With a curved canal knife, a horizontal incision is m a d e parallel to the annulus, approximately 10 mm lateral to it in the posteroinferior quadrant (Fig. 1 0 4A). A small flap is elevated and the middle ear cavity is entered beneath the annulus (Fig. 1 0 - 4 B ) . A small bur is used to drill a canal in the posterior bony wall. The tube is placed with the inner flange medial to the annulus (in the middle ear) (Fig. 1 0 4 C ) . T h e flap is repositioned and held in place with Gelfoam and antibiotic-saturated gauze (Fig. 1 0 - 4 D ) . After one week the gauze is removed.

Complications

1. Those of pressure-equalizing (PE) tubes. 2. Edema of the skin that obscures the tube. Treatment with topical antibiotics and steroids usually solves the problem, allowing the tube to become visible again. 3. Blockage with debris or cerumen, or both. This complication is m o r e c o m m o n with permanent tubes than with regular tubes. Measures for removal of the blockage are similar to those lor regular tubes; h o w ever, removal with hooks, requiring a local or general anesthetic, is more c o m m o n . (This is equivalent to reinserting a No. 2 tube.) In addition, a number of patients over time develop complications or sequelae involving the tympanic membrane or middle ear, or both. These include an atrophic or atelectatic tympanic membrane, myringosclerosis, chronic otitis media, cholesterol granuloma, disruption or fixation of the ossicular chain or tensor tympani tendon, and so on. Such complications highlight the need for periodic checkups and close observation in the treatment of otitis media. In unresponsive cases or in those in which underlying middle ear pathology is suspected, there should be no hesitation in proceeding with exploraTransmeatal Permanent tory tympa lotomy; the surgeon should not sit and wait for a localized disaster to occur. Exploratory Aeration Tubes tympanotomy, tympanoplasty, and ossiculoplasty are described in different chapters in this book. Persistent dysfunction of the eustachian tube m a y Instrumentation is similar to that for stapedeclead to tympanic membrane retraction, thinning, and tomy.

Surgical P r o c e d u r e s in Different F o r m s of Otitis Media

Surgical Procedures in Different F o r m s of Otitis Media formation of adhesions of the m e m b r a n e to the p r o m o n t o r y . A tympanoplasty for an atrophic or atelectatic tympanic membrane (described below) may be required. On occasion, persistent effusions a n d underlying histopathologic c h a n g e s may lead to hypocellularity of the mastoid and lack of aeration of the middle ear cavity. Once these are clinically and radiologically documented, surgical procedures to increase aeration—either a mastoidotomy or a cortical ("intact wall") mastoidectomy (described below)— are r e c o m m e n d e d . Surgery for major complications of otitis media is described elsewhere in this chapter. Surgery for an atrophic or atelectatic tympanic m e m b r a n e can be performed using a transcanal, endaural, or postauricular approach. Different methods can be used; two of the most c o m m o n , cartilage tympanoplasty and tympanoplasty for atelectatic tympanic membrane, will be described. The basic objectives are (1) to reinforce an exceedingly weak tympanic m e m b r a n e , which is usually collapsed a n d not uncommonly attached to the medial wall of the middle ear; (2) to inspect the middle ear cavity, repair ossicles, and lyse adhesions (re-establishing function); and (3) to re-establish the middle ear space and prevent further disease. These measures, in turn, can be combined with aeration procedures such as a cortical mastoidectomy or mastoidotomy. The procedure and approach to follow depend on the judgment, expertise, and preference of the surgeon. A cartilage tympanoplasty will be described as a transcanal procedure and a tympanoplasty for atelectatic tympanic m e m b r a n e (adhesive otitis) as an endaural approach, with the understanding that they can be done either way or even by a postauricular approach. Similarly, a cortical mastoidectomy or a mastoidotomy can be done by an endaural or postauricular approach. It is important for the surgeon to realize that different approaches can be used interchangeably or combined as necessary; there are so m a n y forms of presentation in otitis media that a "single surgical a p p r o a c h " can be, at times, a very limiting concept. The two methods described only suggest alternatives. The surgeon should decide what is best for the patient and modify these approaches according to need.

Cartilage Tympanoplasty for Atrophic Tympanic Membrane Surgical

Steps

1. Transcanal incisions. 2. T y m p a n o m e a t a l flap.

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3. Widening of the bony canal. 4. Harvesting tragus (cartilage-perichondrium graft). 5. Elevation of the tympanic membrane. 6. Inspection of the middle ear cavity. 7. Inspection of the a n t r u m and atticotomy-mastoidotomy, if necessary. 8. Placement of Silastic, Gelfilm, graft, and PE tube (optional). 9. Packing and closure.

Highlights 1. C r e a t e a large tympanomeatal flap. 2. Carefully harvest and prepare a cartilage-perichondrium graft. 3. Perform a canalplasty. 4. Carefully elevate the thin tympanic membrane. 5. Adequately position the cartilage-perichondrium graft.

Procedure A large tympanomeatal flap is elevated with vertical incisions at 6 and 1 or 2 o'clock (Fig. 1 0 - 5 / 4 ) . A large flap is useful since an underlay cartilage-perichondrium graft extending into the posterior canal is to be used. The posterior canal may need to be widened. If necessary, the approach can be turned into a postauricular or endaural approach. If the posterior canal is not wide enough, the canal wall can be widened carefully with a bur (after elevating the flap). If an anterior bony overhang is present, a window shade is developed and the overhang removed (see Chapter 8). A wide and open canal favors visualization, postoperative healing, and even hearing (to a small degree). A cartilage-perichondrium graft is harvested. This can c o m e from different sources, the most c o m m o n being the tragus. An incision is made in the dorsal (posterior meatal) side of the tragus, and by gentle, sharp dissection the tragus is isolated and a piece harvested (Fig. 1 0 - 5 B ) . The tragus has perichondrium on both sides. An incision is made with a scalpel in one of the borders and the perichondrium on one side is elevated (under the microscope) with a duckbill, leaving the perichondrium as a single continuous strip with one side attached to the cartilage (Fig. 1C-5C). The cartilage can be left as is or carefully thinned with a scalpel. It can also be compressed briefly and gently; if compressed firmly or for


Surgical Procedures in Different F o r m s of Otitis Media too long, the cartilage will separate from the perichondrium. The graft is preserved in saline. The tragal incision is closed with appropriate sutures after meticulous hemostasis with cautery (or ligation); otherwise, a localized hematoma m a y develop postoperatively. The tympanic membrane is very carefully elevated while trying to maintain its integrity. If the membrane has sclerotic plaques, they can be gently and meticulously removed with a t knife or its equivalent. It is not imperative to remove all plaques; excessive removal can cause tears in the membrane. (To make matters worse, the m e m b r a n e is poorly vascularized, so the surgeon must be careful here.) Any adhesions are carefully sectioned. A No. 20 or 24 suction tip with the finger "off the hole" is used. The ossicular chain is inspected and, if necessary, reconstructed (see Chapter 12). If the tympanic m e m b r a n e is retracted or the tensor tympani is fixed, or both, the tendon is sectioned. (Fig. 1 0 - 5 D ) . The main aim of this procedure is to mobilize the malleus and widen the mesotympanic space. (This does not produce increased aeration.) At this point, the attic and antrum are inspected (Fig. 10—5E). Palpation with a Whirlybird can give a good idea of the adequacy of communication between the middle ear and the mastoid antrum. If there is any question, further inspection is made. It is not u n c o m m o n to find a so-called "aditus block" that obstructs communication and significantly impairs aeration despite the presence of an adequately sized mastoid cell system. An atticotomy is done, the extent of which depends on the degree of visualization needed. The attic is gently curetted d o w n with stapes curets in a superior to inferior direction (away from the ossicles), which helps to avoid ossicular disruption. The attic is then inspected, adhesions are sectioned and removed, and the ossicles are freed of excessive adhesions and connective tissue. If there is any question of insufficient age, the mastoid should be inspected. Some authors create "observation windows" by drilling openings in the posterior superior bony canal (over the a n t r u m ) (Fig. 1 0 - 5 f ) - Others advocate the use of mirrors. While these methods are acceptable and work well, the authors prefer a complete inspection that at the s a m e time provides a solution. This is achieved by a mastoidotomy (see C h a p t e r 7 ) , which provides direct visualization, ease of cleansing, and removal of any blocks; increases aeration; and permits irrigation of the mastoid and middle ear (Fig. 1 0 - 6 4 ) . An antibiotic-steroid solution should flow freelv between

FIGURE 10-5.

175

these two cavities. On occasion, a small strip of thin Silastic can be placed between the antrum and middle ear to ensure patency. If a wider communication is needed, a mastoidectomy and a facial recess opening could be helpful, but usually this is not the case in the types of problems discussed here. If the mastoid is found to be involved with disease, a mastoidectomy is done. O n c e the ossicles are reconstructed, communication of the middle ear and mastoid is ensured, and aeration is felt to be adequate, a thin Silastic sheeting is placed that extends from the eustachian tube to the tympanic sinus and round window niche (Fig. 1 0 - 6 B ) . The cartilage-perichondrium graft is laid over a piece of Gelfilm, which is placed over the long process of the incus under the tympanic membrane (Fig. 1 0 - 6 C ) . The perichondrium that is not attached to cartilage is placed over the posterior canal wall (Fig. 1 0 - 6 D ) . This type of graft also is very useful in covering atticotomy defects, and in areas where retraction pockets tend to occur or recur. It is an easy and very effective resource for ear surgery. A slightly thicker anterior tympanic membrane remnant usuplly is present, through which a No. 1 ventilation tube can be inserted (Fig. 10—6E). The authors prefer to do this since it helps to ensure postoperative aeration and healing of the middle ear. The flap is then repositioned covering the graft, and the ear canal ss packed. If endaural or postauricular incisions w e r e used, they are closed in layers and a dressing is applied.

Tympanoplasty for Atelectatic Tympanic Membrane (Adhesive Otitis) Surgical Steps 1. Endaural incisions (Lempert 1 and 11). 2. Harvesting of temporal fascia. 3. Tympanomeatal flap. 4. Widening of the bony canal. 5. Elevation of the tympanic membrane. 6. Repair of ossicles. 7. Inspection of the a n t r u m . 8. Placement of Silastic, Gelfilm, underlay fascia, and pharyngoesophageal tube. 9. Packing and closure.


Highlights 1. 2. 3. 4.

Create a large tympanomeatal flap. Perform a canalplasty. Carefully elevate the thin tympanic membrane. Section the tensor tympani tendon.

Procedure Endaural incisions (Lempert I and II) are made. Using two-prong self-retaining retractors, temporal fascia is harvested via the Lempert II incision, placed in Ringer's solution, and pressed for two to three minutes before being used (Fig. 1 0 - 7 . 4 ) . A tympanomeatal flap is elevated with vertical incisions at 6 and 1 o'clock; a large flap is best since a large underlay fascia will be placed extending into the posterior canal. The posterior canal wall is widened carefully with a bur (Fig. 1 0 - 7 B ) . If an anterior bony overhang is present, a window shade is developed and the overhang is removed (see Chapter 8). The canal should be wide and open. This is true for all middle ear reconstructive procedures except for some cases of stapedectomy. The thin tympanic membrane is very carefully elevated; an attempt should be m a d e to maintain its integrity. Meticulous sectioning of adhesions is the key to this elevation. A No. 24 suction tip with the finger "off the hole" is used. The field should be as dry as possible; any bleeding is treated with cotton saturated in epinephrine solution. The ossicular chain is inspected. Necrosis of the lenticular process often is found; if so, the area is reconstructed. If tympanosclerosis is fixating the ossicles, this also is corrected (see Chapter 12). Fixation of the tensor tympani tendon, including the cochleariform process, is a c o m m o n finding and requires a tympanoplasty. The tendon is severed, which mobilizes the malleus and widens the mesotympanic space (Fig. 1 0 - 7 C ) . If the malleus adheres to the promontory, the adhesions are freed. If necessary, the distal tip of the long process of the malleus is severed after being carefully separated from the overlying tympanic membrane (Fig. 1 0 - 7 D ) . At this point the attic and antrum should be inspected (as discussed in the previous procedure for an atrophic tympanic m e m b r a n e ) . O n c e the ossicles have been reconstructed and the tympanic membrane has been elevated, a piece of thin Silastic sheeting is placed extending from the eustachian tube to the tympanic sinus and round window niche (Fig. 1 0 - 7 E ) . Gelfilm that was kept in

177

Ringer's solution for softening is placed above the ossicles between the eustachian tube and the facial recess (Fig. 1 0 - 8 / 1 ) , and the fascia is placed beneath the thin tympanic m e m b r a n e (Fig. 1 0 - 8 C ) . Usually a slightly thicker anterior tympanic membrane remnant is present through which a No. 1 ventilation tube can be inserted (Fig. 1 0 - 8 D ) . (Some surgeons thread a small piece of synthetic nonabsorbable suture through the tube and into the canal in order to avoid plugging of the tube with packing and debris. The authors have not observed plugging to be a problem in these cases.) The ventilation tube helps ensure postoperative aeration and healing of the middle ear. The ear canal is packed, the Lempert II incision is closed in two layers, and a mastoid dressing is applied. Figure 1 0 - 9 depicts three alternative methods for improving aeration of the middle ear.

Mastoid and Tympanomastoid Procedures in Otitis Media If intractable disease develops in the mastoid and middle ear cavity, more extensive surgical procedures are necessary. These may range from a cortical mastoidectomy to a tympanomastoidectomy and even a radical mastoidectomy. The comments below are intended to contribute to the overall concepts of specific procedures; a complete discussion of specific indications for;these surgical alternatives is beyond the scope of this atlas. The basic aims of mastoid surgery for chronic, medically intractable otitis media cannot be emphasized enough. The first is the eradication of disease; the second is functional reconstruction. Both endaural and postauricular incisions and their corresponding approaches have already been described. It should be mentioned that if a mastoid obliteration procedure is planned, a postauricular incision is m a d e far behind (posterior to) the sulcus preparatory to the use of a muscle flap (described below). Although the authors tend to prefer postauricular approaches for tympanomastoid surgery, the endaural approach provides easy access to the middle ear and mastoid, and is very useful in revision surgery as well. It can be limited in exposure posteriorly in cases of large, well-pneumatized mastoid cavities. It is useful to describe the alternative approaches in mastoid surgery. The simple mastoidectomy (which derives its name from its original use for simple drainage and not from the simplicity of the procedure) was described in Chapter 7; it involves


FIGURE 10-7.

FIGURE 10-8.

1 5urgical Procedures in Different F o r m s of Otitis Media opening

the

mastoid

e x e n t e r a t i n g all a i r c e l l s .

allows m o r e effective tympanoplasty (reconstruction;

T h i s a p p r o a c h c a n b e u s e d for p u r p o s e s o f aeration

p r o c e d u r e s . Finally, t h e radical m a s t o i d e c t o m y is the

or removal of disease,

as in acute coalescent

s a m e as a modified radical mastoidectomy, with the

It does not involve entering the middle

addition of removal of middle ear m u c o s a and ossi-

ear, e x c e p t w h e n c o m b i n e d with a facial r e c e s s a p -

cles (excepting the s t a p e s ) , and closure (plugging) of

proach

the

mastoiditis.

(posterior

approach

and

181

such

tympanotomy).

The

allows exploration of the

facial

recess

middle ear and

removal of diseased tissue; h o w e v e r , it must be kept in

mind

that

in

cases

of chronic

ear

disease

eustachian

tube.

The

mastoid

and

middle

ear

b e c o m e an open (exteriorized) cavity with, obviously, a loss of h e a r i n g

this

access often is limited and removal of diseased mu-

Cortical

cosa m a y b e - i n c o m p l e t e . N e v e r t h e l e s s , this can be a very

useful

approach,

depending on

what

the

sur-

Mastoidectomy

geon w a n t s to a c h i e v e in a specific c a s e . S i n c e chronic otitis involves both the middle ear and m a s t o i d , it is often n e c e s s a r y to directly a p p r o a c h both

cavities;

tomy.

If the

hence

the

term

both cavities are entered dure

is

tympanomastoidec-

posterior canal wall

termed

"canal

i s left

intact and

independently,

the proce-

wall u p , "

"intact canal

wall

mastoidectomy," or "closed-cavity tympanomastoide c t o m y . " Intact canal wall procedures are preferable since

they

prevent

an

open

mastoid

cavity.

They

s h o u l d be p e r f o r m e d if there is a g o o d possibility of eradication

of disease

(the first aim

of

mastoidec-

tomy) and if the mastoid is sufficiently pneumatized to a l l o w a safe p r o c e d u r e .

A sclerotic mastoid

pre-

s e n t s a s e r i o u s risk of c o m p l i c a t i o n s . In t h e s e c a s e s , a

tympanomastoid

unless

the

procedure

otologist

is

is

not

extremely

A c o r t i c a l m a s t o i d e c t o m y w i t h or w i t h o u t a facial recess approach in

detail

Suffice

to

mention

it

carefully

in

the

and

will

that

not

be

drilling

has been

repeated should

presence of diseased

here.

be

done

tissue,

since

complications are easily caused. T h e use of curets to u n r o o f m a s t o i d c e l l s t h a t a r e full o f g r a n u l a t i o n t i s s u e is a g o o d a n d safe h a b i t , especially w h e n there are doubts as to the underlying structures.

If in doubt,

p a l p a t e t h e air c e l l w i t h a W h i r l y b i r d a n d t h e n c u r e t . Special

considerations

in

mastoid

procedures

described elsewhere in this chapter.

are

F o r an overall

view of t h e s e c a s e s , it is r e c o m m e n d e d that the entire chapter be read,

not j u s t individual a p p r o a c h e s .

recommended

familiar

with

the

a p p r o a c h , its r i s k s , a n d its l i m i t a t i o n s . U s e o f a " c a n a l

Closed-cavity Tympanomastoidectomy

wall u p " o r " c a n a l wall d o w n " a p p r o a c h will d e p e n d upon each individual

(posterior tympanotomy)

described

case. T h e primary aim

of the

p r o c e d u r e is to eradicate disease, not to maintain an intact

posterior

should what

canal

be done

the

surgeon

purposes, endaural

this

wall.

In

is w h a t the would

like

procedure

other

patient to

will

do.

be

words,

what

needs and For

not

practical

described

as

an

approach.

P r o c e d u r e s that

Incisions are m a d e with a scalpel, and e x p o s u r e is improved

by

first i n c i s i o n

using a Lempert

curved

nasal

speculum.

The

1) is m a d e s e m i c i r c u m f e r e n -

tially b e t w e e n 6 a n d 1 2 o ' c l o c k o n t h e p o s t e r i o r wall of the posterior

at the b o n y c a r t i l a g i n o u s junction. T h e s e c o n d inci-

canal wall are k n o w n a s " c a n a l wall d o w n " o r " o p e n -

s i o n ( L e m p e r t II) r u n s b e t w e e n t h e t r a g u s a n d helix

cavity"

Bondy

and incisura; the extent of this incision d e p e n d s upon

tympanomastoidec-

the degree of -'xposure of the mastoid needed, but a

mastoidectomies.

procedure, tomy,

involve removal

the

They

intact-bridge

include

the

the modified radical m a s t o i d e c t o m y ,

and

the

l e n g t h o f 0 . 7 5 c m i s n o t u n c o m m o n . T e m p o r a l fascia

radical m a s t o i d e c t o m y . T h e p r o c e d u r e originally de-

is

scribed

p o s e s . T h e r e m a i n i n g p o s t e r i o r canal skin (cartilagi-

by Bondy is indicated only

for a n u n u s u a l

harvested

through

this incision

for grafting

pur-

case of primary cholesteatoma, and involves "exter-

nous portion) is preserved and gently elevated with

iorizing"

the

a small periosteal elevator, leaving the w h o l e poste-

canal

rior b o n y c a n a l c l e a r l y e x p o s e d , ( O n o c c a s i o n , a s m a l l

inner wall

the

matrix is

cholesteatoma or

capsule.

The

the

posterior

free s k i n graft c a n b e r e m o v e d s a f e l y f r o m t h i s a r e a . )

mastoidectomy

in-

T h e spine of H e n l e is identified and the periosteum

volves e n t r a n c e into the middle ear cavity, allowing

e l e v a t e d o f f t h e m a s t o i d , e x p o s i n g its l a t e r a l s u r f a c e

tympanoplasty

( c o r t e x ) in its e n t i r e t y

modified

middle

bony

not

The

but

preserving is

entered.

removed,

while

radical

procedures.

The

ear cavity

intact-bridge

tym-

p a n o m a s t o i d e c t o m y is a c o n t e m p o r a r y version of the modified radical procedure in which a bridge of b o n e i s left w h e n t h e p o s t e r i o r c a n a l w a l l i s r e m o v e d ; t h i s

from the t e m p o r a l line (linea

t e m p o r a l i s ) s u p e r i o r l y t o t h e m a s t o i d tip interiorly T h r e e - p r o n g self-retaining retractors are is

helpful

to

position

them

at

right

angles

used. to

It

one

183

Surgical Procedures in Different F o r m s of Otitis Media another, with one pointing cephalad (superiorly) and

hearing.

one c a u d a d (posteriorly) (Fig. 1 0 - 1 0 / 1 ) . S c h u k n e c h t

oval w i n d o w is sealed with collagen tissue a n d c o v -

retractors

ered with Gelfoam saturated in antibiotic solution.

allow

tractors in

wider

exposure

these cases.

At

than

Wullstein

this point,

re-

the mastoid

and ear canal are well e x p o s e d .

If the stapes is accidentally r e m o v e d ,

the

6. In surgery (or chronic ear disease, the surgeon should give special attention and care to three areas

If n e e d e d for e x p o s u r e , a c a n a l p l a s t y ( p r e v i o u s l y

o r s t r u c t u r e s : t h e facial n e r v e , t h e h o r i z o n t a l s e m i c i r -

described) is done, and the entire fibrous a n d bony

cular canal, and the stapes (Fig. 1 0 - 1 1 ) . T h e s e areas

annulus

require early a n d clear identification during the pro-

is

exposed

without entering

the

temporo-

mandibular t space.

cedure a n d very careful m a n a g e m e n t w h e n involved

With the scalpel, incisions can be m a d e at 6 and 1 o r 2 o ' c l o c k . T h e s e i n c i s i o n s a l l o w for e a s i e r d e v e l -

with disease. 7. It

is

unwise

to r e m o v e

too much

of the attic

o p m e n t o f the flap; h o w e v e r , the flap c a n b e e l e v a t e d

wall for p u r p o s e s of e x p o s u r e ; this m a y result in a

without these incisions.

potential

is entered

(beneath

larged

that

so

inspection

of

the

After the middle ear cavity

the a n n u l u s ) , incus

is

readily

epitympanum

seen,

allowing

pocket

area.

graft

If

this

(described

occurs,

a

earlier

in

this c h a p t e r ) can be placed to c o v e r t h e defect. 8. C h o l e s t e a t o m a s and granulation tissue have the

ad antrum (Fig. 1 0 - 1 0 B ) . T h e technique of a mastoid-

c a p a c i t y t o e r o d e b o n e a n d r e s u l t i n fistula f o r m a t i o n .

ectomy

bone

There is no agreement as to the m a n a g e m e n t of these

s h o u l d b e o b t a i n e d i n all d i r e c t i o n s , b u t s a u c e r i z a t i o n

fistulae. In general, w h e n a c h o l e s t e a t o m a e r o d e s the

of

promontory

the

been

outer

complete

described.

through

retraction

cartilage-perichondrium

the aditus

has

the

the aditus is en-

cortex

is

not

Cortical so

white

important

mastoidectomy since there is

as

no

in

a

residual

place,

the

o p e n cavity. T h e s a m e p r i n c i p l e s d e s c r i b e d for m a s -

loss associated

toidectomy

(small)

some

as

an

important

should be

approach points

apply

relative

here. to

However,

chronic

otitis

mentioned.

1 . I n c a s e s i n w h i c h t h e m a s t o i d i s full o f i n f l a m matory tissue,

the surgeon can easily lose m o m e n -

tarily the s e n s e o f d e p t h a n d location o f t h e a n t r u m . S i n c e the middle ear is clearly e x p o s e d , a Whirlybird

matrix

(capsule)

should

be

left

in

o w i n g t o t h e h i g h f r e q u e n c y o f total h e a r i n g w i t h its r e m o v a l .

If a

fistula

of the

horizontal semicircular canal exists with no

apparent

involvement

nous

labyrinth,

many

fistulae

the are

of

the

matrix

underlying

can

identified

in

be

membra-

removed.

surgery

for

Very which

there were no preoperative s y m p t o m s or diagnostic suspicions based on laboratory studies. 9. O n c e again,

the

primary aim

of these

proce-

c a n b e i n t r o d u c e d i n t o t h e a n t r u m via t h e m i d d l e e a r

dures is to eradicate disease.

side and visualized or palpated to help regain surgical

second

orientation.

M a i n t a i n i n g the posterior canal wall intact is not an

2. Inflamed

tissue must be

a step-by-step fashion (Fig.

removed carefully,

in

1 0 - 1 0 C ) . Do not "pull"

l a r g e p i e c e s o f t i s s u e o r drill i n t o " h o l e s . "

aim

a i m ; it is a

will

be

described

in

Chapter

12.

p r e f e r e n c e if c o n d i t i o n s a l l o w it to be

d o n e safely a n d Closure

3. Special attention should be given to identifying

and

Reconstruction is the

and

properly. the

technique

of

meatoplasty

have

already been described.

t h e l o c a t i o n o f t h e f a c i a l n e r v e a t all l e v e l s . I t s b o n y canal

may

be

eroded

(exposing

the

nerve)

or

the

n e r v e m a y b e o u t o f its u s u a l a n a t o m i c p o s i t i o n , o r both.

Intact-bridge Tympanonnstoidectomy

(IBM)

4 . C l e a n s i n g o f all d i s e a s e d t i s s u e i n t h e a r e a o f the

facial

tympanic

recess sinus

thorough (Fig.

(suprapyramidal (infrapyramidal

recess)

recess)

and

the

should

be

10-10D). The surgeon must be espe-

T h i s p r o c e d u r e is described here as a postauricular approach.

Its a i m s will b e l i s t e d a n d t h e b a s i c s t e p s

cially careful in c l e a n s i n g this area; this is a c o m m o n

only

site for i a t r o g e n i c injury to t h e facia! n e r v e . W i t h this

earlier ( s e e C h a p * e r 5 ) . T h e s a m e principles as for a

surgical

c l o s e d - c a v i t y t y m p a n o m a s t o i d e c t o m y for c h r o n i c oti-

approach,

removal

of diseased

mucosa

in

5. Ossicles should be carefully cleansed of diseased mucosa

(Fig.

and

10—10£).

It

is crucial

of the ossicular chain

removal

or

dislocation

of

upon since

tis m e d i a a p p l y

this area s o m e t i m e s is difficult.

dislocation

touched

(or

the

to avoid

both

its r e m n a n t s ) stapes,

which

w o u l d h a v e o b v i o u s l y c a t a s t r o p h i c c o n s e q u e n c e s for

ferent skin

tere.

they have been described

As discussed previously,

dif-

flaps c a n be u s e d — a K o r n e r ' s flap or a

flap m a d e b y a n i n c i s i o n i n t h e p o s t e r i o r c a n a l wall skin at the b o n y cartilaginous junction. This incision c a n b e m a d e w h e n t h e p o s t a u r i c u l a r flap i s lifted, o r t h r o u g h t h e c a n a l b e f o r e lifting t h e flap.

r

184


Surgical I rocedures in Different F o r m s of Otitis M e d i a

Aim

185

" f r e s h e n " t h e e d g e s (if n e c e s s a r y a n d i f p o s s i b l e ) o f a perforated

To exteriorize the d i s e a s e p r o c e s s within the epi-

tympanic membrane.

The mastoid work is n o w begun; Figure 10-13/4

tympanum, antrum, and mastoid to the meatus. T h e

s h o w s the site of the o p e n i n g to be m a d e .

I B M is a c o n t e m p o r a r y version of the modified radical

cases,

mastoidectomy with bridge preservation, allowing a

small

better tympanoplasty

lend

repair.

In these

the surgeon usually is dealing with sclerotic mastoids

(large,

themselves

better

well-pneumatized to

intact

canal

mastoids

wall

proce-

d u r e s ) . Figure 1 0 - 1 3 B , C s h o w s the r e m o v a l of diseased

Highlights

tissue

from

the

mastoid

and

antrum.

It

is

important to saucerize the e d g e s (Fig. 1 0 - 1 3 D ) , since this leads to a smaller cavity a n d frequently m a k e s it

1. Enlarge the anterior canal wall without o p e n i n g the t e m p o r o m a n d i b u l a r t, and visualize the entire fibrous a n d b o n y annulus.

unnecessary (mastoid low).

2. P e r f o r m a l a r g e m e a t o p l a s t y ; t h i s is c r u c i a l for the s u c c e s s of the procedure.

to

obliterate

obliteration

This

the

cavity

procedures

mastoidectomy

with

are

muscle

described

implies

be-

leaving

the

" b r i d g e " intact (Fig. 1 0 - 1 3 E ) . T h e bridge is the m o s t medial

portion

of the

posterosuperior

meatal

wall,

a n d c r o s s e s the attic t o w a r d the t e g m e n . It h a s both

Pitfalls

anterior and

posterior buttresses.

T h e anterior but-

tress is the superior portion w h e r e the posterior b o n y 1.

Incompletely

removing

the

posterior

meatal

canal m e e t s the tegmen; the posterior buttress is the inferior portion w h e r e the posterior b o n y canal m e e t s

wall.-

the floor of the external a u d i t o r y c a n a l , lateral to the

2. P e r f o r m i n g a p o o r m e a t o p l a s t y .

facial

nerve

(Fig.

\0-\4A-C).

O n c e diseased tissue has been r e m o v e d , an ossic-

Surgical S t e p s

uloplasty is done; Figure 1 0 - 1 4 D , E and Figure 1 0 15 s h o w p r e p a r a t i o n for a n d p l a c e m e n t of a partial

1.

Meatoplasty.

2.

Canalplasty.

ossicular r e p l a c e m e n t prosthesis ( P O R P ) . A tube is then placed ri the t y m p a n i c m e m b r a n e , followed by

3. Circumferential saucerization of the mastoid. 4. Enlargement of the aditus and

sculpturing of

the bridge to w i d e n the m e s o t y m p a n u m . 6. Preservation,

when and

c o v e r e d by t h e flap.

possible,

of the anterior

manubrium.

A T h i e r s c h graft c a n be placed

primarily b u t is u s u a l l y d o n e after six to e i g h t w e e k s , w h e n healthy granulation tissue is covering the mas-

7. U s e of a ventilation tube. 8. Ossiculoplasty,

periosteum or cartilage) (Fig. 1 0 - 1 6 ) . T h e cavity (by now the " o p e n " or "exteriorized" mastoid cavity) is

5 . R e m o v a l o f all d i s e a s e . tympanic membrane

a graft a n d the obliteration of the aditus (with either

toid cavity ( " b o w l " ) . O n o c c a s i o n , c o v e r a g e with the

tympanoplasty

flap

9. Obliteration of the aditus with periosteum or cartilage.

alone

essary.

10. Mastoid obliteration (usually not necessary).

allows

adequate

epithelialization

of

the

cavity, a n d skin grafting (Thiersch graft) is not necThe

aim

is

to

obtain a

well-epithelialized,

safe, " e x t e r i o r i z e d " m a s t o i d cavity.

11. T h i e r s c h graft (three to four w e e k s postoperatively).

Modified

Radical

Mastoidectomy

Procedure This procedure involves removal of the posterior Exposure of the mastoid cortex with a postauricular a p p r o a c h

FIGURE 10-11

T h e s a m e principles o b s e r v e d in an intact bridge mastoidectomy apply here.

meatal wall with preservation of the " b r i d g e . " has already been described. T h e type

ever,

the

bridge

p o s s i b l e for

is

In this procedure, h o w -

removed.

Two

approaches

are

he m a s t o i d e c t o m y in the m o d i f i e d rad-

of flap to be u s e d is s e l e c t e d a n d a p p r o p r i a t e i n c i s i o n s

ical

are m a d e (Fig. 1 0 - 1 2 , 4 ) . T h i s is f o l l o w e d by a m e a -

antrotomy,

toplasty (see C h a p t e r 7) a n d a c a n a l p l a s t y , until the

a t t i c o t o m y (starting from the m a s t o i d side). T h e latter

entire

is the approach

fibrous and

bony annulus

is

fully v i s u a l i z e d

approach:

without entering the t e m p o r o m a n d i b u l a r t space

for m a s t o i d e

(Fig.

the mastoid

10-12B-E).

This

is

the

time

to

trim

and

and

(1) (2)

the the

"inside-out"

or

"outside-in"

atticotomy-

or antrotomy-

that has b e e n described

previously

t o m y — t h a t is, drilling is initiated from side toward

the antrum Text

continued

on

page

191

FIGURE 10-12

FIGURE 10-13

188



Aditus

Cartilage

A

POAP

Pathology

c c

Tensor tympani

Graft

Laleralize malleus

FIGURE 10-14.

FIGURE Io-IS.

189

191


In sclerotic m a s t o i d s with s c a r c e air cells or cells filled

with diseased

tissue,

dure can be extremely

a

safe outside-in

difficult.

inside-out approach is utilized.

In

proce-

such cases,

the

In of orienta-

age,

and

packing

that

favors

epithelialization.

The

primary o b j e c t i v e is a well-epithelialized, dry mastoid c a v i t y . ous

flap

Epithelialization is a c h i e v e d by a gener-

(with

further

epithelialization)

or

by

skin

tion, it is easier to start drilling at the e p i t y m p a n u m ,

( T h i e r s c h ) grafts d o n e d u r i n g the primary procedure

moving in the direction of the antrum.

This allows

o r six t o e i g h t w e e k s after s u r g e r y . O n c e epitheliali-

immediate identification of the antrum, the d o m e of

zation is achieved, o p e n cavities tend to accumulate

t h e s e m i c i r c u l a r c a n a l , a n d t h e p o s i t i o n o f t h e facial

epithelial debris and

nerve. With these landmarks u n d e r direct vision, the

every six m o n t h s to o n e year. B e c a u s e a small cavity

mastoidectomy

is d e s i r e d , a d e q u a t e s a u c e r i z a t i o n is i m p o r t a n t .

is

posterior wall ridge. As

is

more

easily

lowered

to

mentioned

earlier,

performed,

the

level

this

approach

and

of the

the

facial

involves

removal of the bridge. In an intact-bridge mastoidectomy,

however,

it

may

be

antrum with a Whirlybird, and

drill

an

opening

possible

to

palpate

the

identify the antral space,

immediately

superior

to

the

large cavity

geons prefei

procedure

modified

leaving

radical

can

and

used;

o t h e r sur-

a rosebud pack fashioned from O w e n ' s

cotton

saturated

with

an

antibiotic-steroid

( F r e e c o t t o n e n c o u r a g e s i n f e c t i o n a n d for-

bridge

intact.

mation of granulation tissue.) This packing is advan-

performed

in

tageous w h e n a t y m p a n o p l a s t y is d o n e a n d a certain

the be

G e l f o a m with anti-

biotic o i n t m e n t or solution can be

solution.

thus

If a

obliteration

P a c k i n g o*' t h e c a v i t y v a r i e s a c c o r d i n g t o t h e s u r -

silk

procedures

mastoid

geon's preference and expertise.

This o p e n i n g is carefully enlarged a n d an inside-out initiated,

to be obtained,

require cleansing

(described b l o w ) preferably should be done.

bridge (as in the so-called "observation w i n d o w s " ) .

Tympanoplasty

is

cerumen and

a

d e g r e e o f p r e s s u r e i s d e s i r a b l e ; t h i s i s a l s o t r u e for

mastoidectomy.

a p p o s i t i o n of the skin flap to the w a l l of the n e w l y

Radical

Mastoidectomy

formed

cavity.

usually

is

The

packed

outer with

one-third

gauze

(meatal

saturated

area)

with

an

antibiotic o i n t m e n t . O w e n ' s silk m u s t be r e m o v e d a maximum This

procedure

is

seldom

performed

at

present.

Eradication of disease can be achieved by the procedures

described

struction,

above;

these

in

turn

allow

recon-

thus avoiding the hearing loss inherent in

T h e aim of this p r o c e d u r e is to create an exteriorcavity

that

includes the

tympanum,

and

mesotympanum,

ithelialized meatus. radical

cavity

This

procedure,

mastoid,

continuous

approach

is

antrum,

leaving a with

similar

to

epi-

dry,

ep-

the

external

the

modified

but also i n v o l v e s r e m o v a l of the

m u c o s a , the m a l l e u s , a n d the incus while leaving the stapes intact. T h e eustachian tube o p e n i n g is obliter-

new

procedure

tibiotics

it

(such

as

curetting

are

used

routinely,

since

these

or

procedures

are p e r f o r m e d in severely infected tissues.

External

d r e s s i n g s are r e m o v e d s e v e n days after s u r g e r y a n d inner dressings at 10 to 14 days. T h o r o u g h cleansing of the cavity is essential.

R e m o v a l or cauterization

(or b o t h ) of a n y small a r e a s of granulation tissue is crucial. If n e c e s s a r y , local acidification with solutions of boric acid p o w d e r s h o u l d be d o n e ; at times, daily

epithelialization

needed

of

(see

the

occurs.

discussion

If

skin

of Thiersch

grafting

is

grafting

in

C h a p t e r 7 ) , it is d o n e six to eight w e e k s after surgery.

The "Exteriorized" Mastoid Cavity care

remove

r a t i o n a l e f o r s e l e c t i n g it.

until

Postoperative

to

c l e a n s i n g ) . T h e packing u s e d is not so crucial as the

cleansing is n e e d e d . This meticulous care is essential

ated with a b o n e plug.

"canal

otherwise it

Topical antibiotics, steroids, a n d p r o p h y l a c t i c an-

a radical m a s t o i d e c t o m y .

ized

of t w o w e e k s after surgery;

adheres to the walls of the cavity a n d necessitates a

Skin coverage prevents infection of exposed areas.

an

open

(exteriorized

wall d o w n " ) cavity is of the

utmost

or

Mastoid Obliteration Procedure

impor-

t a n c e . N o t i n f r e q u e n t l y , a s a t i s f a c t o r y p r o c e d u r e fails owing KICURFC 10-16.

The

to lack of a d e q u a t e

importance of a

postoperative

local care.

procedure

is

not

stressed. C a r e of the mastoid cavity is initiated during

procedure

is

necessary,

the

smooth

course of a t y m p a n o m a s t o i d e c t o m y . During the mas-

a d e q u a t e flap c o v e r -

t o i d e c t o m y e v e r y effort s h o u l d b e m a d e t o m a k e the

itself

by

mastoid bowl (cavity)

has already

W h e n the mastoid cavity is small, an obliteration

been

procedure

meatoplasty

obtaining an

surface,

even,

needed.

If a it

mastoid

usually

is

obliteration done

in

the

92

Surgical Procedures in Different F o r m s of Otitis M e d i a


testoid cavity small.

W i d e drilling a r o u n d

the mas-

o'clock in the canal extending out to the auricle (Fig. 10-17D).

j i d c a v i t y h e l p s t o r e d u c e its s i z e .

The

meatus

it the surgeon's placed

between

packing (Fig.

Aim

closed gauze

and

the

should

musculoperiosteal

the

lateral

canal

is

packed

with

'/2-ir*

C o m p l i c a t i o n s of s u p p u r a t i v e otitis m e d i a are clas-

J 3. S p l i t - t h i c k n e s s skin graft.

extratemporal.

I, 4. Closure and packing

clude coalescent

mastoiditis,

petrositis,

labyrinthitis.

into

two major

categories,

infratemporal

and

I n t r a t e m p o r a l b o n y c o m p l i c a t i o n s in-

and

facial

nerve

paralysis,

Extratemporal

bony

complications are divided into intracranial and extra-

i Pitfalls

cranial. Intracranial complications include extradural, subdural sigmoid

I n c o m p l e t e r e m o v a l of u n d e r l y i n g d i s e a s e

and sinus

cerebellar

abscesses,

thrombophlebitis,

and

meningitis, otitic

hydro-

cephalus; extracranial complications include subper

i n f e c t i o n of t h e flap.

iosteal,

R e s o r p t i o n a n d retraction o f the graft.

4.

tht

two weeks

sified

F

flap a n d

with antibiotic ointment. T h e

L 2. E l e v a t i o n a n d i n s e r t i o n of a m u s c u l o f a s c i a l flap,

3.

to

Surgery for Complications of Suppurative Otitis Media

L 1. P o s t a u r i c u l a r a p p r o a c h .

I 2-

enough

1 0 - 1 7 E ) . T h e postauricular incision i*

strips saturated

packing in

I™ 1.

large

T h e K o r n e r ' s flap i s

outer packing is removed in one w e e k and the inner

To m a k e the mastoid cavity smaller or to minimize croblems arising from a large m a s t o i d cavity.

I

be

forefinger.

scesses.

S w e l l i n g of the flap, c a u s i n g disruption of os-

iicles.

postauricular, Owing

to

Bezold's, the

use

and

of

zygomatic

antibiotics,

ab-

these

c o m p l i c a t i o n s a r e r e l a t i v e l y r a r e b u t still o c c u r . N e w imaging techniques ( C T scan and MR1) have revolutionized

the

treatment of these complications,

espe-

cially intracranial c o m p l i c a t i o n s . Surgical t r e a t m e n t s

Procedure

pertinent to otologic surgeons are described below.

M J e f o r e a postauricular incision muscular

flap

that will be

is m a d e ,

used

the type

to obliterate

Coalescent

the

Mastoiditis

nastoid cavity should be decided upon. T h e flap can DE b a s e d either superiorly or interiorly, but in general in

inferiorly

pedicled

flap

is

more

17/1).

T h e flap i n c l u d e s m u s c l e ,

teum.

Before

the

flap

is

useful

fascia,

turned

into

(Fig.

and the

mastoid

: a v i t y , all d i s e a s e , e s p e c i a l l y a c h o l e s t e a t o m a i n t h e :avity, elevated the

should from

mastoid

epithelium

be the

removed. bone,

cavity;

it

previously

The

pedicled

rotated, can

and

then

elevated

be from

flap

inserted covered the

Patients

10-

perios-

is

into with

with

coalescent

mastoiditis

are

treated

with a c o m p l e t e m a s t o i d e c t o m y (see Chapters 5 and 7).

Communication

the

mastoid

and

the

should middle

be

established

ear

cavity.

between

The

facial

recess m a y have to be o p e n e d . A large myringotomy* and insertion of a t y m p a n o s t o m y tube help drainage, after

surgery.

mastoid

cavity or the posterior canal A P a l v a ' s flap is b r o a d l y b a s e d on the c o n c h a .

A

Facial Nerve Paralysis

wide area of the postauricular musculoperiosteum is included in this flap (Fig. 1 0 - 1 7 6 ) . A large m e a t o p l a s t y s h o u l d be d o n e as part of an obliteration procedure. tilage is

removed

A l a r g e p i e c e of c o n c h a ] car-

w i t h o u t t e a r i n g or p e n e t r a t i n g the

^Bthal s k i n ( F i g . 1 0 - 1 7 C ) . A Bffd b y m a k i n g l o n g i t u d i n a l

Facial

nerve paralysis may develop in association

with an acute s u p p u r a t i v e otitis m e d i a , especially in younger (pediatric) patients.

A w i d e m y r i n g o t o m y is

K o r n e r ' s f l a p is d e v e l -

done and pus is drained. A large-bore t y m p a n o s t o m y

incisions

tube m a y be inserted at the s a m e time to help further

at

12 a n d

6

FIGURE 10-17.

194


drainage.

Intensive parenteral antibiotics are given;

steps

S u r g i c a l P r o c e d u r e s in "Hfferent F o r m s of Otitis M e d i a

include

a

postauricular

incision,

mastoidectomy,

patient is followed with electrodiagnostic tests.

De-

the abscess. T h e b o n y plate over the dura is carefully

corticosteroids

are

c o m p r e s s i o n o f t h e facial n e r v e rarely i s n e c e s s a r y .

removed

On

19B).

the

other

hand,

facial

paralysis

occurring

with

chronic otitis m e d i a requires p r o m p t exploration and decompression of the nerve.

with

a

diamond

bur

and

complete

The

doses,

exposure of dura,

a

added.

after several

and

drainage

curet

(Fig.

of 10-

Granulation tissue over the dura can be care-

fully p e e l e d o f f o r left a l o n e . A subdural or brain abscess is m a n a g e d in c o o p eration

with

neurosurgical

colleagues.

It

can

be

drained to the mastoid cavity.

Petrositis Petrositis manifests itself clinically with d e e p pain,

Meningitis

palsy of cranial nerve VI, a n d otorrhea (Gradenigo's syndrome).

Pain

may be the only complaint.

Once

the diagnosis is m a d e , the patient with petrositis is

Meningitis is the most c o m m o n intracranial c o m -

treated with intensive antimicrobial t h e r a p y and sur-

plication. T h e primary m o d e of treatment is intensive

gery.

antimicrobial

with

A c o m p l e t e extended m a s t o i d e c t o m y is done, special

emphasis on

of t h e cell t r a c k s a r o u n d

location and

exenteration

the semicircular canals; if

indicated,

therapy;

w h e n surgical intervention is

the procedure is essentially

t h e s a m e ar;

that for a n e x t r a d u r a l a b s c e s s

this is u n s u c c e s s f u l , an a p i c e c t o m y m i g h t be necessary. be

Surgical approaches

made

through

the

to the

petrous apex

subarcuate

air cell

may

tract;

the

Sigmoid

Sinus

Thrombophlebitis

[ s i n o d u r a l a n g l e ; the tract b e n e a t h t h e p o s t e r i o r canal a n d vertical p o r t i o n o f t h e facial n e r v e ; t h e h y p o t y m s panic cells;

the

peritubal

cells to the

petrous apex

[ b e t w e e n the c o c h l e a a n d the carotid artery; and the middle fossa (Fig.

10-18).

Suppurative otitis around

the

phlebitis. thrombus, and

Labyrinthitis

sigmoid

Phlebitis which

become

media can cause sinus,

resulting

promotes

may

infected.

inflammation in

formation

enlarge,

occlude

Symptoms

a

localized

of a

mural

the

lumen,

of sigmoid

sinu:

t h r o m b o p h l e b i t i s include spiking fever, chills, h e a d ache,

increased

intracranial

pressure,

and

post

auricular e d e m a (Griesinger's sign) ;

Patients

neural

with

hearing

labyrinthitis loss,

treatment

includes

microbial

therapy,

present

tinnitus,

and

with

sensori-

vertigo.

hospitalization,

The treatment is appropriate antimicrobial thcrap\

Initial

and surgery

anti-

toidectomv,

hydration,

sigmoid

sinus,

nccdU

and

aspiration of the sinus, e v a c u a t i o n of the t h r o m b u s ,

a m y r i n g o t o m y ; if there is no i m p r o v e m e n t , surgical

ligation of the internal jugular vein, and packing and

intervention should be considered.

closure

toidectomy

is

antivertiginous medications,

Surgical steps include a complete m a s e x p o s u r e of the

done.

The

labyrinth

with a labyrinthectomv approach. the

posterior and

A complete mas-

horizontal

can

be

drained

In this p r o c e d u r e ,

semicircular canals arc

o p e n e d . T h e b o n y wall b e t w e e n

the oval and

w i n d o w s is removed, along with

round

the lateral e n d of

A t tor a c o m p l e t e m a s t o i d s l o m v i s d o n e , t h e b o m plate

ovcrlving

diamond

the

burs and

sigmoid removed

sinus

with a curet or e l e v a t o r until After the sigmoid

is

thinned

proximallv and

will,

distallv

norma] sinus appears.

sinus is e x p o s e d , a

needle (with

the internal auditory canal. In addition, the sigmoid

syringe) is inserted into the sinus distally. If blood is

sinus and

aspirated

dura

of the middle and

fossa are e x p o s e d

to identify and

posterior crania] drain a n y

pus in

these areas.

clot,

the

moved

Intracranial

freely,

no

further

and the w o u n d is closed. sinus

until

is

blood

procedure

is

necessary

If there is e v i d e n c e of a

opened

and

flows

freely

the

thrombus

(Fig.

is

10-19C,

reD).

P a c k i n g i m p r e g n a t e d with antibiotics is inserted be-

Abscess

tween

the wall o f t h e s i n u s a n d

the overlying bony

plate. Intracranial abscesses m a y occur at an extradural

If there is no retrograde bleeding and t h r o m b u s is

or a subdural site, or in t h e brain itself (Fig. 1 0 - 1 9 / 1 ) .

suspected at the b u l b or inferior location, the internal

I

An extradural location is the most c o m m o n .

jugular vein

T h e extradural (epidural or subperiosteal) abscess

may

be

at

the

middle

or

posterior

fossa.

Surgical

is

ligated

in

the

neck;

the incision

is

m a d e along the anterior border of the sternocleidomastoid muscle (Fig. 10-20/1). T h e muscle is retracted

195

Surgical Procedures in Different F o r m s of Otitis Medi, Surgical Procedures in Different F o r m s of Otitis Medi

Dura

FIGURE 10-19 FIGURE 10-20

198



posteriorly, and the internal jugular vein is identified

lion

and d o u b l y ligated (Fig.

simple

should

be

positively

1 0 - 2 0 8 ) . T h e vagus nerve

identified

before

the

vein

is

ligated. The

of

a

tympanostomy

tube

with

or

withou

199

a

mastoidectomy

Frequently the mastoid returns to normal by

he

t i m e t h e a b s c e s s i s d r a i n e d . H o w e v e r , a m a s t o i d !Cwound

sinus are

is

removed

partially closed. in

7 to

Packings

10 days;

on

this should

the be

tomy is helpful in r e m o v i n g any remaining focus of infection or underlying pathology.

Any blockage at

d o n e in the operating room o w i n g to the possibility

the

of bleeding.

a n d i n s e r t i o n of a t y m p a n o s t o m y t u b e h e l p furtl er

aditus ad

drainage.

antrum

is

removed.

A

myringotony

A P e n r o s e drain m a y be inserted into t i e 1

abscess cavity during surgery; it is advanced grac i-

Periauricular

ally a n d r e m o v e d in t w o to t h r e e d a y s .

Abscesses

Infection of the middle ear a n d mastoid can cause abscess may

formation

develop

(zygomatic),

around

posteriorly or

interiorly

the

auricle.

An

(postauricular), (Bezold's)

(Fig.

anteriorly 10-20C)

The postauricular abscess is the most c o m m o n . Surgical

treatment

consists

of

incision

FIGURE

10-21

T h i s section s h o w s an e p i s o d e of acute otitis m e d a

T r e a t m e n t i n c l u d e s antimicrobial therapy and surgery.


abscess

and

drainage of the a b s c e s s , a m y r i n g o t o m y , a n d inser-

with that

perforation the

of the

mucoperiosteum

tympanic overlying

membrane. the

No.e

promontoy

is t h i c k e n e d .

FIGURE

10-22

This section s h o w s a middle ear effusion occupying the middle ear cavity. T h e m u c o p e r i o s t e u m

is t h i c k e n e d . T h i s is a typical i m a g e of m u c o i d otitis.

202

Surgical P r o c e d u r e s in Different F o r m s of Otitis Media

FIGURE

10-25

This section s h o w s a markedly retracted, atrophic .tympanic pocket. Elevation

203


membrane

with

a

so-called

"retraction

Note the small middle ear space available, of

this

membrane

without

any

tears

is

obviously a

difficult

thinness

the

task

to

10-26

properly

reinforcement

This section s h o w s an atelectatic tympanic m e m -

with fascia d u r i n g surgical repair ( e v e n if the m e t i-

brane against the promontory. Atelectatic or retracted

mobility

brane is elevated intact).

membranes

Sectioning

membrane

The

FIGURE

perform justifies

of

tend

to

ear effusions. T h e membrane and

have

small

amounts of middle

"adhesiveness"

of the

tympanic

the c o m m o n formation of adhesions

in otitis m e d i a p r o c e s s e s justify the u s e of thin Silastic sheets,

which

tend

to

preclude

these

formations,

thus

maintaining of

the of

a

middle

tympanic

the

tensor

ear space

and

the

membrane

and

ossicles.

tympani

(when

there

free is

fibrous involvement) also allows a larger middle ear space and

better tympanic m e m b r a n e mobility (not

s h o w n in this figure).

!04


FIGURE

B e n e a t h the small " r e t r a c t i o n p o c k e t " lies a middlemastoid containing a cholesterol granuloma (CO) and other changes. both

205

10-27

e a r c a v i t y filled w i t h c o n n e c t i v e t i s s u e a n d a d i s e a s e d

from


This r e q u i r e s e r a d i c a t i o n

of disease

ihe middle car and mastoid. T h e gradual

s y s t e m a t i c a p p r o a c h d e s c r i b e d in this c h a p t e r a l l o w s

the s u r g e o n

to deal with this c a s e propcrlv. S i m p l e

insertion ol a t u b e or exploration ol

the middle car

not o n l y w o u l d n o ! suffice but w o u l d l e a v e d i s e a s e d mucoperiosteum

with

all

of

its

potential

complica-

FIGURE

10-28

This section chronic moval. surgical

s h o w s a n o t h e r c a s e o f otitis

middle

ear

involvement

that

re-

N e w b o n e formation in the cavity m a k e s the task

Incomplete

difficult,

removal

disease behind;

of

requiring diseased

the

the

utmost

tissue

will

window.

The

stapes

by

fibrous

replacing it into

a

tissue.

with a

surgical

Removing

prosthesis

tragedy

this

stapes

and

w o u l d turn this c a s e

because

of

the

middle

ear

process i n v o l v i n g the vestibule. In c h r o n i c otitis, the

leave

stapes

which has a

b o n y c o v e r i n g laterally a n d is d e h i s c e n t oval

fixed

care.

too aggressive an approach can ex-

p o s e a n d c o m p r o m i s e t h e facial n e r v e , very thin, toward

media

requires

footplate

is

footplate

and

the

malleus

tend

to

become

fixed b y fibrous tissue. T h e l o n g p r o c e s s o f the incus and

stapes

head

and crura

undergo

sulting in ossicular discontinuity.

resorption,

re-

206

Surgical P r o c e d u r e s in Different F o r m s of Otitis M e d i a


207

FIGURE 10-30 FIGURE

10-29 This

This section s h o w s a middle ear cavity containing not only t h i c k e n e d m u c o p e r i o s t e u m but also a chol e s t e a t o m a e r o d i n g i n t o t h e facial n e r v e . T h i s l e s i o n , if

untreated,

will

lead

to

facial

paralysis.

Careful

dissection facial

of

the

paralysis

procedure,

is

cholesteatoma a

likely

is

important

complication

since

of s u c h

a

panic

section membrane

shows with

a

t y p e 111 t y m p a n o p l a s t y ) , periosteum

thickened,

adhesions

(parallel arrows),

(A)

retracted

tym-

(spontaneous

a thick middle ear m u c o and

involvement

of the

mastoid with a chronic inflammatory process. If the

mastoid

and

antrum

be inadvertently

are

not

left b e h i n d

explored, and

the

disease

will

p r o c e d u r e will

be inadequate. This case should be a p p r o a c h e d syst e m a t i c a l l y as d e s c r i b e d in t h e text,

208



FIGURE 10-31

I I

FIGURES 10-31, These

two

10-32

sections

FIGURE 10-32.

are

from

an

individual

who

terol

granuloma

and

granulation

tissue

eroded

the

h a d c h r o n i c otitis media b e h i n d an intact tympanic

bone, and the mass shown in Figure 10-32 was found

membrane,

i n t h e m i d d l e c r a n i a l f o s s a . T h i s w a s n o t t h e caus<:

with a large cholesterol granuloma and

fcflammatory t i s s u e

(parallel

mastoid and antrum. ME

arrows) =

occupying

the

middle ear. T h e choles-

of d e a t h ,

Exploratory T y m p a n o t o m y

with curettes in order to clearly visualize the round

CHAPTER 11

and

oval

windows.

(If

involvement

of

the

lateral

semicircular canal is suspected, an endaural approach T h e middle ear cavity,

including both

windows,

is completely inspected. It should be noted whether round

window

membrane

is

visible

or

in

a

covered position in the niche. It is also important to distinguish the m e m b r a n e itself from m u c o s a l

Exploratory Tympanotomy T h e exploratory t y m p a n o t o m y (exploration o f the middle ear cavity) is highlighted

in

this c h a p t e r as

an e x t r e m e l y helpful and i n n o c u o u s diagnostic and, often,

therapeutic procedure.

As an integral part of

A fistula m a y be o b v i o u s at this p o i n t (Fig.

the s y m p t o m s are isolated and require a high d e g r e e of suspicion on the part of the surgeon. Fistulae

can

involve

the

round

window

at

times

even

or

oval

window,

e n c e of an intact tympanic m e m b r a n e w h e n a diag-

semicircular canal. T h e y can be caused by implosive

nosis of ear d i s e a s e is in doubt, it is diagnostic. This

or explosive

exploration can be performed as a transcanal proce-

themselves

dure ( w h e n suspected disease is limited to the middle

causative

or as an

endaural

procedure

(when

suspected

Hisease i n v o l v e s t h e attic or m a s t o i d , or b o t h ) . T h e ympanotomy

can

be

done

under

local

or

general

i

tissue,

or

and

forces; but

thus

they

manifestations

problem.

Fistulae

cholesteatoma,

and

are

not

of an

caused other

the

lateral

entities

by

underlying

or

by

granulation

factors

constitute

different clinical entities from those discussed here; they

are

described

anesthesia ( d e p e n d i n g on the c a s e ) , a n d can be used

involve

u n d e r m a n y different clinical c i r c u m s t a n c e s , s u c h as

windows.

in cases of unexplained conductive hearing loss and

both,

structures

Round

in

different

other

window

than

fistulae do

chapters

the

oval

not

and

and

can

round

necessarily imply

o c c a s i o n a l s e n s o r i n e u r a l h e a r i n g l o s s e s (for e x a m p l e ,

a f l o w o f p e r i l y m p h a s a n e s s e n t i a l e l e m e n t for t h e

if there

or

diagnosis. Since the approximate average volumes of

w h e n the presence of adhesions or a loculated middle

perilymph and e n d o l y m p h are 78.3 and 2.76 cu mm

is

suspicion

of p e r i l y m p h a t i c

fistulae),

ear effusion is s u s p e c t e d . T h i s c h a p t e r d i s c u s s e s the fcse of

the

exploratory

tympanotomy

for

possible

p e r i l y m p h a t i c fistulae a n d for t y m p a n i c n e u r e c t o m y , Hhese

topics

essential which

do

not

concept

can

diagnostic

be

is

used

procedure

fit

into

other

chapters.

that exploratory routinely as a for

a

variety

The

tympanotomy,

safe and of

simple

middle

ear

conditions, is also potentially therapeutic

respectively, round

"a

free

flow

w i n d o w " or "a

opening

the

of

perilymph

from

the

free flow o f e n d o l y m p h after

endolymphatic

sac"

can

only

be

ac-

c o u n t e d for b y o t h e r e x p l a n a t i o n s . F r e e " f l u i d " g u s h ing

from

the

round

cerebrospinal

fluid

window and

is

requires

not a

perilymph patent

but

cochlear

a q u e d u c t and m o d i o l u s . At the s a m e time, w h e n this anatomic

pathway

is

not

present

there

is

no

"free

f l o w , " a l t h o u g h a f i s t u l a still e x i s t s

Exploratory Tympanotomy for Perilymphatic Fistula

Procedure

P e r i l y m p h a t i c fistulae h a v e no c o n s i s t e n t pathognomonic dearly

signs.

Although

suggestive

some

symptoms,

patients

such

as

have

tory t y m p a n o t o m y flaps a n d e n t r a n c e into the m i d d l e

hearing

fluc-

ear

tuations associated with vestibular disturbances,

1

Local or general anesthesia can be used. Explora-

may

tin-

beneath

previous

the

chapters.

annulus The

have

posterior

been

described

canal

is

in

lowered

FIGURE 11-1

and

the w i n d o w s

are o b s e r v e d

leaks. reflex

(when mobilizing the ossicular chain) is to be noted; solution can be placed in the niche in order to observe such a reflex. In the p r e s e n c e of o b v i o u s leaks or if the reflex is absent,

a

patch

of

connective

tissue

(collagen)

is

placed over the w i n d o w and reinforced with Gelfoam (Fig. 1 1 - 1 B ) . ( T h e r o u n d w i n d o w m e m b r a n e is three-

11-

\A). I f n o t , t h e o s s i c u l a r c h a i n i s m o b i l i z e d a n d g e n t l y

a t y m p a n o p l a s t y , it is t h e r a p e u t i c ; u s e d in t h e pres-

ear)

folds

in the niche (the so-called "false m e m b r a n e " ) .

nitus, a n d a positive fistula test, m o r e often than n o t

for

The presence or absence of a round w i n d o w

if the w i n d o w is not visible, a few d r o p s of saline

is p r e f e r r e d . )

the

palpated

211

layered, with a central layer of c o n n e c t i v e tissue.) In unclear cases,

small pieces of Gelfoam are used to

213

Exploratory T y m p a n o t o m y cover

such

visually

areas

since

evident.

under local

(If

small

the

anesthesia

fistulae

procedure

may

is

not

being

be

done

the patient can be asked

to

perform Valsalva's maneuver.)

vessels m a y obscure visualization of these

thin

fi-

b e r s ) . Pieces o f t h e n e r v e s (at l e a s t 3 m m i n l e n g t h ) should be r e m o v e d (Fig.

11-3B). It is important to

r e m e m b e r that s o m e nerves traverse the p r o m o n t o r y

T h e flaps are repositioned, the ear canal is packed, a n d a d r e s s i n g is a p p l i e d .

through bony grooves and n e e d to be curetted carefully.

Drilling should be avoided. On occasion, ac-

c o m p a n y i n g v e s s e l s c a n b e relatively large (for t h e area); m i n o r localized b l e e d i n g m i g h t require application of Gelfoam saturated in epinephrine solution.

Tympanic Neurectomy

It is also important to visualize the h y p o t y m p a n u m ; in about 5 0 % of cases a larger h y p o t y m p a n i c branch

A t y m p a n i c n e u r e c t o m y implies transection of the tympanic

plexus

with

or

without

division

of

the

c h o r d a t y m p a n i . It is u s e d m a i n l y for c a s e s of drooling a n d c h r o n i c parotitis. S o m e s u r g e o n s h a v e u s e d this

procedure

to

treat

certain

forms

of aural

pain

a n d e v e n t i n n i t u s . T h e r a t i o n a l e for its p r i m a r y u s e s is

founded

the

on

the

parasympathetic

sublingual

and

submandibular

chorda

tympani)

and

of the

innervation

of

glands

(via

the

gland

(via

the

parotid

tympanic plexus). O t h e r indications are based on the multiple sites of interconnection of these nerve endings with o t h e r n e r v e s in this small a n a t o m i c area

is present (Fig.

11-3C).

This branch,

which some-

times has an anterior direction, should be located. The

area

is

packed

pressed Gelfoam,

with

small

pieces

of com-

t h e flap i s r e p o s i t i o n e d ,

and

the

ear is p a c k e d . Results are consistently satisfactory in term,

the short

but after a year reinnervation s e e m s to occur

i n a t least 3 0 % o f c a s e s ( u s u a l l y m o r e ) . T h e e x p l a n a tion for this, a s w e l l a s for t h e r e c o v e r y o f t a s t e after sectioning

of

the

chorda

tympani,

is

unclear.

A

discussion of this p h e n o m e n o n is outside the scope of this b o o k .

(which is not clearly defined) (Fig. 1 1 - 2 ) .

Pertinent Histopathology Procedure FIGURES 11-4 TO 11-6 Exploratory the

middle

tympanotomy

ear

beneath

the

flaps a n d annulus

entrance of have

already

three photomicrographs of horizontal sectemporal

bones

show

the

nerves

of

the

tympanic plexus (TP), a c c o m p a n i e d by their corre-

lated a n d a piece sharply r e m o v e d . T h i s is followed

sponding bk od vessels ( B V ) in b o n y canals within

by a careful search of the b r a n c h e s of the t y m p a n i c

the p r o m o n t o r y .

plexus

tors to be c o n s i d e r e d for a p r o p e r n e u r e c t o m y . A d -

traversing

interiorly via

the

to

superiorly

promontory

from

the

prominence

T h e s e are i m p o r t a n t a n a t o m i c fac-

ditionally, Figures 1 1 - 5 a n d

11-6 show a thickened

(Fig. 1 1 - 3 A ) . For easier visualization, G e l f o a m pledg-

mucoperiosteum overlying the

ets s a t u r a t e d

identification

with

epinephrine solution

can

be ap-

plied to the h y p o t y m p a n u m a n d p r o m o n t o r y (blood

II-2.

of

b e e n d e s c r i b e d . Initially, the c h o r d a t y m p a n i is iso-

hypotympanum

FIGURI;

These tions

of

these

surgeon must "peel"

grooves

promontory, very

making

difficult.

this m u c o p e r i o s t e u m .

The

FIGURE 11-3

Exploratory T y m p a n o t o m y

FIGURE 11-6.

217

219

Tympanoplasty

has been done, and

CHAPTER 12

Overview

planning

can

lead

to

a

good

"recipient"

c

ear

or

r e c o n s t r u c t i o n a n d a so-called " d r y e a r " for s u r g e r y . This can m a k e the practical difference b e t w e e n perT h e aim of a t y m p a n o p l a s t y is surgical reconstruction of

the

damaged

tympano-ossicular chain.

The

basic principles involved are eradication of disease, reconstruction

of

the

tympanic

membrane

and

the

forming

a

tympanoplasty

or

a

tympanomastoidac-

In addition to the status of the middle ear m u c o s a and

the

underlying disease,

c e r t a i n i m p o r t a n t <'ria-

sound transformer mechanism, and re-establishmenl

tomic elements must be considered.

of an aerated cavity. Ideally, the operations discussed

1. A

in this c h a p t e r are p e r f o r m e d solely to restore func-

wide

ear canal.

provides sound

(A

wide,

there

is

an intact

transmission,

c . n.il

promotes heal :ij,,

2. A vibrating, intact t y m p a n i c m e m b r a n e .

are several indications (for e x a m p l e , a t y m p a n o m a s -

3. Properly functioning oval and round w i n d o w •.

toidectomy).

4. A well-aerated m i d d l e ear cavity:

1. T h o r o u g h evaluation of the status of the patient 2. A

surgical

approach

A. Eustachian

based

on

the

Proper

is

tomy.

The

malleus,

and crura

of

a

head,

visualization

and

exploration

o f the

6. Closure and

methodical

postoperative

follow-

fixed

between

that the s u r g e o n is r e s p o n s i b l e to the patient. M a n -

types Vo, w h i c h refers to the classic type described,

ufacturers (no matter h o w dedicated a n d ethical) are

and

r e s p o n s i b l e to a board of directors a n d ultimately to

footplate. V(j,

Paparella

which

refers

to

differentiates a

purposeful,

complete

In order to succeed,

tympanoplasty must be ap-

For purposes of described

two

useful

ones

are

here,

the stockholders.

ginated into the o p e n w i n d o w .

side by s i d e w i t h i n d u s t r y for the g o o d of t h e patient,

Farrior classified t y m p a n o p l a s t y according to the basic

pathologic anatomy at

surgery.

the completion

. Type I .

Tympanic

Type II.

membrane reconstruction

R e c o n s t r u c t i o n of a

new tympanic

e d g e o f all

lenge, and not to a " h a v e to learn it" attitude.

a v a i l a b l e al-

ternatives is essential. Evaluation disease,

its

entails

Zollner and knowledge

pathogenesis,

and

of

the

originating

its c u r r e n t s t a t u s a t

Wullstein

classified

ossicular

placed against the malleus

neoplastic,

and

its

status

c a n b e a c t i v e , p r o g r e s s i v e , r e g r e s s i v e , l a t e n t , o r resolved.

In

large part,

t h e r e s u l t s will d e p e n d u p o n

this evaluation and c o n s e q u e n t d e c i s i o n s .

Adequate

tympanoplas'. es

chain

is

intact

mobile.

The

graft

is

T y p e 11. T h e o s s i c u l a r c h a i n i s p a r t i a l l y d e s t r o y e d , damaged

(anatomic

type

II)

Either the malleus is

or an

atticoantrotcray

Grafts are classified by the relationship b e t w e e n the d o n o r a n d the recipient into the following cate1. Autograft

(adjective,

autologous).

Donor and

recipient are of the s a m e organism. 2. lsograft

(isogeneic).

Donor

and

recipient

are

twins (with the same genotype). ossicular

replacement

pros-

3. Allograft

or

homograft

(allogeneic,

homolo-

gous). D o n o r a n d recipient h a v e different g e n o t y p e s . R e c o n s t r u c t i o n of a n e w t y m p a n i c m e m This is

4. Xenograft or heterograft (xenogeneic,

heterol-

ogous). D o n o r and recipient are different species. In addition to tissues, other sources and materials

IV—Classic.

are available. T h e y include plastic,

I V I G — I n c u s graft

ramics (alloplastic materials); and denatured animal

I V M G — M a l l e u s graft.

skin gelatin,

I V B G — B o n e graft.

In o r d e r to a c h i e v e a safe, l o n g - t e r m graft, additional

IV

TORP—Total

metals, and ce-

film ( G e l f i l m ) , a n d s p o n g e ( G e l f o a m ) .

criteria m u s t b e c o n s i d e r e d .

ossicular

replacement

pros-

1. B i o c o m p a t i b i l i t y — t h e reaction of the i m p l a n t in the b o d y ( s u c h as p r e s e n c e or a b s e n c e of cytotoxic-

thesis. mem-

ity), a n d

i n f l u e n c e o f t h e b o d y o n t h e i m p l a n t (for

b r a n e , e i t h e r o v e r a fistula in t h e h o r i z o n t a l s e m i c i r -

example,

degradation).

Type

V. canal

Reconstruction or

with

of

the

secondary

tympanic

fenestration

of

the

horizontal semicircular canal. to

be

performed,

alone

or

in

membranes—myringoplasty/tympa-

Labyrinthine

windows—tympanoplasty

with

2. Biotolerant—good

factors—eustachian

tube

(PE

tube),

capsule

around

it

without

signs of m a r k e d cellular activity (such as giant cells) 3. Bioactive—bonding

stapedectomy 4. Aeration

1. B i o i n e r t — n o reaction of the surface to the body (at m o s t a s m a l l , f i b r o u s c a p s u l e is s e e n ) .

2. Ossicular chain—tympanoplasty/ossiculoplasty. 3.

I n t e r m s o f its i n t e r a c t i o n w i t h t h e b o d y , a m a t e r i a l can be:

combination, include the following: 1. T y m p a n i c

2. Biofunctionality—symbiosis of the implant with the i m p l a n t site.

either

noplasty.

b u t its c o n t i n u i t y i s p r e s e r v e d .

Grafts

gories:

PORP—Partial

Procedures

and

to the s u r g e o n .

R e c o n s t r u c t i o n of a n e w t y m p a n i c m e m -

IV C G — C a r t i l a g e graft.

cular

Type / . T h e t y m p a n i c m e m b r a n e i s p e r f o r a t e d ; I h e

traumatic,

or

ib-

i n t o t h e f o l l o w i n g five t y p e s :

the time of surgery. The disease can be inflammatory, congenital,

mem-

the following subcategories:

iri-

l e m . T h i s n e c e s s a r i l y will l e a d t o a g r e e m e n t o r c h a l -

the decision of what to use a n d h o w to use it belongs

with

brane on top of a mobile stapes. This is divided into

with

based on his or her o w n u n d e r s t a n d i n g of the pi

to work

b r a n e i n its n a t u r a l p o s i t i o n .

in

not as a m e r e surgical technique. T h o r o u g h knowl-

A l t h o u g h it is essential

He identified the following types:

divided into the following subcategories:

proached as a rational m e t h o d of reconstruction and i n t e r d e p e n d e n t factors and

of the

thesis.

the e x p e c t a t i o n that the r e a d e r will rationalize th •m

t o r e m e m b e r a t all t i m e s

s t a p e d e c t o m y in s e l e c t e d c a s e s , w i t h the graft inva-

Type IV.

entation

here.

the s u r g e o n m u s t " s w i m in a sea of g a d g e t s . " It is

HI

standing of these procedures.

overall

of p a r a m o u n t importance

o n e s e n s e o r a n o t h e r , c o n t r i b u t e t o a n o v e r a l l u n r er-

up.

an

described

f e n e s t r a t e d , a n d t h e graft is p l a c e d a g a i n s t it a n d the

III B G — B o n e g r a f t .

There are m a n v systems of classifications that

are

of

study is r e c o m m e n d e d , especially in these days when

Assessment

5. R e c o n s t r u c t i o n ( o n l y after s t e p s 1 t h r o u g h 4 are

purposes

aspects

fixed footplate. T h e horizontal s e m i c i r c u l a r canal is

ear.

done).

basic

the

Type V . T h i s i s s i m i l a r t o t y p e I V ,

b u t t h e r e is a

some

For

K n o w l e d g e of these e l e m e n t s is essential and further

Ill M G — M a l l e u s h e a d graft.

Classifications of Tympanoplasty

tympanoplasty.

T h e graft is placed against the footplate.

brane a n d columella or footplate of stapes.

3. Complete

cavity—tympanomastoidec-

concept,

tube.

patient's

Tympanomastoid

A n u m b e r of grafts a n d materials can be used in incus,

Ill 1 G M — I n c u s graft to m a l l e u s .

mastoid-middle ear communication,

5.

graft

The

Ill I G — I n c u s graft.

needs.

4.

stapes.

the stapes are missing. T h e r e is a mobile footplate.

B. M a s t o i d air cells. C.

mobile

III—Classic.

a n d facilitates c l e a n s i n g a n d inspection.)

under control. T h e y are also performed w h e n there

and the affected ear as a w h o l e .

and

placed against the stapes.

Type III.

well-aerated

tion, with the originating or u n d e r l y i n g d i s e a s e well

T h e s e procedures involve the following steps:

(mastoidotomy/mastoidectomy).

an intact ossicular chain.

tomy.

m a s t o i d air cells, m a s t o i d m i d d l e ear c o m m u n i c a t i o n

Type 111. T h e m a l l e u s a n d i n c u s a r e m i s s i n g , a n d

Type IV.

Tympanoplasty

t h e graft i s p l a c e d a g a i n s t the

incus or malleus, or b o t h (physiologic type II).

surrounding

tissue.

of

the

material

with

the

220

Tympanoplasty

Grafting of the Tympanic Membrane

the

perichondrium,

and

the veins.

The

most

cctn-

m o n l y used fascia is the temporal, w h i c h is available via the s a m e a p p r o a c h i n c i s i o n or a s m a l l s e p a r a t e i n c i s i o n , b u t i n t h e s a m e o p e r a t i v e field ( F i g . 1 2 - 1 D ,

T h e t y m p a n i c m e m b r a n e has three layers: (1) an outer (lateral) stratified s q u a m o u s e p i t h e l i u m (continu o u s with that of the ear canal); (2) a m i d d l e c o n n e c tive t i s s u e c o r e c o n t a i n i n g c o l l a g e n a n d e l a s t i c fibers (plus the vascular e l e m e n t s ) ; a n d (3) an inner layer ( c o n t i n u o u s with that of the m i d d l e ear m u c o p e r i o s -

E). It is i m p o r t a n t to obtain fascia proper a n d not the l a y e r o f a e r o l a r c o n n e c t i v e t i s s u e o v e r l y i n g it, t h e s o called "fool's fascia" (the latter also has collagen and can b e u s e d for grafting). P e r i c h o n d r i u m c a n a l s o b e obtained

the

tragus

as

such,

or

as

a

A vein from the d o r s u m of the h a n d also is easily

Perforations that heal s p o n t a n e o u s l y tend to exclude the connective tissue layer ( m o n o m e r i c membrane). T h o s e m e m b r a n e s that do not ingrowth

covering

the

of

the

outer

edges of the

heal tend

squamous

perforation.

to

epithelium The aim of

grafting is a truly a n a t o m i c reconstruction. T h e collagen

layer

placed

as a

graft

reinstates

the

middle

layer, allows epithelial cells to migrate, re-establishes

obtainable (see C h a p t e r 13).

vibratory characteristics. This s the concepts reinforcing

monomeric

membranes

and

peeling

costochondral cartilage,

and so on can be used,

as

well as allogeneic dura mater, a m n i o t i c m e m b r a n ; , and

cornea.

the

last

The

three;

authors

have

reports on

no

their

experience

use,

as well

with as cn

other tissues (such as heart valves), are not definitive. Allogeneic successful

tympanic

(under

the

membrane proper

are

very

circumstances),

grafts

and

represent a good anatomic and functional alternative. A

the e d g e s of a perforation before grafting.

In addition, allogeneic

( h o m o l o g o u s ) p e r i c h o n d r i u m from the tibia, s e p t u m ,

c o n t i n u i t y , a n d p e r m i t s t h e m e m b r a n e t o r e c o v e r its of

from

also c o m e from conchal cartilage.

teum).

have

easily

c a r t i l a g e - p e r i c h o n d r i u m g r a f t ( s e e C h a p t e r 1 0 ) . I t ct.n

long-term

donor

drawback

tissue;

this

is

might

that

of viruses

compromise

living

the

use

in cf

allogeneic grafts in the future. The

Tissues and Materials

and

ideal

elastic

graft

material

w o u l d be

fibers

capable

of

pure collage i

providing the

middle

layer, b e c o m i n g i n c o r p o r a t e d to the m e m b r a n e , a

d

allowing and favoring epithelial migration. X e n o g e n e i c ( h e t e r o l o g o u s ) materials, s u c h as b i-

Skin. S k i n i s v e r y u s e f u l f o r c o v e r i n g r a w a r e a s i n mastoid

bowls

coverage grafts)

and,

over

and at

meatoplasty. times,

collagen

thickness and,

more

from

and

infection

It

also

provides

vine dura

(in

pedicled

some

vascularity

grafts;

this

importantly, granulation

gives

additional

mater,

groups

are currently

and,

if

being

successful,

evaluated

could

Sy

eventual v

b e c o m e available.

p r o t e c t s t h e graft

tissue.

It

must

be

r e m e m b e r e d t h a t a free c o l l a g e n graft (for e x a m p l e ,

Grafting of the Ossicular Chain

f a s c i a ) h a s n o b l o o d s u p p l y o f its o w n ( w h e n origin a l l y p l a c e d ) , a n d i s a n e a s y p r e y f o r i n l c c t i o n .inc.1 granulation tissue.

As useful as skin

mav be,

ever, it d o e s not replace c o l l a g e n grafts.

hou -

Placed bv

I hose three inlcrlockcd ossicles (under the prote\ live

influence

itself as sole c o v e r a g e of a perforation, it is d o o m e d

transmit

sound

Iwo

middle ear

w a v e s as a

totally fixated, d i s l o c a t e d , or d e s t r o y e d . T h e p u r p o s

area

from

the

upper arm,

forearm,

thigh,

or abdo-

of

grafting

to

re-establish

functional

1

continuit/-

from

12-

Ideally,

M).

the

tioned a n d shaped; be readily available; c a u s e mini

postauricular

region

full-thickness graft

(Fig.

12-18)

c a n a l s k i n (for e x a m p l e , via a

or

from

the

posterior

L e m p e r t 11 incision

grafts a n d

remain

in

tympanic

or p e d i c l e d graft.

clude

advantage of being thick a n d c u m b e r s o m e

to work

with, but they have their o w n blood supply Collagen.

S o u r c e s of collagen are

mainly

t h e fascia,

the oval w i n d o v

materials should

be easily pos

mal tissue reaction; r e m a i n stable with infection; a n c

[Fig. 1 2 - 1 C ] ) , or f r o m t h e m e d i a l c a n a l skin as a free P e d i c l e d s k i n grafts h a v e t h e dis-

to

partly

men, by using a d e r m a t o m e (DaSilva-Doval-Silver) also be a

tympanic membrane

be

or a plain r a z o r b l a d e on a straight c l a m p (Fig. It can

the

is

can

t :

membrane

non-hair-bearing

window,

whic i

the t v m p a m :

(0.003

from a

oval

muscles), from

to failure. S k i n c a n be o b t a i n e d as a split-thickness 0.004 cm)

the

unit

graft

to

to

ol

position,

not extruding or d a m a g i n g

membrane.

resorption,

Common

rejection,

complications

fixation,

thin-

displacement,

and extrusion. A brief overall a s s e s s m e n t follows; a comprehensive

description

is

outside

the

scope

o'

this book. FIGURE 12-1

222

Tympanoplasty

Tissues and Materials

d e n t i s t r y . G l a s s - c e r a m i c s a r e p r o d u c e d b y t h e r m illy treating glass, obtaining a polycrystalline microstjucture.

Ossicles

and

Cortical

Bone.

Ossicular

and

cortical

that

The

advantages of

these

they are biocompatible,

dense

materials

biofunctional,

are

easy

to

b o n e ( a u t o l o g o u s or allogeneic) grafts are available,

place

are easily s c u l p t u r e d , are the best t o l e r a t e d , and are

shape. T h e authors have found,

least likely to extrude. T h e i r d r a w b a c k s i n c l u d e dis-

are hard to r e s h a p e and s o m e t i m e s break, e v e n wl en

placement,

shaped with

the

refixation,

margins

of

the

and a oval

t e n d e n c y to a d h e r e to

window,

to

extrude

or

and

manipulate,

and,

reportedly,

easy

to

h o w e v e r , that tl ey

a d i a m o n d drill u n d e r c o n s t a n t irriga-

t i o n . A l t h o u g h p r o m i s i n g , t h e s e m a t e r i a l s h a v e still

displace if there is no m a l l e u s (the latter is c o m m o n

to withstand

t o all p r o s t h e s e s ) , a n d t o a t r o p h y .

s u g g e s t s that t h e y p r o b a b l y will; t i m e a n d e x p e r i e n c e

Cartilage.

Cartilage

grafts are available, erated,

and

cartilage

show

few

years

denied

(autologous

(this

by

is

Evidence

the most c o m m o n l y used ceramic is the bioactive,

little

and

ed In

extrusion.

working well at

However,

porous, crystalline form of calcium p h o s p h a t e .

the onset

glass is an e x a m p l e of glass a n d ceravital, a form of

"fall a p a r t " after a

by

some

addition,

reports

cartilage

but

tolerates

infection poorly. Plastics.

time in otology.

s h o u l d tell u s ( n o t t h e m a n u f a c t u r e r s ) . I n p r o s t h e t i c s ,

rigidity

others).

test of

a r e e a s i l y s h a p e d a n d w e l l tolvery

or

the

allogeneic)

lacks stiffness,

but t e n d i n g to lose

calcium phate

phosphate

ratio

apatite,

as

with

the

which

to

obtain

bone

perhaps

s t a p e d e c t o m y . A l t h o u g h this solid plastic h a s s m o o t h

possible,

surfaces, it has no long-term inflammatory reaction

same."

An excellent material w h e n properly used,

it is not

materials fulfilling

the

Plastics.

that are the

mineral

most

as

close to natural

concept

of

Silastic is c o m m o n l y

"replacing

is

wj h

in m i d d l e e i r

used

surgery as thin s h e e t s a n d as PE tubes. It is bioineri

t h e s i s ) . T e f l o n is a g o o d m a t e r i a l for PE t u b e s .

(that is, it elicits no l o n g - t e r m i n f l a m m a t o r y r e a c t i o n ) ; its

uses are (1)

to

prevent adhesions when

placed

b e e n u s e d in T O R P s a n d P O R P s , is still a s u b j e c t of

over

c o n t r o v e r s y . Its i n i t i a l l y i m p r e s s i v e s u c c e s s w a s fol-

prostheses or grafts,

lowed by an equally unimpressive and disappointing

space; and (2) to avoid a d h e s i o n s b e t w e e n different

rough,

lacerated

surfaces

or

surrounding

thus allowing an aerated open

failure in t e r m s of e x t r u s i o n rate. Plastipore is easilv

middle ear structures

available; is not so rigid as o s s i c l e s or c e r a m i c s ; can

function.

be easily s h a p e d according to need; is hiomechani-

smoothly at the e d g e s , it can extrude. Specific uses

cally s o u n d ; is relatively e a s y to position a n d sterilize

are described in various c h a p t e r s of this b o o k

(this requires skill to do p r o p e r l y ) ; d o e s not a d h e r e

If

Celfonm.

not

that

could

positioned

Gelfoam

compromise

properly

(denatured animal

or

skin

the r

trimmed

g e l a t r.)

to the m a r g i n s of the oval window-; a n d is an efficient

is used universally in otologic surgery. This absorb-

s o u n d c o n d u c t o r . Its d r a w b a c k s are that it c a u s e s a

a b l e g e l a t i n i s a v a i l a b l e a s a s!> r i l e p o w d e r , s p o n ; e ,

foreign

o r film ( 0 . 0 7 5 m m t h i c k ) . O n l v t h e last t w o f o r m s ; r e

extrude and

reaction

in

the

middle

ear,

and

can

slip. T h e high e x t r u s i o n rate is signifi-

used. T h e sterile s p o n g e form, w h i c h is c a p a b l e

>(

cantly d i m i n i s h e d by placing cartilage over the pros-

a b s o r b i n g a n d h o l d i n g w i t h i n i t s m e s h e s m a n y tirr, ' s

thesis (beneath the tympanic m e m b r a n e or tympanic

its w e i g h t i n w h o l e b l o o d , i s a b s o r b e d c o m p l e t e l y

m e m b r a n e graft, ideally u n d e r t h e m a l l e u s ) . S l i p p a g e

four to six w e e k s . It is u s e d as a h e m o s t a t i c a g e r t,

n

at the oval w i n d o w ( w h e n placed over intact, mobile

to

footplates) can be reduced by creating a small open-

between

the graft a n d

ing in the footplate, through w h i c h a T O R P with a

promote

a

peg in

(described below).

c e r t a i n p o i n t s , a n d as a v e h i c l e for a n t i b i o t i c - s t e r o i

its d i s t a l e n d i s i n s e r t e d

pack

the

middle mild

ear

cavity,

the

to

apply

pressu-e

tympanic membrane,

inflammatory

reaction

needed

o :>. 1

P O R P s c a n b e s t a b i l i z e d b y m a k i n g a slit t h a t a l l o w s

s o l u t i o n s . G e l f i l m is an a p p a r e n t l y brittle film th t

a m o r e stable c o n t a c t with the stapes head. In spite

b e c o m e s soft a n d r u b b e r y w h e n m o i s t e n e d i n salin

of

of

It is u s e d to d i s c o u r a g e a d h e s i o n s , such as in s e p : •

Plastipore w o r k very well in properly selected cases

ration of the i n c u d o s t a p e d i a l t from the t y m p a n . c

these

and

drawbacks,

remain

a

first

TORPs

choice

and

under

PORPs the

made

proper condi-

tions. Ceramics. produced at

.

m e m b r a n e . I n its d r y f o r m , G e l f o a m s h o u l d b e d t • c o m p r e s s e d ; w h e n saturated, it should be s q u e e z e i

Ceramics,

inorganic

high temperatures,

crystal are

the

materials "in"

mate-

rials i n o s s i c u l o p l a s t y a n d r e c o n s t r u c t i v e e a r s u r g e r y T h e y have been used successfully in orthopedics and

l o o k e d for ( F i g . 1 2 - 2 D , E ) . T h e t y m p a n i c m e m b r a n e itself m a y be n o r m a l , a t r o p h i c , sclerotic,

b e c o m e a focus of infection.

tracted, or adhesive.

Tissue

Adhesions

("Glues").

in o r d e r to r e m o v e air b u b b l e s . Gelfilm is not useft,! as a graft for t y m p a n i c m e m b r a n e p e r f o r a t i o n s . G e l f o a m s w e l l s as it a b s o r b s fluid. As it e x p a n d ? it i m p i n g e s on neighboring structures (which is whi

thick,

re-

the

T h e s e conoitions give an index of such factors as

Histoacryl (cy-

the u n d e r l y i n g c a u s e , e u s t a c h i a n tube function, aer-

Glues have been

d r e a m o f m a n y o t o l o g i s t s for y e a r s .

anobutyl acrylate) a n d Fibrin, the t w o t y p e s that are

ation, vascularity of the m e m b r a n e , and so on.

available,

of t h e s e will affect the graft take a n d influence the

ideal. must

work

fairly

acceptably

but

are

far

from

Either they m u s t await the test of time or we await

a

better

adhesive.

The

description

All

selection of the type of repair.

of

them is b e y o n d the s c o p e of this book.

Approach Myringoplasty-Type I Tympanoplasty

T h e r e are

no

fixed

rules

for a c h i e v i n g

t h e final

purpose, which is adequate visualization through an o p e n canal, allowing a g o o d a s s e s s m e n t and repair.

hydroxy-

biocompatible

efficient as a T O R P (total o s s i c u l a r r e p l a c e m e n t prosPlastipore (high-density polyethylene), which has

it w o r k s well in filling the middle ear cavity w h e n a n u n d e r l a y graft i s p l a c e d ) . G e l f o a m p o t e n t i a l l y m a y

the s a m e calcium-to-phcs-

natural

is

Bio-

material available. T h e essential aim in prosthetics is

T e f l o n is u s e d p r i m a r i l y as a p i s t o n for a

body

223

Tympanoplasty

A m y r i n g o p l a s t y a n d a t y p e I t y m p a n o p l a s t y in-

The approach

should

provide

a

clear

visualization

volve repair of the tympanic m e m b r a n e alone. " M y -

around the borders of the perforation and,

ringoplasty" is

clear visualization of the entire annulus. Otologists

the

term

used

when

the

operation

ideally,

d o e s not i n c l u d e raising flaps t o e n t e r t h e m i d d l e e a r

should be capable of adapting the approach

cavity,.whereas a tvpe I tympanoplasty implies the

n e e d s of the case a n d not vice versa. T h e r e are a

opposite.

Different' types' of

tympanoplasties

and

ossiculoplasties involve procedures in the different

number of

situations

structures of the middle ear at or b e y o n d (medial to)

lighted with

the

are relative.

tympanic membrane.

T h e broad

term

"tympa-

in

which

certain advantages over others.

n o p l a s t y " i s u s e d for a n y p r o c e d u r e w h o s e p u r p o s e

the

one

approach

T h e y will

understanding

to the

that

all

has

be highguidelines

T h e alternative a p p r o a c h e s are the transcanal, the

is to eradicate disease and reconstruct the hearing

endaural, and

mechanism

p r o a c h is u s e d in g e n e r a l for small p e r f o r a t i o n s , or

with

or

without

tympanic

membrane

the

postauricular.

A

for m e d i u m

previously described

that allows a clear visualization of the anterior border

under control,

an

overall

analysis of the required procedure involves several

of the perforation.

aspects.

'hat are

T h e anatomy of the tympanic m e m b r a n e must be

large

in

a

ap-

g r a f t i n g . P r o v i d e d t h a t all t h e i n t e r d e p e n d e n t f a c t o r s are

posterior perforations

transcanal

wide canal

I t i s i n a d e q u a t e for p e r f o r a t i o n s

or

that

involve

the

annulus,

or

for

c a s e s that m i g h t n e e d a n associated m a s t o i d proce-

considered. T h i s includes not only the site and extent

dure. An e n d a u r a l a p p r o a c h p r o v i d e s g o o d visibility,

of the perforation but also the status of the m e m b r a n e

especially

(atrophic, atelectatic, with tympanosclerotic plaques,

perforations, an associated canalplasty is necessary,

and so o n ) . Based on this information, an approach

This approach

i s s e l e c t e d , t y p e s o f s k i n flaps (if a n y ) a n d g r a f t i n g

small,

of

the

posterior quadrants.

allows a

thick meatus.

meatoplasty

provides good

visibility,

especially

the graft is d e c i d e d ( u n d e r l a y u n d e r t h e m e m b r a n e

margin of

tympanic

membrane:

or overlay o v e r the m e m b r a n e ) .

view without a canalplasty.

A

tympanic

membrane

perforation

may

be

re-

in

cases

of a

A postauricular a p p r o a c h also

material to be used are chosen, and positioning of

the

For anterior

of

the

it

anterior

allows

this

It is useful for m e d i u m

to large perforations as well as anteroinferior perfo-

stricted to o n e quadrant a l o n e — t h e posterosuperior,

rations,

posteroinferior, anterosuperior, or anteroinferior. A

Regardless of the approach,

with

or

without

alteration

of the

annulus.

preservation of the an-

perforation of Shrapnell's m e m b r a n e constitutes an

nulus maintains the middle ear space, provides sup-

e x c e p t i o n t o t h i s ; e x p l o r a t i o n i s a d v i s e d i n all c a s e s .

port, a n d r e d u c e s the risk of retraction.

B e c a u s e of the anatomic position of Shrapnell's m e m brane,

epithelial

ingrowth

is

always

a

possibility,

R e v i s i o n s u r g e r y i n g e n e r a l i s d o n e via a n a l t e r n a t e incision that a l l o w s a graft to be o b t a i n e d . T h e m a i n

e v e n w i t h a n o r m a l a u d i o g r a m (for e x a m p l e , a " c o n -

q u e s t i o n s in revisions are (1) W h y did the p r o c e d u r e

ductive" cholesteatoma).

fail

A p e r f o r a t i o n a l s o c a n in-

volve m o r e than o n e quadrant (Fig. 1 2 - 2 A , B), or it

initially?

(2)

Was

failure

caused

by

exposure,

clinical error, or u n d e r l y i n g d i s e a s e ?

m a y i n v o l v e the a n n u l u s . It can be total (Fig. 1 2 - 2 C ) ,

Whichever approach is chosen,

the canal should

central, or marginal. If there are several perforations,

be smooth and there should be no bony overhangs,

underlying disease (such as tuberculosis) should be

If

the

annulus

is

missing,

a

sulcus

(if

necessary)

224

Tympanoplasty 225

Tympanoplasty

should be created (to prevent blunting). If an attico-

a

tomy is performed,

perforation a n d toward the a n n u l u s (Fig.

the attic m u s t be reinforced.

If

flap,

an

incision

is

made

in

the

middle

of

the

1 2 - 5 / 1 , B)

the eustachian tube is dysfunctional a PE tube should

T h e t y m p a n i c m e m b r a n e is carefully reflected, allow-

be considered.

ing e n o u g h space to apply G e l f o a m in

Once formed

the and

approach the

has

tympanic

been

selected

membrane

and

per-

is visualized,

the next decision is the canal incisions to use. (Before elevating

the

flaps,

any

tympanic

membrane

work

the middle

ear a n d a m e d i a l ( u n d e r l a y ) graft (Fig. 1 2 - 5 C ) . T h e tympanic m e m b r a n e is repositioned and Gelfoam is applied over it (Fig. 1 2 - 5 D ) . F o r a s m a l l central p e r f o r a t i o n , an u n d e r l a y graft

[such as trimming the edges] should be performed,

is placed through the perforation (Fig.

12-5E), The

since it is simpler at this time a n d the m e m b r a n e is

edges of the perforation are trimmed

meticulously,

i n its n a t u r a l p o s i t i o n . ) T h e b a s i c p r i n c i p l e i s t o e n t e r

and

the

scraped

middle ear cavity (type

way and

that

allows

adequate

1

tympanoplasty)

inspection

efficient p l a c e m e n t of a graft.

of

the

in

a

cavity

T h e alternatives

the

undersurface

of

(freshened);

this

the

membrane

includes

is

gently

cleansing

(if

n e e d e d ) of the m a n u b r i u m . T h e middle ear cavity is filled with c o m p r e s s e d G e l f o a m (Fig.

12-5F) and a

are m a n y a n d vary according to n e e d a n d preference,

fascia graft is placed t h r o u g h the perforation, m a k i n g

as well as the imagination of the surgeon, A classic

sure that the e d g e s of the perforation are overlapped

p o s t e r i o r c a n a l flap (1 a n d 6 o ' c l o c k vertical i n c i s i o n s )

by the graft by m o r e t h a n 3 0 % . If n e e d e d , a piece of

offers a d e q u a t e e x p o s u r e in

m o s t (if n o t all) c a s e s

fascia i s p l a c e d b e t w e e n the t y m p a n i c m e m b r a n e a n d

a n d is a g o o d alternative. An anterior or an inferior

the long process of the malleus. T h e malleus handle

flap m i g h t suffice ( F i g .

can be de-epithelialized a n d a piece of fascia placed

12-3A-C),

or a

"swinging

d o o r " technique can be used (Fig. 1 2 - 3 D , E). If skin reinforcement

is

needed,

a

pedicled

flap

can

be

utilized. S o m e o f the m o s t c o m m o n l y u s e d flaps will

laterally. T h e s e procedures require a healthy, well-vascularized

tympanic membrane.

be described in the discussion of specific procedures. T h e y are simply alternatives and are not necessarily the only choices.

Overlay Technique in Central Perforation

Small Central Perforation Critical Points T h e edges of the perforation are

touched

with a

blunt pick m o i s t e n e d in trichloroacetic acid (Fig. 1 2 4/1). U p o n with the acid, the e d g e s acquire a white a p p e a r a n c e . A p a p e r patch (cigarette paper) is

1. C o m p ' e t e

de-epithelialization.

2. A well-defined,

well-placed anterior tympano-

meatal angle junction. 3 . A t t a c h m e n t o f graft t o h a n d l e o f m a l l e u s .

applied overlying the perforation (Fig. 1 2 - 4 6 ) . It is important

to

prevent a n y acid

from

falling into the

middle ear cavity since this is e x t r e m e l y painful; the

Procedure

i n s t r u m e n t s h o u l d be barely m o i s t e n e d . If this c o m plication

occurs,

neutral

pH

otic

drops

should

be

temporal

i c a t i o n . T h i s d o e s n o t w o r k all t h e t i m e a n d c a n o n l y

posterior c a n a l is m a d e at t h e j u n c t i o n of the lateral

be u s e d

and m i d d l e thirds of the canal.

for a

small

perforation

in

a

healthy mem-

For

T h i s p r o c e d u r e in-

tiny

central

perforations,

the

edges

can

be

d o w n to 2 mm lateral to the a n n u l u s (excepting the

trimmed (Fig. 1 2 - 4 C , D); a small triangle w e d g e with

area of skin c o n t a i n i n g the vascular strip).

its b a s e i n t h e a n n u l u s i s t h e n c r e a t e d ( F i g . 1 2 - 4 E ) .

incisions are m a d e at 10 a n d 1 o'clock (Fig. 1 2 - 6 / 1 ) .

The annulus is elevated (anteroposterior edge) and

T w o circumferential incisions are m a d e ,

slid t o w a r d t h e p r o x i m a l ( n o n e l e v a t e d ) e d g e , a l l o w -

mm

ing

tween 10 and 1 o'clock) and the second at the junction

the edges of the

together (Fig. FIGURI; 12-2

fascial graft o b t a i n e d . T h e incision of the

volves r e m o v a l of the canal skin from this junction

brane.

E

A postauricular approach has been selected and a

used in conjunction with an anti-inflammatory med-

12-4F).

tympanic membrane Small

to come

pieces of Gelfoam

are

applied over the approximated e d g e s F o r a very small central perforation that requires grafting, the e d g e s are t r i m m e d a n d the undersurface of the m e m b r a n e is gently scraped. Instead of raising

lateral

to

the a n n u l u s

(excepting

Vertical

t h e first 2

the

area

be-

of the lateral and middle thirds of the canal. (This is an extension of the canal

incision along the whole

circumference.) T h e skin is carefully elevated in one piece a n d preserved. A canalplasty is d o n e if n e e d e d . The tympanic m e m b r a n e is meticulously de-epitheText

continued

on

page

230

226

Tympanoplasty

Tympanoplasty

1

(~

....""

.....

----------------.,

\

E

fiCURE 12-4 rieUR!' 12-3

227

228

Tympanoplasty

Tympanoplasty

229

Tympanoplasty 230

Tympanoplasty

lialized curets

with

a

(Fig.

t or

12-68).

No.

The

2 canal

knife or s m a l l

middle ear is

filled

vertical i n c i s i o n s at 1 a n d 6 o ' c l o c k is u s e d ( F i g . 1 >-

with

7 A); t h i s i s a g o o d c h o i c e b u t n o t t h e o n l y o n e . T u e

c o m p r e s s e d G e l f o a m , a n d t h e g r a f t i s n o t c h e d t o fit

flap is raised, a n d

around

beneath

the

manubrium

(Fig.

12-6C).

(The

manu-

the

the m i d d l e ear cavity is enter, d

annulus

that

the

annul, s

b r i u m is d e - e p i t h e l i a l i z e d a n d c l e a n s e d . ) T h e graft is

p r o v i d e s s u p p o r t a n d a l l o w s for m a i n t e n a n c e of ti e

placed e m b r a c i n g the m a n u b r i u m ; if n e e d e d , a piece

middle ear space. T h e middle ear space is inspecte i.

o f fascia i s p l a c e d o v e r the m a l l e u s h a n d l e (Fig. 1 2 -

(For inspection and evaluation,

6 D ) . T h e s k i n graft i s t h e n r e t u r n e d , o v e r l a p p i n g the

for A t e l e c t a t i c T y m p a n i c M e m b r a n e i n C h a p t e r I f . )

fascia

F o r this p r o c e d u r e (repair of a perforation a n d rein-

for a

few

millimeters.

Special care

must be

o b s e r v e d anteriorly in order to a v o i d b l u n t m g of the

f o r c e m e n t of

graft in the anterior t y m p a n o m e a t a l a n g l e . T h e canal

normal.

is packed,

usually with G e l f o a m in the medial two

the

membrane)

see Tympanoplas y

it

is

assumed

to

t e

A p i e c e o f t h i n S i l a s t i c s h e e t i n g i s p l a c e d f r o m tl"2

thirds (Fig. 1 2 - 6 F ) . In c a s e s w h e r e there is no fibrous

sinus

a n n u l u s , the sulcus should be c h e c k e d ; if shallow, it

m i d d l e e a r c a v i t y is filled w i t h c o m p r e s s e d G e l f o a n ,

can be drilled with a small bur.

a n d a piece of Gelfilm is placed over the i n c u d o s t i -

Incisions are closed

with appropriate sutures a n d a d r e s s i n g is applied.

tympanic

pedial t

area

(not

to

under

the

the

eustachian

annulus),

tube.

Ths

between

th t

t and the m e m b r a n e , in order to avoid adhesions from t h e graft t o t h e j o i n t ( F i g . 1 2 - 7 8 ) .

P r o b l e m s and C o m p l i c a t i o n s

The

Blunting of the anterior tympanomeatal the

most

feared

complication,

and

angle is

usually

occurs

w h e n there is no a n n u l u s and no sulcus. Drilling of the sulcus is helpful. Tight packing at this angle is i m p o r t a n t ( r o s e b u d p a c k i n g with O w e n ' s silk w o r k s quite graft

well

for

(lateral

this

purpose).

displacement)

Lateralization

happens

less

of

the

frequently

if the tip of t h e m a l l e u s h a n d l e is p l a c e d o v e r the fascia.

Residual cholesteatoma occurs w h e n dc-epi-

thelialization

of the

tympanic membrane

is incom-

fascia

greater than

graft the

is

positioned

extent

of the

over an

area 3 0 ?

perforation,

since

i:

will retract b y a b o u t 3 0 % ( F i g . 1 2 - 7 C ) . O n e c o n c e r t : with

grafts

is

the

possibility

of

lack

of

adequati

with the overlying tympanic m e m b r a n e .

B)

this "falling into the m i d d l e e a r c a v i t y " the bridging function

might

be

lost.

Although

compressed

Gel-

foam p r o v i d e s a d e q u a t e c o n t a c t (if placed c o r r e c t l y ) , a s o u n d alternative (with proven g o o d results) is the use

of

microclips

to

overlying membrane.

secure

the

graft

against

the

If the tympanic m e m b r a n e is

plete. Reperforation anteriorly is especially c o m m o n

w e l l d e - e p i t h e l i a l i z e d t h e c l i p s will not c a u s e a p r o b -

if there is no a n n u l u s . This is involved with

lem;

o f t h e graft ( b y t h e a n n u l u s ) a n d v a s c u l a r i z a t i o n i n

nique is not d e s c r i b e d in this atlas.) It is useful to

eventually

thev

will

be

extruded.

(This

tech-

l e a v e a tail ( o f t h e f a s c i a ) t o w a r d t h e p o s t e r i o r b o n •

the area

canal

to

be

removed.

c o n s e r v a t i v e l y ( i f a t all having

Underlay Graft for Posterior Perforation in Atrophic Membrane

the

graft

This

should

possible)

rest o v e r the

be

done

verv

in o r d e r to a v o i d

incudostapedial t

( w h i c h by n o w is c o v e r e d with G e l f i l m ) . T h e graft is placed e m b r a c i n g the handle of the malleus. A small p i e c e of fascia can

then be placed

over the handle.

T h e p i e c e o f s k i n h a r v e s t e d via t h e L e m p e r t I I i n c i Using

an

endaural

approach,

a

temporal

fascia

graft (by L e m p e r t I i n c i s i o n ) a n d a s m a l l s k i n graft (by a L e m p e r t II incision) h a v e b e e n obtained. T h e tympanic

membrane

is

visualized;

if

necessary,

a

sion is placed over the fascia ( c o v e r i n g the perforation) (Fig. Endaural

12-7D). incisions

T h e ear is packed are

closed

with

(Fig.

the

12-7E).

appropriate

sutures, a n d a d r e s s i n g is a p p l i e d .

canalplasty is d o n e . T h e e d g e s of the perforation are trimmed, the undersurface of the m e m b r a n e is gently scraped,

and

the

membrane

is

de-epithelialized.

C o m p l e t e de-epithelialization m u s t be d o n e if a skin graft

is

to

• however,

be

used.

complete

If the

membrane

de-epithelialization

Underlay Graft for Large Anterior Perforation

is atrophic, might

be

m o r e h a r m f u l t h a n useful (an u n d e r l a y graft i s b e i n g u s e d ) b e c a u s e o f t h e p o t e n t i a l for t e a r s . If a PE t u b e is being c o n s i d e r e d , this is the time t o s e l e c t a n a r e a a n d p l a c e it. In this e x a m p l e , a c l a s s i c p o s t e r i o r c a n a l flap w i t h

A t e m p o r a l f a s c i a g r a f t h a s b e e n o b t a i n e d v i a th< postauricular approach. A posterior canal incision v made at

the b o n y cartilaginous junction.

The

tym

p a n i c m e m b r a n e i s v i s u a l i z e d , t h e e d g e s o f t h e perforation

are

trimmed,

the undersurface

is

scraped,

FIGURE 1 2 - 7 .

231

233

Tympanoplasty

a n d t h e m e m b r a n e i s d e - e p i t h e l i a l i z e d . (It i s a s s u m e d

it

that a c a n a l p l a s t y is n o t n e e d e d . )

ossicles,

I n c i s i o n s are m a d e for t h e flap ( a c l a s s i c p o s t e r i o r canal tympanoplasty incision, although others could

the

use

of

the

tympanic

membrane

or

or a t y m p a n i c m e m b r a n e with ossicles.

A

d o n o r m e m b r a n e m u s t be selected of the p r o p e r size a n d s i d e t o fit w e l l i n t h e r e c i p i e n t .

have b e e n m a d e a s well) (Fig. 1 2 - 8 4 ) . T h e " s w i n g i n g doors"

allows

Assuming

either

an

endaural

or

a

postauricular

i m p l y t h e e l e v a t i o n o f s u p e r i o r l y a n d inferi-

approach, e n o u g h b o n e is r e m o v e d (by canalplasty)

orly b a s e d skin flaps. T h e horizontal incision is m a d e

to c o m p l e t e l y visualize the a n n u l u s (or the sulcus, if

5 to 7 mm lateral to t h e a n n u l u s . T h e flap is d i v i d e d

the a n n u l u s is not present).

w i t h a v e r t i c a l i n c i s i o n a t 9 o ' c l o c k (it c o u l d a l s o b e

meticulously cleansed, and the tympanic membrane

at 11 o'clock); this incision involves both the tympanic

remnants

m e m b r a n e a n d the a n n u l u s . T h i s results in two flaps

absent, the sulcus is carefully drilled in o r d e r to seal

(one superiorly a n d o n e inferiorly b a s e d ) , w h i c h are

the allograft in g o o d position.

elevated anteriorly up to (and b e y o n d

if necessary)

the m a l l e u s superiorly, a n d to 6 o'clock (or further) inferiorly.

(It i s a s s u m e d t h a t all t h a t i s n e e d e d i s p l a c e m e n t o f a graft.)

Incisions are

m a d e at

include the annulus,

11,

If

2,

the

and

annulus

is

7 o'clock and

unless the a n n u l u s is complete

S o m e G e l f o a m is placed, a n d allograft is positioned first o v e r t h e m a l l e u s ( F i g . 1 2 - 9 B ) . T h e f l a p s a r e t h e n repositioned.

I f o n l y t h e a n n u l u s i s left a n t e r i o r l y , t h e p r o b l e m

becomes

an

issue.

foam p a c k i n g should be planned.

Abundant

incisions

3

to 4

mm

in

length

(or

longer

if

Packing

is

done,

the

incisions

are

closed (Fig. 1 2 - 9 C ) , and a dressing is applied

Gel-

A good choice is

to de-epithelialize the a n n u l u s anteriorly and to make small

de-epithelialized.

(Fig. 1 2 - 9 4 ) . T h e flaps e x p o s e the m i d d l e e a r cavity.

T h e middle ear cavity is entered and examined

of.graft

are

T h e malleus handle is

A n a l l o g e n e i c t y m p a n i c m e m b r a n e graft tain

drawbacks.

Different

sides

(right

has cer-

or

left)

sizes m u s t be available in the operating room. not

easy

to

position

the

graft

properly.

and It is

Allografts

n e e d e d ) a n d raise a s m a l l anterior flap. T h e a n n u l u s

tend

i s g e n t l y e l e v a t e d a n t e r i o r l y for t h e s a m e e x t e n t a s

granulation tissue in the middle ear cavity.

the incision ( m a d e in the skin of the canal), a n d the

should be used, as well as G e l f o a m [conservatively]).

fascia

Immunologic

graft is

anterior

canal

flap (Fig. graft

in

pulled and

12-8B,

with

the

small

anterior

C). T h i s avoids retraction of the

critical

rejection

and

are

sometimes

associated

occurs.

a

potential

for t r a n s m i t t i n g viral

positioning is similar to that in the e n d a u r a l a p p r o a c h

easily

eliminated

s o u r c e of the allograft o b v i o u s l y is critical

tympani

to

the

(This

particles from

d e s c r i b e d a b o v e . ) A p i e c e of thin Silastic s h e e t i n g is sinus

with

(Silastic is

fairly w e l l c o n t r o l l e d , h o w e v e r . ) I n a d d i t i o n , t h e r e i s to

the

area.

adhesions

donor

from

a

covered

the

form

( T h e rest of t h e graft

placed

such

beneath the annulus onto

to

the

recipient, by

the

since s o m e viruses are not sterilization

processes.

The

eustachian

t u b e . T h e c a v i t y i s filled w i t h c o m p r e s s e d G e l f o a m ; a piece of Gelfilm is placed over the incudostapedial t. T h e graft is p l a c e d p o st er i o r l y as well, a n d the

Tympanoplasty-Ossiculoplasty

flaps are r e p o s i t i o n e d (Fig. 1 2 - 8 D ) . ( N o t e the distinct advantage of leaving

the vascular strip u n t o u c h e d . )

Packing is d o n e . Incisions are closed with appropriate s u t u r e s , a n d a d r e s s i n g is applied.

The

title

of

this

section

is

chosen

for

didactic

p u r p o s e s . H o w e v e r , the r e a d e r s h o u l d b e a w a r e that an o s s i c u l o p l a s t y is part of a t y m p a n o p l a s t y . T h e s e procedures involve

restoring

the sound

conduction

capabilities of the ossicular chain with or without a t y m p a n i c m e m b r a n e graft. T h e e n d result s h o u l d b e

Allograft for Total Perforation

continuity in vibration of the n e w c h a i n , with a solid with

l

he

tympanic membrane and a

mobile

oval w i n d o w m e m b r a n e o r plate. The allograft

use

of

an

constitutes

allogeneic one

more

tympanic

restoring continuity of the m e m b r a n e .

The

ossicular

chain

or

its

components

can

be

affected by fixation, dislocation, fracture, or dissolu-

Its i n d i c a t i o n s

tion (resorpti j n ) . T h e s e c o n d i t i o n s m a y b e c o n g e n i -

means

are s i m i l a r to o t h e r s , but this graft is e s p e c i a l l y u s e d

tal, o r t h e y c a n b e c a u s e d b y t r a u m a ,

for f a i l u r e s o f s t a n d a r d

re-

i n f e c t i o n . Th-.> c h o i c e o f p r o c e d u r e w i l l d e p e n d u p o n

tympanoplasty

(such

as

neoplasm, or

and

the type of ossicular p r o b l e m , the a n a t o m i c environ-

in c a s e s in w h i c h t h e r e is a high risk of failure with

m e n t , the s p a c e available (intact post wall, canal wall

standard tympanoplasty.

down,

and

(which

in

current

rïCURE 12

membrane of

effective

perforations or lateralization

of grafts),

An allograft is not a pana-

cea and is not easy to position adequately; however,

so turn

on),

and

depends

the

status

upon

the

of

the

status

mucosa of

the

234

Tympanoplasty

•

underlying

disease).

For

practical

purposes,

it

is

a s s u m e d that the u n d e r l y i n g disease is u n d e r control and that the middle ear space is adequate. sible

ossicular

changes

and

examples

b o d y for fitting u n d e r t h e m a l l e u s h a n d l e (Fig.

12-

114, B).

All p o s -

of

235

Tympanoplasty

3. U s i n g

cortical

bone.

A

graft

that

is

shaped

surgical

similar to a sculptured incus or malleus head can be

repair in s e l e c t e d s i t u a t i o n s will be d i s c u s s e d , w i t h

d r i l l e d , c r e a t i n g a c o n c a v e h o l e t o fit o v e r t h e h e a d

the u n d e r s t a n d i n g that there are o t h e r choices avail-

of the stapes a n d a n o t c h or a g r o o v e to fit u n d e r

able.

t h e m a l l e u s h a n d l e ( F i g . 1 2 - 1 1 C , D ) . (If d e s i r e d , a T shaped cortical b o n e can be used.) 4. U s i n g a partial ossicular r e p l a c e m e n t prosthesis

Isolated Ossicular Lesions

( P O R P ) . T h e larger surface area of a P O R P provides more stability; h o w e v e r ,

it m u s t be covered with a

thin piece of cartilage ( s u c h as tragal cartilage) that

Malleus

exceeds

(Fig. 1 2 - 1 0 4 )

must

T h i s is an essential b o n e in ossiculoplasty repair. T h e presence or a b s e n c e of the handle of the malleus, together with

the presence or absence of an

and mobile stapes,

intact

will d e t e r m i n e in great part the

type of procedure to be performed. T h e m a l l e u s is rarely affected alone; if it is, the may

also

associated

be

with

a a

traumatic mobile

dislocation.)

stapes,

an

If

it

is

atticotomy

is

d o n e with e x p o s u r e of the incudomalleal t (Fig 1 2 - 1 0 B , C) (see C h a p t e r 13). T h e fixation is verified, and the t is separated with a t knife. Points to :

slight

PORP.

tension

When

over

placed,

the

it

tympanic

the

PORP

and

the

malleus

handle.

If there is no

malleus handle, the cartilage is placed directly under the

tympanic

graft;

in

membrane

these

cases,

a

or

tympanic

large

piece

membrane

of cartilage

is

S o m e s u r g e o n s even suture the cartilage

to the h e a d of the P O R P . In the distal portion of the P O R P , a n o p e n i n g o r n o t c h i s m a d e for b e t t e r c o n t a c t with the h e a d of the stapes and stapedial tendon. In s o m e c a s e s a P O R P can be carved from cartilage, and t h i s t y p e o f g r a f t fits q u i t e w e l l ( F i g . 1 2 - 1 2 B ) . I t a l s o allows trimming of the head of the cartilage P O R P t o fit t h e a n g l e d p o s i t i o n o f t h e m e m b r a n e ( F i g .

12-

the incudosta-

12C). In positioning P O R P s (and T O R P s ) , abundant

pedial t b e f o r e drilling in the attic. T h i s will h e l p

Gelfoam is placed in the middle ear cavity in order

to avoid inner ear d a m a g e . Reinforcing the postero-

to

superior canal quadrant (atticotomy site) before clo-

positioning the

sure

ramic P O R P s are also available (Fig. 1 2 - 1 2 D ) .

will

discourage

Disarticulate

a

m e m b r a n e (Fig. 1 2 - 1 2 4 ) . T h e cartilage is b e t w e e n

preferred.

p r o b l e m usually is an anterior fixation of the h e a d . (It

the edges of the

provide

retraction

pockets

and

other

provide

and

maintain

flaps a n d

position

after re-

tympanic membrane.

Ce-

complications. The

head

of

the

malleus

is

amputated

with

a

m a l l e u s n i p p e r (Fig. 1 2 - 1 0 D ) . T h e i n c u s a l s o i s re-

Incus

(Fig. 1 2 - 1 3 4 )

m o v e d , s i n c e it h a s lost its a r t i c u l a t i o n to the h e a d o f t h e m a l l e u s . R e c o n s t r u c t i o n will b e b a s e d t o w a r d the head of the stapes. laying

the

tympanic

There are two alternatives:

membrane

(intact

or

grafted)

The assume

incus an

problems

intact

and

malleus

repairs handle

discussed

and

here

stapes.

The

incus is the ossicle most c o m m o n l y affected by ear

o v e r t h e h e a d o f t h e s t a p e s ( c l a s s i c t y p e III t y m p a -

infections

n o p l a s t y ) (Fig. 1 2 - 1 0 E ) , a n d placing a graft or pros-

trauma (fracture-dislocation).

(erosion

of

the

lenticular

process)

and

It may also be absent

thesis b e t w e e n the mobile handle of the malleus (the

( o w i n g to t r a u m a or p r e v i o u s s u r g e r y ) or fixed (usu-

fixed h e a d has b e e n a m p u t a t e d ) a n d the h e a d of the

ally i n a s s o c i a t i o n w i t h t h e m a l l e u s h e a d ) .

stapes.

The

establishing

latter course continuity

is

in

better

an

in

adequate

of

middle

reear

space. This can be d o n e in a n u m b e r of ways: 1. Using

the

head

of

the

malleus.

Holding

If e r o s i o n involves a

small

p o r t i o n of the distal

e n d o f t h e l e n t i c u l a r p r o c e s s , c o n t i n u i t y c a n b e reestablished by any of the following methods:

the

1. U s i n g a cortical b o n e c h i p . A s q u a r e of b o n e is

head of the malleus with an ossicle holder, shape it

delineated

t o fit b e t w e e n t h e h e a d o f t h e s t a p e s a n d h a n d l e o f

s m a l l a c e t a b u l u m i s drilled for t h e h e a d o f t h e s t a p e s ,

the m a l l e u s . Drill a h o l e in it to r e c e i v e the h e a d of

a n d a g r o o v e for t h e r e m a i n i n g l o n g p r o c e s s o f t h e

t h e s t a p e s . T h e n flatten it ( n o t c h it a little, m a k i n g a

incus (Fig. 1 2 - 1 3 B - E ) .

g r o o v e ) t o fit u n d e r t h e h a n d l e ( F i g . 1 2 - 1 0 F ) .

2. U s i n g

2. U s i n g the incus. T h e short p r o c e s s of the incus

FIGURE 12-9. is

clipped.

An

acetabulum

is

drilled

in

the

long

shaped

in

a

the cortex,

cartilage

similarly

to

the

removed,

chip.

A

cortical

and shaped.

piece bone

of chip

A

cartilage can

be

used.

p r o c e s s for fitting o v e r t h e h e a d o f t h e s t a p e s . T h i s

3. U s i n ^ a p r o s t h e s i s that e m b r a c e s b o t h t h e re-

is followed by drilling a g r o o v e o v e r the remaining

maining le iticular process and the head of the stapes. Text

continued

on

page

241

236

Tympanoplasty

Tympanoplasty

lncudoma/leal

t

II

A

B

c D

Graft

E

FIGURE 12-10.

Type III

FIGURE 12-11

237

Tympanoplasty

FIGURE 12-13.

241

Tympanoplasty

[f there is dislocation, the ideal p r o c e d u r e is reapproximation

and

repositioning

using

Gelfoam

or

rosis. H o w e v e r , it is e s s e n t i a l to do this s t a p e d e c t o m y in a " d r y e a r " a n d as a s i n g l e p r o c e d u r e .

It s h o u l d

" g l u e " (Fibrin or H i s t o a c r y l ) , or both. H o w e v e r , this

not

tympano-

is s e l d o m possible.

plasty b e c a u s e of a high risk of s e n s o r y hearing loss.

In traumatic dislocations, adhe-

sions a n d fixations are very c o m m o n .

be

performed

in

conjunction

If a t y m p a n o p l a s t y is p e r f o r m e d ,

If r e a p p r o x i m a t i o n is not possible, or interposing

a

the stapedectomy

is delayed. Careful staging is crucial.

b o n e o r c a r t i l a g e i n l e n t i c u l a r e r o s i o n d o e s n o t suffice, t h e r e are a l t e r n a t i v e s :

with

Fractures of

the crura

are

treated

with

a

piston

prosthesis from the incus to the oval w i n d o w , unless

1. I n c u s t r a n s p o s i t i o n . A small a t t i c o t o m y is d o n e ,

the fracture is the rare o n e that allows a c r u r o t o m y .

and the incus is carefully separated from the malleus.

Again, t h e s e p r o c e d u r e s are d o n e in a "dry ear." In

It is

cases of fractured crura a n d footplate,

s h a p e d by

removing the

long process,

and

a

it is safer to

n o t c h for t h e s t a p e s h e a d i s m a d e a t t h e e n d o f the

remove

short process. T h e articulating surface is enlarged to

seal the w i n d o w . (A wire c o n n e c t i v e tissue prosthesis

accept the m a l l e u s h a n d l e (Fig. 1 2 - 1 4 / 1 ) .

is preferred but it is not essential.) An alternative in

2. Use

of

the

malleus

head.

Once

the

head

is

r e m o v e d , t h e s i t u a t i o n is as d e s c r i b e d for fixation of

the

footplate a n d

use

connective

tissue

to

fractured crura a n d intact mobile footplate is the use of an inverted allograft s t a p e s (Fig. 1 2 - 1 4 C ) .

the h e a d of the m a l l e u s . T h e s a m e p r o c e d u r e s apply, except

that

if

the

malleus

is

mobile and

the head

Combined Ossicular Problems

itself is not used (and any of the o t h e r alternatives are not preferred),

t h e m a l l e u s h e a d i s left i n p l a c e Repairs b e c o m e more troublesome if the malleus

and only the incus is removed. In

the case of a missing incus,

native

remains

valid.

In

all

of

the s e c o n d alterthese

procedures,

allogeneic (allograft) ossicles and cartilage are also a good

alternative is

to

use

an

thesis m a d e of hydroxyapatite. The

the

malleus

large end

of the

and

interposition

A pocket is created

the overlying

prosthesis

n e w l y created p o c k e t (Fig. that

stability

tympanic

is

membrane.

placed

over

the

is

12-14B). The advantage

provided

membrane

and

by

utilizing

malleus

both

handle,

the

with

no

c o n n e c t i o n t o t h e b o n y a n n u l u s o r facial ridge. T h i s i s a c l e v e r p r o s t h e s i s ( w h i c h still m u s t s t a n d t h e test of time, however).

It must be mentioned, however,

that

is

drilling

in

it

not

so

simple

as

suggested

Patience, carefulness, and copious irrigation are recommended. material

(the

An

This means

w h i c h carries a h i g h e r risk of

failure, or a l o n g e r p r o s t h e s i s m u s t be u s e d from the

additional

Wehrs

incus

prosthesis prosthesis)

of

this

fulfills

same very

Fixation of the head of the malleus associated with a

fixed

paired

stapes with a

has

the

drawbacks

the

drilling

and

been

shown

to be

re-

lateralization

and

loss

It must be r e m e m b e r e d

of that

of the oval w i n d o w is a potential c o m p l i c a t i o n . Reg a r d l e s s of t h e graft or p r o s t h e s i s , an a d e q u a t e seal is essential. Alternatives include the use of a T O R P , a TORP-shaped ceramic

cortical

prosthesis,

or a

bone

ossicle,

sculptured

cartilage,

or

ossicle (autolo-

gous or allogeneic). In c a s e s of fixation of the ossicular c h a i n by tymcompletion

without

has

w h e n e v e r t h e s t a p e s f o o t p l a t e is r e m o v e d , a fistula

malleus

head

of

adequate conductivity.

panosclerosis,

stapes

footplate

malleus-to-oval-window wire connec-

tive t i s s u e p r o s t h e s i s . W h i l e this is a g o o d a l t e r n a t i v e , it

nicely the function of a sculptured incus b e t w e e n the and

(or b o t h ) are a b s e n t .

tympanic membrane,

pros-

h e a d of the s t a p e s a n d the distal (thin) e n d in this is

or stapes

that the p r o s t h e s i s m u s t b e s u p p o r t e d b y t h e grafted

tympanic m e m b r a n e to the oval w i n d o w .

Another method between

handle

of

the the

first

stage

malleus,

implies

mobilization,

disarticulation

of

the

sculpturing of the incus. This too m u s t be evaluated

i n c u s , a n d S J o n . T h i s p r e p a r e s for a s e c o n d p r o c e -

over time.

dure

in

which

the

stapedectomy

is

done.

Surgical

repair involves the alternatives described below. When

both

the

malleus

and

incus

are

absent

(usually s e e n in c h r o n i c otitis m e d i a c a s e s , a n d not

Stapes

uncommonly

in

tympanomastoidectomy

proce-

dures), or w h e n both ossicles are a single, congenital, Fixation of the stapes by otosclerosis is dealt with in C h a p t e r 13.

F i x a t i o n r e l a t e d t o i n f l a m m a t i o n (fi-

nonfunctional t y p e III

" m a s s , " the alternatives are a classic

t y m p a n o p l a s t y or use of a short

prosthesis

brosis) or t y m p a n o s c l e r o s i s is rare in an isolated form

or graft ( d e s c r i b e d a b o v e ) , if the s t a p e s is intact a n d

(that is, n o t affecting o t h e r o s s i c l e s a t t h e s a m e t i m e ) .

mobile.

In t h e s e e x c e p t i o n a l c a s e s , a s t a p e d e c t o m y will suf-

prosthesis ( t y m p a n i c m e m b r a n e to footplate or oval

fice a n d t h e r e s u l t s s h o u l d b e a s g o o d a s i n o t o s c l e -

w i n d o w graft) is n e c e s s a r y

If

the

stapes

is

fixed

or d a m a g e d ,

a

long

243

Tympanoplasty

If the malleus is absent and there is an intact a n d

15C).

A c e r a m i c T O R P can also be u s e d (Fig.

12-

However,

15D), as well as a sculptured incus. T h e latter should

a l o n g p r o s t h e s i s is indicated if the s t a p e s is d a m a g e d

be flattened toward the t y m p a n i c m e m b r a n e in order

(Fig.

to provide a s m o o t h and w i d e . If the malleus

mobile stapes, a short prosthesis is used. 12-14E).

In

cases of tympanomastoidectomy,

the concept

handle

is

present,

drilling

a

groove

in

the

TORP

of space b e c o m e s relevant in of reconstruction

provides better stability. W h e n e v e r a long prosthesis

At this point a n d with this type of disease, an intact-

( T O R P type) is placed o v e r an oval w i n d o w without

b r i d g e t y m p a n o m a s t o i d e c t o m y m a k e s g o o d s e n s e (if

a f o o t p l a t e , t h e r e is a p o s s i b i l i t y of a fistula a n d g o o d

n e e d e d , of course; if possible, an intact-wall proce-

seal is n e e d e d .

dure is preferred).

(for

As m e n t i o n e d earlier, a critical factor is t h e p r e s ence or absence of the malleus handle.

An equally

example,

If t h e r e is a p o t e n t i a l for retraction eustachian

prostheses may the oval

tube

dysfunction),

lead to fistulization

by

these

sliding into

window.

important factor ( s o m e t i m e s o v e r l o o k e d ) is the prese n c e or a b s e n c e of a mobile footplate. For practical purposes,

the

use

of

a

TORP

will

be

described,


followed by other alternatives.

Placement of a

FIGURES 12-16 TO 12-18

TORP

C h r o n i c otitis media with perforation of the tymT w o points of c o n t a c t are crucial. T h e usual ten-

panic m e m b r a n e . T h e lower magnification (Fig. 1 2 -

dehcy.is.to think in of extrusion a n d forget the

16)

distal

brane; (1) the o u t e r e p i t h e l i u m (stratified s q u a m o u s

end

window

of the T O R P (over the

footplate or oval

graft).

shows

the

three

layers

of the

tympanic

mem-

epithelium), c o n t i n u o u s with that of the external ear

T h e T O R P is cut to the n e c e s s a r y length. T h i s m a y

canal;

(2)

the

middle

ear

connective

tissue

layer,

b e 3 . 5 m m for a n o p e n c a v i t y , 4 m m i f t h e m a l l e u s

continuous with both the connective tissue layer of

h a n d l e is p r e s e n t , or 5 mm if it is a b s e n t .

the external ear canal and

A thin but large piece of cartilage is placed over the T O R P ( b e n e a t h brane

graft)

to

the

malleus or tympanic mem-

provide

protection

from

extrusion

inner

mucosal

layer,

m i d d l e ear; a n d (3)

continuous

with

that

of

the the

middle ear. T h e higher magnifications (Figs, 12-17, 1 2 - 1 8 ) clearly s h o w the i n g r o w t h o f o u t e r stratified

( s o m e s u r g e o n s suture it to the T O R P ) . If there is a

squamous

footplate or m e m b r a n e , the T O R P is placed o v e r it

removed

and

graft; o t h e r w i s e t h e r e will b e n o m i g r a t i o n o f e p i t h e -

is ed

it in

position.

provide more

with

abundant Gelfoam

A T O R P with a stability at the

to secure

p e g can be u s e d

(arrows).

placement

This

of

a

epithelium

connective

is

tissue

lial c e l l s o v e r t h e g r a f t . T h e p u r p o s e o f t h e g r a f t i s

prevent

to " r e p l a c e " the lost c o n n e c t i v e tissue a n d to serve

slipping (Fig. 1 2 - 1 5 A ) . O n c e the T O R P is placed, it

as a b r i d g e for m i g r a t i o n of e p i t h e l i a l c e l l s to c l o s e

tension

footplate and

to

epithelium before

should

impart s o m e

brane.

A T O R P - s h a p e d piece of cartilage or cortical

to

the

tympanic mem-

the g a p ( p e r f o r a t i o n ) . T h e s e p h o t o m i c r o g r a p h s illustrate

the c o n c e p t s of perforation and grafting; they

b o n e can be used, as well. A small piece of Silastic

are

can be placed, s u r r o u n d i n g the prosthesis at the oval

perforation during an a c u t e e p i s o d e of otitis media,

w i n d o w area, in o r d e r to prevent a d h e s i o n s (Fig. 1 2 -

even if s u p e r i m p o s e d over a chronic process.

not

meant

to

imply

or

to

suggest

grafting

a

244

Tympanoplasty

Tympnnoplasty

.) EXlerna! ear canal .~

External ear canal

,"""

FIGURE 12-17.

245

246

Tympanoplasty

CHAPTER 13 Surgery for Stapes Fixation S t a p e s procedures aim to re-establish s o u n d transmission dary

through

to'

a

fixation

involve partial replacement

stiffened ossicular chain, of

the

or total

with

stapes. removal

mobile

These of

portions

secon-

procedures

without

however,

of

of

it

or

with

a

for

speculum

holders;

speculum holders are

used by a

majority

surgeons.

the

Tjhe

need

authors

prefer

a

procedures

that

have

been

used

ap-

is not hard

to stabilize

at

hand

right-handed surgeon),

here.

Although

a

detailed

description

is

A

well-fitted ear s p e c u l u m holds in place quite well. It

s u c c e s s f u l l y for s t a p e s fixation will not be d i s c u s s e d length

transcanal

proach, u s i n g an ear s p e c u l u m w i t h o u t a holder.

surgical

(for a

the

speculum with while

t h e left using an

b e y o n d the scope of this atlas, the reader should be

i n s r u m e n t (such as a suction tip) at the s a m e time.

a w a r e of t h e m . T h e y are (1) fenestration of the lateral

The procedure

semicircular canal, and (2) sonoinversion. Fenestra-

ulum; o n c e the incisions h a v e b e e n m a d e , a tightly

tion o f t h e lateral s e m i c i r c u l a r c a n a l a l l o w s v i b r a t i o n s

fitting o n e is u s e d .

to reach

the

hair cells t h r o u g h

bying the ossicular chain,

the scala

smaller spec-

S m a l l e x o s t o s e s o f t h e c a n a l (if a n y ) a r e r e m o v e d . should

stapedectomy

by

a

(If t h e y a r e l a r g e o r i f a c a n a l p l a s t y i s n e c e s s a r y , t h i s

has

replaced

with

with a resultant mild

a i r - b o n e g a p o f 2 5 t o 3 0 dF3. A l t h o u g h t h i s p r o c e d u r e been

can be started

vcstibuli,

stapedectomy,

it

should

be

kept in m i n d . It can be of use in s o m e unusual cases

be

done

as

a

separate

delayed

until

procedure

complete

and

the

healing

has

been achieved, which could be a matter of months.)

of otosclerosis, as an interval operation in s o m e forms

It should be r e m e m b e r e d that entrance to the middle

of

ear

tympanoplasty,

as a surgical FIGURE 12-1K

surgery

this ossicle and

prosthesis. Two

S o m e s u r g e o n s prefer a small endaural approach, since it provides good exposure and allows bimanual

and

could

eventually

re-emerge

t e c h n i q u e for d e l i v e r y of d r u g s to the

must

be

made

in

a

dry

field

and

beneath

the

annulus. F r o m this point on, the m i c r o s c o p e is used

inner ear. Sonoinversion (technique of Garcia-Ibanez)

at a magnification of at least 10

delivers

there are three basic types of stapedectomy—partial,

vibratory

stimulation

through

the

round

w i n d o w m e m b r a n e by utilizing a prosthesis from the

total,

incus or malleus to the round w i n d o w . T h e normal

general

mechanism of sound

described

transmission

via

the ossicular

chain to the oval w i n d o w is successfully " i n v e r t e d . " T h e basic head position with slight hypertension and

the

transcanal

approach

have already been

and

piston.

approach, on

the

The and basis

x. In general

procedure the of

here

different the

will

types

findings

be

will

and

a be

their

indications O n c e t h e a n n u l u s i s e l e v a t e d , t h e first o b j e c t i v e i s

de-

to obtain a d e q u a t e e x p o s u r e and then to e x p l o r e the

s c r i b e d ; t h e d i s c u s s i o n will f o c u s o n p r o c e d u r e s after

ear. W o r k on the stapes is the final step, a n d is only

the a n n u l u s has b e e n elevated.

begun

S t a p e s p r o c e d u r e s g e n e r a l l y are d o n e u n d e r local anesthesia can be

with

used;

preventing

sedation.

however,

the

surgeon

it

General has

from

the

anesthesia

also

disadvantage

monitoring

of

vestibular

s y m p t o m s or hearing gains in the operating room.

after all o t h e r w o r k is c o m p l e t e d .

A

useful

rule o f t h u m b for e x p o s u r e o f t h e o v a l w i n d o w i s t o achieve clear visualization of the pyramidal e m i n e n c e a n d t h e s u p e r i o r a s p e c t o f t h e facial n e r v e . M o s t o f the

time,

posterior

this canal;

requires in

removal

doing

so,

of

the

bone chorda

from

the

tympani

249

S u r g e r y for S t a p e s F i x a t i o n m u s t be freed. U s u a l l y a fine n e e d l e can be u s e d to

On

the b a s i s o f t h e s e o b s e r v a t i o n s a n d t h e pref-

mobilize the chorda anteriorly toward the incus (Fig.

erence and

13-1/1').

surgical

If

maneuver,

the

chorda

will

be

stretched

it is b e t t e r to s e c t i o n

by

this

it s h a r p l y with

a

Bone

of

curetted. stapes

the

The

curets

posterior

authors in

canal

prefer

strokes

can from

ossicles).

O n c e visualization has been achieved,

footplate

is

to

be

removed,

and

a

membrane

If a p r o s t h e s i s will be e m p l o y e d , a firm a n d l a s t i n g m u s t be established with the long process of

re-

the incus (or the m a l l e u s handle).

13-1B).

all a n a t o m i c

The presence of an open round window is imporDrilling a round

the

large

l a n d m a r k s are i n s p e c t e d (Fig. 1 3 - 1 Q . tant. T o t a l o b l i t e r a t i o n will lead

of

ossicles

Meticulous

moval of b o n e chips should be d o n e (Fig.

the specific

Regardless

( p r e f e r a b l y c o l l a g e n o u s ) u s e d i n its p l a c e for a s e a l .

with

the

selected.

or

drilled

to curet it

away

(avoiding luxation of the

be

is

p r o c e d u r e , t h e u n d e r l y i n g i d e a i s t h a t all o r p a r t o f the

knife or a Bellucci scissors (Fig. 1 3 - 1 / 1 ) .

experience of the surgeon,

procedure

to a p o o r e r result.

Total Stapedectomy with Prosthesis

w i n d o w also leads to poor results

and complications a n d is not r e c o m m e n d e d . A very s m a l l o p e n i n g (»70/ s u r g i c a l l y i n d u c e d ) i n t h e w i n d o w s h o u l d suffice for a s a t i s f a c t o r y o u t c o m e ; t h i s s h o u l d be

kept in mind.

However,

in

some

patients

with

obliterated round w i n d o w s s o m e gain in hearing can be obtained; since such an improvement might make a s i g n i f i c a n t d i f f e r e n c e in their l i v e s , a s t a p e d e c t o m y should The

be attempted. ossicular

chain

is

then

palpated

(using

an

angled hook or H o u g h hoe) in order to locate points of ossicular fixation (Fig. 1 3 - 1 D , E ) . Special attention is paid to cases of unilateral hearing loss, in which nonotosclerotic fixations are m o r e frequent. Fixation of

the

malleus

fixation

is

atticotomy

at

most the

often

head.

(previously

is

congenital,

This

finding

described)

the h e a d of the m a l l e u s (Fig.

and

the

requires

an

and exposure

of

T h e c l a s s i c total s t a p e d e c t o m y i s u s e d h e r e a s the primary procedure to describe general principles and problems encountered

during surgery. T h e descrip-

tion a s s u m e s that t h e r e i s n o n o b l i t e r a t i v e fixation o f the stapes,

the rest of the ossicles are m o b i l e ,

the

round w i n d o w is patent, a n d the oval w i n d o w is of norma! size. T h e distance between the incus and the footplate

is

measured.

The

average

measurement

from the h e a d of the stapes to the footplate is 3.29 mm

±

0.15

mm,

to w h i c h

is added

1

mm

of

the

lenticular process. T h e average length of a prosthesis is 4.0 mm in w o m e n and 4.25 to 4.50 mm in men. If a wire c o n n e c t i v e tissue p r o s t h e s i s is to be u s e d , it should

be

made

at

this

time.

Connective

tissue

should be h a r v e s t e d at this point as well.

13-2/1). The authors

p r e f e r to u s e c u r e t s , b u t if a drill is u s e d , t h e i n c u s should be separated from the head of the stapes with a

t

knife

in

order

to

avoid

acoustic

Attachments can sometimes be released,

and small

pieces of Silastic can be placed to avoid fixation (Fig. 13-26); however, mal,

Harvesting a Graft

trauma.

u n l e s s the a t t a c h m e n t s are mini-

this is usually f o l l o w e d by refixation.

A solid

O n c e the stapes has been removed,

the vestibule

is e x p o s e d and a n e w m e m b r a n e is n e e d e d to seal the o p e n i n g . C o n n e c t i v e tissue, specifically collagen,

fixation requires r e m o v a l of the h e a d of the m a l l e u s

allows the formation of a stable seal

with m a l l e u s n i p p e r s (Fig. 1 3 - 2 C ) a n d p l a c e m e n t of

part o f t h e w i n d o w . W h i l e G e l f o a m s t i m u l a t e s tissue

a m a l l e u s to oval w i n d o w p r o s t h e s i s , a b o n e strut,

growth a n d is u s e d satisfactorily by m a n y surgeons,

or a

(TORP)

these m e m b . a n e s tend to be thin and carry a higher

(Fig. 1 3 - 2 D - F ) . ( S e e a l s o C h a p t e r 1 4 for a l t e r n a t i v e

r i s k o f f i s t u l a f o r m a t i o n a n d p e r i l y m p h l e a k a g e . Dif-

procedures utilizing a laser.)

f e r e n t s o u r c e s a r e u s e d , s u c h a s fat a n d c o n n e c t i v e

total

Under

ossicular replacement prosthesis

10

X

or

16

x

magnification,

the

oval

tissue from the earlobe or postauricular area,

w i n d o w and stapes are inspected (Fig. 1 3 - 3 ) . Is there

perichondrium,

a

and

normal-sized

oval

window,

a

promontory

over-

tissue

over

footplate?

Is

there

a

vein.

prostheses,

and

is

T i s s u e from used

tragal

the earlobe

for w i r e c o n n e c t i v e

from p e r i c h o n d r i u m or vein

stapedial

as sealing m e m b r a n e s with simple wires or pistons.

artery? Is the s t a p e s fixed anteriorly or posteriorly?

Type of prosthesis, ease of handling, and individual

I s t h e f o o t p l a t e o f n o r m a l size ( o n a v e r a g e , 1.4 m m

p r e f e r e n c e s will d e t e r m i n e s u c h c h o i c e s

wide a n d 3 . 0 mm long)? Is part,

persistent

or a

postauricular area

h a n g , or a d e h i s c e n t facial n e r v e ? Is t h e facial n e r v e the

that b e c o m e s

h a l f , o r all o f t h e

A s m a l l i n c i s i o n s u f f i c e s for h a r v e s t i n g t i s s u e f r o m

f o o t p l a t e i n v o l v e d ? Is t h e r e obliteration of the foot-

the e a r l o b e or postauricular area (Fig.

plate a n d w i n d o w b y otosclerotic foci?

incision is closed with o n e or two appropriate sutures

13-4A, 6 ) . T h e

250

S u r g e r y for S t a p e s F i x a t i o n


FIGURE 13-3.

FIGURE 13-2.

251

S u r g e r y for S t a p e s Fixation

253

a n d t h e t i s s u e i s left i n s a l i n e s o l u t i o n . T r a g a l p e r i -

incus) large • or s h o r t e r , a c c o r d i n g to the size of the

chondrium

long process of the incus.

is

obtained

via a

small

incision in

the

The wire-cutting scissors

undersurface of the tragus, exposing the perichon-

a r e slid u p t o t h e k n o t i n t h e m i d d l e o f t h e g r a f t a n d

d r i u m , w h i c h c a n b e p e e l e d off t h e u n d e r l y i n g c a r -

the wire is sectioned.

tilage (Fig.

unless

1 3 - 4 C ) . Meticulous hemostasis is done,

the

N o s h a r p e n d s s h o u l d b e left

patient has

otosclerosis associated

the incision is closed with t w o or t h r e e a p p r o p r i a t e

endolymphatic hydrops;

sutures,

posely

and

the

perichondrium

is

gently

pressed

left

sharp

in

might

this c a s e ,

work

as

a

an end

with pur-

"conservative

a n d r i n s e d i n s a l i n e . All i n s t r u m e n t s a n d m a t e r i a l s

t a c k . " T h e p r o s t h e s i s i s left i n s a l i n e u n t i l u s e .

u s e d in this a r e a s h o u l d be rinsed in o r d e r to r e m o v e

5-mm

any particles from their surfaces.

in Figure 1 3 - 5 D .

Vein hand

can

by

a

be

harvested

small

from

incision.

the

d o r s u m of the

Both e n d s are carefully

malleus-to-oval

window

prosthesis

is

A

shown

T h e m a k i n g of a wire piston is s h o w n in Figure 1 3 - 6 ; the t e c h n i q u e (after Rosales) is self-explanatory

tied; t h e m i d s e c t i o n of t h e vein (size as n e e d e d ) is removed

and

split

open,

the

endothelial

layer

is

r e m o v e d , a n d the vein is pressed a n d rinsed in saline (Fig.

13-4D).

In

general,

the

adventitial

layer

placed facing the vestibule. W i t h p e r i c h o n d r i u m , the side

in

direct

with

the

cartilage

is

Procedure

is

placed

facing the middle ear; o t h e r w i s e small cartilage r e m n a n t s m a y fall i n t o t h e v e s t i b u l e , p o t e n t i a l l y c a u s i n g complications.

T h e footplate is f r a c t u r e d at the midline with a needle (Fig. 1 3 - 7 4 ) . C r e a t i n g a hole in the footplate is f r e q u e n t l y d e s c r i b e d , b u t for a total s t a p e d e c t o m y an a c t u a l f r a c t u r e is b e t t e r a n d p r e v e n t s a floating footplate. T h e m u c o s a is not elevated at the footplate; this a v o i d s bleeding a n d h e l p s to p r e v e n t small, loose f r a g m e n t s f r o m falling i n t o t h e v e s t i b u l e . I f t h e r e i s

Making the Prosthesis

bleeding,

small pieces of G e l f o a m s a t u r a t e d with a

s o l u t i o n o f MOOO e p i n e p h r i n e a r e a p p l i e d t o p i c a l l y . A N o . 2 4 s u c t i o n tip w i t h t h e f i n g e r off t h e h o l e i s Many

satisfactory

available. Celfoam

Except

prostheses

for

prostheses

polyethylene

will

geon's

preference

m a d e at that

on

tissue

surgery.

have

stood

c o n n e c t i v e tissue

wire

used.

It

cannot

be

emphasized

higher

all t i m e s .

pistons

(which

can cause a "dead ear."

the vast majority of

surgical

used.

that

the

Suctioning p e r i l y m p h in the oval w i n d o w

T h e i n c u d o s t a p e d i a l t is gently s e p a r a t e d with a t knife (Fig.

1 3 - 7 8 ) ; t h e k n i f e i s slid b e t w e e n

the incus a n d the h e a d of the stapes to e n s u r e that

the

sur-

wire

and

separation is total. T h e stapedial t e n d o n is sectioned

be

with t h e t knife or a Bellucci scissors (Fig. 1 3 - 7 C ,

T h e s e are the classic prostheses

D). S o m e t i m e s it is possible to g e n t l y peel it a l o n g

and and the

findings a n d

Their

enough

s u c t i o n tip m u s t s t a y a w a y f r o m t h e o v a l w i n d o w a t

have a

satisfactory if properly

depend

connective

struts and

to

tend

t e n d to c a u s e local r e a c t i o n s ) , use

commercially

Plastipore

(which

i n c i d e n c e of fistulae) a n d prostheses are

are

experience. wire test

Teflon of

Both

pistons

time.

The

prosthesis can be

can

wire

tailored

to

and the

with the m u c o p e r i o s t e u m a n d

leave it attached

to

the long p r o c e s s of t h e incus (Fig. 1 3 - 7 E , F ) . This

needed length or bent or c u r v e d in n a r r o w w i n d o w s

allows

o r p r o m i n e n t facial n e r v e s ; i t a l s o p r o v i d e s a n e x c e l -

p e r m i t s better vascularity to the long p r o c e s s of the

lent seal.

incus. In the unusual e v e n t of a p r o m i n e n t pyramidal

The

technique

for

making an

of c o n n e c t i v e

some

protection

from

sound

and

win-

eminence, the tendon is sectioned and the eminence

1 3 - 5 . A piece

curetted. T h e head and c r u r a of the stapes (stapedial

incus-to-oval

d o w prosthesis is depicted in Figure

perhaps

t i s s u e is c u t to a size of 2

x

3 mm.

arch) are mobilized with an angled hook toward the

This is p l a c e d on the e d g e of the die a n d is tied at

p r o m o n t o r y a n d not i n a n a n t e r o p o s t e r i o r d i r e c t i o n

its m i d p o r t i o n w i t h a 0 . 0 0 5 - m m s t a i n l e s s s t e e l w i r e

( w h i c h c a n c a u s e p a r t o f t h e footplate t o d r o p into

(Fig.

the oval w i n d o w ) . Usually the arch fractures at the

13-5/1).

A d r o p of saline helps handling a n d

placing of the tissue in the desired position. W i t h an

junctions

alligator forceps h o l d i n g both e n d s , t h e k n o t is tight-

removed

ened

forceps (Fig. 1 3 - 7 G ) . M e a s u r e m e n t s a r e n o w m a d e

until it d i s a p p e a r s into the c o n n e c t i v e tissue

The wire is looped a r o u n d the larger post of the die

(Fig.

of with

the

crura

with

the angled

the

footplate,

hook or a

and

is

baby alligator

13-7H).

at 4 mm

At this poi.it, the patient is i n s t r u c t e d not to m o v e

T h e connective tissue end is rotated

o r talk. S i m i l a r r e c o m m e n d a t i o n s a p p l y t o t h o s e i n

with

the bottom of the connective

(Fig.

13-58).

tissue

1 3 - 5 C ) . Wire-cutting

the o p e r a t i n g r o o m . T h e footplate is r e m o v e d with a

scissors a r e used to cut the loop (to h o o k into the

H o u g h h o e or a right-angled h o o k (Fig. 1 3 - 8 4 ) . It is

a r o u n d the smaller post (Fig.

254

Surgery for Stapes Fixation

Surgery lor Stapes Fixation

Gelloam

._{f-. . . -,. . -,-,- ~ 0.005 starnless steel wire

A '"

1---4mm--j B

o FICURE 1:\-5

Malleus to oval window

FlCURE 13-<>.

255

256

S u r g e r y for S t a p e s Fixation


257

important to place the instrument just barely beneath

( X y l o c a i n e ) w i t h e p i n e p h r i n e s h o u l d >iof b e u s e d i n

the

the open vestibule since it can cause m a r k e d vestib-

fragments

to

be

removed

in

order

to

avoid Bone

ular d i s t u r b a n c e s . T h e p r e s e n c e o f a n a b n o r m a l j u g -

removed

ular bulb has been described in another chapter; if

damaging the underlying vestibular structures. fragments

are

either

totally

or

partially

(usually by r e m o v i n g the posterior t w o thirds of the

its

footplate), depending upon the procedure to be done

procedure,

(Fig.

persistent

13-8A).

With an alligator forceps or a horizontal o p e n i n g forceps

(which

allows

better visualization)

holding

location

allows it

a

should

stapedial

safe not

exploration

be

artery

a

and

stapes

contraindication.

(running

over

the

A

foot-

p l a t e ) is a v e r y u n u s u a l f i n d i n g . T h i s a r t e r y is fairly large

and

shojld

not

be

confused

with

small

but

the prosthesis is placed

prominent mucoperiosteal vessels in the footplate. If

(Fig. 1 3 - 8 B ) . If it c a n n o t be placed easily in position,

a small o p e n i n g on the footplate can be m a d e and a

it is r e l e a s e d a n d m o b i l i z e d b i m a n u a l l y (for e x a m p l e ,

small

with the s u c t i o n tip a n d a H o u g h h o e ) . If the w i r e is

otherwise, the operation should not take place.

the bare edge of the wire,

bent

during

positioning,

it

is better to

use a

new

p r o s t h e s i s t h a n t o fix it. T h e o v a l w i n d o w s h o u l d b e left

open

time

of

for

the

shortest

exposure

hearing.

excessive effects

done;

Obliteration of the r o u n d w i n d o w and fixation of the malleus have been described. Accidental

Dislocation

of

the

Incus.

The

incus

should

on

be palpated. If the dislocation is partial a n d the incus

d o w p r o s t h e s i s (or an e q u i v a l e n t prosthesis,

tissue is u s e d , the o v a l w i n d o w graft is p l a c e d b e f o r e

scribed in C h a p t e r 12) is substituted.

(Fig.

13-8C).

Such

a

is

be

u s u a l . If it is totally l u x a t e d , a m a l l e u s - t o - o v a l w i n -

precisely;

tissue

can

seal the w i n d o w . If a prosthesis without connective

fit

connective

to

procedure

moves with the malleus, the prosthesis is placed as

prosthesis

wire

possible;

related

the

well

should

the

time

directly

placed,

centered, additional connective tissue can be used to

the

Once

is

piston

graft

ideally

it cannot be too small

or too

Fracture crimping

of

the

the

long

process of the

prosthesis

as de-

incus

while

is rare; if it h a p p e n s ,

the

large. If a piston is used, c o n n e c t i v e tissue is w r a p p e d

prosthesis

a r o u n d it. S m a l l p i e c e s o f G e l f o a m c a n t h e n b e p l a c e d

(Fig. 1 3 - 9 4 ) . If this is i m p o s s i b l e , a malleus-to-oval

over the c o n n e c b v e tissue and around the prosthesis.

window

Piston w i d t h in a s t a p e d e c t o m y is from 0.6 to 0.8

instead.

m m , w h e r e a s in a s t a p e d o t o m y (described b e l o w ) , it is 0 . 4 m m . or an alligator forceps. T h e crimper has the advantage of not closing completely; thus there is less c h a n c e

be

crimped

prosthesis

on

the

remaining

(or its e q u i v a l e n t ) c a n

strut

be

used

Pain. A n o c c a s i o n a l p a t i e n t m i g h t c o m p l a i n o f p a i n when

T h e prosthesis is crimped with a M c G e e crimper

can

the

middle

application

ear

mucosa

of ':.% lidocaine

is

in

touched.

cotton

Topical

or

Gelfoam

drilled

carefully

pledgets suffices. Prominent

Promontory.

This

can

be

of fracturing the long process of the incus (Fig. 1 3 -

i n o r d e r t o pro* ide a d e q u a t e v i s u a l i z a t i o n (Fig.

8D).

9C).

It is a l s o light a n d thin a n d d o e s n o t obstruct

13-

D e p e n d i n g upon the visualization obtained, a

vision. C r i m p i n g is d o n e in an anteroposterior direc-

small piston or A wire c o n n e c t i v e tissue prosthesis is

tion

placed.

and

involves only

otherwise,

the

ring

around

the

incus;

t h e p r o s t h e s i s will b e b e n t a n d will h a v e

An

abnormal

(open

or

redundant)

n e r v e in itself is not a c o n t r a i n d i c a t i o n .

to be changed. Teflon wire pistons bend very easily

possible

if n o t c r i m p e d properly. T h e r o u n d w i n d o w reflex,

a l l o w i n g a n o p e n i n g t o b e m a d e i n t h e f o o t p l a t e for

the mobility of the ossicular chain, and the adequacy

placement

of the prosthesis position are c h e c k e d at this point,

upon

after w h i c h

the flap Is r e p o s i t i o n e d .

T h e patient is

the

to

mobilize of

a

it

gently

prosthesis.

anatomic

with

a

seventh

It m a y be

blunt

Sometimes,

conditions,

a

wire

hook,

depending connective

t i s s u e p r o s t h e s i s c a n b e b e n t t o fit. O n o c c a s i o n , a n

then asked if there is a n y i m p r o v e m e n t in hearing.

o f f s e t R o b i n s o n p r o s t h e s i s fits p r e c i s e l y .

Finally, the ear canal is packed (described below).

a n d u s e o f a p r o s t h e s i s t o fit t h e n e e d a r e p a r a m o u n t ;

Flexibility

the c o u r s e of action s h o u l d reflect the a n a t o m i c and functional n e e d s of the patient and the rational and

Problems and Variations During Surgery

safe a p p r o a c h o f the s u r g e o n . Narrow

Oval

Window.

can

also

represent

u n c o m m o n l y leads Bleeding. S m a l l v e s s e l s r e s p o n d v e r y w e l l t o t o p i c a l

FIGURE 13-7

A

narrow

window

can

be

s e c o n d a r y to a p r o m i n e n t overlying p r o m o n t o r y ; it a

congenital

to a

defect,

perilymph

which

"gusher."

not It

is

a l s o v e r y i m p o r t a n t t o a s s e s s t h e facial n e r v e a n d its

application of cotton balls or Gelfoam saturated with

relationship

epinephrine.

w i n d o w itself is quite narrow a n d a congenital defect

In the footplate it is preferable to use

Gelfoam in order to avoid cotton strands. Lidocaine

is s u s p e c t e d ,

to

the

footplate

(Fig.

13-9D).

If

the

a small o p e n i n g can be m a d e with a

258



A

A

c

HGURE 1:1-8

FIGURE 13-9.

259

261

S u r g e r v for S t a p e s Fixation

small, s h a r p n e e d l e ; if a g u s h e r is f o u n d , it is c o v e r e d

is

with c o n n e c t i v e t i s s u e a n d G e l f o a m . T h e h e a d o f t h e

delay such procedures but s o m e surgeons do perform

not an e a s y one; in general,

patient is raised a n d the p r o c e d u r e is t e r m i n a t e d . If

them, reportedly with g o o d results.)

there is no g u s h e r , the small o p e n i n g c a n be e n l a r g e d to place a 0 . 4 - m m p i s t o n or a t h i n p r o s t h e s i s . Cerebrospinal

Fluid

Leak.

or

diamond

bur

with

slow

rotation

and is g e n e r a l l y (but not e x c l u s i v e l y ) s e e n in c a s e s

izing e v e n l y and applying just e n o u g h pressure over

of a c o n g e n i t a l l y fixed s t a p e s ( a n d a p a t e n t c o c h l e a r

the

aqueduct). T h e patient's h e a d is elevated a n d a large

lously r e m o v e d . If the footplate is t h i n n e d e v e n l y (to

connective

a

prosthesis

is

cutting

(Fig. 1 3 - 1 1 8 ) . T h i s is d o n e anteroposteriorly, saucer-

wire

"gusher"

A thick footplate m u s t be t h i n n e d with a 0 . 6 - to 1-mm

uncommon,

tissue

A

it s e e m s better to

used

for a

seal,

with a d d i t i o n a l c o n n e c t i v e tissue. Dry Vestibule.

footplate

thin

to be effective.

bluish

plate),

a

Bone

small

dust is meticu-

(0.5-mm)

opening

is

m a d e a n d a piston s u r r o u n d e d by c o n n e c t i v e tissue

If t h e p e r i l y m p h is a c c i d e n t a l l y s u c -

i s p l a c e d (Fig. 1 3 - 1 1 C - E ) . L e s s c o m m o n l y , the foot-

tioned o u t o f the oval w i n d o w (the s u c t i o n tip s h o u l d

plate is fractured a n d r e m o v e d , a n d a graft is placed.

nettcr b e p u t i n t o t h e o v a l w i n d o w [ F i g . 1 3 - 1 0 E , F ] ) , the w i n d o w will refill. If it d o e s n o t , a f e w d r o p s of s a l i n e a r e u s e d t o fill it.

Blood m i g h t stimulate an

inflammatory reaction in the vestibule. Floating

Footplate.

This

refers

to

a

footplate

Stapedotomy

that

becomes mobile before an opening is m a d e in it and after r e m o v a l o f t h e a r c h ( t h e s u p e r s t r u c t u r e c o n s i s t ing o f t h e h e a d a n d c r u r a ) . T h i s i s a difficult c h a l lenge. O n e w a y to a v o i d it is to fracture the footplate before r e m o v i n g t h e a r c h . A floating footplate t e n d s to occur in a s t a p e s that has b e e n previously mobilized o r i n o n e w i t h p o o r f i x a t i o n . S o m e t i m e s the footplate can be carefully r e m o v e d with a n a n g l e d h o o k . I f t h i s i s i m p o s s i b l e , a n o p e n i n g can be m a d e w i t h a d i a m o n d b u r or s m a l l b u r in the anteroinferior

margin,

and

the

footplate

removed

with a h o o k (Fig. 1 3 - 1 0 4 , 8 ) . If this t o o is i m p o s s i b l e and

the

placed

footplate over

refixation

it

not

and

occurs

can b e r e v i s e d

is

a

depressed, shorter

(which

is

fascia

piston

likely),

This

procedure

advocates

a d h e s i o n s b e t w e e n the graft a n d vestibular c o n t e n t s , and less mobility of the oval w i n d o w as a w h o l e . As with

all

surgical

innovations,

time and

experience

will tell. T h e p r o c e d u r e a l s o c a n be d o n e with a laser (see C h a p t e r 14). T h e operation is similar to a classic stapedectomy,

u p t o t h e p o i n t o f o p e n i n g t h e foot-

plate. T h e n the footplate is perforated with a sharp needle (or special microdrill) in three different spots. E n l a r g e m e n t of these o p e n i n g s is d o n e very carefully

placed.

If

o p e n i n g that is slightly larger than 0.4 m m . T h e size

footplate

can be m e a s u r e d with a 0 . 4 - m m measuring rod. This

the

with angled

fragments

can

be

hooks,

trying to leave a single central

step can be d o n e without removing the stapes arch, mobilization

of

the

stapes.

Once

c r u r a a r e sectioned w i t h c r u r o t o m y s c i s s o r s ;

vestibule s h o u l d be a v o i d e d ; it is better to leave the

thesis

fragments

footplate

the vestibule and

use ample amounts

of steroids, topically and parenterally. S o m e authors recommend

placing

a

few

drops

of

blood

in

this

is

d o n e , the incudostapedial t is s e p a r a t e d and the

removed carefully with a hook, but " f i s h i n g " in the in

in

involves less risk of inner ear d a m a g e , less c h a n c e of

avoiding Depressed

many

be

with better c h a n c e s of s u c c e s s (Fig

Fragments.

gained

can

13-10C). Depressed

has

recent years b e c a u s e it has b e e n suggested that it

is

then

placed

opening

and

over

the

incus

surrounded

and

with

the prosinto

the

connective

tissue.

the

vestibule a n d a l l o w i n g t h e m to clot; w h e n t h e clot is removed the fragments m a y c o m e out with it (Fig. 13-10D).

Stapes Interposition

Obliterative Otosclerosis

In the p r e s e n c e of a wide niche, an anterior fixation,

and a healthy posterior crus,

procedure If an obliterative focus is f o u n d — f o r e x a m p l e , if

is a

rational alternative.

an interposition It

represents

a

safe a n d logical a p p r o a c h b u t is difficult to p e r f o r m

the o v a l w i n d o w h a s n o d i s c e r n i b l e f o o t p l a t e o w i n g

properly, requiring ability and e x p e r i e n c e . T h e pro-

to otosclerotic c h a n g e (Fig. 1 3 - 1 1 4 ) — t h e p r o c e d u r e

cedure involves removing a portion of the footplate

is different.

(fixed) a n d mobilizing the posterior crus (as a "pros-

focus,

it

is

If the p a t i e n t is a c h i l d w i t h an active better

to

delay

question of operating on

!

this

children

procedure. with

(The

otosclerosis

t h e s i s " ) o v e r an u n d e r l y i n g graft, t h u s re-establishing the continuity and mobility of the ossicular chain.

S u r g e r y for S t a p e s Fixation Initially the anterior crus is s e c t i o n e d with a n g l e d c r u r o t o m y scissors (Fig.

1 3 - 1 2 / 1 ) . P o r t m a n n (an ad-

263

thesis, but it is p l a c e d at a right a n g l e to the m a l l e u s handle (Fig.

13-146).

O n c e it is over the malleus

vocate of this p r o c e d u r e ) r e c o m m e n d s sectioning in

handle

the main axis of the stapes, introducing the scissors

d o w n so that it is p e r p e n d i c u l a r to the handle; this

b e t w e e n the malleus a n d the incus, since the simpler

m a n e u v e r m a k e s positioning easier.

approach through the p r o m o n t o r y carries the risk of

satisfactory,

fracturing the stapes at a n o t h e r site. T h i s is followed

the

by sectioning of the stapedial tendon. T h e posterior

graft i s p l a c e d o v e r t h e o v a l w i n d o w . T h e p r o s t h e s i s

crus is t h e n carefully fractured with a m i c r o h o o k at

is

its j u n c t i o n

W h e n the posterior

a n a n g l e d h o o k a n d s u c t i o n tip o r b l u n t i n s t r u m e n t )

crus is free (from m u c o s a l a d h e s i o n s as w e l l ) , it is

along the undersurface of the malleus (Fig. 1 3 - 1 4 C ) .

m o b i l i z e d a n t e r i o r l y w h i l e the i n c u s is lifted w i t h a

It

H o u g h h o e (thus avoiding fractures in the posterior

well the prosthesis m i g h t fit, it is anatomically a n d

crus) (Fig. 1 3 - 1 2 B ) . T h e footplate is fractured a n d the

functionally less efficient than a s t a p e d e c t o m y pros-

posterior t w o thirds are r e m o v e d (Fig.

1 3 - 1 2 C and

thesis; at the s a m e time, the oval w i n d o w is subjected

Fig. 1 3 - 1 3 A ) . A graft is p l a c e d a n d t h e p o s t e r i o r c r u s

to m o r e trauma (the mobility of the malleus is greater

is

than that of the incus a n d has less d a m p e n i n g effect).

with

repositioned

lifted),

the footplate.

over

the

graft

(while

the

incus

re-establishing ossicular continuity and

is

(under

the

footplate positioned

should

the

be

is

periosteal

prosthesis removed,

and

then

is

pocket),

turned

anteriorly,

connective

tightened

that,

is

If the length is

displaced

and a

ed

it

tissue

bimanually

regardless

(with

of h o w

mo-

bility (Fig. 1 3 - 1 3 B - D ) . S o m e s u r g e o n s perform this p r o c e d u r e b y r e m o v ing part of the a n t e r i o r crus a n d the anterior half of

Closure and Packing

the footplate (an anterior c r u r o t o m y ) . T h e r e m a i n i n g mobile plate

posterior

are

crus

mobilized

and

underlying

toward

the

mobile

center of

foot-

the

oval

T h e flap is carefully r e p o s i t i o n e d . If a small tear is

w i n d o w (over the graft). T h e stapedial tendon might

present,

or

necessary,

might

posterior

not

be

sectioned,

crurotomy

also

according

can

be

to

done

need.

in

A

reverse

the

edges

small

are

carefully

pieces

approximated.

of Gelfoam

or

If

connective

t i s s u e c a n b e u s e d , a n d t h e flap left s o m e w h a t l o o s e .

fashion, but usually the point of footplate fixation is

For larger perforations,

anterior.

a m o u n t s of antibiotics and anti-inflammatory medications are used. scribed.

a graft is p l a c e d a n d a m p l e

Packing techniques h a v e b e e n de-

T h e p a t i e n t m u s t lie w i t h t h e o p e r a t e d ear

up and is closely followed postoperatively; the need

Malleus-to-Oval Window Prosthesis

to a v o i d straining, lifting, or u n d u e effort c a n n o t be emphasized enough.

Complications continue

to be

v e r y p o s s i b l e until c o m p l e t e h e a l i n g h a s o c c u r r e d (at four The

aim

of

this

procedure

a

weeks)

and

may

still

occur

thereafter.

prosthesis from the h a n d l e of the malleus to the oval

operative procedure. It has been argued that prophy-

window.

lactic antibiotics are u n n e c e s s a r y ; h o w e v e r ,

place

place

six

S o m e failures can be traced to o v e r c o n f i d e n c e in the

to

to

to

wire

It is i m p o r t a n t

is

the wire u n d e r a

the au-

J

subperiosteal pocket in the handle of the malleus, as

thors strongiy r e c o m m e n d the use of intraoperative

close to the short process as possible.

and postoperative antibiotics.

Such prostheses are commercially available, but a wire connective tissue can be m a d e . S t a p e s prosthesis wire and

a

b e n d i n g die are

used

to

manufacture a

prosthesis; only the large post of the die is used to

Complications

shape the " c r o o k " or " h a n d l e " (see Fig. 1 3 - 5 ) . With

a t knife,

an

incision

is

made

through

the m u c o p e r i o s t e u m on the undersurface of the handle of the malleus, (Fig.

13-14/1).

of to

place

with

creating a

subperiosteal

pocket

On occasion it is necessary (because the overlying tympanic m e m b r a n e )

the prosthesis at the

neck of the

malleus.

A s i n a n y surgical p r o c e d u r e , a w a r e n e s s a n d prevention of possible c o m p l i c a t i o n s are the keys. nosis,

a n d rational surgical plans are of paramount

importance.

The

patient

on

T h e s t a p e s a r c h i s r e m o v e d first, a n d t h e p r o s t h e s i s

a s s u m e d to have had a

is p l a c e d to e n s u r e correct length. Initially the pros-

cluding

thesis is held in a m a n n e r similar to a s t a p e s pros-

logic p r o b l e m s , and so o n ) .

!

Ad-

equate preoperative evaluation, a well-defined diag-

cardiovascular

the

operating

table

is

t h o r o u g h overall c h e c k (instatus,

allergies,

endocrino-

264



B

c

FIGURE 13-12.

FIGURE 13-13.

265

t • S u r g e r y for S t a p e s Fixation D y s g e u s i a following injury to the chorda t y m p a n i

b i m a n u a l l y a n d the

prosthesis shortened.

is characterized by tingling or a metallic taste on the

i m p o s s i b l e "or i n a d e q u a t e ,

tongue on

the operated

replaced.

rteplacement

improves,

but

vestibular

adhesions.

the

side,

reason

or both.

for

the

This always

improvement

is

the

Infection is rare, especially if a d e q u a t e prophylaxis

carries

the

Vertigo

risk

leading

persist

eventually require surgical correction.

obtained

(if

possible),

and

anti-

pulling sensory

but can occur up

(including meticulous cleansing of the ear canal) has cultures

of to

is be

t o t h r e e t o »ix y e a r s later. O n o c c a s i o n , v e r t i g o m i g h t

b e e n undertaken. If it occurs, the packing should be removed,

If this

prosthesis should

d e a f n e s s is rare after o n e m o n t h ,

unclear.

267

for

years,

even

with

good

hearing;

it

may

Patients usually have a mild sensation of echoing

biotics given (or c h a n g e d ) topically a n d parenterally.

along with

Infection

a n d a feeling of r e s o n a n c e m a y indicate fistulae or

may

lead

to

labyrinthitis

and

should

be

palsy

may

follow

injection

of

thetics, but should be only temporary. diately

following

damage

to

an

stapedectomy

exposed

during the procedure. dicated.

It

should

rare*

nerve;

nerve

the

anes-

Palsy i m m e -

probably

in

kept

in

mind

to local e d e m a

sectioning of the

Delayed

local

signals

oval

window

S u r g i c a l r e - e x p l o r a t i o n i s in-

be

probably is restricted of the

paralysis

must

that

damage

or puncturing

nerve is extremely

be

evaluated,

and

is

treated in the s a m e m a n n e r as Bell's palsy. Vertigo

is

fairly

common

postoperative

days;

however,

during

the

symptoms

first

few

should

be

ular sedatives. V e r t i g i n o u s s y m p t o m s s h o u l d not be left

lightly;

they could be a

unattended

deafness.

significance,

but tinnitus

might

Persistence

lead of

warning sign,

to

irreversible

vertigo

or

Reparative granuloma is o n e of the few e m e r g e n cies

following stapedectomy.

It occurs one to two

w e e k s after surgery and

is characterized by dimin-

ished

an

hearing

following

initial

gain.

Additional

s y m p t o m s include aural fullness, loss of discrimination,

and

disequilibrium.

The

tympanic

m a y be dull, red, a n d thickened, cular

flap

quadrant.

and

inflammation

in

membrane

with a hypervas-

the

posterosuperior

R e m o v a l of the granuloma

is d o n e in a

p i e c e m e a l fashion, a n d fascia is placed o v e r the graft.

mild, short lived, a n d r e s p o n s i v e to rest a n d vestibtaken

no

labyrinthitis, especially if a c c o m p a n i e d by vertigo.

treated aggressively. Facial

tinnitus of

severe

which

sensory vertigo

T h e prosthesis can be replaced by a n e w connective tissue

wire

prosthesis.

Granulomas

have

not

been

s h o w n to recur. Conductive

hearing

losses

occurring

after

initial

g a i n s are i n d i c a t i o n s for revision. A p r u d e n t w a i t i n g period

is

suggested.

A

perforated

tympanic

b r a n e will r e q u i r e a m y r i n g o p l a s t y .

mem-

A delayed con-

m i g h t be indicative of a p e r i l y m p h fistula, a thin or

ductive

leaky graft, p e r i p r o s t h e s i s leak a r o u n d a Teflon

pis-

b r a n e s u g g ists p r o b l e m s with t h e p r o s t h e s i s . I f t h e r e

ton (associated with fluctuating h e a r i n g loss), a pros-

are a d h e s i o n s a r o u n d the p r o s t h e s i s , t h e y s h o u l d b e

thesis

sharply

that

granuloma.

is

too

long,

labyrinthitis,

or

reparative

hearing loss with

excised

and

an intact t y m p a n i c m e m -

Gelfilm

or

Silastic

placed.

If

Operative causes include trauma during

n e c e s s a r y , the prosthesis is replaced. P r o s t h e s e s that

the operation or loose b o n e fragments in the vesti-

are d i s p l a c e d can be e i t h e r r e p o s i t i o n e d or r e p l a c e d ;

bule.

if the latter, t h e y are g e n t l y l o o s e n e d from the l o n g

Early

trauma

or

barotrauma

mnv

displace

a

p r o s t h e s i s , l e a d i n g to a fistula. If these s y m p t o m s persist

process of the incus with angled hooks bimanually.

in

spite of therapeutic

m e a s u r e s and clinical j u d g m e n t

suggests a compli-

If this is impossible, they can be s e c t i o n e d with small scissors a n d replaced. If necrosis of the long process

cation, or if there is a s e n s o r y hearing i n v o l v e m e n t ,

of the incus is present,

exploration is indicated. W h e n revising a stapedec-

the r e m n a n t . If this is i m p o s s i b l e , a malleus-to-oval

tomy

(or a n y ear p r o c e d u r e ) ,

w i n d o w p r o s t h e s i s ( o r p l a c e m e n t o f a b o n e graft o r

taken

in

lifting

a

thin

skin

important point might lead sary

tears

general, and

in

the

flap

or

special flap.

w i n d o w graft.

tissue The

is

round

this

to serious and unnecestympanic

not m u c h graft i s r e m o v e d

connective

care must be

Overlooking

placed window

membrane.

In

w h e n revising,

around

the

is evaluated

oval for

the prosthesis is placed in

T O R P ) is indicated. A piston is used if there is recurrent b o n e d e p o sition with c l o s u r e of the oval w i n d o w . If the focus is active a n d risk is i n v o l v e d ,

t h i n g s s h o u l d b e left

a s t h e y a r e for t h e t i m e b e i n g .

It should be kept in

mind

that

'.he

results

of revision

stapedectomy

are

tears; if it is q u e s t i o n a b l e , a s m a l l p i e c e of G e l f o a m

not so g o o d as in primary procedures; at the s a m e

can be used to obliterate the niche. If the prosthesis

time, vestibular involvement with secondary sensory

is found to be too long, the wire can be gently bent

hearing loss is m o r e likely.

I

268



269

Pertinent Histopathology FIGURE

13-15

This horizontal section s h o w s a large otosclerotic

of ( a c o b s o n ' s

nerve

on

focus fixing the s t a p e s a n t e r i o r l y a n d posteriorly. T h e

rows) a r e a l m o s t e n t i r e l y

stapes footplate is thickened. N o t e that the branches

bone.

the

promontory

(parallel

it-

s u r r o u n d e d by otosclerc'.ic

FIGURE

13-16

This section at the level of the oval w i n d o w area

footplate h a s b e e n e x c i s e d ; the site is evident. T h e

is from the temporal b o n e of an individual w h o had

vestibule is intact.

a successful stapedectomy.

vestibular contents.

1

Part of the otosclerotic

N o t e t h e close proximity of the

270



271

Cochlea

FIGURE This

13-17

section

individual

who

FIGURE 13-18 is

can

be

seen

the

underwent

piston prosthesis. it

from

a

temporal

bone

stapedectomy

of

an

with

a

T h e site of p l a c e m e n t is evident;

that

the

piston

was

too

deep

and

impinged on

the vestibular structures.

The surgicij

result w a s not ideal, a n d the patient had t w o piston ; placed subsequently

This

horizontal

otosclerosis and a caused

by

otitis

section shows a

stapes

middle ear cavity media.

The

section

fixed

by

with c h a n g e s shows

very

clearly that if the footplate w e r e r e m o v e d under these

conditions,

the

middle

ear

process

would

immedi-

ately penetrate the vestibule, with disastrous potential c o m p l i c a t i o n s . ( S o m e i n f l a m m a t i o n o f t h e v e s t i bule is evident.)

Fi Lasers in Otologic Surgery . Power density

CHAPTER 14

273

Power = Spot size

Lasers in Otologic Surgery T h e w o r d l a s e r i s a n a c r o n y m for light a m p l i f i c a -

T h e d e v e l o p m e n t of the laser in otologic surgery

tion by stimulated emission of radiation. In the early

has

2 0 t h century Albert Einstein predicted that this form

tool, h o w e v e r , it m u s t be used correctly. U n d e r s t a n d

o f e n e r g y e x i s t e d . I t w a s not until 1 9 6 0 that T h e o d o r e

ing

M a i m o n d e v e l o p e d t h e first w o r k i n g l a s e r , m a d e o f

training

a ruby crystal. Next, the gas laser was developed by

before one can

Alec Javon

tool.

come

the

in

1961.

many

From

advanced

these

early

lasers

have

models

in

medical

use

today.

been

a

the

remarkable

laser

is

advance;

absolutely

through

a

any

essential,

"hands-on"

efficiently

like

and

course

and

safely

is

prope-

use this

nev

t e r m s m u s t be d e f i n e d : power,

spot size,

anc

pulse duration. T h e p o w e r o f t h e b e a m i s i t s e n e r g y

for u s e i n t h e h e a d a n d n e c k a r e a . T h e a u t h o r s feel

o u t p u t a n d i s m e a s u r e d i n w a t t s . S p o t s i z e r e f e r s t'/

that the visible-wavelength lasers—the argon a n d the

the d i a m e t e r o f the b e a m , a n d c a n vary from microns

K T P - 5 3 2 — a r e b e s t s u i t e d for o t o l o g i c w o r k .

to millimeters. Pulse duration is the a m o u n t of timi

lasers

are

most

useful

for a n u m b e r of r e a s o n s : 1. T h e y

allow

fiberoptic cables. arms

are

intricate

needed spaces

for and of

energy

transmission no

delivery

the

in

which

the

function;

Therefore,

through

articulating, of

middle

the

ear

beam

is

bulky to

more

may

accomplished.

be

beam

actively

it m a y be m e a s u r e d continuous.

All

performs in

its

surgicc

m i l l i s e c o n d s or i

of these

functions can

b>

varied at a n y t i m e for different surgical n e e d s .

the

easily

Power

density

understood.

It

is

is

another concept defined

as

the

that

power

must per

bun:

v o l u m e (Fig. 1 4 - 1 / 1 ) . T h e p o w e r of the laser b e a m i

2. T h e visible-spectrum lasers do not need a car-

constant, but by varying the spot size of the b e a m a

FIGURE 14-1.

rier b e a m to be seen by the n a k e d eye. W i t h the C O ,

the focal point, t h e p o w e r d e n s i t y c a n b e s i g n i f i c a n t ! "

b e a m , w h i c h u s e s an invisible w a v e l e n g t h , a carrier

altered. Focusing the b e a m to a very small spot siz :

beam

in order to focus the b e a m on the

greatly increases the p o w e r d e n s i t y ; with a large spo*

s u r g i c a l s i t e ; i f t h e s e b e a m s a r e n o t exactly c o a x i a l , o r

size the p o w e r density is decreased. T h i s is a crucia'

is needed

r

if the mirrors of the articulating arm are imperfectly

c o n c e p t in laser s u r g e r y a n d is vital in u n d e r s t a n d s ; ,

aligned,

the surgical ramifications of the laser.

the

surgical

beam

may

not

be

delivered

precisely w h e r e it is n e e d e d . 3. The

visible-wavelength

T h e surgical b e a m s are readily

ab-

s o r b e d b y p i g m e n t a n d not b y c l e a r fluids, s o h e m o stasis can be accomplished. 4. Along

with

cutting,

and

tissue

tissue vaporization

spot

size

of

the

beam

and

varying

the

power.

Cutting of tissue requires the highest p o w e r density,

h a n d pieces have b e e n developed, allowing the b e a m

so a very small spot size and large a m o u n t s of p o w e r

to

are

delivered

by

an

alternate

a

effects of the laser b e a m are coagulation,

( F i g . 14— I S ) . T h e y c a n b e a c h i e v e d b y m a n i p u l a t i n g the

fiberoptic capability

tissue

n u m b e r of

be

COAGULATION Large spol Low power

necessar

A n u m b e r of laser systems are currently available

visible-wavelength

VAPORIZATION Large spol High power

In discussing the surgical applications of the laser three

These

CUTTING Small spol HiQh power

surgici!

method.

The

hand

used.

For vaporization of tissue,

full

power

i;

p i e c e is held like a scalpel, a n d the b e a m is focused

used with a larger spot size; the depth of vaporization

by moving it up and down.

can be controlled. Coagulation requires a large spot

size a n d a l o w p o w e r setting. Coagulation of vessels

site. Pulse duration a n d p o w e r are set on the m a c h i n e

can

visible-wavelength

itself or by a r e m o t e control at the operating table.

not

T h e b e a m is activated by a foot pedal.

only

lasers

be

(argon

accomplished and

KTP-532)

with and

with

the

C 0

2

laser. Actual

manipulation of the beam is d o n e by

the

surgeon. T h e spot size c a n be altered in two w a y s . With

Laser Stapedotomy

the b e a m delivery device attached directly to

the m i c r o s c o p e , the spot size is c h a n g e d by a rheostat-type

device

on

the

visualizing the beam,

microscope;

while

directly

t h e s u r g e o n c a n v a r y t h e di-

This section describes applications of the laser in the

middle

ear,

but

the

principles

and

techniques

ameter of the b e a m as n e e d e d . T h e hand-held deliv-

also apply to mastoid work. Specific approaches to

ery system

the surgical site (incisions,

focuses as

the hand

piece is m o v e d up

and d o w n while the b e a m is w a t c h e d at the surgical

flaps,

and

so on)

have

b e e n d e s c r i b e d e l s e w h e r e . T h e d i s c u s s i o n will focus

274

Lasers in Otologic Surgery

only

on

laser

applications

to


tissues;

any

The

specific

stapes

flap

is

rotated

anteriorly

until

thj

posterior border of the malleus is directly visualized

a p p r o a c h e s t h a t are c a l l e d for a r e e x p l a i n e d .

The

bony

scutum

is

then

removed

until

the

facial

nerve is visualized above the stapes and the pyramidal

Highlights

process

of

posteriorly.

It

the is

stapedial

tendon

very important

is

identified

to visualize

their

two structures to ensure adequate working room. Manipulation

1. G o o d local a n e s t h e s i a 2. Cood

done

hemostasis.

5. Superior

the

malleus

fixation

and

incus

is

thei.

of either structure as

th •

Attention

I •

n o w f o c u s e d o n t h e s t a p e s ; a g a i n , m a n i p u l a t i o n wiMi

nursing assistants

a small right-angled h o o k is d o n e to confirm fixation

instrumentation

T h e i n c u s - s t a p e s j o i n t i s s e p a r a t e d . T h e s t a p e s hold,?

6. U s e of a stapes holder.

is then b r o u g h t into the field.

7. Preservation of the chorda tympani.

With adjustment of the laser spot size and b e a -

8. Visualization of the p y r a m i d a l p r o c e s s a n d the

parameters

facial n e r v e .

done

preoperatively,

the

actual

lasei

work begins. T h e stapedial tendon is focused on a n c

9. Understanding of laser techniques and use. 10.

of

rule out

c a u s e of the c o n d u c t i v e h e a r i n g loss.

3. R e m o v a l of the s c u t u m . 4. Knowledgeable

to

vaporized, using the laser at 2.0 watts of p o w e r a r o

C o m p l e t e visualization of the ossicles.

a

pulsed

b e a m o f 0.;1

second.

T h e b e a m is sharp';

focused on the tendon by a " j o y stick" m o u n t e d cr t h e m i c r o s c o p e , a n d i s fired b y a foot c o n t r o l w h e n

Pitfalls

the

operator is

ready.

The

smoke

plume

is drawr

a w a y by a N o . 22 s u c t i o n tip h e l d in t h e o p e r a t o r ? left h a n d ( F i g . 1 4 - 2 A ) . 1. F o r m i n g

blebs

in

the

external

auditory

canal

while injecting

O n c e the tendon has been vaporized, a m e a s u r e m e n t i s t a k e n f r o m t h e l a t e r a l s u r f a c e o f t h e i n c u s ::•

2. Tearing the tympanic m e m b r a n e during elevation.

the

footplate of the stapes.

measurement

3. Inadequate

exposure.

4. Tearing the chorda

gives

Adding 0.5 mm to th s

the proper

length

t h e s i s . T h i s l e n g t h will v a r y w i t h

tympani.

for t h e

pro: -

the type of p r e -

thesis, point of m e a s u r e m e n t , a n d other factors. Th-'

5. Inexperienced scrub nurse.

laser b e a m

is then

6 . I n j u r i n g t h e facial n e r v e .

the stapes

Again, with a pulsed b e a m and (he sam •

7. Placing

the

prosthesis

too

deep

in

the

oval

window.

f o c u s e d on

the posterior crus t i

p o w e r settings, the crus is lased a w a y (Fig.

14-28).

T w o s u g g e s t i o n s m a y b e helpful a t this s t a g e : 1 . I f t h e h e m e i s v e r y w h i t e , v a p o r i z a t i o n m a y r>.» slow because the b e a m is absorbed

Procedure

help gre.itlv. ops. The

laser

stapedotomv

efficient procedure. draped done

in

the

under

bv pigment.

/.

d r o p o f b l o o d , b o n e c h a r , o r e v e n g e n t i a n violet will

usual

local

is

a

verv

successful

and

Initially the ear is p r e p a r e d and fashion.

All s t a p e d o t o m i e s are

anesthesia;

the

authors

use

2%

O n c e the

initial d a r k h o n v c h a r d e v e l

vaporization proceeds verv quicklv.

2. W h e n excess char builds up around

the b o n e

vaporization may again be slow. The char should bi gently chipped a w a y with a small right-angled pick O n c e the posterior crus has been is

addressed.

Often

it

can

be

th*

anterior

quadrant injection is m a d e with a 2 7 - g a u g e needle.

directly and r e m o v e d in the s a m e w a y as the poste

T h e ear is then

rior c r u s .

irrigated with povidone-iodine (Be-

crus

vaporized,

l i d o c a i n e with 1:20,000 e p i n e p h r i n e . A s t a n d a r d four-

W h e n the anterior crus cannot be directly

visualized because of the body of the Incus,

tadine) through a bulb syringe.

seei

a spe

round

cially d e s i g n e d m i r r o r is n e e d e d to reflect the b e a m

knife. A s e m i c i r c u l a r incision is m a d e starting at the

o n t o it. T h e b e a m i s f i r s t f o c u s e d o n t h e p r o m o n t o r v

6 o'clock

just

A

standard

stapes

position,

flap

is

traveling

elevated up

the

with

a

posterior canal

wall, and e n d i n g at the 12 o'clock position just above

anterior

introduced

to

until

the

anterior

crus.

The

mirror

the anterior crus is reflected.

is

The

t h e s h o r t p r o c e s s o f t h e m a l l e u s . T h e flap i s e l e v a t e d

b e a m is then b o u n c e d off the m i r r o r o n t o the anterio'"

to the a n n u l u s a n d the m i d d l e e a r is e n t e r e d in the

c r u s until it is v a p o r i z e d (Fig. 1 4 - 2 C ) .

usual fashion. T h e chorda t y m p a n i nerve is identified and

preserved

Attention

is

then

turned

to the

footplate of

the

stapes. T h e authors use either a 0 . 8 - m m or a 0 . 6 - m m FIGURE 14-2.

275

276

Lasers in O t o l o g i c S u r g e r y

o p e n i n g into

the

inner ear;

the


former is

preferred

Ossicles

unless there is not e n o u g h room. A template is placed on the footplate,

m a k i n g a visual i m a g e of the 0 . 8 -

m m site ( F i g . 1 4 - 2 D ) . T h e l a s e r i s t u r n e d t o 1.8 w a t t s and a 0.1-second pulsed beam.

A rosette pattern is

T h e laser has b e e n very beneficial in w o r k a r o u n d the ossicles. Since manipulation of the ossicles and

m a d e on the footplate, corresponding to the 0.8-mm

corresponding

stapedotomy opening.

rineural hearing loss and ossicular disarticulation,

the footplate.

Usually one

p u l s e will o p e n

It is important to overlap these laser

is

desirable

trauma to

potentially

minimize

this

may cause sensomanipulation.

i*

The

" h i t s , " b e c a u s e t h e c h a r f r o m e a c h p r e v i o u s hit will

highly focused b e a m of the laser can virtually elimi-

absorb

nate manual trauma involving the ossicles.

The

the

heat

template

and

is

allow

for

reintroduced

better to

vaporization

ensure

that

the

opening is the proper size. T h e prosthesis is then positioned over the incus

in

the presence of

cholesteatoma or adhesions around

T h e laser is especially useful

the stapes or ir

the oval w i n d o w niche.

a n d into the s t a p e d o t o m y o p e n i n g and c r i m p e d into

disarticulation

position (Fig. 14—2£). T h e part of t h e p r o s t h e s i s that

w a y s a hazard. U s i n g a finely f o c u s e d b e a m of short

fits i n t o t h e v e s t i b u l e i s e x a c t l y 1 m m i n l e n g t h ; w h e n

pulse duration (0.1 to 0.3 s e c o n d s ) a n d low p o w e r (i

p r o p e r l y p o s i t i o n e d , h a l f o f it, o r 0 . 5 m m , s i t s i n t h e

to 3 watts), disease can be vaporized without trauma

vestibule. S i n c e this section of t h e prosthesis is only

to the nearby ossicles.

1 mm long, it is easy to j u d g e the correct depth.

with

With very adherent disease

adhesions and

1. If s o m e of the laser hits do not c a u s e perilymph

for

the way

t h r o u g h the

or reducing and

through

the

bone,

the

prosthesis

will

easily break through the remaining ones 2. S o m e t i m e s from

a

small

amount

t h e v a p o r i z a t i o n i s left o n

of

the

the

crimped, All

sound

prosthesis

the in

tympanic the

is

at

material.

parameters,

Setting

surface

the b e a m

coagulation

of

faster

this

nuisance bleeding

procedure.

In

permits a

addition,

safer

vaporization

of

residual

char

o f the b e a m p a r a m e t e r s . A g a i n , this eliminates m u c h

footplate.

It is

of the vibratory trauma, reduces bleeding, and allows the surgeon to r e m o v e the a d h e s i o n s layer by layer

correctly

membrane

operating

is

the adhesions can be accomplished with adjustment

not n e c e s s a r y to r e m o v e this. Once

leak

these small vessels can be accomplished. Eliminating

the

go

polypoid

coagulation

f o o t p l a t e b o n e , t h i s i s n o t c a u s e for a l a r m . I f m o s t o f hits

perilymph

A n o t h e r u s e for t h e l a s e r i s i n t h e e a r filled w i t h

T w o additional suggestions are relevant here; t o f l o w a n d d o n o t e x t e n d all

resultant

suite

positioned is

and

repositioned.

(monitors,

fans,

(Fig. 1 4 — 3 8 ) . T h i s precision, e s p e c i a l l y in the d e p t h s of the oval w i n d o w with disease around the stapes greatly e n h a n c e s the ability to r e m o v e tissue w i t h o u

lasers, and so o n ) is reduced, and the patient is asked

trauma

to c o u n t n u m b e r s to obtain a subjective hearing level.

tures.

W h e n the s u r g e o n is satisfied with the hearing level,

to

the

surrounding

normal

anatomic

struc

A n o t h e r i d e a l s i t u a t i o n for L i - . l t w o r k i s e r o s i o r

the footplate is revisualized. If the p r o s t h e s i s is firmly

of

fixed in position, o n e or t w o small drops of autoge-

eroded

the

lenticular and

process

n o u s blood are instilled in the oval w i n d o w to act as

stapes,

the lenticular process often has e n o u g h bont

a seal. T h e flap is t h e n r e p o s i t i o n e d a n d p a c k e d with

left t o m a k e r e c o n s t r u c t i o n d i f f i c u l t .

G e l f o a m , a m a s t o i d dressing is placed, a n d the pa-

the surgeon can vaporize the b o n e quickly, sharply,

tient is taken to the recovery room.

a n d atraumatically to allow m o r e r o o m (or the recon-

lacking

a

of

bony

the

incus.

Although

connection

with

the

Using the laser

structive procedure (Fig. 1 4 - 3 / 1 ) . The

laser also is quite useful

in

tympanic mem-

brane work. Freshening the e d g e s of a perforation ir p r e p a r a t i o n for a graft c a n b e d o n e e a s i l y a n d q u i c k l y .

Laser Applications in the Middle Ear

A pulsed or continuous b e a m focused on the periplv ery of the

perforation

can

be

used

to

remove

thf

rolled e d g e s of the perforation (Fig. 1 4 - 3 C ) . W h e n elevation of the periosteum of the malleuc is required

Initially restricted to s t a p e d o t o m y p r o c e d u r e s , use of the laser has b e e n e x p a n d e d to include every case

the

umbo

in grafting techniques, is

pulling of this

always

very

the area around

adherent.

Tugging

and

tissue causes considerable vibratory

in the authors' otologic practice. It has proved to be

trauma

extremely useful in reconstruction and cholesteatoma

again, tissue can be lased a w a y without trauma (Fig

w o r k in the middle ear and mastoid.

14-3D).

throughout

the

ossicular

chain.

Once

FIGURE 14-3.

277

278



As m e n t i o n e d previously, the argon a n d KTP-532 lasers are readily a b s o r b e d by p i g m e n t a n d h e m o g l o bin.

Because

of

this

affinity,

hemostasis

of

Neurotology and the Laser |:

small

m i d d l e e a r cleft b l e e d i n g can often be a c c o m p l i s h e d .

T h e laser also is used extensively in neuroto!oj;ic

W i t h a large spot size, pulsed b e a m , a n d low power,

practice,

nuisance

be con-

a c o u s t i c n e u r o m a w o r k . It is u s e d for t h r e e f u n c t i o ; s:

A g a i n , the s p e e d a n d precision of the laser

(1) h e m o s t a s i s , (2) vaporization of the t u m o r , a n d i3)

trolled.

bleeding

from

mucosal

areas can

in h e m o s t a s i s lends itself greatly to the e n h a n c e m e n t

and

has

been

an

invaluable

addition, to

t u m o r c u t t i n g for r e m o v a l .

of reconstructive work. The

laser

is

ideally

suited

for

repair of a

fixed

m a l l e u s . T h e difficulty in drilling a r o u n d the ossicles

Procedure

In the attic is greatly reduced. Also, disarticulation of the incus-stapes t is not n e e d e d b e c a u s e of the atraumatic bone vaporization.

A standard

postauric-

ular incision is m a d e a n d an a t t i c o t o m y is p e r f o r m e d (described e l s e w h e r e in this b o o k ) .

Drilling is d o n e

until the fixed o s s i c l e s are identified. In the a u t h o r s ' e x p e r i e n c e , the difficulty lies in freeing the fixation, which is usually anterior and medial to the malleus and incus.

I t i s e x t r e m e l y difficult t o drill this b o n e

a w a y ; c u r e t t i n g also i s c r u d e a n d difficult. O n c e the fixation is v i s u a l i z e d , the laser p r o v i d e s an ideal w a y to remove the bone without trauma

to the ossicles.

A pulsed or continuous b e a m sharply focused on the b o n y f i x a t i o n v a p o r i z e s t h e b o n e , a l l o w i n g free m o bility of the chain

(Fig.

14-3E).

A

small

piece of

Silastic is then inserted b e t w e e n the ossicles and the area of fixation to help prevent b o n e r e g r o w t h .

T u m o r exposure is accomplished by the standard approaches to the posterior and middle fossa, which have been described elsewhere. thine approach,

the internal

t h i n n e d o n its s u p e r i o r ,

posterior, and

is

inferior bor-

d e r s . O n c e t h e e g g s h e l l - t h i n b o n e i s left, t h e l a s e r j s used initially

for s u r f a c e c o a g u l a t i o n ( F i g .

14-4.").

T h e a r e a o v e r t h e facial n e r v e in t h e a n t e r o s u p e r i >r quadrant

is covered

with

Cottonoid

for

protection.

T h e laser is u s e d at a p p r o x i m a t e l y 4 to 6 w a t t s power

with

Because

a

of

pulsed

the

beam

beam's

and

affinity

a

large

for

spot

pigment,

if

sizr. it

is

absorbed by the hemoglobin. Coagulation is accomplished the

over

the surface of the

eggshell-thin

small

capillaries

bone.

tumor and

Surface

before

internal auditory canal

Summary

In the translabyrin-

auditory canal b o m

opening

through

coagulation the

dura

of

the

of

the

reduces and sometimes com-

pletely p r e v e n t s n u i s a n c e bleeding from small duril tumor vessels.

O n c e surface coagulation

is accom-

p l i s h e d , t h e facial n e r v e is identified in t h e i n t e r n i l The

laser

has

markedly

reduced

the

degree

of

auditory

canal.

Dissection

is

vibratory trauma to the ossicles and thus to the inner

c a n a l in the s t a n d a r d f a s h i o n .

ear

is identified a n d C o t t o n o i d

fluids.

By

minimizing

trauma,

the

surgeon

re-

jccomplished

in

is p a c k e d a r o u n d

it

duces the chances of iatrogenic sensorineural hearing

protection,

loss. T h e precision of the b e a m allows the surgeon

a w a y (Fig.

t o r e a c h a r e a s o f t h e m i d d l e e a r cleft s a f e l y , quickly,

tings and

and with

safely and quickly, often with m i n i m a l b l e e d i n g . '

less potential

for i n j u r y

to the patient.

A

s e c o n d m a j o r a d v a n t a g e lies in the h e m o s t a t i c prop-

the

After the facial ne ' e -dr

the tumor bulk in the canal is v a p o r L e c 14-4B). beam

Standard

By manipulating the p o w e r iet

spot size,

posterior

tumor can

fossa

be

vaporb ec

procedures—protect'jn

erties of the visible-spectrum laser. T h e confines of

of

the

m i d d l e e a r h a v e a l w a y s b e e n difficult to

brainstem with Cottonoid—are followed o n c e tun or

for

conventional

tive

properties

coagulation.

of the

The

reach

pigment-absorp-

visible-spectrum

beams

have

greatly e n h a n c e d this p r o c e d u r e . T h e s e two features

other

cranial

removal in

nerves,

the

cerebellum,

and

he

the a n g l e is b e g u n . T h e facial n e r v e is

a l w a y s kept in view but is protected with C o t t o n o . d T u m o r r e m o v a l b y v a p o r i z a t i o n i s d o n e a l m o s t e x c tt-

of the laser have added a n e w dimension to otologic

sively with

surgery.

The authors use

the laser in the cerebellopontine angle. full

p o w e r (8 to 10 watts) witt

a

FIGURE 14-4.

279

280

L a s e r s in O t o l o g i c S u r g e r y

continuous beam removal

is

and

done

a

from

medium the

spot

interior

size.

Tumor

protected with Cottonoid; the vestibular nerve is t h e t

the

tumor,

vaporized away.

of

In this c a s e ,

however,

the authora

initially k e e p i n g the c a p s u l e intact. S u c t i o n is used

feel t h a t c o n v e n t i o n a l s e c t i o n i n g w i t h s c i s s o r s is ju t

to draw a w a y the s m o k e p l u m e from the vaporization

as

sule collapses a n d further dissection of the capsule

icum

from

Small

surrounding

structures

With very large tumors, away

with

the

laser.

can

be

accomplished.

the t u m o r itself c a n be cut The

beam

parameters

are

tumors,

also can be debulked

with

the

lase:.

feeder vessels are easily coagulated with

th";

visible-spectrum beam. T h e capsule of the tumor cauterized

with

low

power

settings

and

a

;

diffused

c h a n g e d t o a v e r y s h a r p f o c u s w i t h full p o w e r a n d

beam. This use of the laser " t o u g h e n s " the capsule

c o n t i n u o u s duration. Using this b e a m , tumor bulk is

allowing

cut a w a y easily with m i n i m a l b l e e d i n g (Fig. 1 4 - 4 C ) .

tumor.

Large vessels cannot be coagulated with thr

beam,

but

T h e t e c h n i q u e s and u s e s of the laser in the suboccipital a p p r o a c h are similar. that

the

dura

over the

An additional step is

p o s t e r i o r lip

of the

for

easier

by

and

reducing

safer the

manipulation

feeder

vessels,

of

th'i

tumo •

removal is facilitated. In s u m m a r y ,

internal

the laser has proved to be an inva!

auditory canal is lased away; again, it can be removed

uable tool in otologic and n e u r o t o l o g i c w o r k . S t a m

quickly and without bleeding, and less time is needed

dard t e c h n i q u e s are greatly facilitated by the laser; if

for b i p o l a r c a u t e r y o r d r i l l i n g .

is

Sectioning of the vestibular nerve can also be done with

the

laser.

techniques,

and

The

nerve

is

isolated

the cochlear and

facial

by

standard

nerves are

CHAPTER 15

effective. Vascular lesions, especially small glomus t y m p a r -

p r o c e s s . A s its i n t e r i o r i s v a p o r i z e d , t h e t u m o r c a p -

precise,

probably

fast,

become

safe,

and

standard

very in

the

efficient, near

and

future.

wB Tht

next hurdle in otology is the inner ear, a n d the l a s » m a y be of benefit in the not too distant future.

Surgical Approach for Bone Conduction Hearing Devices B o n e conduction hearing devices are in an early

Aim

p h a s e o f d e v e l o p m e n t , b u t a first g e n e r a t i o n i s n o w available for clinical u s e . T h i s area o f o t o l o g y s h o u l d w i t n e s s significant positive c h a n g e s in future years. C o n d u c t o r s are neous the

and

available

in

transcutaneous.

surgical

two

This

types,

chapter

technique (Hough's

percutadescribes

technique)

for im-

T o e x p o s e i a site i n the area o f the linea t e m p o r a l i s for s a f e

placement

of the

receiver,

while

allowing

a d e q u a t e s k i n c o v e r a g e a n d a p o s i t i o n for t h e e x t e r n a l device that is comfortable and harmless.

plantation of the X o m e d audiant bone conductor. This

bone

c o n d u c t o r is

a

transcutaneous

device

consisting of an external and an internal c o m p o n e n t . Externally

(outside

the

patient),

a

microphone

re-

Procedure

ceives s o u n d and c h a n n e l s it to a s o u n d processor; this d i r e c t s an a m p l i f i e d signal a c r o s s the skin to the implant (the internal c o m p o n e n t ) ,

which is screwed

After preparation a n d s h a v i n g of the postauricular

into the skull. T h e amplified signal is transmitted by

area, the ear is sterilely d r a p e d . A postauricular line

skult vibration into the inner ear and

is traced h o r i z o n t a l l y at a level i m m e d i a t e l y superior

sound

is per-

ceived. T h e external and internal parts of the device are h e l d t o g e t h e r e l e c t r o m a g n e t i c a l l y . T h e s y s t e m is battery This

operated. device

to the tragus. T h e receiver (implant) is to be placed behind

the

mately 15

currently

is

used

in

patients

with

posterior to

template is

conduction

delineated (Fig,

benefit

from

congenital other

discrimination

conventional

hearing

who

aids

cannot

(owing

to

m a l f o r m a t i o n s , c h r o n i c external otitis or

factors).

expanded.

speech

Indications

for

the

device

will

be

edge

of

from

this

the

pinna.

positioned

and

Approxi-

posterior edge and

i m m e d i a t e l y a b o v e the horizontal line,

external or middle ear impairments with good bone and

18 mm

the bur hole

the site of the

receiver

15-24).

An incision site is traced at least 1 cm posterior to the edge of the receiver a n d injected with 2% caine (Xylocaine)

with 1:100,000 epinephrine.

lidoThe

S o m e b a s i c i n s t r u m e n t s ( X o m e d kit) are

i n c i s i o n is d e e p e n e d d o w n to t h e p e r i o s t e u m , a flap

required in order to position the internal receiver in

is e l e v a t e d , a n d the linea t e m p o r a l i s is identified. If

the skull; they are s h o w n in Figure 1 5 - 1 .

t h e s u b c u t a n e o u s t i s s u e s a r e t h i c k , t h e a r e a t h a t will

282

Surgical Approach for Bone Conduction Hearing Devices

Surgical Approach for Bone Conduction Hearing Devices

TIghtening tool

Universal wrenell handle

Full tap

Spanner attachment

Implant Guide cylinder

Deplh SlOp burs

Template

fiGURE 15-1

FIGURE 15-2.

283

S u r g i c a l A p p r o a c h for B o n e C o n d u c t i o n H e a r i n g D e v i c e s cover

the

adequate

receiver

is

thinned

in

order

transcutaneous transmission

to

and

permit

until t h e g a p b e t w e e n t h e w r e n c h h a n d l e a n d g u i d e

magnetic

c y l i n d e r i s c l o s e d . T h e full t a p i s t h e n r e m o v e d f r o m

coupling between the external and internal devices. The

area

where

reidentified, without

the

marked,

drilling

deep

receiver

will

and

evened

into

the

(This area needs depth

be

placed

with

bone

285

a

is

bur

(Fig.

kit

15-2B).

to receive the screw of the

implant.)

the s c r e w hole. T h e thread in the center hole is n o w r e a d y for t h e s c r e w o f t h e i m p l a n t . T h e full t a p i s r e m o v e d f r o m t h e u n i v e r s a l w r e n c h handle

and

replaced

with

the

spanner

attachment,

which is designed to hold the implant both mechanically a n d e l e c t r o m a g n e t i c a l l y . T h e i m p l a n t i s placed

U s i n g the larger bur in

t h e kit ( t h e b u r s h a v e a

in the spanner and inserted

through the guide cyl-

depth s t o p ) , the c e n t e r hole is drilled (Fig. 1 5 - 2 C ) . If

inder until it faces the center hole (Fig. 1 5 ^ 3 4 ) . T h e

a c e r e b r o s p i n a l fluid l e a k o c c u r s ,

implant

the site is sealed

with b o n e w a x a n d an adjacent site is used. Using the small

b u r in the set a n d

guide,

three

small

turned

the bur hole

control

holes

are

(with

the

screw

facing the

hole)

'/i-turn c o u n t e r c l o c k w i s e (again,

is

gently

in order not

to alter the thread in the hole), a n d then clockwise

template as

a

drilled (Fig.

1 5 - 2 D ) . T h e larger central hole is des-

cylinder is c l o s e d a n d there is a feeling of resistance

until t h e g a p b e t w e e n t h e w r e n c h

handle and guide

tined for t h e central s c r e w of t h e i m p l a n t . T h e three

(Fig. 1 5 - 3 B ) . T h e w r e n c h a n d the g u i d e c y l i n d e r are

a d j a c e n t control h o l e s will receive the three p e g s of

r e m o v e d . T h e i m p l a n t i s g e n t l y c h e c k e d for t i g h t n e s s

t h e g u i d e c y l i n d e r a n d i m p a r t s t a b i l i t y t o it.

(Fig. 1 5 - 3 C ) . T h e flap is r e p o s i t i o n e d , the i n c i s i o n is

T h e next step is to develop a thread in the center h o l e for t h e s c r e w of t h e i m p l a n t . T h i s is d o n e in t w o stages,

using

the

"half

tap"

and

"full

tap"

instruments. The

closed

in

layers

with

appropriate

sutures,

and

a

mastoid dressing is applied. Testing and use of the external device begins at 8 to 12 w e e k s , d e p e n d i n g u p o n the healing process.

guide

cylinder

is

placed

upright.

The

three

pegs are inserted in the corresponding three holes to keep the cylinder perpendicular to the b o n e surface. The

first

tightened

tap

to

to be

the

used

universal

is the

half tap;

wrench

this

handle with

the

tightening tool. T h e universal w r e n c h (with the half tap

tightened

cylinder

t o it)

and

is

rotated

then

slid

through

clockwise,

firmly

the guide pressing

This

is a

trauma; raising

the m a i n

handle and guide

The

half

loosened

tap

and

is

a

postauricular potential

fluid l e a k . removed

removed

from

from the

the

skull,

universal

then

wrench.

procedure

in

be d o n e u n d e r local

of surgical

anesthesia and

has few complications. O t h e r than those inherent in

until

the gap b e t w e e n the wrench

simple

it can

a g a i n s t t h e s k u l l . R o t a t i o n c o n t i n u e s for % of a turn, cylinder is closed.

FIGURE 15-3.

Complications

is

flap

(discussed

elsewhere),

problem is that of cerebrospinal

B u r s with a " s t o p " (such as those in the

kit) do n o t a l l o w a d e e p p e n e t r a t i o n ; if a l e a k d o e s occur,

sealing the ;

opening

Prophylactic

with

bone

slid t h r o u g h t h e g u i d e c y l i n d e r , a n d p l a c e d o v e r t h e

these cases.

c e n t e r o f t h e s c r e w h o l e . F i r s t , i t i s g e n t l y t u r n e d '/2-

intravenous antibiotics is r e c o m m e n d e d . O t h e r comare

initial

t u r n c o u n t e r c l o c k w i s e (in o r d e r n o t t o a l t e r t h e t h r e a d

plications

previously m a d e by the half tap)*«nd t h e n c l o c k w i s e

surgical techniques.

caused

high by

dose

failure

be

should

suffice.

An

antibiotics could

wax

T h e full t a p i s n o w t i g h t e n e d t o t h e u n i v e r s a l w r e n c h ,

useful

in

of intraoperative to

follow

careful

287

Surgical A p p r o a c h e s for C o c h l e a r I m p l a n t s

CHAPTER 16

4. Removal of temporal muscle.

securing the electrode at this level with

5. D r i l l i n g of a s e a t for t h e i n t e r n a l r e c e i v e r .

sutures.

6. Simple mastoidectomy.

The

window

niche

is

visualized

through

7 . O p e n i n g o f t h e facial r e c e s s .

t h e facial r e c e s s ( F i g . 1 6 - 2 D ) . U s i n g a s m a l l b u r , t h e

8. Exposure of the round window.

a n t e r o s u p e r i o r lip o f t h e n i c h e i s r e m o v e d a n d

9. Placement of the internal receiver.

round

window

view.

If the

10. Insertion of the electrode via the round window

Surgical Approaches for Cochlear Implants

round

permanent

membrane

is

brought

directly

w i n d o w cannot be visualized,

the into

drilling

toward the p r o m o n t o r y will h e l p to p r o v i d e a straight

opening.

11. Securing of the internal receiver.

view of the basal turn, bying the " h o o k . " This

12. Closure, packing, and a mastoid dressing.

should be d o n e cautiously, in a step-by-step fashion. If b o n e

g r o w t h is

position"

p r e s e n t in

this area,

a

"straight

is reached a n d drilling is d o n e anteriorly

(forward) into the scala t y m p a n i . T h i s will lead to an

Procedure

o p e n s c a l a or p r o v i d e a s p a c e for p l a c i n g t h e e l e c trode.

i:

A

dummy

postauricular

electrode

is

position

of

used the

to

determine

internal

the

receiver.

It

should be at or a b o v e the linea temporalis, allowing enough

space

eyeglasses.

without

Some

interfering

surgeons

with

prefer

to

the

use

of

place

the

re-

ceiver m o r e inferiorly. T h e receiver site can be traced with a m a r k i n g p e n or a circular i m p r e s s i o n can be

The electrode

is

then

w i n d o w niche is sealed nonserrated should blunt

be

or used

wire

introduced

specially

coated

for e l e c t r o d e

guides

or

and

the

with fascia (Fig.

hoes.

alligator

insertion,

Extreme

round

16-3). helped

care

A

forceps must

by be

used w h e n handling the electrode in order to avoid damaging

it.

With

the

3M

House

type,

only

the

noninsulated portion is introduced.

left b y p r e s s i n g a d u m m y r e c e i v e r a g a i n s t t h e s k i n . A l t h o u g h there are m a r k e d differences a m o n g the different types of cochlear implants, ciples of and

the b a s i c prin-

s u r g i c a l a p p r o a c h e s for t h e s e d e v i c e s

detail.

As

in

the

facial

recess

approach,

a

larfe

Infiltration of the postauricular incision site is the

L

p o s t a u r i c u l a r flap i s e l e v a t e d i n c o n t i n u i t y w i t h t e

membrar?I

skin of the posterior canal a n d t y m p a n i c

same

as

in a

mastoidectomy;

directly exposing the middle ear cavity. A groove, s

sion.

T h e incision is

surgical a p p r o a c h e s that apply to implants in wide-

created

edge

of

spread

region of the round w i n d o w to the anterior margi i

the

of the

toward

Cochlear implants consist of an external

and

an

in

the

posterior canal,

extending

from

tte

mastoid cortex. T h e groove is covered with

it is m o r e

extensive b e c a u s e of the posterior e x t e n t of the inci-

are similar. T h i s c h a p t e r will d e s c r i b e o n l y the b a s i c use.

however,

the internal

level

of

it,

the

in

made

cm behind

receiver and

mastoid

order

1

to

outer

extends down

process avoid

the

without

to

bending

compromise

of

the

internal c o m p o n e n t . Externally, a m i c r o p h o n e picks

cortical b o n e a n d t e m p o r a l fascia o r with acrylic b o n e

occipital

up the s o u n d stimulation and sends it to the sound

cement,

b e t w e e n the scalp a n d the t e m p o r a l m u s c l e until the

processor,

the groove and ing the electrode lead. Surgic? 1

stimulus

transforming

that

An internal

is carried

it

into

a

coded

to

the internal

electrical

component.

receiver c h a n n e l s this s t i m u l u s through

preparation and

purpose of stimulating the auditory

is

more

that

is the

artery.

The

flap

is

developed

spine of Henle is exposed.

similar

to

that flr

area

be

shavíl

portion of the temporal b o n e is r e m o v e d , as well as

a

regu'r

t e m p o r a l f a s c i a . T h i s a l l o w s for a n a d e q u a t e s e a t for

extensive

to

than

in

A

piece

of temporal

muscle over

the

squamous

the receiver, and

of cautery.

n e o u s d e v i c e is to be used.

away

field, t h e use o f c a u t e r y m i g h t lead t o t h e t r a n s m i -

receiver is drilled (Fig. 16—IB). It is i m p o r t a n t to do this in a p l a n e parallel to t h e s c a l p surface.

usually

placed

in

the

temporal

types of implant devices ground

if the latter,

require

it

is

muscle.

Different

sión

different

types of

potentially

electrodes.

The

internal

receiver can be

placed

either under

of

When

electrical

the electrodes are in the surgi'iil currents

into

devastating effects.

the

cochlea,

Judicious

use

through

the

round

surgical a p p r o a c h e s

window

of

the

cochlea.

Two

for p l a c e m e n t o f the e l e c t r o d e

it

receiver

W i t h a 2 - m m pilot drill,

with

permanent

1

A s e a t for* t h e i n t e r n a l

is

useful

sutures

to

(Fig.

(facial

recess);

(2)

the

mastoi-

sutures

are

ed

through

the

2-mm

holes

drilled a r o u n d the seat (Fig. 1 6 - 4 / 1 ) . F o r a percutaneous

plug,

an

opening

is

created

just

above

the

p l u g , a v o i d i n g s k i n t e n s i o n a t all c o s t s . T h e o p e n i n g is m a d e with a skin p u n c h of the s a m e size as the p l u g p r o v i d e d i n t h e m a n u f a c t u r e r ' s s u r g i c a l kit. T h e postauricular incision is closed with 3-0 abs o r b a b l e s u t u r e s for t h e s u b c u t a n e o u s t i s s u e s a n d 4 0 silk for t h e s k i n . A P e n r o s e drain c a n be u s e d . T h i s is followed by application of a m a s t o i d dressing.

Mastoidotomy/Tympanotomy Approach

With a

secure

the

16-2A,

8).

i

Advantages

two holes 2 mm apart are

Posterior Tympanotomy (Facial Recess)

to 0.75 cm from the outer edge; a age b e t w e e n

1. T e c h n i c a l simplicity.

the holes is m a d e with a 0 . 5 - m m cutting b u r at a 3 0 -

2. Involves less b o n e drilling a n d tissue removal.

degree angle. For a percutaneous device, additional

3 . C a r r i e s a l m o s t n o r i s k t o t h e facial n e r v e .

h o l e s c a n b e drilled for p l a c e m e n t o f s c r e w s (Fig. 1 6 2/V).

T h r e e basic a p p r o a c h e s can be used: (1) the pos-

silk

drilled on both sides of the seat, at a distance of 0.5

will be d e s c r i b e d .

terior t y m p a n o t o m y

device,

the e l e c t r o d e s are in the surgical field.

protruding from the skin ( p e r c u t a n e o u s stimulation). the active electrode is placed on or

transcutaneous

for a t h i n n e r s c a l p if a t r a n s c u t a -

polar c a u t e r y , o r n o c a u t e r y a t all, i s i n d i c a t e d o n i ;

the skin ( t r a n s c u t a n e o u s stimulation) or with a plug In most cases,

wilt of ri-

the internal

anteriorly

mastoidectomy. An important point concerns the e » *

the active electrode;

"in-

prepared

positioning except

from dipping into

different" or g r o u n d electrode is placed close to or from

An

and

mastoidectomy,

o n e o r m o r e a c t i v e e l e c t r o d e s t o the c o c h l e a , for t h e nerve.

in order to prevent skin

O n c e the electrode has b e e n placed,

receiver is secured. For a t r a n s c u t a n e o u s device, 4-0

Surgical Steps

d o t o m y / t y m p a n o t o m y ; a n d (3) the external auditory

4 . A l l o w ; for direct v i e w o f a n d w o r k i n t h e r o u n d window

A s i m p l e m a s t o i d e c t o m y a n d o p e n i n g o f t h e facial recess is d o n e (Fig. 1 6 - 1 A ) (see C h a p t e r 7 ) ; the only

tissue

difference

ously).

is

that

the

edges

of

the

cavity

are

not

groove

for

niches.

5. A c t i v e electrode is c o v e r e d by a thick layer of along

its

entire

course

(not

just

subcutane-

' c a n a l g r o o v e . T h e a p p r o a c h via t h e e x t e r n a l a u d i t o r y

1. Positioning of the internal receiver site.

saucerized

the

6. P r o v i d e s a better a n g l e in the basal turn of the

i canal

2. Postauricular incision.

electrode. T w o additional holes c a n be drilled in the

c o c h l e a for s l i d i n g t h e e l e c t r o d e , m a k i n g full i n s e r t i o n

3. E l e v a t i o n of a p o s t a u r i c u l a r flap.

border

easier.

I San

groove has been used Francisco devices;

for s o m e o f t h e S t o r z -

it will

not be d e s c r i b e d

in

of

in the

order

to

mastoid

allow cavity

for for

a

the

purpose

of

288

Surgical Approaches for Cochlear Implants Surgical Approaches for Cochlear Implants

Internal receiver seat

B

Round window niche

FIGURE 16-1. FIGURE 16-2

289

Surgical

Approaches

for C o c h l e a r

Implants

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s

Internal receiver 1

FIGURE l ( M FIGURE 1 6 - 3

291

292


7. S m a l l p o s t a u r i c u l a r flap c a r r i e s less risk of h e -

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s small

bur

and

the

round

window

m a t o m a or infection; requires no drains; m a k e s heal-

brought directly into view (Fig.

ing easier;

tional

and

percutaneous

allows

no tension

of the

skin

with

plugs.

drilling n e e d e d

8. Allows faster recovery and shorter hospitaliza-

piece of G e l f o a m

is

used

to c o v e r the round

window and a

large piece of cotton

the

This

ear

canal.

A

mastoidotomy

mastoidea opening

1. E n d a u r a l i n c i s i o n s ( L e m p e r t 1 a n d II).

is placed over

avoids contamination

by

bone

is d o n e by drilling in t h e fossa

toward

should

the

be

antrum

large

(Fig.

enough

16-5D).

to

The

visualize

the

a n t r u m . T h e p o s t e r i o r e d g e i s b e v e l e d a n d all s h a r p

2. C a n a l i n c i s i o n s at 6 a n d 2 o ' c l o c k .

bony e d g e s are s m o o t h e d . T h e incus is disarticulated

3. Exposure of the middle ear. 4.. Drilling of the r o u n d w i n d o w niche a n d visalization of the round w i n d o w m e m b r a n e .

from its s t a p e s a n d m a l l e u s a t t a c h m e n t s w i t h a j o i n t knife

and

totally

removed.

If

desired,

a

dummy

electrode can be inserted through the m a s t o i d o t o m y

5. Small atticotomy.

o p e n i n g and into the niche to the a d e q u a c y of

Mastoidotomy.

the exposure. T h e middle ear a n d

7. Postauricular incision. 8. Removal of temporal muscle and periosteum s e a t for t h e i n t e r n a l r e c e i v e r .

1 0 . T u n n e l i n g of the e l e c t r o d e from the postauricular incision into the m a s t o i d o t o m y o p e n i n g 11. Introduction of the electrode into the a n t r u m and

until

dust a n d debris from the m a s t o i d o t o m y drilling.

Surgical Steps

a

is delayed

[Facial Recess] A p p r o a c h ) . A

9. Drilling of

for e x p o s u r e

is

A n y addi-

the electrode is inserted (see Posterior T y m p a n o t o m y

tion

6.

membrane

16-5C).

middle ear

mastoid are then

filled w i t h a n a n t i b i o t i c s o l u t i o n . A

postauricular

incision

is

needed

for

the

sole

purpose of placing the internal receiver; it should be made

at

enough

or

above

space

the

without

linea

temporalis,

interfering

with

allowing

the

use

of

e y e g l a s s e s . Lidocaine ( X y l o c a i n e ) 2% with 1:100,000 e p i n e p h r i n e is injected. T h e circumferential incision

12. Insertion of the electrode into the cochlea.

m e a s u r e s 3 to 3.5 cm and is d e e p e n e d

13. S e c u r i n g of the internal receiver. 14. C r e a t i o n of a skin o p e n i n g (for p e r c u t a n e o u s receivers).

subcutaneous

tissues

until

the

t h r o u g h the

temporal

muscle

is

r e a c h e d ( F i g . 1 6 - 5 E , F). T h e s e a t s i z e f o r t h e i n t e r n a l receiver is m e a s u r e d , and the corresponding under-

15. Closure, packing, and a mastoid dressing.

lying temporal m u s c l e a n d p e r i o s t e u m are r e m o v e d . T h e p e r i o s t e u m i s s a v e d for g r a f t i n g t h e r o u n d wind o w niche. T h e b o n e seat is drilled d o w n to accom-

Procedure

modate

the

receiver

(Fig.

16-6/1)

and,

depending

u p o n the type of receiver, a d d i t i o n a l Iw4es are drilled e i t h e r for s u t u r e s o r for s c r e w p l a c e m e n t ( s e e P o s t e T h e first i n c i s i o n ( L e m p e r t I ) i s m a d e s e m i c i r c u m -

rior T y m p a n o t o m y [Facial R e c e s s ] A p p r o a c h ) .

ferentially b e t w e e n 6 and 12 o'clock on the posterior

An electrode guide is ed from the endaural to

wall at the b o n y cartilaginous junction. T h e second

the postauricular incision bv t u n n e l i n g it b e n e a t h the

incision

(Lempert

II)

runs

between

the

tragus and

temporal muscle.

An electrode guide, which is sim-

h e l i x (at t h e i n c i s u r a ) . T h e e x t e n s i o n o f t h i s i n c i s i o n

ilar t o a n a n t r u m t r o c a r , i s s p e c i a l l y c u r v e d a n d h a s

is approximately 0.75 cm.

a

(cartilaginous portion)

The

posterior canal skin

blunt

distal

opening

to avoid

d a m a g i n g the elec-

is p r e s e r v e d a n d g e n t l y ele-

t r o d e (Fig. 1 6 - 6 8 ) . T h e o b t u r a t o r i s r e m o v e d a n d the

vated with a small periosteal elevator, clearly expos-

e l e c t r o d e i n t r o d u c e d into the g u i d e (Fig. 1 6 - 6 C ) ; the

ing the entire posterior b o n y canal (Fig. 1 6 - 5 / 1 ) . T w o -

guide is then withdrawn and,

prong retractors are used

is carried into the m a s t o i d o t o m y o p e n i n g . It is then

three-prong

for e x p o s u r e ; o c c a s i o n a l l y

retractors are needed.

ed

W i t h a scalpel, vertical incisions are m a d e at 6 a n d

to the a n t r u m and

exposed

w i t h it,

the electrode

into the middle ear.

The

round w i n d o w m e m b r a n e is detached with

2 o ' c l o c k . In a c o m p l e t e l y d r y field, a flap is e l e v a t e d

an a n g l e d pick, and the electrode is introduced with

and

a

the

annulus.

middle

ear

cavity

is

entered

beneath

the

All a n a t o m i c s t r u c t u r e s a n d l a n d m a r k s a r e

visualized.

Using stapes curets,

the posterior canal

nonserrated

baby

pointing toward

alligator

the basal

mediately past the h o o k (Fig.

wall is e n l a r g e d and a small a t t i c o t o m y is d o n e (Fig.

of

1 6 - 5 8 ) . Special attention is paid to the round w i n d o w

wrapped

niche. T h e anterosuperior portion is removed with a

pieces

the

round of

window

around

the

Celfoam

is

of

then

in

an

angle

the cochlea,

im-

16-6D). The opening

sealed

electrode are

forceps

turn

with

periosteum

(Fig.

16-7A).

placed

lateral

Small to

the

FIGURE 16-5

293

294

Surglcal Approaches for Cochlear Implants

Surgical Approaches for Cochlear Implants

Ground electrode

A

FIGURE 1&--7

295

296


p e r i o s t e u m graft.

With a S y m b i o n implant,

the pro-

plug is

made anterior

to

the

periauricular incision

m o n t o r y electrode is positioned over the p r o m o n t o r y

with a skin p u n c h of the s a m e s i z e as the plug (Fig.

and secured

1 6 - 7 C ) . Skin tension should be avoided.

w i t h a c o v e r i n g of p e r i o s t e u m graft as

well.

T h e canal

T h e internal receiver is then s e c u r e d in place with sutures o r s c r e w s (Fig.

1 6 - 7 B ) , the ground electrode

flap

is

repositioned.

Gelfoam and

of the canal,

and

gauze

is e m b e d d e d

in antibiotic

(if s e p a r a t e ) is p l a c e d in t h e t e m p o r a l m u s c l e fibers,

o i n t m e n t in the distal o n e third. Incisions are closed

and

with

the

antrum.

rest of the If a

periosteum

percutaneous

is

used

plug is being

t o seal, t h e used,

im-

p e d a n c e i s c h e c k e d a t t h i s p o i n t . A n o p e n i n g for t h e

CHAPTER 17

an

antibiotic o i n t m e n t are used in the distal t w o thirds

s u b c u t a n e o u s 3-0 c h r o m i c catgut and

skin su-

tures of 4-0 silk (Fig. 1 6 - 7 D ) , a n d a m a s t o i d dressing is a p p l i e d .

Surgery for ; Incapacitating Peripheral Vertigo The

title o f this c h a p t e r h a s b e e n

lected

to

indicate

that

the

surgical

purposely seprocedures

Endolymphatic Sac Procedures

de-

scribed h e r e a r e d e s i g n e d for t r e a t m e n t o f v e r t i g o o f labyrinthine origin.

At the s a m e time,

the term "in-

These procedures constitute a conservative,

usu-

c a p a c i t a t i n g " i m p l i e s t h a t s y m p t o m s a r e still p r e s e n t

a l l y e f f i c i e n t a p p r o a c h for v e r t i g o , a n d a r e t h e initial

after a d e q u a t e m e d i c a l e v a l u a t i o n a n d

It

choice (not u n c o m m o n l y the only choice necessary)

procedures are

of m a n y surgeons. Despite the location of the sac in

is understood,

therefore,

that

these

treatment.

performed in a small p e r c e n t a g e of patients, since in

the posterior fossa dura,

the m a j o r i t y o f c a s e s

and

adequate

safe

operation.

suffice.

(Evaluation

m e d i c a l t r e a t m e n t a l o n e will

and

medical

treatment are out-

side the s c o p e of this b o o k . ) In a d d i t i o n ,

it should

surgical In

the

k n o w l e d g e o f its a n a t o m y

technique event

usually

of

failure,

permit any

a

other

p r o c e d u r e can be d o n e w i t h o u t a d d e d difficulty

be kept in m i n d that vertigo is a m a n i f e s t a t i o n of an underlying

problem

that

must

be

assessed

and

(if

possible) defined; d e p e n d i n g on the c a u s e , different surgical a l t e r n a t i v e s will b e s e l e c t e d . T h i s i s o n e o f

Aim

the a r e a s i n o t o l o g y w h e r e o u r l a c k o f t r u e k n o w l e d g e is most evident; therefore, careful and nondestructive c h o i c e s a r e r e c o m m e n d e d i f a t all p o s s i b l e . Surgical procedures can be destructive or conser-

To

identify

overlying

the

and

expose

dura

mater

the of

endolymphatic

the

posterior

sac

cranial

fossa.

vative i n n a t u r e . T h e y m a y b e a i m e d a t d r a i n i n g a n assumed

endolymphatic

hydrops,

whether

at

the

endolymphatic sac level or at the saccule, they m a y involve

destruction

tomy) and/or other

nerves,

of

sectioning such

as

the

labyrinth

of

the

the

singular

posterior semicircular canal.

(labyrinthec-

vestibular

nerve

nerve

of

the

N o n e of the m a n y sur-

gical p r o c e d u r e s a v a i l a b l e a r e u n i v e r s a l l y a c c e p t e d o r provide

1009c

relief.

T h e s e are

factors

to

keep

in

mind w h e n selecting a specific approach. This chapter

will

most

describe

commonly,

those

that

without

are

used

implying

described are useless or unimportant.

or

that

discussed those


or

not

1. P e r f o r m a c o m p l e t e s i m p l e m a s t o i d e c t o m y . 2. Drill to, b u t not b e l o w ,

the d o m e of the hori-

zontal semicircular canal. 3. Identify,

preserve, and measure the hard angle

c o n t a i n i n g the posterior semicircular canal. 4. Identify the position of the sigmoid its r e l a t i o n s h i p t o T r a u t m a n n ' s t r i a n g l e .

sinus and

298

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o


I.

Decompress

the lateral

sinus and

dissect

the

6.

tends to partially c o v e r the dura or m a k e a c c e s s to it difficult,

i n f r a l a b y r i n l h i n e cell tract.

the

patient's

position

should

be

checked

first; t h e h e a d m i g h t b e b e n t t o o far f o r w a r d . I f a f t e r

Incise the e n d o l y m p h a t i c sac.

r e p o s i t i o n i n g t h e h e a d o f t h e p a t i e n t t h e s i n u s i s still prominent,

it should be d e c o m p r e s s e d by removing

part o f its b o n y c o v e r i n g l a c i n g t h e d u r a ,

Pitfalls

infralaby-

rinthine cells m a y h a v e to be drilled (leading toward, the jugular bulb). T h e sac is identified. At this point, there are several alternatives:

1. S k e l e t o n i z i n g or d a m a g i n g the posterior semicircular canal. 3. Failing

to identify

1. D e c o m p r e s s i o n of the sac (removal of the b o n y c o v e r i n g ) i s all t h a t i s d o n e .

2. Insufficiently unroofing the dural plate. the e n d o l y m p h a t i c sac and

its l u m e n .

2 . T h e s a c i s i n c i s e d i n its l a t e r a l s u r f a c e w i t h a s h a r p knife (for e x a m p l e , a sickle knife). T h i s is the o r i g i n a l ( a n d c u r r e n t ) P o r t m a n n p r o c e d u r e ( F i g . 17-

4. D a m a g i n g the incus.

2C).

5. Debris in the middle ear.

3 . A v a l v e i s p l a c e d i n t h e l u m e n (in t h e e x p e c t a -

6. B l e e d i n g in the lateral sinus,

tion

that

microliters

of

excessive

endolymph

wiF

drain). 4. A small incision is m a d e on the medial surface

Procedure

of

the

sac

space.

inserted. In e n d o l y m p h a t i c sac surgery, a thorough simple

in

Into

order

this

to

open

opening

a

up

the

flanged

subarachnoid

Teflon

tube

is

The o u t e r s u r f a c e is tightly p a c k e d (a p i e c e

of fascia can be u s e d ) .

mastoidectomy (see Chapter 7) is advocated. During

5. A thin piece of Silastic s h e e t i n g (0.01 c m ) is cut

this step the b o n y plate o v e r l y i n g the posterior cra-

in a T - s h a p e d fashion a n d placed in the l u m e n . S m a l l

nial f o s s a d u r a i s i d e n t i f i e d . T r a u t m a n n ' s t r i a n g l e i s

pieces of Silastic s h e e t i n g (spacers) are used to sep-

defined and

arate the dura from the floor of the posterior canal.

the hard b o n e containing the poslerior

semicircular cana!

is identified

(Fig.

\7-\A.

H).

The

s a c c o m e s toward the dura from the direction of (he

A Silastic " a p r o n " is applied a n d held in place with C-elfoam (Fig.

it

exits

(he

hard

angle

intact.

A

good

method

of

17-3/1-D).

1 lie m a s t o i d c a v i t y i s p a c k e d w i t h G e l t o a m o v e i

posterior semicircular canal and can be identified as

the d e c o m p r e s s e d a r e a , and the incision is c l o s e d in

preventing d a m a g e to the posterior semicircular canal

lavers

i s t o m e a s u r e t h e a r e a c o n t a i n i n g t h i s s t r u c t u r e ,uul

procedure,

l e a v e it u n t o u c h e d ( u n d r i l l e d ) . W i t h a l e n e s t r o n i e t e r ,

t v m p a n i c m e m b r a n e (Fig.

measure

t h o r o u g h l y c l e a n s e the m a s t o i d c a \

the

H I m m f r o m t h e tip o f t h e s h o r t p r o c e s s o t

incus

or

horizontal

fossa

incudis,

along

semicircular canal

[he

a\is

(30 d e g r e e s

ol

[he

from

the

with

a p p r o p r i a t e Mitures. a ventilation

the end

of

the

ho p l a c e d

in

the

At

tube m a \

11

I7--3/ V 1

is i m p o r t a n t to h e I ore c l o s u r e .

'

I h e e f f e c t i v e n e s s of this p r o c e d u r e m a v he d u e to decompression

ol

oveilving

hone,

drainage

of

en

l e g m e n ) ; t h e n m e a s u r e 12 mm from Ihe loss.i i m u d i s

d o l v m p h b v o p e n i n g o l I h e sac, i n c r e a s e d v a s c u l a r -

at an angle ot

i t y , o r o t h e r l a c l o r s , , i d i s i u s s i o n i s o u t s i d e the s c o p e

IS d e g r e e s k o n i the l e g m e n l l i g .

17

\H). T h i s a r e . i i s lett u n t o u c h e d w h i l e ( h e i n l r a l . i l n -

nl

r i n t h i n e cell tract is drilled In e x p o s e the s a c location

that i n v o h e s o p e n i n g t h e s a c h a s c o m p a r a b l e r e s u l t s .

(Fig.

C).

\7-\H.

Special

attention

is

paid

to

the

this book.

Ihe

Complications

are

remains

those

of

(he dural

plate,

reducing

triangle (interestingly,

this

merit is

prevention.

posterior

(see

c a n a l , a n d c e r e b r o s p i n a l fluid f i s t u l a e . T h e b e s t treat- '

Trautmann's

the

mastoidectomy

sion,

partially overlies

of

procedure'

Chapter

it

opening

that a n v

position of (lie s i g m o i d s i n u s (Fig. 1 7 - 2 / 1 ) ; on o c c a the size of

7),

lad

semicircular

T h e technique of isolating the

i s fairly c o m m o n i n p a t i e n t s w i t h M e n i e r e ' s d i s e a s e ) .

hard angle is practical. If the posterior semicircular

The

plate

canal

then

gently elevated and separated

is

thinned

down

to

eggshell from

thickness, the

under-

is accidentally o p e n e d ,

lying d u r a with a duckbill elevator. T h e sac is iden-

certain.

tifiable as a t h i c k e n e d w h i t e area

uncommon

t h e thin s u r r o u n d i n g dura (Fig.

o f t h e d u r a ewer

I 7 - 2 R ) . T h e posterior

semicircular canal s h o u l d not be t h i n n e d or skeletonized.

Drilling

is

done

immediately

inferior

to

this

a r e a . If t h e lateral s i n u s is in s u c h a p o s i t i o n that it

the

fistula

should

be

grafted i m m e d i a t e l y ; h o w e v e r , a " d e a d e a r " is a l m o s t

should

Fistulae and

be used

uncommon

that

leak

cerebrospinal

self-limiting;

high-dose

in o r d e r to a v o i d

fluid

meningitis.

to h a v e to re-explore and

are

antibiotics

place a

It is large

piece of fascia a n d m u s c l e ( a l o n g with tight p a c k i n g of the mastoid eavitv with C e l f o a m ) .

FIGURE 17-1

300

Surgery for Inc~pacitaling Peripheral Ver";;n

Surgery for Incapacitating Peripheral Vertigo

Apron 0.01 ern Silastic

T-strut IOserted

E IICUgl: 17-2. HCUgE 17-}

301

302



Saccule Procedures

a t t e m p t i n g this p r o c e d u r e ,

a

reasonable

n u m b e r of

temporal b o n e dissections are r e c o m m e n d e d . Destruction T h e s e a r e m e n t i o n e d for t h e s a k e o f c o m p l e t e n e s s and an overall concept. T h e most c o m m o n (such as the

Fick and

severe, are

tack

procedures)

irreversible

rarely

used.

are

sensorineural

(An

associated hearing

intermediate,

loss

with and

safer alternative

of

the

posterior

labyrinth

by

ultra-

sound

(Arslan's p r o c e d u r e ) is not described in

book.

Its i n d i c a t i o n s a r e f e w a n d c a n b e c o v e r e d b y

the

other

procedures;

furthermore,

the

author

this has

n o e x p e r i e n c e w i t h it. T h e r e a d e r i s r e f e r r e d t o t h e

Incus

literature.

used occasionally in cases of otosclerosis associated flfcith h y d r o p s is a wire c o n n e c t i v e tissue prosthesis with a small peg [from the wire a r o u n d the c o n n e c tive tissue] [Fig. 1 7 - 4 4 ) ; this is d e s c r i b e d in C h a p t e r

Labyrinthectomy

13.) Both procedures are intended to d e c o m p r e s s a dilated s a c c u l e u n d e r the a n t e r i o r portion of the oval window, through

which a

is clearly

transcanal

exposed.

approach.

T h e v are

done

T h e Fick operation

involves o p e n i n g the footplate and then the saccule (Fig.

17-4C),

whereas

the

tack

procedure involves

the p l a c e m e n t of a sharp tack through the footplate ( a n t e r i o r a s p e c t ) ( F i g . 1 7 - 4 8 ) . It is i m p o r t a n t to seal the

footplate with connective

Icom presses"

the

saccule

tissue.

when

it

The

tack

"de-

b e c o m e s dilated.

Labyrinthectomy, a monly

employed,

labyrinth. usable

p r o c e d u r e that is fairly c o m -

entails

total

destruction

of

hearing;

even

then,

the

significance

of

the

p r o c e d u r e m u s t be c o n s i d e r e d . Is the causative disease bilateral? C o u l d it eventually b e c o m e bilateral? Is t h e r e a n y c h a n c e that the patient n e e d s a c o c h l e a r implant? A l a b y r i n t h e c t o m y c a n be d o n e t h r o u g h a

C l o s u r e is s i m i l a r to t h a t for a s t a p e d e c t o m y .

the

It s h o u l d be r e s e r v e d for p a t i e n t s w i t h no

trans-

canal or a t r a n s m a s t o i d a p p r o a c h .

Singular Neurectomy Transcanal

Approach

1 his selectively destructive p r o c e d u r e entails sec-

Highlights

tioning the n e r v e of the posterior semicircular canal (.singular n e r v e )

for t h e t r e a t m e n t o f b e n i g n

periph-

eral positional v e r t i g o ( c a u s e d by an alteration in the

1. C l e a r i d e n t i f i c a t i o n of t h e facial n e r v e is e s s e n -

fflpsterior semicircular canal, such as cupulolithiasis).

tial

T h e nerve r u n s parallel to the a n t e r o s u p e r i o r portion

the oval

of the round w i n d o w m e m b r a n e (Fig. ft T h e round canal

17-5/1).

w i n d o w n i c h e i s e x p o s e d via a

approach.

If

necessary,

(he

to avoid a n y potential lesions

hile drilling in

window.

2. R e m o v a l of the oval w i n d o w c o n t e n t s m u s t be trans-

posteroinferior

done without d e e p e n i n g the w i n d o w or pushing the instrument

hard

into

the

walls.

Only

a

thin

plate

c a n a l w a l l i s c u r e t t e d for b e t t e r e x p o s u r e . T h e b o n v

s e p a r a t e s this area

r o u n d w i n d o w n i c h e is drilled carefully with a small

a n d a c e r e b r o s p i n a l fluid leak is a p o t e n t i a l c o m p l i -

bur

cation.

and

the

anterosuperior

portion

of

the

round

w i n d o w m e m b r a n e i s e x p o s e d (Fig. 17-5H). T h e b o n e Htmcdiately

anterior

to

the

membrane

is

thinned

from

the internal auditory canal,

E x p o s u r e i s o b t a i n e d via a n e x p l o r a t o r y t y m p a n otomy approach (see Chapter 5).

Both the oval and

d o w n (without involving the m e m b r a n e and leaving

the r o u n d

It is i m p o r t a n t to

a

the m e m b r a n e and

visualize and identify the position and status of the

1.5 t o 2 m m d e e p

facial n e r v e i n r e l a t i o n s h i p t o t h e o v a l w i n d o w ( F i g .

piece of b o n e

the thinned

intact

area).

The

between nerve is

(slightly d e e p e r is the basal turn of the c o c h l e a ) ; it is •rentified

and

sectioned

with an angled

h o o k (Fig.

p—5C), and the area is covered with Gelfoam. I

T h i s p r o c e d u r e is m o r e e a s i l y d e s c r i b e d t h a n per-

w i n d o w s are exposed.

1 7 - 6 ) . T h e stapes is r e m o v e d a n d the c o n t e n t s of the oval w i n d o w a r e s u c t i o n e d . W i t h a h o o k , the rest of the c o n t e n t s are r e m o v e d (Fig.

f o r m e d . It is q u i t e difficult to find t h e n e r v e { e v e n in

(Fig.

a

saturated with

temporal

bone

in

the

laboratory).

For

anybody

1 7 - 7 / 1 , B). T h e p r o -

m o n t o r y is drilled a n d both w i n d o w s are c o n n e c t e d 17-7C).

The

labyrinth is filled

with G e l f o a m

streptomycin sulfate. Text

continued

on

page

307

FIGURE

V-4

303


FIGURE 17-6.

307


Transmastoid Approach (Transmastoid Labyrinthine Dissection)

4. Bone

must

be

completely

sinodural angle and 5. A

dural

flap

removed

from

the

posterior fossa. is

hinged

anteriorly

and

draped

nerve

is sec-

over the posterior semicircular canal. 6. T h e superior half of the eighth tioned.

Aim C o m p l e t e removal of the semicircular canals and

Pitfalls

the soft t i s s u e o f t h e v e s t i b u l e

Highlights

1. Failing

to

remove

bone adequately

up

to

the

posterior semicircular canal. 1. T h e

sinodural

angle

must

be

completely

2. Inadvertently entering the labyrinth.

thinned for a d e q u a t e e x p o s u r e o f the vestibule.

3. Failing to d e c o m p r e s s the sigmoid sinus ade-

2 . T h e t e g m e n m u s t b e t h i n n e d for a d e q u a t e vis-

quately, leading t3 poor visualization.

ualization of the superior aspect of the semicircular

4. Incompletely sectioning the vestibular nerve.

canals.

5. Inadvertently sectioning the cochlear nerve fi-

A simple m a s t o i d e c t o m y is done. T h e three semi-

bers.

circular c a n a l s are s k e l e t o n i z e d until t h e m e m b r a n o u s labyrinth is visible t h r o u g h the b o n e as a thin blue line ( F i g . 1 7 - 8 / 1 ) . T h e r e l a t i o n s h i p o f t h e f a c i a l n e r v e

Procedure

to the h o r i z o n t a l s e m i c i r c u l a r c a n a l is d e f i n e d (Fig. 1 7 - 8 8 ) . T h e three canals are drilled ( o n e b y o n e ) a n d their c o n t e n t s carefully r e m o v e d b y s u c t i o n a n d t h e use o f h o o k s (Fig.

1 7 - 8 C ) . T h e s p a c e i s filled w i t h

Gelfoam saturated with streptomycin sulfate.

For

this

approach,

the

patient

lies

supine.

The

preparation a n d draping of the patient are the s a m e as for a s t a n d a r d ear p r o c e d u r e ,

with the exception

that a larger area of the head is s h a v e d . T h e patient's h e a d is p o s i t i o n e d at t h e foot of t h e table to a l l o w

Retrolabyrinthine Approach to the Cerebellopontine Angle and Sectioning of the Vestibular Nerve

the

surgeon's

T h e patient since

legs

frequent

patient's

ample

room

beneath

the

table.

must be securely strapped to the table,

left

side-to-side low;er

rotation

abdomen

is

is also

needed.

The

prepared

and

d r a p e d f o r h a r v e s t i n g o f a n a b d o m i n a l fat g r a f t . T h e postaurictilar incision is m a d e as usual but is located

further

posteriorly—2

to 3 cm

(at

its

most

p o s t e r i o r p o s i t i o n ) — t o allow drilling p o s t e r i o r to the

Aim

sigmoid

sinus,

compression

this

of

is

the

essential

sigmoid

for

sinus,

complete which

de-

permits

proper angulation and visualization into the cerebelExposure

of

eighth cranial

the nerve

cerebellopontine with

angle

preservation

and

of the

the

laby-

rinth.

lopontine

angle.

The

incision

runs

in

a

semilunar

fashion and is carried t h r o u g h the p e r i o s t e u m of the mastoid cortex, avoiding the temporal muscle superiorly. T h e p e r i o s t e u m is then elevated a n d the ear held

Highlights

forward

with

cerebellar

retractors.

Retractors

p l a c e d in a s u p e r i o r - t o - i n f e r i o r d i r e c t i o n will h o l d t h e t e m p o r a l m u s c l e o u t o f t h e s u r g i c a l field. Using

1. M a n n i t o l m a y be g i v e n to aid s h r i n k a g e of the cerebellum.

as

2. T h e a n t e r i o r limit of the d i s s e c t i o n is the posterior s e m i c i r c u l a r c a n a l . 3. The sigmoid sinus must be adequately decompressed and

mobilized.

the

largest cutting

bur and

suction

irriga-

tion, drilling is b e g u n . T h e m a s t o i d cortex is r e m o v e d in

a

saucerize opening

routine the as

mastoidectomy.

edges

wide

as

and

to

possible.

Care

keep

the

Removal

is

taken

to

lateralmost of bone

is

e x t e n d e d b e h i n d t h e s i g m o i d s i n u s for a d i s t a n c e o f up to 1 c m ; the b o n e is thinned to eggshell thickness,


309

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o and

final

removal

accomplished

from

later

the

with

for e m i s s a r y v e i n s that

sigmoid

and

the d i a m o n d

bur.

run

from

dura

is

Be alert

the sigmoid sinus

lated e n d of t h e posterior s e m i c i r c u l a r canal a n d runs in a

plane

canal.

in

line with

the horizontal

With adequate exposure,

be seen anterosuperiorly,

to the mastoid cortex. At this point the operating m i c r o s c o p e is b r o u g h t

semicircular

t h e fifth

nerve may

Inferiorly the ninth, tenth,

and eleventh nerves can be seen. T h e seventh nerve

mastoidectomy is completed as

lies m e d i a l to the e i g h t h a n d c a n be visualized with

described in C h a p t e r s 5 and 7, a n d the basic land-

g e n t l e retraction of the latter. O f t e n the lateral b r a n c h

marks (the

of the anteroinferior cerebellar artery is seen between

into the

and

field.

the

The

horizontal semicircular canal,

course

of

the

facial

nerve)

the incus,

are

visualized.

the

seventh

and

eighth cranial

nerve

rootlets (Fig.

W i t h t h e s e l a n d m a r k s , accurate identification of the

1 7 - 1 0 / 1 ) . A r a c h n o i d a d h e s i o n s m a y o b s c u r e the cer-

posterior semicircular canal can be m a d e . T h i s rep-

ebellopontine angle and

resents

section

the

exposure

anterior

into

the

limit

for r e m o v a l o f b o n e a n d

cerebellopontine

angle;

if

bone

with

a

sharp

its s t r u c t u r e s .

hook

may

be

Careful

needed

dis-

to

lyse

these adhesions.

r e m o v a l is not c o m p l e t e up to the posterior semicir-

At

this

level,

the

eighth

nerve

consists

of one

c u l a r c a n a l , a t r o u b l e s o m e r i d g e o f b o n e will h i n d e r

trunk.

adequate exposure to the angle. Interiorly the dissec-

perior to the c o c h l e a r s e g m e n t . Usually, careful high-

tion is c o n t i n u e d into the infralabyrinthine a n d retro-

p o w e r i n s p e c t i o n o f t h e n e r v e t r u n k will r e v e a l t h e

facial cell t r a c t s . B o n e r e m o v a l i s a l s o n e c e s s a r y h e r e

cleavage

for a d e q u a t e e x p o s u r e o f t h e c e r e b e l l o p o n t i n e a n g l e

often h i g h l i g h t e d by a small v e s s e l on the surface of

and

the nerve (Fig.

the

dura

eighth

cranial

is.followed

superiorly

nerve.

The

medially and

located,

is

posterior

fossa

the jugular bulb,

exposed.

The

superior

if

limit

T h e v e s t i b u l a r s e g m e n t o f the n e r v e lies su-

patients,

plane

separating

the

segments;

it

is

1 7 - 1 0 8 ) . (In a p p r o x i m a t e l y 2 0 % o f

this p l a n e is difficult to d i s c e r n . ) U s i n g a

small hook, the cleavage plane is developed. Section-

w i t h i n t h e i n f r a l a b y r i n t h i n e cell tract will b e the h a r d

ing of the vestibular division

bone of the labyrinth.

hook

Although it is not necessary

two

or

microscissors,

facial

or cochlear

is d o n e with a sharp

carefully

avoiding

injury

to

t o " b l u e - l i n e " it, c o n s t a n t a w a r e n e s s o f t h e l o c a t i o n

the

of

vestibular d i v i s i o n is s e c t i o n e d the e n d s will retract,

the

descending

portion

of

the

facial

nerve

is

n e e d e d t o a v o i d i n j u r y t o it. T h e e n d o l y m p h a t i c s a c

irrigation.

The

removal Bill's

and

island

the

large

diamond

avoids of b o n e

diamond bur

tearing

bur and

suction

allows

for

safer

of

dura

or

is often

the

17-10C).

As

the

After sectioning of the nerve, the cerebellopontine

B o n e removal from the posterior fossa dura is n o w with

(Fig.

leaving a 3- to 4 - m m gap.

is located within the dura at this level. completed

nerves

bone sinus.

left o v e r t h e s i g m o i d

a n g l e is i n s p e c t e d for g o o d

hemostasis.

The previ-

o u s l y h a r v e s t e d a b d o m i n a l fat i s c u t i n t o l o n g s t r i p s , which

are

placed

just

into

the

dural

opening

t h e tails b r o u g h t o u t t o the m a s t o i d c a v i t y . and

tight

with

Careful

placement of these strips has been

found

sinus to protect it d u r i n g retraction or further drilling

to p r o v i d e a g o o d seal a g a i n s t p o s t o p e r a t i v e c e r e b r o -

medially

spinal fluid

T h e dural o p e n i n g is m a d e with a N o . 59S Beaver

leakage.

The l o n g tails are t h e n

into the

mastoid and antrum, is

and

knife or similar sharp instrument. T h e

first i n c i s i o n

incision

parallels

between

the

a p p l i e d a n d left i n p l a c e f o r t w o d a y s .

sinus and the e n d o l y m p h a t i c sac interiorly (Fig.

17-

the

sigmoid

sinus

and

runs

closed.

A

mastoid

folded

the postauricular

pressure

dressing

is

9/1). T h e superior incision parallels the superior petrosal s i n u s a n d

runs in

the sinodural angle.

(Care

Intraoperative Complications or Problems

must be taken to avoid injury to the vessels and the cerebellum

immediately

under the dura.) T h e

dural

flap c r e a t e d i s h i n g e d a n t e r o m e d i a l l y a t t h e l e v e l o f the posterior semicircular canal (Fig.

17-98);

it is With good training and expertise,

draped o v e r the canal a n d a stay suture is placed if needed.

Long

Cottonoids

are

placed

over

the

ex-

p o s e d c e r e b e l l u m (for p r o t e c t i o n ) a n d g e n t l e r e t r a c tion

is

bluntly

probed

The to

cisterna

provide

a

lateralis profuse

inferiorly

is

cerebrospinal

remarkably

free

of

this p r o c e d u r e

intraoperative complications.

T h e most c o m m o n p r o b l e m s are caused by bleeding from injury to the s i n u s e s ;

they are treated as dis-

c u s s e d in C h a p t e r 5 (Translabyrinthine A p p r o a c h to

the

the Internal Auditory Canal).

With careful prepara-

cerebellum to relax. G o o d visualization of the cere-

tion and m e t i c u l o u s e x p o s u r e ,

o t h e r p r o b l e m s listed

b e l l o p o n t i n e a n g l e a n d its s t r u c t u r e s i s t h e n o b t a i n e d .

there should be avoided.

fluid

FIGURI-'

applied.

is

leak if one

has

not occurred;

this allows

T h e e i g h t h n e r v e lies near the level o f the a m p u l -

Additional

potential

prob-

lems are those a c c o m p a n y i n g a m a s t o i d e c t o m y .

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l Vertigo

F1CUKE 17-9 FIGURE 17-10.

312



313

Pertinent Histopathology FIGURE

17-11

canal sided

This

temporal

bone was

from

an

individual

who

u n d e r w e n t fenestration of the horizontal semicircular

appear

for a v e r t i g i n o u s s y n d r o m e . T h e v e r t i g o sub- | temporarily. to

be

This

simple

section

shows

conservative

that

what I

"fenestrations"

result in localized reactions with n e w b o n e formation. ,

FIGURE This

17-12

patient

underwent

an

unsuccessful

w i n d o w l a b y r i n t h o t o m y " for v e r t i g o . sorineural

hearing

loss

lively did

not c h a n g e

that

was

"round

A severe sen-

present

postoperatively.

preopera-

This

section

s h o w s the marked localized inflammatory reaction in the

round

window

niche

that

seemingly m i n o r surgical trauma,

is

associated

with

314


CHAPTER 18 Intratemporal Facial Nerve Surgery

Middle c a r caviry

T h e a i m of the p r o c e d u r e s d i s c u s s e d in this c h a p -

Transmastoid Approach

ter is to re-establish safe c o n t i n u i t y of the a x o n s of the

facial

trauma the

or

nerve

that

disease.

procedure

have

This

involves

rcanastomosing.

been

compromised

remains freeing,

constant

by

whether

decompressing,

A c o m p l e t e d i s c u s s i o n of the indi-

c a t i o n s for s u r g i c a l e x p l o r a t i o n o f t h e facial n e r v e o r

1

T h o s e of a simple mastoidectomy

a n y of its s e g m e n t s is o u t s i d e the s c o p e of this atlas;

2

T h o s e o f a f a c i a l r e c e s s a p p r o a c h (if n e e d e d )

3

I d e n t i f y i n g t h e d i f f e r e n t s e g m e n t s o f t h e facial

here ate intended onlv

the c o m m e n t s to a

t h o r o u g h u n d e r s t a n d i n g of specific

to contribute procedures

I n f r a t e m p o r a l facial n e r v e p a r a l v s i s c a n b e c a u s e d b v I-TCUKF

nerv : a n d s k e l e t o n i z i n g t h e facial c a n a l <]

difterent lactors and can i n c u r in different s e g m e n t s

17-1.1

based on adequate "1'liis p a t i e n t u n d e r w e n t .in i i i i s v m r - s l n l l . u k p r o t c c l u r e for . 1 v e r t i g i n o u s s v m l r o m c .

Surgical Steps

or

I he o p e n i n g in

t h e footplate c o r r e s p o n d s to the site of the lack.

1 he

s e c t i o n s h o w s that in spite of the lack t h e h y d r o p s

not

achieve

qucnl.

iN

puipose,

bill

such

lailurc

is

infre-

I h i - sei lion is p r e s e n t e d in o r d e r to R i v e aj

quired omy,

preoperative assessment,

procedure a

might

involve

a

wide

mvringot-

transcanal or transmastoid approach, an ex-

v i s u a l o r i e n t a t i o n t o e n d o l y m p h a t i c h y d r o p s a n d thejl

ploration

r a t i o n a l e for a t a c k p r o c e d u r e ,

a u d i t o r y c a n a l , or a total facial n e r v e e x p l o r a t i o n .

of the

first

nerve

segment

at

R e m o v i n g the bony covering O p e n i n g t h e s h e a t h o f t h e n e r v e (if i n d i c a t e d ) .

t h e re-

the

internal

Procedure

p e r s i s t e d (nn-rnes). I n t h i s p a r t i c u l a r c a s e t h e t a c k d i d For can

Myringotomy

practical

be divided

surgical into

purposes,

the

three segments:

(1)

facial

nerve

within

the

internal auditory canal a n d labyrinth; (2) the mastoid (vertical);

and

(3)

the

tympanic

(horizontal

middle

ear). Facial paralysis m a y o c c u r during an a c u t e e p i s o d e of otitis m e d i a .

P e r f o r m i n g a w i d e m y r i n g o t o m y for

T h e t r a n s m a s t o i d a p p r o a c h p r o v i d e s a c c e s s t o the tympanic and

n a s t o i d s e g m e n t s of the nerve. S i m p l e

d r a i n a g e o f p u r u l e n t e f f u s i o n , o b t a i n i n g a s a m p l e for

mastoidectomy

and

culture,

been described

up to the point of clearly identifying

and

placing

adequate medical jority of c a s e s .

a

large-bore

t r e a t m e n t ) will

tube

(along

with

suffice in the ma-

It is i m p o r t a n t to u s e a large tube

Small type I tubes tend to b e c o m e plugged, requiring a second

drainage procedure.

facial

recess

approaches

have

the facial ( f a l l o p i a n ) c a n a l . T h e a n a t o m y o f t h e c a n a l should n o w be reassessed (Fig. 18-1/1).

Mastoid Segment. F r o m t h e e v t o — ' proceeds

316

317

Intratempora) Facial N e r v e Surgery

Infratemporal Facial N e r v e S u r g e r y

Eustachian tube

Cochleariform process

the level of the anterior e d g e of the digastric ridge

ingrowth.

(Fig. 1 8 - 1 A 8 ) . T h e nerve usually is medial to the

the nerve fibers.

horizontal canal (a g o o d

Fascia

should

not

be

used

directly

over

l a n d m a r k ) , hut at t i m e s it

m a y be lateral to it (congenitally or by i n f l a m m a t o r y disease) or it m a y h a v e a posterior projection at the

Transcanal Approach

genu, lending itself to potential d a m a g e . It is useful to visualize the nerve anterior to the digastric ridge, n o t i n g h o w lateral it b e c o m e s as it r e a c h e s the m a s toid tip.

This approach allows access to the tympanic segm e n t of the facial n e r v e a n d ,

Tympanic Segment.

T h e n e r v e a p p e a r s in

the region

makes

it

possible

to

expose

if e x t e n d e d interiorly, the

mastoid

segment

of the cochleariform process at the geniculate gan-

d o w n to the stylomastoid foramen. This can be used

glion, then runs posteriorly t o w a r d the oval w i n d o w

adequately

(not u n c o m m o n l y , it is d e h i s c e n t at this p o i n t ) to a

p n e u m a t i z e d m a s t o i d it m i g h t result in a large cavity

point just inferior a n d generally medial (deeper) to

with an underlying e x p o s e d nerve. Risks of infection

the

in these c a s e s m u s t be considered. This e x p o s u r e can

horizontal

semicircular canal.

Exposure

of

the

t y m p a n i c s e g m e n t is helped by enlarging the aditus

in

a

sclerotic

mastoid,

but

in

a

well-

also be obtained by an endaural approach.

ad antrum. This dissection, c o m b i n e d with enlargem e n t o f t h e facial r e c e s s a p p r o a c h , a l l o w s v i s u a l i z a tion

anteriorly

toward

the

cochleariform

Drilling with a small

bur is d o n e

without

dislocating

damaging

or

process.

under the it;

if

this

incus is

possible (which usually is the case), the incus can be r e m o v e d with a t knife (Fig. 1 8 - 2 / 1 ) . If necessary, the t e n d o n of the tensor t y m p a n i can be s e c t i o n e d , permitting elevation of the malleus;

t h i s will a l l o w

c o m p l e t e drilling toward the geniculate ganglion.

If

required for better e x p o s u r e , a n e x p l o r a t o r y t y m p a n otomy

flap

(previously

and additional

described)

can

be

Procedure

not

elevated

transcanal exposure can be obtained.

A large t y m p a n o m e a t a l flap is c r e a t e d w i t h vertical incisions at 2 a n d 6 o'clock, a n d the m i d d l e ear cavity is entered b e n e a t h the a n n u l u s (see C h a p t e r 7). T h e posterior and superior walls are enlarged

with

burs

a n d c u r e t s to facilitate e x p o s u r e . T h e i n c u s is s e p a rated from t h e stapes with a t knife. If necessary, the

tendon

of

the

tensor

tympani

is

sectioned

to

allow elevation of the malleus. T h e fallopian canal is

T h e m a s t o i d s e g m e n t c a n b e d i s s e c t e d from the level

thinned, the sheath is exposed, and the procedure is

of the fossa incudis or from the digastric ridge. From

continued as in the transmastoid approach (including

the ridge, it c a n be followed superiorly to the external

r e p o s i t i o n i n g o f t h e i n c u s ) . T h e flap i s r e p o s i t i o n e d

g e n u ; a l t h o u g h this a p p r o a c h is perfectly a c c e p t a b l e ,

and the canal is packed (Fig.

18-3).

the a u t h o r s tend to follow nerves peripherally rather than centrally a n d to start at t h e level of the fossa incudis.

Drilling is d o n e with parallel s t r o k e s in the

direction

of the

nerve

(superior to inferior or vice

versa).

Special Situations and Manage.nent of the Nerve

T h e e n t i r e facial c a n a l s h o u l d b e t h i n n e d t o e g g shell c o n s i s t e n c y with a d i a m o n d or p o l i s h i n g bur. However,

External genu

the

facial

nerve

sheath

should

be

The

techniques

described

for the

a n e x p o s e d n e r v e a n d facial p a r a l y s i s ) w i t h n o p e n -

a fulcrum (Fig. 1 8 - 2 8 ) . T h e sheath is split o p e n with

etration

a s h a r p sickle knife or a B e a v e r knife (Fig. 1 8 - 2 C ) .

tissue

Special situations and h a n d l i n g of the nerve itself are

o p e n the s h e a t h . T h e r e is a risk that the n e r v e can

described below. W h e n closing, the incus is reposi-

be involved by the underlying inflammatory process.

tioned a n d held in place by several small pieces of

A thorough

Gelfoam. Both articulations (with the stapes and the

proach, allowing cleansing a n d aeration of the cavity

are

carefully done

as

in

mastoid

In cases of acute mastoiditis (with facial

nerve

cholesteatoma,

it

sheath might be

by

granulation

better

not

to

m a s t o i d e c t o m y w i t h a facial r e c e s s ap-

Closure

and

a n d m i d d l e e a r , m i g h t suffice. It is a l s o p o s s i b l e that

procedure.

The

opening of the sheath,

repositioned. a

the

not

need

c a s e a t all t i m e s . of

is

the

w i t h a W h i r l y b i r d , w i t h o u t u s i n g the facial n e r v e as

or

which

necessarily

w i t h a p i c k a n d t h e b o n e f r a g m e n t s a r e lifted g e n t l y

packing are

decompression,

assume

total

malleus)

e x p o s e d n e r v e is then c o v e r e d with gold FIGURI- 18-1

not

e x p o s e d with the bur. T h e thinned b o n e is fractured

foil ( o r a

similar material) in order to avoid fibrosis a n d tissue

followed by bulging of the

n e r v e until n o r m a l n e r v e a r e a s are e x p o s e d at both e n d s of the bulge, m a y be sufficient.

318

!nlratemporal Facial Nerve Surgery

Intralemporal Facial Nerve Surgery

Incus

Cochleariform process

A

Exposed nerve

Whirlybird

B

Gold toil

\

Exposed nerve

c

FIGURE 1B-3

319

320

In

cases

of

herpes

zoster,

it

is

appropriate

to

d e c o m p r e s s up to the geniculate ganglion. F r a c t u r e s o f t h e t e m p o r a l b o n e i n v o l v i n g t h e facial

with

length),

and

appropriate

the wound

sutures.

The

sheaths

fractures tend to occur along the axis of the internal

mal e n d of greater auricular nerve,

distal

auditory

with 9-0 or 10-0 nylon

approach involve

(described the

the

plasty,

middle

below).

ossicles

facial n e r v e . affect

a

and

cranial

Longitudinal

tympanic

fossa

fractures

segment

sutures.

the to

bone

segment.

fragments

Along

with

impinging

on

the

nerve

1. T e a r i n g of the dura with herniation a n d d a m a g e to the temporal lobe.

to distala

Adhesive glue alsd

1

2. Avulsion

of

greater

superficial

petrosal

artery. to the cochlea or superior semicircular

canal.

to

accidental

the

nerve

may

the

injury by a

bur or other instrument, and

can occur at any level.

This h a p p e n s m o r e c o m m o n l y

in

the

recess should

tympanic s e g m e n t on

the

while

removed.

be

trauma,

is

observed

which

approach sidual

tissue may

or an the

in

cases

be

the

In

these

original

landmarks, and

then

floor of the

of

facial

To

Special care

facial

previous

result

uncompleted

disease.

complete

being

of an

operation

cases,

it

operation,

is

surgical

inadequate that

left

re-

necessary

reassess

to

anatomic

the

labyrinthine s e g m e n t of the

the

geniculate

the m i d d l e

The fossa

is

slowly

advanced

to

provide

the

needed

1 8 - 4 C ) ; this m a r k s the a n t e r i o r limit

in

Brisk bleeding often

this

area,

necessitating

will

be en-

packing

with

Surgicel. T h e dissection is then continued medially, again in a posterior-to-anterior direction. T h e greater

the

F o r this a p p r o a c h the patient lies s u p i n e , a n d the

superficial petrosal nerve is identified; it runs ante-

hearing.

s u r g e o n sits at the h e a d of the operating table. T h e

riorly on the surface of the middle fossa after exiting

( A l t h o u g h d e s c r i b e d h e r e for facial n e r v e e x p l o r a t i o n ,

incision extends superiorly

to the auricle;

the

this

head

to

nerve

internal

from

auditory

procedure

canal,

also

is

and

to

used

ganglion preserve

for

removal

intracanalicular acoustic n e u r o m a s while g o o d residual

to

of

small

preserving

h e a r i n g , a n d o c c a s i o n a l l y for s e c t i o n -

shave extends

anteriorly

and

nearly

posteriorly

the

until

thus

top of the

virtually

the

the

skull entire

facial

hiatus.

elevation

will

Careful

avoid

posterior-to-anterior dural

inadvertent

elevation

of

this

n e r v e , w h i c h a uld p l a c e t r a c t i o n u p o n t h e g e n i c u l a t e ganglion

s i d e o f t h e h e a d i s p r e p a r e d for s u r g e r y . T h e incision is m a d e approximately 0.5 cm anterior

ing of the vestibular n e r v e . )

repair the nerve d a m a g e .

craniotomy.

r e t r a c t i o n . T h e first l a n d m a r k t o b e i d e n t i f i e d i s t h e

countered

Procedure

fully e x p o s e

being caught in

a n d temporal lobe are elevated medially, the retractor

of dural elevation.

Aim

result of

the e d g e s of the

gently elevated from

s p i n o s u m (Fig.

also be

from

middle m e n i n g e a l artery as it exits from the foramen

should be meticulously removed. Trauma

from

dura is then

blade

4. Injury

To prevent the dura

floor in a posterior-to-anterior direction. As the dura

3. E x c e s s i v e b l e e d i n g from the middle m e n i n g e a l

Middle Cranial Fossa Approach

the

the b l a d e s of the retractor, it is reflected with a blunt instrument

the

n e r v e a n d i n j u r y t o t h e facial n e r v e .

can be used.

of the

ossiculo-

18-46).

two

proxi-

F r a c t u r e s t h r o u g h t h e m a s t o i d b o n e will

mastoid

T h e House-Urban retractor is then placed on

parallel vertical e d g e s of the c r a n i o t o m y defect (Fig.

in layers

of

stump

require

n e r v e s are a p p r o x i m a t e d

is closed

(proximal

and

Pitfalls

tified. T h e n e r v e i s s e c t i o n e d s h a r p l y ( s e l e c t i n g t h e desired

nerve may be longitudinal or transverse. Transverse canal

321


i n t r a t e m p o r a l Facial N e r v e S u r g e r y

facial

and

nerve.

Muse

injury

In

small

a

it,

as

well

geniculate

p r o x i m a t e l y 6 to 8 c m ; it is carried to t h e level of the

defect

either through decompression or by restoring conti-

temporal fascia. Often the superficial temporal artery

previous mastoidectomy, it is n o w encountered. T h e

is e n c o u n t e r e d

surgeon

Highlights

nuity of disrupted n e r v e fibers. If the area of disrupis

small,

the

edges

of

the

fibers

should

sectioned sharply and repositioned in anatomic continuity. ( H o w e v e r , ate

adequately.)

transected, and

both

the

macerated edges do not regener-

If

the

edges

extremes

nerve should

brought

has be

been

completely

sectioned

together

sharply

anatomically

S u t u r i n g is e x t r e m e l y difficult in t h e s e c a s e s a n d is seldom adequate; adhesive glue serves

the

1

prior facial n e r v e e x p l o r a t i o n t h r o u g h the

and

tympanic

segments

has

been

accom-

plished, a t e g m e n t a l defect is m a d e with a d i a m o n d b u r at the level

of the cochleariform

will aid a c c u r a t e o r i e n t a t i o n w h e n

process. This

the m i d d l e fossa

2. T h e surgeon is seated at the head of the table

together or

the patient supine.

3.

The horizontal limb of the c r a n i o t o m y is two-

if part of the nerve must be r e m o v e d (as in excision

thirds anterior and one-third posterior to the external

of a n e u r o m a ) , a n e r v e graft is c a l l e d for. T h i s graft

auditory canal.

will s e r v e as a m a t r i x or p a t h w a y for the a x o n s that

4. T h e

anterior

limit

a r e g r o w i n g from the p r o x i m a l p o r t i o n into the distal

middle meningeal artery,

end.

a

grafts,

Although

there

branches

of

are the

many

sources

superficial

of

cervical

nerve plexus

of

dural

with

5. T h e

most

consistent

b e c a u s e they are found in the vicinity of the operative

helpful but is often indistinct

obtained.

The

greater auricular

a n d they are easily nerve traverses

lat-

is

the

petrosal

nerve;

the

is

arcuate

the

greater

eminence

is

of

the

fallopian

canal

is

very

narrow;

only

erally to the s t e r n o c l e i d o m a s t o i d m u s c l e after e m e r g -

millimeters

i n g a r o u n d its p o s t e r i o r e d g e as a s i n g l e n e r v e trunk.

s e m i c i r c u l a r canal posteriorly from the c o c h l e a ante-

An

infra-auricular

subcutaneous

incision

tissues.

flaps are d e v e l o p e d , is e x p o s e d , and

is

Anterior

deepened and

through

posterior

skin

the s t e r n o c l e i d o m a s t o i d muscle-

the greater auricular nerve is iden-

separate

the

ampulla

of

the

superior

riorly. 7. Familiarity

Weitlaner

retractors

are

placed.

The

with

the

House-Urban

r e c o m m e n d e d b e f o r e its u s e .

retractor is

Its m e c h a n i s m a l l o w s

for t h r e e a d j u s t m e n t s d u r i n g r e t r a c t i o n .

will

know

that

in

the

the

dehiscent. tegmen

geniculate

If

a

during

a

ganglion

is

j u s t m e d i a l t o it. T h e next l a n d m a r k to be identified is the a r c u a t e

temporal

m u s c l e is i n c i s e d in a T f a s h i o n w i t h t h e h o r i z o n t a l

eminence,

l i m b e x t e n d i n g a l o n g t h e z y g o m a t i c a r c h for 3 to 4

semicircular canal. This is not a c o n s i s t e n t landmark

cm; the m u s c l e is then elevated from the s q u a m o u s

a n d is frequently indistinct.

portion of the temporal b o n e and

medial to the geniculate ganglion. Again the retractor

A

the retractors are

blade

craniotomy

is

then

made

by

outlining

a

flap

is

which

marks

continually

the

dome

of

the

superior

It lies slightly p o s t e r o -

advanced

to

provide

needed

retraction as the dural elevation c o n t i n u e s medially.

approximately 2.5 cm square with a large cutting bur

Important

(Fig. 1 8 - 4 / 4 ) . T h e horizontal limb s h o u l d be located

have n o w been identified.

surface

landmarks

that

aid

orientation

R e m o v a l o f b o n e a n d e x p o s u r e o f t h e facial n e r v e

so that two-thirds of it lies anterior to the external auditory c a n a l , a n d one-third lies posterior. To avoid

is

injury to t h e dura, t h e c r a n i o t o m y cuts are drilled to

irrigation (to p r e v e n t heat transfer to the u n d e r l y i n g

paper-thin

facial

thickness.

The

"bone

flap"

is

fractured

a j o k e r or similar blunt i n s t r u m e n t ; it is t h e n

now

begun.

A

nerve and

large

diamond

structures)

is

bur with

used

suction

initially.

Bone

r e m o v a l is b e g u n at the facia) h i a t u s a n d c o n t i n u e d

carefully elevated, avoiding any tearing of the dura,

a

which

superficial petrosal n e r v e to the geniculate ganglion

would

lead

possible injury.

6. Medial to the geniculate, the labyrinthine portion

and

with

landmark

superficial

they are of adequate size,

elevation

the dura elevated in

postcrior-to-anterior direction.

(especially the greater auricular nerve) are preferred field,

it is b e s t to tie it w i t h a

reinserted.

floor is e x p o s e d .

with

If the nerve e d g e s c a n n o t be brought

It a

mastoid

purpose

m o r e effectively.

inferiorly;

suture. This plane of dissection is developed bluntly

be

created

be

the the

t o t h e t r a g u s a n d e x t e n d s p o s t e r o s u p e r i o r l y for a p -

been

may

to

cases

M a n a g e m e n t of the affected nerve itself is a i m e d

has

itself

as

of

at re-establishing safe continuity of the nerve axons,

tion

ganglion

to

percentage

to

temporal

lobe

herniation

For o p t i m u m visualization,

and

t h e flap

m u s t be as close to the floor of the m i d d l e cranial

short

(Fig.

distance

18-5/1).

toward

the

posteriorly,

Here

internal

the

following

facial

auditory

nerve

the

runs

meatus.

greater medially

Immediately

fossa as possible; thus the inferior cut is m a d e at the

medial to the geniculate ganglion, a small d i a m o n d

level of the z y g o m a t i c root. If a l e d g e of b o n e r e m a i n s

bur is u s e d , since only a few millimeters separate the

after the flap h a s b e e n e l e v a t e d , it m a y be r e m o v e d

ampulla of the superior semicircular canal (posterior)

sharply with the rongeur to place the o p e n i n g at the

from

level of t h e m i d d l e fossa floor.

Bleeding may occur

through this small space. B o n e removal is c o n t i n u e d

vessels on the dural surface of

m e d i a l l y t o fully e x p o s e t h e l a b y r i n t h i n e s e g m e n t o f

from b o n e a n d

from

the

facial

angle

posteriorly

room,

from

the

since

runs

plane of the superior semicircular canal runs in a 4560-degree

more

nerve

the to

this affords

The

w a x a n d the latter with light c a u t e r y .

care m u s t be taken to avoid injuring the dura

nerve;

(anterior).

the temporal lobe; the former are stopped with b o n e Again, special

facial

cochlea

the

ampulla.

324


Bone

is

facial

nerve.

thinned

around

The

removed with a

approximately

eggshell-thin

bone

50% may

h o o k or blunt i n s t r u m e n t .

of

the

then

be

T h e defect in the internal auditory canal is c l o s e s with a temporal

m u s c l e plug and the temporal lob£

It is not

i s a l l o w e d t o r e - e x p a n d . T h e b o n e flap i s t h e n repoV

n e c e s s a r y t o e x p o s e the facial n e r v e a l o n g t h e entire

sitioned and the w o u n d is closed in l a y e r s — t e m p o r ; 1

length of the internal auditory canal. tion

to

the

constitutes spinal

narrowest adequate

fluid

flow

point

of

the

decompression.

will

be e n c o u n t e r e d

Medial disseccanal

usually

Here

cerebro-

upon

entering

muscle,

subcutaneous

external

drainage

is

tissue,

used.

and

skin.

Usually

CHAPTER 19

n.*

A sterile d r e s s i n g is ap

plied.

the internal auditory canal. The

facia]

nerve

is

then

fnilv

exposed

from

the

geniculate ganglion distally to the t y m p a n i c s e g m e n t


up to the cochleariform process (Fig. 1 8 - 5 B ) . (This is easily ated

performed previously.)

through Care

the

must

tegmental be

taken

defect

not

to

cre-

injure

the malleus h e a d or o t h e r ossicles in order to prevent sensorineural

h e a r i n g l o s s . O p e n i n g t h e facial n e r v e

F1CUKE

18-6

T h i s p a t i e n t d e v e l o p e d a facial p a r a l y s i s d i a g n o s e s initially

as

Bell's

s h e a t h (if d e s i r e d ) m a y b e a c c o m p l i s h e d b y e x t e n d i n g

decompression

the

tumor

opening

from

the

tympanic

labyrinthine s e g m e n t (Fig.

I8-5C).

segment

to

the

was

involvement

palsy.

An

unsuccessful

performed. of

the

The

facial

section

nerve

surgict

Tumors of the Middle and Inner Ear

show%

(metastatic

carcinoma of the prostate).

T u m o r s of the middle and inner ear include glo-

Small G l o m u s T y m p a n i c u m T u m o r s

mus tumors and acoustic neuromas. Glomus tumors, or

are

An exploratory t y m p a n o t o m y approach is used to

classified according to their location and size. G l o m u s

primary

vascular

e x p o s e t h i s t u m o r , i f all o f i t s b o r d e r s c a n b e v i s u a l -

tympanicum

the

ized t h r o u g h a transcanal a p p r o a c h (Fig. 1 9 - 1 / 1 ) . If

the

n e e d e d , endural incisions also m a y be used to aid in

jugular bulb, middle ear, and base of the skull. This

exposure (see Chapter 7). Often it is useful to elevate

chapter describes

the

mus

tumors

glomus as

three

based

tympanicum

glomus

jugulare

jugulare

on

tumors

approaches

size. are

tumors.

the

tumors

surgical their

to

ear,

ear

glomus

limited

middle

middle

mastoid;

are

of

involve

and

tumors

tumors

Small

to

and

discussed,

The

chapter

glolarge

as

well

also

de-

tympanic

membrane

off

the

malleus

(using

a

sharp knife or pick) to increase exposure. W h e n adequate exposure is obtained, the

tumor

is b e g u n .

important

profuse

realize

quickly and effectively. Topical Adrenaline and Sursimilar packing may also be

the p r o c e d u r e as n e e d e d . mucous The

membrane

tumor

necessitates

that

romas

Glomus Tympanicum Tumors

and

removal of

to

bleeding or a

be

is

s c r i b e s a t r a n s l a b y r i n t h i n e a p p r o a c h for a c o u s t i c n e u -

gicel

may

It

is

at

then

working

used

during

An incision is m a d e in the

the

periphery

elevated

from

of

the

the

tumor.

promontory,

m o b i l i z i n g all b o r d e r s ( F i g . 1 9 - 1 8 ) . O c c a s i o n a l l y , a major

Highlights

(care

feeding artery must

be

is

taken

seen;

not

to

it

may

touch

be

the

fulgurated promontory

with the c u r r e n t ) . T h e t u m o r is t h e n r e m o v e d intact (Fig. 1 9 - 1 C ) . A g a i n , if b l e e d i n g is brisk the s u r g e o n 1. Accurate preoperative a s s e s s m e n t of the tumor

must work quickly

(with

large suction

and

packing

is essential to e n s u r e that the t u m o r is limited to the

as n e e d e d ) to r e m o v e the t u m o r totally; the b l e e d i n g

middle ear or mastoid.

will

2. If a g l o m u s t u m o r is limited to the p r o m o n t o r y and

all

o f its b o r d e r s c a n

approach, approach FIGURE 18-6.

an

exploratory

be

seen

by a

transcanal

by

a

assessment

jugular bulb, used.

the

to

control

Closure and

standard

once

the

packing are

tumor

has

been

t h e s a m e a s for

approaches

may be used.

visualized

erative

easy

tympanotomy or endaural

3. W h e n the entire circumference of tumor cannot be

be

removed.

transcanal shows

an extended

approach

no facial

and

involvement

Larger G l o m u s T y m p a n i c u m T u m o r s

preopof

recess approach

the is

If the entire border of the t u m o r c a n n o t be visualized and

radiologic studies s h o w that it is limited

to the middle ear, a posterior approach is used. T h i s

T u m o r s of the Middle and

2. T h e

allows visualization of the superior, posterior, a n d — most importantly, bulb

to e n s u r e that t h e r e is no j u g u l a r

involvement—inferior

tympanotomy

for

borders.

A

3. T h e

transcanal

anterior border exposure

may

be

external

auditory

canal,

327

tympanic

incus, and malleus are r e m o v e d

facial

nerve is mobilized

and

transposed

anteriorly.

used if there is any question of carotid artery involvement.

bony

membrane,

Inner Ear

4. T h e jugular vein

is identified in

the neck and

controlled inferior to tumor.

The

posterior

incision,

approach

complete

includes

a

mastoidectomy,

postauricular

5. T h e s i g m o i d sinus is controlled distal to tumor.

opening of

6. T h e tumor is r e m o v e d in an anteroinferior-to-

and

the facial r e c e s s . T h e facial r e c e s s i s t h e n e x t e n d e d

superior direction,

interiorly to e x p o s e the h y p o t y m p a n u m ; this requires

the internal carotid artery anteriorly.

sacrificing extended

the

chorda

facial

tympani.

recess

are

the

The

borders

fibrous

of the

annulus

lat-

7. A dled

erally a n d the fallopian canal m e d i a l l y . T h e r e c e s s is

smaller

with

with constant attention given

intracranial

extension

8. T h e

external

auditory

canal

is

(creating

middle ear.

c a v i t y i s p a c k e d w i t h fat o r m u s c l e .

the inferior border of the

tumor is seen in the h y p o t y m p a n u m . probe,

be

han-

this approach.

carried inferiorly until it is flush with the floor of the At this point,

may

to

a

blind

pouch);

with

a

sutured closed

dural

defect,

the

With a blunt

the b o n y wall of the h y p o t y m p a n u m m a y be

palpated

to

ment

the

of

ensure

bone

jugular

integrity

bulb.

should

also

be

opened

extend

into

this

space

The

since (this

access to this area) (Fig.

and

noninvolve-

retrofacial larger

air

often

allows

good

approach

may need to be disconnected and the incus r e m o v e d to allow safe removal of the tumor. may

be

1. Injuring

1 9 - I D ) . Superiorly, if the

tumor involves the ossicles, the incudostapedial t

tympanotomy

Pitfalls

cells

tumors

performed

commonly

help expose a superiorly located tumor.

to

Again, ele-

internal

the

artery

(most

caroticotympanic

2. C a u s i n g deficits or injuries to the ninth, tenth, eleventh, a n d twelfth cranial nerves, with associated postoperative

problems.

3. Failing to recognize associated lesions (such as

v a t i n g t h e t y m p a n i c m e m b r a n e off t h e m a l l e u s will e n h a n c e e x p o s u r e (and also allow delineation of the

pheochromocytomas,

tumor's

on).

anterior border).

carotid at

branch).

An exploratory concurrently

the

infratemporally

carotid

body

tumors,

and

so

4 . C e r e b r o s p i n a l fluid l e a k s . At

this

point,

tumor

removal

may

commence.

Again, brisk b l e e d i n g n e c e s s i t a t e s rapid and efficient work.

If possible,

t h e t u m o r i s f r e e d i n its e n t i r e t y

Procedure

and r e m o v e d (Fig. 19—1E). Usually the t u m o r is too large to permit this, a n d it is r e m o v e d in pieces after freeing

of

its

encountered,

periphery.

When

brisk

bleeding

is

After p r e o p e r a t i v e evaluation

this a r e a m a y b e p a c k e d a n d attention

directed elsewhere.

Care must be taken

to look

for

d e h i s c e n c e or i n v o l v e m e n t of the j u g u l a r bulb infe-

has established jug-

ular b u l b i n v o l v e m e n t , a m o r e e x t e n s i v e a p p r o a c h to the

skull

base

is

indicated

for

total

tumor

removal

with the s m a l l e s t risk of m o r b i d i t y or mortality.

riorly a n d of the carotid artery anteriorly.

T h e patient is placed in the supine position. T h e W h e n complete removal is accomplished, ossicular r e c o n s t r u c t i o n i s p e r f o r m e d (if n e e d e d ) . T h e i n c i s i o n s are c l o s e d i n t h e u s u a l m a n n e r .

involved side is s h a v e d , prepared, a n d d r a p e d in the usual sterile m a n n e r ; the surgical field includes the ipsilateral n e c k . A p o s t a u r i c u l a r incision is m a d e in a

curvilinear

crease

Infralabyrinthine, Infratemporal Approach for Glomus Jugulare Tumors

fashion

(slightly

more

following posterior

the

than

postauricular for a

standard

m a s t o i d e c t o m y ) (Fig. 1 9 - 2 / 1 ) . T h e inferior limb of the incision is carried into the n e c k , e x t e n d i n g along the anterior border of the sternocleidomastoid muscle. A c o m p l e t e m a s t o i d e c t o m y is p e r f o r m e d , ating

the

tended

Highlights

tegmen,

sigmoid

sinus

posteriorly to the sinus),

(exposure antrum,

delineis

ex-

and bony

l a b y r i n t h . T h e m a s t o i d tip i s c o m p l e t e l y o p e n e d a n d removed. FIGURI-: I ' M

1.

A

complete

mastoidectomy

(mastoid

tip

re-

m o v e d ) i s p e r f o r m e d w i t h a n e x t e n d e d facial r e c e s s

T h e external

auditory canal

is

transected

with a scalpel at the level of the c a r t i l a g i n o u s - b o n y junction

and

then

brought

forward

with

retractors.

T u m o r s of the M i d d l e and Inner Ear T h e c a n a l i s t h i n n e d a n d a n e x t e n d e d facial r e c e s s i s

inferiorly

o p e n e d to the floor of the h y p o t y m p a n u m

Dissection

T h e i n c u d o s t a p e d i a l t is dislocated with a t knife a n d the incus is r e m o v e d . T h e t h i n n e d p o s t e r i o r

and

involved

the

tympanic membrane,

r e m o v e d , as well as

was

transected.

continues

superiorly,

carotid.

Anteriorly

with

larger

the

carotid

tumors

and

artery

often

presents

a

is

formi-

dable task to safely mobilize a n d separate the tumor. I n f r a t e m p o r a l l y , w h e r e t h e c a r o t i d t u r n s t o its hori-

while

preserving

the

with

periosteum

a diamond bur

(this

aids anterior

e x p o s u r e a n d r e t r a c t i o n ) . T h e s t a p e s i s left i n t a c t . With a d i a m o n d bur, removed

from

the bony

fallopian canal

the geniculate ganglion

zontal

course,

branch)

particularly is

to the stylo-

sected

a

often a

small

supplies

branch the

troublesome

short

distance

(caroticotympanic

tumor

and

presents

Ideally

it is dis-

from

carotid

lesion

the

afford an o p p o r t u n i t y to safely control

point w h e r e distal control of b l e e d i n g is difficult.

soft

tissue

sling

may

be

the carotid

to

however,

it m a y be avulsed,

A

injuring

it;

transposed

anteriorly.

a

problem.

m a s t o i d f o r a m e n . T h e facial n e r v e i s m o b i l i z e d a n d

l u m e n at a If

c r e a t e d to h e l p h o l d t h e n e r v e o u t of the field. W i t h

carotid injury o c c u r s , repair of the l u m e n w i t h a fine

the facial n e r v e n o w l o c a t e d anteriorly, an o b s t r u c t e d

a r t e r i a l s u t u r e (if p r o x i m a l a n d d i s t a l c o n t r o l c a n b e

view of the jugular bulb and t u m o r is possible (Fig.

obtained)

1 9 - 2 8 , C). With large cerebellar retractors, the man-

accomplished,

dible c o n d y l e m a y be dislocated a n d retracted ante-

b l e e d i n g ( w i t h its a c c o m p a n y i n g r i s k o f s e v e r e m o r -

riorly

bidity or mortality).

for an a d d i t i o n a l

infratefrtpora!

region.

1- to 2-cm e x p o s u r e to Care

must

be

taken

not

the to

should

be

attempted.

If

packing of the area

this

cannot

will c o n t r o l

be the

As the tumor dissection continues superiorly, the

injure t h e t r a n s p o s e d facial n e r v e with t h e r e t r a c t o r s .

ninth,

If necessary, the mandible ramus m a y be transected.

will b e e n c o u n t e r e d .

Decompression of the sigmoid sinus must be com-

tenth,

eleventh,

and

twelfth

cranial

nerves

An attempt should be made to

identify these nerves a n d preserve them if possible.

p l e t e d t o a l l o w for distal c o n t r o l o f v e n o u s b l e e d i n g .

Often

Bone decompression is

m a s s (or a r e difficult t o identify), a n d a r e sacrificed

the

sinodural

angle

performed

and

carried

from just below interiorly

to

the

they are

the

b e c l e a r l y v i s u a l i z e d f r o m t h e j u g u l a r b u l b , w i t h its

tumor

The

neck is n o w entered

posure and artery.

If

control not

of

the

already

to obtain

jugular vein

accomplished,

and the

carotid mastoid

process attachments of the sternocleidomastoid and The

lateral

process of

the

first

cervical

with

the

tumor

wall

mass,

of the

leaving

sinus

is dissected

the dura

intact

is e n c o u n t e r e d

in

from

(Fig.

the

19-38).

the area of the

bulb from the inferior petrosal sinus, w h i c h e m p t i e s into t h e b u l b o n its m e d i a l s i d e . to

control

this bleeding,

since

Packing is needed there

is

no

way

to

obtain control of this s i n u s .

digastric muscles are sharplv dissected and reflected anteriorlv.

medial

Profuse bleeding

proximal ex-

involved

At the level of the j u g u l a r bulb and s i g m o i d sinus,

posterior fossa also is r e m o v e d . T h e t u m o r can n o w extension into the middle ear or mastoid

intimately

or injured.

jugular bulb (or tumor). Interiorly, the b o n e over the

Temporomandibular

vein

and

skin of the

is also r e m o v e d

and

jugular

here

bony external auditory canal. T h e bony anterior and inferior canal

malleus,

the

begins

developing and following a plane b e t w e e n the tumor

external auditory canal

is then

where

329

Following

dissection

tumor

is

the

mass

anteriorly

hinged

in

the

and

posteriorly,

hypotympanic,

vertebra is palpated. Just inferior to this p r o c e s s is

infralabyrinthine area

the e l e v e n t h n e r v e . By following this n e r v e f o r w a r d ,

i n t r a c r a n i a l e x t e n s i o n is p r e s e n t , a c e r e b r o s p i n a l fluid

the

jugular

vein

is

found.

The

relationship

of

the

and

leak will b e e n c o u n t e r e d

is

removed

upon

carefully.

If

tumor manipulation.

eleventh nerve to the vein varies; most c o m m o n l y it

T u m o r bulk

runs laterally to the jugular vein, but occasionally it

tion, and the dura m a y be o p e n e d wider to e n h a n c e

runs m e d i a l l y . T h e vein is isolated, ties are placed,

posterior fossa e x p o s u r e . A small intracranial exten-

and

sion m a y then be carefully r e m o v e d , protecting and

the

vein

is

proximal control.

ligated

medial

to

the

tumor

for

Distal control is a c c o m p l i s h e d at

may be

r e m o v e d to improve visualiza-

preserving intracranial

structures (anteroinferior and

the d e c o m p r e s s e d s i g m o i d sinus. Usually p a c k i n g is

posteroinferior cerebellar arteries, brainstem, cranial

used either e x t r a l u m i n a l l y or intraluminally after an

nerves, and so on).

opening is

made

in

the

lumen

(Fig.

19-3/1).

The

After

the

tumor

has

been

completely

removed,

carotid artery is identified and isolated in case injury

t h e d u r a l d e f e c t is c l o s e d w i t h e i t h e r free a b d o m i n a l

occurs, requiring control of bleeding.

fat o r a m u s c l e p l u g . T h e t r a n s p o s e d f a c i a l n e r v e i s

With

total

exposure

now

accomplished,

tumor

released and

placed in a tension-free position. T h e

removal is begun. T h e superior border is mobilized

transected

from a g a i n s t the b o n y l a b y r i n t h . A n t e r i o r l y the t u m o r

c l o s e d with a p e r m a n e n t s u t u r e ( r e s u l t i n g in a blind

is mobilized adherence

to

unless the

there is

carotid

involvement

artery.

with and

Removal

begins

external

auditory

canal

is

everted

and

pouch). T h e postauricular incision is closed in layers and

dressings

are

applied.

Occasionally

for

large

330

T u m o r s of the Middle and Inner t a r 331

T u m o r s of the Middle a n d Inner Ear dural defects, l u m b a r drains are placed at the e n d of

ear

the

shave.

procedure

to

help

prevent

cerebrospinal

fluid

leakage.

procedure

with

the exception

of a

larger head

By placing the patient's h e a d at the foot of

the table,

t h e s u r g e o n will h a v e r o o m for h i s o r h e r

legs under the table and be m o r e comfortable. T h e patient m u s t be securely strapped to the table, since frequent side-to-side rotation is n e e d e d .

Translabyrinthine Approach for Acoustic Neuromas

Jugular vein

T h e postauricular incision is designed as usual but located farther posteriorly, to allow drilling posterior to the sigmoid sinus (Fig. 1 9 - 4 / 1 ) . T h i s is essential for c o m p l e t e d e c o m p r e s s i o n o f t h e s i g m o i d s i n u s a n d

Aim

o p t i m a l later visualization into the c e r e b e l l o p o n t i n e angle;

W i d e e x p o s u r e of the t u m o r with early identification of t h e facial n e r v e , a l l o w i n g for total e x c i s i o n of

if an

making the

error

made, too

it

far

should

be

posterior.

made

in

T h e incision

lies 1 to l'/2 in ( i t its m o s t p o s t e r i o r p o s i t i o n ) b e h i n d the auricle and

the tumor with preservation of the nerve.

is

incision

r u n s in an e x t e n d e d C s h a p e .

It is

carried through the periosteum of the mastoid cortex, avoiding the temporal osteum

Highlights

with

is

then

muscle superiorly,

elevated

cerebellar

and

retractors.

Retractors

superior-to-inferior direction 1. T h e incision

is m o r e posterior than

the usual

Using

2. Drilling is d o n e posterior to the s i g m o i d sinus

will

forward

placed

hold

in

the

the temporal

muscle out of the surgical field.

postauricular incision. Sigmoid sinus packed

T h e peri-

the ear held

the

largest cutting bur and

suction

irriga-

tion, drilling is b e g u n . T h e m a s t o i d cortex is r e m o v e d

in order to allow posterior d e c o m p r e s s i o n (retraction)

as

o f it.

saucerize the edges and keep the lateralmost opening

3. T h e internal auditory canal is identified and the

a

routine

mastoidectomy.

Care

is

taken

to

as w i d e as possible. In this p r o c e d u r e , it is important to extend the drilling posterior to the sigmoid sinus.

posterior half of the b o n e is removed. 4

in

T h e facial n e r v e is identified at Bill's b a r as it

This bone removal is completed d o w n to the posterior fossa d u r a .

b e g i n s its l a b y r i n t h i n e c o u r s e .

For large tumors,

the posterior dis-

1

5. T h e superior a n d inferior vestibular nerves and

sinus. Final b o n e removal is a c c o m p l i s h e d later with

the c o c h l e a r nerve are avulsed. 6. T h e

tumor

is

removed

section m a y extend 1 to I /; in b e h i n d the sigmoid

away

from

the

facial

the

diamond

bur

to

avoid

tearing of

subsequent cerebellar herniation.

nerve.

the

dura and

In this area e m i s -

sary veins are found r u n n i n g from the s i g m o i d sinus to the cortex; occasionally quite large, they m a y be a source

Pitfalls

of

proached

troublesome

bleeding

and

must

be

ap-

cautiouslv.

At this point the operating m i c r o s c o p e is brought 1. Failing to a d e q u a t e l y d e c o m p r e s s the sinus a n d

to remove bone

from

sigmoid

the posterior fossa

2. Failing

to

open

the

internal

auditory

canal

to

positively

identify

should

horizontal

and

be

able

posterior

to

identify

semicircular

definitely canals.

the With

this b a s i c l a n d m a r k , t h e p o s i t i o n s o f t h e i n c u s , facial

w i d e l y f o r full e x p o s u r e o f t h e t u m o r . 3. Failing

T h e mastoidectomy is completed as

described in previous c h a p t e r s , after w h i c h step the surgeon

dura. Sigmoid sinus (medial wall)

into the field.

the

facial

nerve

nerve,

and

posterior

semicircular canal

e v e n i f t h e y a r e n o t yet fully s e e n .

before avulsing nerves. 4 . S t r e t c h i n g (or c o m p l e t e l y t r a n s e c t i n g ) t h e facial

tegmen,

sigmoid

sinus,

posterior

are

known

B o n e over the fossa,

sinodural

angle, and external auditory canal is thinned to allow

nerve during tumor removal.

full e x p o s u r e a n d d e e p e r d i s s e c t i o n .

5. I n c o m p l e t e l y r e m o v i n g the tumor.

If the sigmoid

sinus is displaced anteriorly, it m a y be d e c o m p r e s s e d FIGURE ] 9 - 3

at this stage; if it is possible to perform the labyrinthectomy now,

Procedure

it m a y be better to delay the actual

decompression. This prevents the problem of cerebellar herniation if the dura is inadvertently o p e n e d

For this approach ration

and

t h e p a t i e n t lies s u p i n e .

draping are

the

s a m e as

for a

Prepa-

standard

or of vision being obstructed by packing if the sinus is injured.

333

T u m o r s of the M i d d l e and Inner Ear A full l a b y r i n t h e c t o m y h a s b e e n d i s c u s s e d i n p r e vious chapters. the

common

angle); facial

Dissection is started

crus

(just

anterior

in

to

the area of

the

this is the safest place to begin,

n e r v e i s far a n t e r i o r .

bone

over the entire sinus.

Final b o n e

removal

is

a c c o m p l i s h e d with the d i a m o n d bur or a blunt pick.

sinodural

A t h i n i s l a n d o f b o n e ( B i l l ' s i s l a n d ) i s left o v e r t h e

since

exposed

s i n u s to p r e v e n t injury from

the

when

the

Dissection is c o n t i n u e d

bur

deeper dissection

the shank of

is resumed.

Bone

m e d i a l l y a n d interiorly until e a c h canal is found a n d

may be removed posterior to the sinus exposing the

completely

dura

"drilled

out."

sinodural angle clean and

to

widely open

keep

the

t o a l l o w for

and

allowing

visualization

m a x i m u m e x p o s u r e later. T h e b o n e here i s t h i n n e d ,

cerebellopontine

and

removed

the

superior

petrosal

sinus

is

seen

as

it

runs

from the s i g m o i d to the p e t r o u s a p e x (Fig. 1 9 - 4 B ) .

sigmoid

more

into

from sinus

internal

angle.

The

the to

retraction

the

level

increased canal

thinned

bone

fossa

medial

posterior

the

with

auditory

that

the

and

is

then

to

the

dissection

has

The posterior canal is encountered first and followed

reached; this is d o n e with the d i a m o n d bur, suction,

as

and blunt

it

courses

anteroinferiorly.

In

approaching

the

instruments.

the dura

(to

Care

must be

prevent cerebellar

taken

not

herniation

to

a m p u l l a , b e a w a r e t h a t t h e facial n e r v e i s j u s t l a t e r a l

tear

and

i n o r d e r t o a v o i d i n j u r y t o it. T h e j u g u l a r b u l b l i e s

a v o i d v e s s e l s ' t h a t m a y lie i m m e d i a t e l y u n d e r n e a t h )

inferior to the posterior canal a n d rarely m a y be so

or to rupture the superior petrosal sinus behind the

high as to touch the posterior canal. By following the

sinodural angle. With large tumors, the w o r k i n g area

common

is

crus

medially,

the

superior

semicircular

improved

r e m o v i n g b o n e from

the

posterior

c a n a l c a n b e e n t e r e d a n d t h e n f o l l o w e d i n its a n t e r o -

e n d of the t e g m e n , a l l o w i n g a b e t t e r a n g l e for instru-

superior course.

mentation.

much

'deeper

canals.

R e m e m b e r that this canal lies in a

(medial)

plane

than

the

other

As the-ampulla of the superior canal

tered,

it

is

left

partially

intact

to

provide

two

is ena

later

l a n d m a r k to the superior vestibular nerve and lateralmost

end

of

the

internal

auditory

canal.

dissection continues anteriorly (forward), canal

As

the

the lateral

is opened completely; the side of the cutting

b u r ( n o t t h e tip) is u s e d , a l l o w i n g for a safer a p p r o a c h with

better visualization

the d i a m o n d bur,

o f t h e facial

nerve.

Using

t h e facial n e r v e is p o s i t i v e l y iden-

tified. T h i s m a r k s the a n t e r i o r limit of the d i s s e c t i o n . Carefully much

skeletonizing

the

facial

nerve

affords

as

r o o m a s p o s s i b l e f o r full v i s u a l i z a t i o n o f t h e

vestibule

and,

later,

auditory

canal.

the lateral

end of the internal

the

well

internal

superior,

defined,

inferior,

full

auditory canal.

and

attention

anterior

is

given

T h e objective

is

limits to

to

the

obtain

180-degree b o n e removal of the posterior half of the canal.

This

is

necessary

for

full

exposure

and

to

prevent b o n y o v e r h a n g s that hinder w o r k within the canal.

T w o important points must be ed.

(I) T h e canal runs anterior to posterior as it becomes m o r e m e d i a l ; t h u s m o r e b o n e will b e r e m o v e d n e a r the

posterior

fossa

dura,

and

only

minimal

bone

r e m o v a l will b e n e e d e d a t the s u p e r i o r c a n a l a m p u l l a l a n d m a r k ( w h i c h w a s left b e h i n d ) . T h e c o u r s e i t will run a p p r o x i m a t e s a line from the s e c o n d g e n u of the f a c i a l n e r v e t o t h e s i n o d u r a l a n g l e . ( 2 ) T h e c a n a l will be very expanded owing to the presence of the tumor

T h e final s t e p s a r e t o fully o p e n t h e v e s t i b u l e a n d to completely

With now

thin

the

m i d d l e fossa

tcgmen,

(Fig.

sino-

19-4C).

Bony troughs are created around the superior and

dural a n g l e , a n d p o s t e r i o r fossa d u r a to the level that

inferior b o r d e r s of the internal auditory canal; they

the dissection has reached. T h e dissection is carried

are d e e p e n e d b e t w e e n the t e g m e n and the canal and

interiorly to identify the jugular bulb; s e e n as a bluish

between the jugular bulb and the canal, respectively,

discoloration

the

until the p o s t e r i o r h a l f o f the canal has b e e n e x p o s e d

inferior limit of dissection. As the dissection is called

and the b o n e has b e e n thinned to eggshell thickness.

interiorly, t h e retrofacial air cells often a r e o p e n e d to

Superiorly, caution is n e e d e d since occasionally the

through

enhance exposure.

the

Also

bone,

found

it

in

represents

this area

is

the

facial n e r v e c r o s s e s t h e s u p e r i o r a s p e c t o f t h e t u m o r

vestibular aqueduct as it runs medially to the poste-

and m a y be injured with the d i a m o n d bur. T h e bur

rior c a n a l from the e n d o l y m p h a t i c s a c . T h e labyrin-

bit s h o u l d a l w a y s r o t a t e t o w a r d t h e t e g m e n , t o pre-

thectomy has now been completed.

vent " j u m p i n g " into the canal if it c a t c h e s on a b o n y

I m m e d i a t e l y m e d i a l t o t h e v e s t i b u l e lies the inter-

l e d g e ; t h i s i n v o l v e s c l o c k w i s e r o t a t i o n i n a left e a r

nal a u d i t o r y c a n a l ( r e m e m b e r t h a t t h e m e d i a l w a l l o f

and c o u n t e r c l o c k w i s e rotation in a right ear. In de-

the s u p e r i o r canal a m p u l l a is the lateral wall of this

veloping the " t r o u g h " interiorly,

canal).

duct is found between the jugular bulb and the canal.

At this point,

the sigmoid sinus should be

d e c o m p r e s s e d so that it can be retracted posteriorly,

It

this provides m o r e

poste-

p i c k into it o f t e n p r o d u c e s a c e r e b r o s p i n a l fluid leak.

A large dia-

This is an important landmark, since the ninth nerve

m o n d b u r and c o n s t a n t irrigation is used to thin the

is just a n t e r o i n f e r i o r a n d m e d i a l to it as it exits the

working area,

especially

riorly at the b r a i n s t e m - t u m o r j u n c t i o n .

u s u a l l y a p p e a r s as a

the cochlear aque-

white spot, and

inserting a

334

T u m o r s of the Middle a n d Inner Ear

T u m o r s of the Middle and Inner Ear

skull to p r o c e e d a c r o s s t h e m e d i a l s u p e r i o r a s p e c t of

blunt right-angled h o o k , the ridge of b o n e (Bill's b r )

the

that

jugular

bulb.

In

order

to

protect

this

nerve,

:

separates

the

superior

vestibular

and

fac a l

dissection s h o u l d not p r o c e e d anteriorly to the coch-

n e r v e s is identified a n d p a l p a t e d by finding the e* d

lear a q u e d u c t .

of

Focusing

on

the superior canal

am-

the

superior

vestibular

nerve

and

following

Hie

is

the

pulla, the s u p e r i o r vestibular nerve can be identified

bone

through

facial c a n a l b e g i n s ) . T h i s i s c r u c i a l t o p r e s e r v i n g H e

mond

the

bur.

bone

by careful dissection

With

continuous

prevent heat can

be

transfer from

blue-lined

labyrinthine

and

portion

onpious

the bur,

identified

of

the

with

a

dia-

irrigation

backward

until

it

ends

(which

where

to

facial n e r v e , s i n c e e v e r y t h i n g l a t e r a l t o t h i s r i d g e i s

t h e facial n e r v e

vestibular nerve a n d m a y be avulsed safely (Fig. 1 9 -

as

it

fallopian

enters

canal,

the

5 C ) . A s t h e a v u l s e d n e r v e i s p u l l e d b a c k , t h e facial

medial

n e r v e i s b r o u g h t i n t o full v i e w b e h i n d . I t i s b e s t n o t

and slightly superior to w h e r e the superior vestibular

to

nerve ends.

t r a u m a t o a n d s w e l l i n g o f t h e f a c i a l n e r v e . T h e first

(It m a y b e f o l l o w e d f o r a s h o r t d i s t a n c e

probe

into

the

facial

canal

in

order to

prevent

i n its l a b y r i n t h i n e c o u r s e f o r p o s i t i v e i d e n t i f i c a t i o n . )

few

Inferior to the s u p e r i o r v e s t i b u l a r n e r v e is the trans-

identify

verse crest, which divides the lateralmost end of the

n e r v e o n its s u p e r i o r a n d i n f e r i o r e d g e s i s s e p a r a t e d

internal

with the h o o k (Fig.

auditory

canal

c o m p a r t m e n t s (Fig.

into

superior

19-5/4).

and

inferior

If the b o n e remaining

millimeters of it

the

positively.

facial

nerve

Arachnoid

are cleaned

that

o

envelops

\h?.

1 9 - 5 D ) . O f t e n t h i s i s diffice.j ,

since the nerve m a y thin considerably a n d m a k e the

over the canal has b e e n t h i n n e d properly, usually it

n e r v e e d g e s hard to distinguish.

can be c r a c k e d with p r e s s u r e from a blunt i n s t r u m e n t

perior

and r e m o v e d in o n e piece, or drilled carefully with

mentioned previously, it separates the superior a

a d i a m o n d bur. It is i m p o r t a n t to c o m p l e t e l y r e m o v e

inferior c o m p a r t m e n t s of the internal auditory canr .

the b o n e

T h e inferior c o m p a r t m e n t is cleaned of t u m o r w i l l

from

the

posterior half of the canal.

The

vestibular

t u m o r itself is n o w e x p o s e d a n d b o n e overlying the

the

posterior fossa

between

dura

has been

removed

completely,

hook.

A

nerve

is

tongue

the

of

the

Inferior to the si transverse

tumor

transverse crest

often

and

crest;

s

extends

-

i

u/>

inferior c o m p a r -

from the s i g m o i d s i n u s t o the p o m s a c u s t i c u s (lateral

ment

to medial) and

inferior vestibular n e r v e is a v u l s e d , a n d usually the

from

the t e g m e n to the jugular bulb

(superior to inferior). A to

dural

the

flap

acusticus

bulb,

and

dura parallel

then

is b e g u n

and

posterosuperiorly

carried

laterally

up

across

the

the

porus

posterior

fossa

to the s u p e r i o r petrosal s i n u s .

Its i n f e -

rior l i m b n i a v b e c a r r i e d l a t c r a l l v a l o n g ( h e s i g m o i d sinus.

must be

swept clean

(Fig.

19-6/A).

Th£

cochlear nerve as well. T h e anteroinferior cerebellar

incision

jugular

and

I h e Hap i s p u l l e d b a c k w a r d a n d t h e p o s t e r i o r

artery

usually

lies

along

the

inferior

border of

the

tumor, anterior to the cochlear nerve. This imported* vessel

must

always

be

watched

for

and

protect?-!

from injurv. T h e t u m o r is pulled t o w a r d the s u r g e o n d u r i n g this lateral m o b i l i z a t i o n . I he

procedure

trom

this

point

depends

on

tie

s u r f a c e o f t h e t u m o r i s \ i s u a l i / e d ( F i g . IS* ^ / * ) . I h e

s i / e ot t h e t u m o r . D i s s e c t i o n m a v p r o c e e d as obo" i ;

incisions

however,

must

he

made cautiouslv

derlying vessels and

so

that

anv

n e r v e s are not i n j u r e d .

the tacial n e r v e t r a v e r s e s the s u p v r i o r a s p e c t ol tumor

(UMUIIV

it

is on

petrosal

vein

is

draining

into

the superior

lound

the .interior surliiie);

along

llir

petrosal

un-

Karelv.

larger

tumor debulking

will

be

•

the

facial n e r v e a s [ l i e t u m o r i s r o l l e d a w a v I r o m it.

the

debulking,

posterior

aspect,

surface

vein.

t h e tu-

larlv,"

At

for a

quired, to p r e v e n t traction from b e i n g placed on t .e the

and

tumor

the

is o p e n e d

conlvnts

allowing

it

,ue

over

its

removed

to c o l l a p s e

inward.

in

p o s t e n *r

"intracapsaThis can

v

m o r ' s inferior aspect, the c i s t e m a m a g n a usuallv can

a c c o m p l i s h e d with an U r b a n d i s s e c t o r , laser (Fig. 1 f

be visualized and gently probed to obtain a profuse

b/*), C a v i t r o n , or c u p f o r c e p s . C a r e is t a k e n to r e m a i n

cerebrospinal

fluid

leak.

This will

a n d allow the c e r e b e l l u m to relax.

release

pressure

inside the capsule in order to prevent injury to nerv '5

The p l a n e b e t w e e n

or v e s s e l s that m a y t r a v e r s e the t u m o r surface. W: h

the p o s t e r i o r a s p e c t of the t u m o r and

the arachnoid

a d e q u a t e d e b u l k i n g t h e t u m o r will c o l l a p s e i n w a r I ,

is d e v e l o p e d , a n d t h e d u r a l flap is laid in t h e p l a n e

allowing

to

anteriorly (Fig.

protect

the

cerebellum

(if

petrosal vein u n d e r the flap).

possible,

include

the

L o n g C o t t o n o i d strips

further

mobilization

from

the

facial

ner

e

19-6C) and the brainstem posterior y

(Fig. 1 9 - 6 D ) . B i p o l a r cautery m a y be u s e d to cont; >1

m a y a l s o b e laid t o p r o t e c t t h e c e r e b e l l u m a n d h e l p

bleeding

in d e v e l o p i n g the plane. D e v e l o p i n g the proper plane

abundant.

will p r o d u c e l e s s b l e e d i n g .

traverse the capsule interiorly. Usuallv the anteroi .-

At

this

point

the

lateral

end

of

the

tumor

is

within

tumor growth.

away

area

vestibular and

is

brought

facial

into

nerves are

tumor,

which the

occasionally

ninth

nerve

:

s

m- v

( e r i o r c e r e b e l l a r a r t e r y h a s b e e n p u s h e d i n f e r i o r l y '~y

m o b i l i z e d from t h e facial n e r v e . B y r o t a t i n g the table the

the

With large tumors,

S u p e r i o r l y t h e fifth

n e r v e m a y ere? s

The

superior

the c a p s u l e in large t u m o r s ; o c c a s i o n a l l y , the s e v e n ; i

identified.

Using a

nerve may

view.

traverse the superior e d g e of the

tumo:.

FIGURE 19-5.

336

T u m o r s of the Middle and Inner Ear

337

Tumors of the M i d d l e and Inner Ear During mobilization and tumor removal, these struc-

loss; h o w e v e r , if b o n e removal has b e e n c o m p l e t e d

t u r e s m u s t b e w a t c h e d for a n d p r o t e c t e d .

there are no b o n y ledges against which to w e d g e the

A f t e r a d e q u a t e d e b u l k j n g , t h e p l a n e for t h e facial

packing. ally;

to

drill, c r e a t i n g a w h i p p i n g a c t i o n w i t h t h e S u r g i c e l .

be

rolled

toward

the

surgeon.

It

is

important

in

Large packs hinder dissection more medi-

nerve is further developed and the t u m o r continues

addition,

b o n e w a x draped over Bill's island; a long strip of

to

follow

the

and

facial

nerve

removing

the

to

the

Cottonoid is then draped over the area and the entire a malleable retractor h o o k e d to the cerebellar retrac-

to be developed.

nerve usually thins considerably,

making

tors.

Again, bleeding usually can be controlled; the

the d i s s e c t i o n difficult. Often it is n e c e s s a r y to return

objective is

to the posterior, inferior, and superior borders of the

without

t u m o r t o d e v e l o p t h i s p l a n e (if n e e d e d Always

for m a n e u -

Bleeding.

Inadvertent

injury

to

the

i m m e d i a t e l y will control the b l e e d i n g . C a u t i o n m u s t be

the

e n h a n c e visualization

(Fig.

tween

tumor

the

remaining

tumor

is

19-6/:). and

the

Bulb

the

of

pushing

Jugular

a n t e r i o r l y . O n c e the facial n e r v e h a s b e e n freed from bulk

avoid

farther medially

jugular bulb is signaled by profuse bleeding. Packing

the

to

to continue dissection

hindrance.

tumor

tumor,

try

packing with

the porus acusticus

the

the

vering).

the

c o m p l e x is retracted with the suction irrigator or with

as

continues facial

to cover

plane

tumor

At

brainstem,

is

the

One

separating

this

m a y be caught in

inward, which m a y stretch the thinned nerve. best

to

packs

( a l t h o u g h difficult) to a v o i d p u s h i n g the t u m o r m a s s It is

solution

the

removed

to

T h e plane be-

the

brainstem

developed and care is exercised superiorly

is

for t h e

exercised

since

the

ninth,

tenth,

and

eleventh

n e r v e s are in this area a n d m a y be injured by injudicious packing. For small tears in the jugular bulb, packing

may

control

the

bleeding

and

allow

the

fifth n e r v e a n d i n f e r i o r l v f o r t h e a n t e r o i n f e r i o r c e r e -

procedure to c o n t i n u e . O n l y large pieces of packing

bellar artery (Fig.

material

1 9 - 6 £ ) . Vessels that traverse the

are

to be

used

here,

in order to

prevent

tumor surface are dissected away, if possible; if not,

d i s p l a c e m e n t of material into the l u m e n of the vein

they are carefully clipped or cauterized. With careful

and a

d i s s e c t i o n , total r e m o v a l o f t h e t u m o r c a n b e a c c o m -

concern with tears in the s i g m o i d ) . For large tears, it

p l i s h e d i n a l m o s t all c a s e s .

i s o f t e n n e c e s s a r y a n d s a f e r t o tie t h e v e i n o f f i n t h e

Before closure,

sufficient time

must be taken to

e n s u r e that a d e q u a t e h e m o s t a s i s is o b t a i n e d the c e r e b e l l o p o n t i n e angle. abdomen

and

placed

in

Fat

is

taken

long strips just

within

against

postoperative cerebrospinal

n e c k by e x t e n d i n g t h e postauricular incision interio r l y ( f o r all n e u r o l o g i c p r o c e d u r e s t h e u p p e r n e c k i s

from

the

included

inside

the

packed intraluminally to prevent back-bleeding,

dural o p e n i n g ; this has b e e n found to provide a g o o d seal

resulting p u l m o n a r y e m b o l u s (this is also a

fluid

leak-

Facial

in

the draping).

Nerw

Avulsion.

If

T h e jugular bulb is then

the

facial

avulsed during tumor removal,

nerve

is

a decision

lost

a g e . T h e l o n g tails o f the strips are t h e n folded into

made whether to attempt immediate or delayed

the m a s t o i d cavitv a n d a n t r u m , and the postauricular

habilitation.

incision is closed.

Because

the best

and

most

or

must be re-

consistent

results are o b t a i n e d from i m m e d i a t e rehabilitation, it should be attempted if possible. If the brainstem side of the avulsed

Intraoperative Complications or Problems

mobilized

in

maneuver, obtained

is long e n o u g h ,

an

its e n t i r e t y

from

additional

1-cm

(bying

the

its c a n a l . length

With

of

labyrinthine and

this

nerve

is

temporal

1. S i g m o i d and superior petrosal sinus bleeding.

course of the nerve) and an end-to-end anastomosis

2. Jugular bulb bleeding.

m a y be a t t e m p t e d . If p o s s i b l e , a s u t u r e is placed to

3. Facial nerve avulsion.

hold

4. Vital sign c h a n g e s .

has been

Sinus Bleeding.

in a p p o s i t i o n ) . If this is n o t feasible, a h y p o g l o s s a l -

B l e e d i n g a r i s i n g from i n j u r y to the

sinus during bone removal may be profuse at times. Although alarming, with proper m a n a g e m e n t it may

FIGURE 19-6.

nerve is found and

t h e i n f r a t e m p o r a l p o r t i o n o f t h e facial n e r v e m a y b e

the avulsed

ends

placed around

together (collagen

[Avitenej

the t w o e n d s to hold them

facial n e r v e a n a s t o m o s i s i s p e r f o r m e d l a t e r . Vital Sign Changes. V i t a l s i g n s a r e c o n s t a n t l y m o n -

be controlled without serious consequences. Sigmoid

itored

bleeding arising from e m i s s a r y veins usually can be

ous cardiac monitoring is d o n e , as well as monitoring

controlled

of blood p r e s s u r e with arterial lines.

b y full e x p o s u r e o f t h e v e i n a n d b i p o l a r

throughout tumor removal surgery.

Continu-

W i t h a n y rise

cautery; packing with b o n e wax or Surgicel is another

or c h a n g e in blood pressure or pulse regularity, the

o p t i o n . For tears w i t h i n the s i n u s itself, p a c k i n g with

surgeon

S u r g i c e l will c o n t r o l t h e i m m e d i a t e p r o b l e m o f b l o o d

Cottonoid packing is r e m o v e d in order to eliminate

is notified,

traction

is stopped,

and

large

CHAPTER 20 Plastic Surgery of the Pinna T h e p i n n a , or auricle, is the projecting part of the

Highlights

ear t h a t lies o u t s i d e t h e h e a d ; its b a s i c a n a t o m y i s s h o w n in Figure 2 0 - 1 .

It consists of two types of

tissue: elastic (yellow) cartilage and, in the ear lobe, fibroareolar tissue.

pressure

on

normal in a they

vessels.

Usually

responses

return

to

few minutes and surgery continues,

it

has

usually

time

improved

the brainstem circulation

from

tumor

debulking

of

superior, the

anterior,

Blood

is

and

supplied

superficial

to

temporal

p o s t e r i o r aurithe

pinna

and

by

posterior

the

greater

auricular

and

auriculotemporal


after

the

repair;

even

a

lightweight

small

branch

of

the

vagus

nerve

in

the concha

Pitfalls

bowl. This chapter describes several surgical proced u r e s for repair a n d r e c o n s t r u c t i o n o f t h e p i n n a .

and

1. F a i l i n g to p e r f o r m a Z - p l a s t y o f t e n r e s u l t s in a FIGURE

notch at the free m a r g i n of the lobe a n d a d e p r e s s e d

19-7

m e n t of blood loss is important to prevent earlv signs of s h o c k ( i n c r e a s e d pulse, d e c r e a s e d B P ) from offset-

hole

e a r r i n g will e n l a r g e the h o l e p o s t o p e r a t i v e l y .

nerves,

release of pressure, a n d total t u m o r r e m o v a l can be performed safely. Constant monitoring and replace-

2. Do not u s e a p o s t - t y p e earring to m a i n t a i n the earring

auricular arteries, and it is innervated by b r a n c h e s of

a

i s left b e h i n d , i t m a y b e r e m o v e d e l e c t i v e l y i n a b o u t By that

the

1. M a k e a Z-plasty or V - p l a s t y at the free m a r g i n to prevent postoperative notching.

the mastoid branch of the lesser occipital nerve, and

surgery but only perform a subtotal removal; if t u m o r months.

by

muscles.

branches ting the effect of vessel traction or s p a s m ( d e c r e a s e d pulse, increased BP).

recur, a decision is m a d e w h e t h e r to continue

six

scalp cular

It is c o n n e c t e d to the head and

This horizontal section of a temporal b o n e show?

Treatment of the Cleft Ear Lobe

the p r e s e n c e o f a n acoustic n e u r o m a .

scar. 2. If the

patient wears an

e a r r i n g too s o o n after

the r e p a i r , a n e n l a r g e d e a r r i n g h o l e will r e s u l t P a t i e n t s are often s e e n in the clinic w i t h cleft ear l o b e s s e c o n d a r y t o t r a u m a f r o m p i e r c i n g t h e e a r for e a r r i n g s . T h e y m o s t often p r e s e n t with a h e a l e d cleft, but o c c a s i o n a l l y w i t h a " f r e s h " or i n c o m p l e t e cleft;

Instruments

v e r y r a r e l y a c o n g e n i t a l cleft is s e e n . R e g a r d l e s s of the p r e s e n t a t i o n , t h e t r e a t m e n t i s the s a m e

No. 11 and N o . 15 scalpel blades and handles. T w o skin h o o k s , either single or double h o o k type. 0.5-mm ophthalmic forceps.

Aim

Fine Storz "stitch" scissors. S u t u r e s : 5-0 Vicryl on a cutting n e e d l e , 6-0 c h r o m i c or 6-0 n y l o n on a small cutting n e e d l e , 0 p r o l e n e

To c o r r e c t a cleft e a r l o b e d e f e c t

or nylon

340

341

Plastic S u r g e r y of the P i n n a

Plastic Surgery of the Pinna

Procedure

2.

Stay as close as possible to

the

stalk of the

keloid during excision, in order to preserve as m u c h Ant. auricular muscle

normal skin of the ear lobe as possible. Lidocaine 1 to 2% with 1:100,000 e p i n e p h r i n e is u s e d . First t h e e d g e s o f t h e cleft a r e e x c i s e d - I f t h e cleft i s n o t q u i t e c o m p l e t e , t h e s m a l l b r i d g e o f s k i n also

is

(Fig.

excised.

20-2-A-C).

A

Z-plasty

One

can

is

also

fashioned be

made

anteriorly

Pitfalls

posteriorly,

but this is not n e c e s s a r y . A Z-plasty s h o u l d also be made

at

the

free

margin

of the

lobe

to

prevent

a

small notch from forming during the healing process A l t e r n a t i v e l y , the free m a r g i n c a n be c l o s e d in a " V "

1. R e p i e r c i n g of the lobe after successful treatment of a keloid is not r e c o m m e n d e d . 2. Failing

to

prevent

a

recurrence

p r o b l e m after e x c i s i o n

the

common

to h a v e a p i e r c e d e a r , a l e n g t h of 0 p r o l e n e s u t u r e is

follow-up

f o r m e d i n t o a 1-in l o o p p a s s i n g t h r o u g h t h e f o r m e r

the best m e t h o d s of preventing a recurrence.

and

the use

of

of a

is

t o n g u e - a n d - g r o o v e f a s h i o n . I f t h e p a t i e n t still w i s h e s

keloid.

intralesional

most Close

steroids are

earring site. S o m e patients, not wishing to have the

3. T h e patient with large keloids m u s t be advised

l o o p o f s u t u r e i n t h e i r l o b e for s e v e r a l w e e k s , m a y

that the ear lobe m a y be less fleshy after e x c i s i o n of

decide

the

the k e l o i d ; t h a t o w i n g t o t h e m a s s o f t h e k e l o i d , little

repair has healed. T h e fibroareolar tissue is closed

fibrofatty t i s s u e is a v a i l a b l e for a d v a n c e m e n t into t h e

with

w o u n d for c l o s u r e ; that t h e l o b e m a y b e s m a l l e r after

simply

to

interrupted

have

the

ear

5-0 Vicryl a n d

repierced the skin

after

is closed

excision of the keloid, o w i n g to the excision of skin

with interrupted 6-0 nylon or 6-0 c h r o m i c sutures. B a c i t r a c i n o i n t m e n t is a p p l i e d to t h e i n c i s i o n for a few d a y s . 6-0 nylon sutures are r e m o v e d at four to five d a y s . I f 6-0 c h r o m i c s u t u r e s a r e u s e d , t h e p a t i e n t can be seen at seven to 10 days, at which time the

on both surfaces of the lobe; a n d that the lobe m a y be rotated slightly anteriorly after the excision of a lateral keloid a n d slightly posteriorly after the excision of a m e d i a l keloid.

r e m a i n i n g w i s p s o f s u t u r e c a n b e g e n t l y w i p e d off. A n e a r r i n g m a y b e w o r n after four w e e k s .

Instruments Treatment of Keloids No. 1 and N o . 15 scalpel blades and handles. 0.5-mm ophthalmic forceps. Keloids are a c o m m o n

problem of the ear lobe,

A fine n e e d l e h o l d e r .

especially in blacks. T h e y usually involve the medial

Storz "stitch" scissors.

aspect of the lobe, a n d m o s t often are the result of

Skin hooks, either single or double.

d e e p dermal injury to the lobe of the ear w h e n the

Sutures: 5-0 c h r o m i c or Vicryl, a n d 6-0 c h r o m i c or 6-

ears are pierced painful

when

for e a r r i n g s .

holding a

telephone

the ear or w h e n sleeping. to c a u s e a

Large lesions can be

0 n y l o n on a small c u t t i n g n e e d l e .

receiver against

A n y keloid large e n o u g h

c o s m e t i c or functional defect should

be

excised.

Aim

Procedure T h e treatment of keloids involves three treatment modalities,

steroid

therapy,

pressure

therapy,

and

excision. T h e s e modalities are often used at different To excise and prevent the recurrence of the ear lobe keloid.

times in the treatment of the s a m e keloid. Small keloids can be treated with injections of 40 mg per ml of triamcinolone acetonide every four to six w e e k s . T h e s t e r o i d c a n e i t h e r b e d e l i v e r e d w i t h a

Highlights

Dermajet apparatus or injected into the d e r m i s with a 25-

or

27-gauge

needle.

A

Dermajet

needleless

injector d i s p e n s e s 0.1 ml of the steroid s o l u t i o n in a 1. T h e key to treatment is to prevent recurrence

fine

droplet

form

uniformly

into

the

tissues;

this

after e x c i s i o n . T h i s is a c c o m p l i s h e d with intralesional

avoids the b o l u s injection of steroids that can result

steroid injections and the use of pressure earrings.

from direct n e e d l e injection i n t o d e n s e s c a r tissue.

343

Plastic S u r g e r y of the Pinna

O v e r z e a l o u s injection can c a u s e skin a t r o p h y , telan-

before

giectasis, a n d h y p o p i g m e n t a t i o n . It m a y t a k e six to

requires more extensive surgery.

the clot organizes.

An

organized

hematoma

12 m o n t h s to resolve the keloid. It is a l s o p o s s i b l e to treat small keloids with pressure therapy.

A pressure-type clasp earring (Padgett

Co, Kansas City, M O ) m a y supply e n o u g h pressure to blanch

the capillaries supplying the fibrous tissue

and cause a regression of the lesion. It must be worn continuously

for s e v e r a l

months.

is

the

can

taken

off

keloid

W h e n the earring

recur;

therefore,

it

is

Aim To drain

the hematoma,

prevent reaccumulation,

avoid s e c o n d a r y cellulitis or perichondritis, a n d prevent

the

deformity

caused

by

organization

of

the

h e m a t o m a (cauliflower ear).

probably best to c o m b i n e use of the pressure earring with m o n t h l y steroid injections.

Highlights

F o r k e l o i d s t h a t a r e t o o l a r g e for p r e s s u r e t h e r a p y or that do not r e s p o n d to s t e r o i d s , e x c i s i o n is indicated. T h e entire keloid should be excised. Delicate handling is necessary to prevent trauma to the surr o u n d i n g tissues. If the keloid is especially large, it is i m p o r t a n t to free up s u r r o u n d i n g fibrofatty tissue t o fill i n t h e s o f t t i s s u e d e f e c t . A W - p l a s t y o r Z - p l a s t y

1. T h e m o s t important s t e p is the p l a c e m e n t of a w e l l - m o l d e d dressing to prevent a recurrence 2. The

incision

should

be

hidden

or should

run

favorably with the a n a t o m y of the pinna. 3. A drain m a y be n e c e s s a r y w h e n treating a large hematoma.

is u s e d to c a m o u f l a g e the repair. S o m e t i m e s a small r o t a t i o n a l flap m u s t b e u s e d for c l o s u r e . S t e r o i d s c a n be injected directly into the surgical site at the end

Pitfalls

o f t h e p r o c e d u r e . 5 - 0 c h r o m i c o r V i c r y l i s u s e d for deep sutures and 6-0 c h r o m i c or nylon

is used

on

1.

R e c u r r e n c e o f t h e h e m a t o m a o w i n g t o a n in-

adequate

the skin.

dressing.

B a c i t r a c i n i s a p p l i e d for a f e w d a y s . N y l o n s u t u r e s can b e r e m o v e d after four t o five d a y s . W h e n e x c i s i o n

I n s t r u m e n t s a n d Supplies

alone is u s e d the r e c u r r e n c e rate is o v e r 50vl; therefore, the s u r g i c a l site s h o u l d be injected w i t h s t e r o i d s

No. 11 or No. 15 scalpel and handle.

every month

Curved

the

scar is

for a p p r o x i m a t e l y six mature.

using the Dermajet, blade against

To stabilize it

m o n t h s or

the ear kibe

is helpful

until when

to p l a c e a t o n g u e

the lateral surface of the lobe.

At the

first s i g n o f r e c u r r e n c e , a p r e s s u r e e a r r i n g s h o u l d b e added to the treatment regimen

hemostat (mosquito)

0.25-in Penrose drain (optional) Cotton balls. Povidone-iodine (Betadine) ointment 5 0 - 5 0 m i x t u r e o f m i n e r a l oil a n d

Betadine solution

(optional). 4 x 4

"Fluffs."

2-in r o l l e d b a n d a g e s 2-0 n y l o n or p r o l e n e on a large cutting n e e d l e

Traumatic Injuries of the Pinna

Hibiclens or Betadine scrub. Normal saline irrigating solution.

Injuries of the p i n n a are classified as follows:

Procedure

1. T r a u m a t i c h e m a t o m a with or without cellulitis or

perichondritis Lidocaine 1%

2. Laceration without tissue loss

with 1:100,000 epinephrine can be

3. Laceration with skin or cartilage loss, or both.

u s e d as a field b l o c k or i n j e c t e d l o c a l l y . T h e e a r is

4. Total amputation of the pinna.

p r e p a r e d with H i b i c l e n s or B e t a d i n e scrub. A vertical curvilinear incision is m a d e over or along the side of the

hematoma

(usually

under either

the

helical

or

a n t h e l i c a l fold to c a m o u f l a g e it). It is b e t t e r to m a k e

Hematoma of the Pinna

a n i n c i s i o n l a r g e e n o u g h for g o o d d r a i n a g e a n d deal with the resultant scar later than to be faced with a persistent

A

hematoma

of

the

pinna

is

caused

by

blunt

trauma a n d m o s t often affects t h e lateral s u r f a c e (Fig. 20-2D).

It

should

be

drained

as

soon

as

possible

or

perichondritis. used

to open

hematoma

recurrent

hematoma

and

secondary

A curved mosquito hemostat m a y be up a n y loculations.

should

be

taken

A culture of the

if cellulitis

is

present.

344

Piasi ic S u r g e r y of the Pinna

The

hematoma

can

then

be


irrigated

gently

Highlights

with

t i m e a s t e n t m u c h like t h a t for a h e a r i n g aid c a n be

s t e r i l e n o r m a l s a l i n e . A >/i-in P e n r o s e d r a i n o r r u b b e r

placed to prevent post-traumatic stenosis of the canal

b a n d d r a i n s h o u l d b e u s e d for e x t e n s i v e h e m a t o m a s .

1. Intracartilaginous s u t u r e s are often

Skin

2. Apparently

sutures

should

then

approximate

the

skin

of

nonvital

tissue

(Fig

necessary.

should

be

saved

l a r g e i n c i s i o n s b u t still a l l o w a d e q u a t e d r a i n a g e . N e x t

whenever possible.

cotton balls saturated

sists, the skin of the pinna h a s a r e m a r k a b l e abtlit.

with

B e t a d i n e o i n t m e n t (or a

If a c u t a n e o u s l i n k o f s k i n

per1

2 0 - 2 H ) . A central hole should be drilled to allow

h e a r i n g . T h e stent s h o u l d be w o r n for three Bacitracin

is applied

t o w i t h s t a n d v a s c u l a r c o m p r o m i s e . T h e n o n v i t a l tis-

crusting.

If

are formed into s h a p e s that precisely c o r r e s p o n d to

sue

dressing

with

the folds of the

debrided

additional

pinna o v e r l y i n g the

piece of cotton

should

hematoma.

be

molded

An

to

fit

into the postauricular c r e a s e (Fig. 2 0 - 2 E ) . A n exact fit

is

necessary

hematomas.

to

prevent

reaccumulation

of

3.

then

days

later

and

can

be

then.

Use

of

pinna

a

stent

with

external

auditory

canal

hematomas

is

extensive,

molding

but

(like

without

a

that

usually

"Fluffs"

two and

will

a

suffice.

2-in

rolled

A

Pitfalls

mastoid

bandage are

the

mattress

1. Post-traumatic tattooing d u e to i n c o m p l e t e de-

mastoid

s u t u r e s ) s h o u l d b e a p p l i e d a n d w o r n for t w o t o t h r e e

dressing and

cotton

balls can

General anesthesia

needed

and

the cotton

two to three days.

bolsters are

rehas

type

of

precise

cotton

packing

with

tissue loss is similar to that after the resection of a

teral

cultures should

antibiotics

started.

through-and-through

A

suction

be

taken and

Penrose irrigation

or

system

a

mav

be necessarv. If there is evidence of cartilage necrosis, w i d e d e b r i d e m e n t o f n e c r o t i c soft t i s s u e a n d cartilage is needed. T h e reconstruction of any defects resulting from p e r i c h o n d r i t i s is similar to that p e r f o r m e d after neoplasm resection (described below).

In

Total Amputation of the Pinna Fortunately,

Procedure

putated Usually can

be

17,

used.

compromised

total

or

subtotal

p i n n a is a rare o c c u r r e n c e . lidocaine with If

there

blood

epinephrine should

are

flaps

supply, be

1:100,000 epinephrine 1V<

used.

or

regions

lidocaine

Simple

with

a

without

lacerations ol

the skin of the pinna should be meticulously c l e a n e d . I t i s i m p o r t a n t t o r e m o v e all d e b r i s t o p r e v e n t p o s t traumatic tattooing. The laceration should be closed with 6-0 c h r o m i c or 6-0 nylon suture.

If necessary,

piece

is

missing

amputation

of

the

C a s e s in w h i c h the amor

grossly

contaminated

o b v i a t e t h e n e e d for i m m e d i a t e r e c o n s t r u c t i o n .

De-

layed total auricular r e c o n s t r u c t i o n or p r o s t h e t i c re-

evert

edges,

renders it vulnerable to lacerations.

Complex

the

skin

neous

rather tissue;

than they

edges;

5-0

Vicrvl

or

chromic

through

the skin differently

any

cryl.

expose

indicated

the

when

subcuta-

there

is

Either running locked

involving cartilage can

be closed

by

the c a r t i l a g e t o g e t h e r with 5-0 Vi-

U n l e s s the cartilage is grossly c o n t a m i n a t e d it

does not need debriding. Horizontal mattress sutures

lacerations should be repaired.

in

without

much

crushing

or

If o n l y a small p i e c e (1

pinna

has been

lost, a n d the a m p u t a t e d part has b e e n saved,

reattached,

Lacerations

through

the

external

auditory

recon-

been

to 2 cm of tissue or the

amputated

it

can

simply

but r e a t t a c h m e n t of a totally

be

amputated

pinna without re-establishment of the circulation by m i c r o v a s c u l a r s u r g e r y often results in a total loss of pinna

pinna

to

secondary the

head,

to

after n e o p l a s m r e s e c t i o n .

the v e n o u s c o n g e s t i o n . when

the pinna

How-

is advanta-

Medicinal leeches have been used

In s o m e cases,

Aim

vascular congestion.

simple reattachment

geous.

to reduce

has been

totally

amputated and microvascular repair is not available or

To reattach the a m p u t a t e d

indicated,

the

cartilaginous

framework

may

be

s a l v a g e d b y d e r m a b r a d i n g all o f t h e e p i d e r m i s from

portion of the p i n n a

the cartilaginous skeleton and burying the pinna in a p o s t a u r i c u l a r p o c k e t for t h r e e to four w e e k s . T h e cartilaginous

Highlights

skeleton

can

then

be "released"

from

this p o c k e t a n d a l l o w e d to s l o w l y re-epithelialize. 1. If the a m p u t a t e d piece is available, reimplantation s h o u l d be a t t e m p t e d unless the patient's medl e n g t h y general an-

esthetic. 2. Close

If only a portion of the pinna has been amputated, all o f t h e s o f t t i s s u e o v e r l y i n g b o t h s u r f a c e s o f t h e amputated

segment

is

removed,

sparing

the

peri-

c h o n d r i u m ; the cartilage s e g m e n t is then reattached postoperative

follow-up

is

needed

to

w a t c h for i n f e c t i o n , v e n o u s c o n g e s t i o n , a n d n e c r o s i s .

to

the

remaining

pinna

reapproximate the segment

is

then

with

cartilage. buried

in

mattress

The a

sutures

denuded

postauricular

to

cartilage pocket,

which has been created by incising the postauricular skin, followed by wide u n d e r m i n i n g (Fig. 2 0 - 3 )

canal

p a c k c a n b e r e m o v e d i n five t o s e v e n d a y s , a t w h i c h

has

struction of the r e m n a n t is similar to that p e r f o r m e d

Pitfalls

are treated initially with a bacitracin g a u z e pack. T h e

rim)

the

of the tissue of the

the plane of the cartilage provide accurate reap-

proximation.

To repair a laceration of the pinna.

amputations

ever, if there is a small c u t a n e o u s bridge linking the

50%

no

t h e c a r t i l a g e t o t h e r i s k o f i n f e c t i o n . All f u l l - t h i c k n e s s

Aim

patient

less than

ical c o n d i t i o n c o n t r a i n d i c a t e s a Lacerations

directly suturing

will

are

through

tension on the w o u n d edges.

is densely a d h e r e n t to the underlying cartilage, and injury of the dermis

drawing

sutures or simple interrupted sutures can be used.

b o d i e s a n d a n y e v i d e n c e o f soft tissue loss. T h e skin full-thickness

clean

helical

s u b c u t a n e o u s sutures also are used to reduce tension

from 6-0 nylon s u t u r e s . C h r o m i c s u t u r e s usually are

l a c e r a t i o n s s h o u l d be carefully e x a m i n e d for foreign

the

habilitation are outside the s c o p e of this text. W h e n

not r e m o v e d a n d only serve to a p p r o x i m a t e the skin

head

W h e n dealing with an

i m p o r t a n t t o let

amputated pinna m a y be indicated. If this service is

6-0 c h r o m i c are placed

the

it is

avulsion of tissue, microvascular reattachment of an

. s u t u r e s w o r k b e s t f o r t h i s ( F i g . 2 0 - 21, C). S u t u r e s o l

T h e ear's p r o m i n e n t and e x p o s e d location on

pinna,

a v a i l a b l e it is p r o b a b l y a w o r t h w h i l e effort.

and

Laceration without Tissue Loss

bag, and then packed in ice. amputated

A basic plastics pack.

n

paren-

drain

in a m o i s t cot*on g a u z e , p l a c e d in a s e a l a b l e plastic

of circumstances.

Instruments

mastoid dressing is reapplied. If there is e v i d e n c e of perichondritis,

owing to

available it should be rinsed in cold saline, w r a p p e d

neoplasm (described below).

If

If reaccumulation

usually is indicated

a n d family k n o w the p o o r p r o g n o s i s e v e n in the best

occurred, the h e m a t o m a must be drained again, and same

instruments.

Procedure

Laceration with Skin or Cartilage Loss R e c o n s t r u c t i o n o f t h e p i n n a after l a c e r a t i o n s w i t h

laceration.

be

there has b e e n no reaccumulation, no further mastoid

the

A basic plastic pack plus a dermabrader. Microvascular

p r o m i n e n t scar-

3. Failing to recognize an external auditory canal

r e m o v e d after t w o days a n d the pinna inspected. is

the thicker

Instruments

for

t h a t c o v e r s f o r s k i n f l o r a , p r e d o m i n a n t l y Slnp/n/locot'-

in

re-epithelialized with

skin.

the length of the repair. W h e n the a m p u t a t e d part is

ring or irregularities in the cartilage formation.

T h e patient s h o u l d b e p l a c e d o n a n oral antibiotic

moved

when

stay

bridement.

P o s t o p e r a t i v e Care

dressing

preventable

the

applied.

The

be

3 . T h e cartilage s k e l e t o n will not b e a s s h a r p o r well-defined

mastoid used

days.

2. Imprecise closure resulting in

cus.

not

to the laceration to prevent

laceration

cotton

may

T h e pieces of cotton are held in place

sutures;

dressing of

several

lacerations to prevent stenosis.

with through-and-through 2-0 nylon or prolene mattress

demarcate

the

congestion

even with pie-crust incisions or leeches.

postauricular

weeks, depending on the severity of the injury

5 0 - 5 0 m i x t u r e o f B e t a d i n e s o l u t i o n a n d m i n e r a l oil)

will

t o six

2. V e n o u s

345

1.

The

larger the a m p u t a t e d

part,

the l i k e l i h o o d of partial or total l o s s .

the greater is

Another

method

of

salvaging

the

cartilaginous

skeleton of the amputated ear is to r e m o v e the skin

347


from

the

medial

tile cartilage.

surface

of the

pinna

and

perforate

The p o s t a u r i c u l a r skin is t h e n r e m o v e d

and the ear is reattached by suturing the helical to

the

(Fig

free

margin

of

remaining

rim

postauricular

tion

of a

neoplasm

can

also be used

to

reconstruct

the pinna after a laceration with tissue loss

skin

2 0 - 4 ) . "Pie-crust" incisions or medicinal leeches

m a y be necessary if v e n o u s congestion is a problem. T h e last be

used to reconstruct defects of the pinna after resec-

lifted

two m e t h o d s require that

after

three

to

four

the helical

weeks

by

the

p o s t a u r i c u l a r s k i n . T h e d e f e c t left i n t h e p o s t a u r i c u l a r area can s o m e t i m e s be closed by primary closure. A split-thickness opposite

or

full-thickness

postauricular

region

vicular area also can be used.

skin

or

graft

from

the

Aim

rim

incising

from

To r e c o n s t r u c t the pinna after resection of a n e o plasm.

the

supracla-

A n o t h e r method is to

place a fossa tissue e x p a n d e r behind the ear, and to

Highlights

use this e x p a n d e d skin to restirface the postauricular area. If the

postauricular area

is badly injured and

not

s u i t a b l e for o n e o f t h e a b o v e m e t h o d s o f r e c o n s t r u c tion, the pinna can be " b a n k e d " u n d e r cervical skin This

is

done

by

removing

the

soft

tissue

from

the

cartilage; m a k i n g a p o c k e t u n d e r a cervical skin flap, and

leaving it there

healed. be

until

the postauricular skin

A crescent-shaped tissue e x p a n d e r can

placed

in

the

slowly expanded

postauricular/mastoid o v e r f o u r t o six

"banked"

beneath

the

cartilage

cervical

panded pocket.

skeleton

flap

and

w e e k s until

is

then

region

as m u c h surface area is e x p a n d e d ( s e c Fig. The

and twice

20-4/3).

removed

placed

has

into

operative

2. Small

defects

or composite

to

are

repaired

by

primary

closure

are

repaired

with

graft.

3. Larger defects postauricular

tissues is necessary

trauma.

m o s t often

pedicled

a

graft.

4. T h e less c o m p l e x the repair, the greater is the likelihood of good results. 5 . All m a r g i n s o f r e s e c t i o n s h o u l d b e h i s t o l o g i c a l l y examined.

from

the

ex-

High-vacuum suction is necessary to

obtain g o o d apposition of the skin

1. G e n t l e handling of the reduce

Pitfalls

to the interstices

of the cartilage. 1. I m p r e c i s e c l o s u r e m a v lead to a c o s m e t i c deformity.

Postoperative C a r e Steroids, and, cated

heparin,

lately, in

medicinal

2. A c o m p o s i t e graft m a y be lost if it is t o o large

antibiotics,

pie-crust

leeches

all

have

the care of the reimplanted

lous w o u n d

care with

pinna.

bacitracin and

incisions

been

advo-

Meticu-

( > 1.5 c m ) . 3. A p i n n a m a y " c u p " after a w e d g e resection if w e d g e s of skin a n d cartilage are not r e m o v e d a l o n g the anthelical

fold.

Adaptic gauze

is n e c e s s a r y . Often there is de-epithelialization of the amputated

part,

pinna usuallv can

but

with

gentle

re-epithelialize.

debridement

the

If the reimplanta-

Instruments

tion is s u c c e s s f u l , t h e patient m u s t be c a u t i o n e d that the n e w circulation

may

be immediately exposed

not be resilient e n o u g h

to

to extremes of temperature

T h e i n s t r u m e n t s listed b e l o w form the basics of a p l a s t i c s tray u s e d for m o s t soft t i s s u e s u r g e r y o f the

or injudiciously exposed to the sun.

head

and

neck.

T h e s e i n s t r u m e n t s will b e u s e d

for

t h e p r o c e d u r e s d e s c r i b e d i n the rest o f this c h a p t e r .

Neoplasms of the Pinna

No. 11 and No Medium and 0.5-mm

The

pinna

s q u a m o u s cell lignant

is

a

frequent

site

carcinomas and,

melanomas.

All

but

ophtnalmic

forceps

cell

and

Brown-Adson

frequently,

ma-

No. 3 single or double skin h o o k s .

of

less

15 scalpel blades and handles

fine n e e d l e holders.

basal

shaved,

punched,

forceps.

or

No. 2 S e n n retractors.

curetted biopsies should be repaired. T h e techniques

Storz "stitch" scissors.

349

Plastic S u r g e r y of the Pinna C u r v e d a n d s t r a i g h t iris s c i s s o r s .

harvested.

Small M e t z e n b a u m scissors

d e s c r i b e d a b o v e . T h e c o m p o s i t e graft i s t h e n s u t u r e d

T e n o t o m y scissors

in place with a minimal n u m b e r of sutures, securing

S u t u r e s : 4-0 a n d 5-0 Vicryl, 4-0 a n d 6-0 nylon, 6-0 pen.

Cotton-tipped Dressing:

donor

site

is

closed

primarily

as

the cartilage with 5-0 Vicryl a n d c l o s i n g the skin with 6-0 c h r o m i c o r nylon suture. T o o m a n y sutures can

chromic. Marking

The

applicators.

Tincture

"Fluffs,"

2-in

of

benzoin,

rolled

Steri-Strips,

bandage,

cotton

4 x 4

balls,

and

compromise

the

grafts

undergo

often

viability

of

the

graft.

epidermolysis

Composite

with

if infection is a v o i d e d .

Betadine ointment.

Pedicled

Skin

Flap.

For

larger

defects,

a

based either anteriorly or posteriorly on ricular skin (Fig.

Procedure

discolora-

tion a n d blister formation, but usually re-epithelialize

is elevated

20-5C,

D).

and sutured

skin

flap

the postau-

into the defect

If the defect has b e e n created by

resection of a n e o p l a s m or a t r a u m a t i c tissue loss, an a n t e r i o r l y b a s e d flap i s n o t feasible. T h e b l o o d s u p p l y

Depending

on

the

extent

of

the

reconstruction,

better

when

the

flap

is

based

posteriorly,

anteriorly b a s e d flaps usually do not

e p i n e p h r i n e or general anesthesia can be used

ondary

After the resection of a n e o p l a s m , be reconstructed by many methods,

the pinna can limited only by

takedown

procedure.

The

but

require a seclength-to-width

ratio i s u s u a l l y l o w (1:1 t o 2 : 1 ) b e c a u s e o f t h e c l o s e proximity of the d o n o r site. A piece of contralateral

the s u r g e o n ' s i m a g i n a t i o n and ingenuity. T h e follow-

conchal

ing discussion,

placed u n d e r the flap primarily, or secondarily w h e n

clopedic,

which

outlines

is not intended

to be ency-

the

neoplasm,

all

margins

must

ear, a n d (3) a p e d i c l e d skin/cartilage flap. l e s s t h a n 307r

When

excised,

the

especially

defect

it

it

often

involves

of the p i n n a can

be

closed

the

upper

and

m i d d l e p o r t i o n s o f t h e p i n n a ( F i g . 2 0 - 5 / 1 . B). W h e n c l o s i n g a d e f e c t p r i m a r i l y , it is u s u a l l y n e c e s s a r y to use a n v of a variety of releasing incisions along the anthelicat

fold

advancement nous

and

conchal

of adjacent

bowl

tissue.

framework of the pinna,

to

allow

T h e rigid

for

the

cartilagi-

the densely adherent

skin, and the lack of s u b c u t a n e o u s tissue hinder the closure

of even

small

defects.

Without

these

inci-

sions, closure of the defect m a y cause c u p p i n g of the pinna. Often, small w e d g e s of conchal bowl cartilage must

be

removed

obtained. 5-0

so

that

proper

Closure is accomplished

Vicryl

suture

in

the

cartilage

closure

can

be

with interrupted and a cutaneous

layer of r u n n i n g locked 6-0 c h r o m i c or interrupted 60 nylon

suture.

Composite

Graft.

can

be

o f p o s t a u r i c u l a r s k i n intact w h e n d e v e l o p i n g the flap. T h e free m a r g i n of skin on the media) surface of the

p r i m a r y c l o s u r e , (2) a c o m p o s i t e graft from the o t h e r

primarily,

cartilage

t h e flap i s t a k e n d o w n (Fig. 2 0 - 5 E ) . For s m a l l d e f e c t s

worked

T h e p i n n a can be r e c o n s t r u c t e d in t h r e e w a v s : (1)

been

costal

ular s u l c u s often c a n be p r e s e r v e d by l e a v i n g a strip

removing

Prunaru Closure.

or

the use of cartilage is not necessary. T h e postauric-

have

be e x a m i n e d histologically.

has

cartilage

well

that

ples of flap d e s i g n . After

bowl

that are b a s e d on g e n e r a l princi-

methods

over the years and

p i n n a is s u t u r e d to the free m a r g i n of the postauricular skin. sutured pinna. can

be

T h e leading edge of the elevated

flap i s

to t h e free m a r g i n of t h e lateral skin of the After

three or

separated

four w e e k s

from

the

the

pedicled

postauricular

skin

flap and

rolled a r o u n d to m a k e a n e w helical rim (Fig. 2 0 - 5 F , C ) . If t h e helical fold is not well d e f i n e d , s m a l l c o t t o n bolsters can pinna and

be

placed

sutured

in

on

the lateral

place with 4-0

surface of the nylon

to help

recreate this portion. S u b c u t a n e o u s and cartilaginous sutures

are

5-0

Vicrvl,

with

6-0 c h r o m i c or

nylon

u s e d for t h e c u t a n e o u s l a y e r . T h e d o n o r site usually can be closed primarily with extensive undermining, but a skin graft m a y be n e c e s s a r y . Defects of the conchal bowl can be closed primarily if t h e y a r e s m a l l . F o r a larger d e f e c t , a full-thickness postauricular

skin

also m a y

be

repaired

graft

works

skin flap,

w h i c h i s e l e v a t e d a n d l a i d t h r o u g h a slit

with

a

well.

Large

defects

postauricular pedicled

m a d e t h r o u g h the c o n c h a l cartilage (Fig. 2 0 - 6 / 1 ) . T h e flap is s u t u r e d anteriorly, superiorly, a n d interiorly,

Another

satisfactory

method

of

leaving the

p o s t e r i o r t h r o u g h - a n d - t h r o u g h slit ( F i g .

repairing small defects of the pinna ( n o greater than

2 0 - 6 8 ) . A f t e r t h r e e o r four w e e k s the flap i s r e l e a s e d

3 c m ) is to u s e a c o m p o s i t e graft from the o p p o s i t e

along

ear.

primarily (Fig. 2 0 - 6 C ) .

A

through-and-through

size can be harvested HCURK 2<M

is

either local anethesia with 1% lidocaine a n d 1:100,000

of the graft that is,

is usually

from

graft

up

to

the d o n o r ear.

1.5 cm

in

T h e size

half the size of the defect—

for a 2-cm defect a

1-cm c o m p o s i t e graft is

the

posterior

slit

and

the

defect

is

closed

Loss of the ear lobe can be repaired by deg a bilobed

flap b a s e d anteriorly,

w h i c h is lifted a n d

folded u p o n itself (Fig. 2 0 - 7 / 1 , B ) . T h e d o n o r site is

350

Plastic Surgery of the Pinna

FIGURE 2 0 - 6 FIGURE 2(1-5

353

Plastic S u r g e r y of the Pinna c l o s e d primarily or with a skin graft. an

interiorly based

flap is elevated

Alternatively, and

the inferior e d g e of the r e m a i n i n g pinna. to

four

weeks

the

flap

is

separated

sutured

Highlights

to

After three

interiorly

and

1. A

dumbbell-shaped

postauricular

incision

is

used.

folded u p o n itself (Fig. 2 0 - 7 C - E ) .

2. E x c e s s cauda helix is resected. 3. Excess conchal bowl cartilage is resected at the

Postoperative

Care

external

Bacitracin o i n t m e n t is applied to the incisions. light

mastoid

dressing

is

applied

to

prevent

A

auditory meatus.

Pitfalls

the

patient from disturbing the repair. T o o tight a dressing m i g h t c o m p r o m i s e the blood supply. T h e dress-

1. Collapse

of

the

external

auditory

canal

may

ing can be r e m o v e d in a few days, a n d the bacitracin

o c c u r if an insufficient a m o u n t of c o n c h a l b o w l car-

i s c o n t i n u e d for a n o t h e r d a y o r t w o .

tilage is r e m o v e d w h e n t h e c o n c h a l - m a s t o i d sutures

If a t a k e d o w n

is n e c e s s a r y , it is p e r f o r m e d after t h r e e to tour w e e k s . After

the second

stage of a

pedicled

flap

there

is

u s u a l l y e d e m a o f t h e flap s i d e o f t h e f l a p / n o r m a l s k i n

are placed. 2. Failing'to resect excess cauda helix. 3. A s h a r p - e d g e d a n t h e l i c a l fold m a y result from

interface; this m a k e s the repair more noticeable and

too d e e p

m a y take several m o n t h s to resolve.

the ear.

If, a f t e r s i x t o

nine m o n t h s , a d e p r e s s e d scar has formed (this can be especially noticeable on the helical rim), a small

crosshatching

from

the

medial

surface of

4. I m p r e c i s e m e a s u r i n g m a y result in a s y m m e t r y between

the two ears.

Z-pIasty can be p e r f o r m e d u n d e r local a n e s t h e s i a .

Instruments Otoplasty A basic plastics pack. Methylene blue dye. Excluding microtia, the two general types of congenital

A 22-gauge needle.

malformations of the pinna are lop ears and

prominent ears.

A lop ear occurs w h e n the superior

p o r t i o n of t h e h e l i c a l rim is f o l d e d d o w n like a h o o d o v e r the rest of t h e p i n n a . T h e cartilage is folded on

Procedure

itself at an acute angle. A p r o m i n e n t ear can be due t o e i t h e r t h e lack o f t h e a n t h e l i c a l fold o r a n o v e r p r o jecling conchal bowl. T h e normal angle of the ears to the skull is 30 d e g r e e s , a n d a n o r m a l projection from

the postauricular area

to the

middle one-third

General

anesthesia

commonly

is

used

since the

operation is m o s t often p e r f o r m e d on children; h o w ever, local a n e s t h e s i a can be u s e d in adults. G e n e r ally,

a

patient

with

lop or

prominent ears presents

of the helix is 17 to 20 m m . Surgical correction is

as a y o u n g c h i l d for c o r r e c t i v e s u r g e r y . O c c a s i o n a l l y ,

p e r f o r m e d w h e n a patient or parent, if the patient is

a n e w b o r n i n f a n t i s s e e n w i t h i n t h e first d a y o r t w o

a child, requests it a n d there are no medical contrain-

o f life w i t h a p r o m i n e n t o r l o p e a r , a n d i t i s p o s s i b l e

dications.

Children

are

usually

operated

on

before

to correct the defect nonsurgically. I m m e d i a t e l y after

starting school to avoid any ridicule their deformity

b i r t h m a t e r n a l e s t r o g e n s a r e still p r e s e n t i n t h e i n f a n t ,

might

w h i c h m a k e s t h e c a r t i l a g e soft a n d m a l l e a b l e ; stent-

cause

ing

of

these

deformities

in

the

neonatal

period

is

successful until the d r o p in maternal e s t r o g e n s c a u s e s

Aim

t h e c a r t i l a g e t o b e c o m e firm a n d r e s i s t a n t t o s t r u c t u r a l change. ear is

To correct the deformity present in either a lop or a p r o m i n e n t ear.

Using

formed

Steri-Strips and

ear m u s t be taped

taped in

this

and

into

cotton, proper

the

infant's

position.

The

manner for.two to three

m o n t h s ( F i g . 2 0 - 8 / 1 , B).

Text continued on page 358

354



PICURE 20-8, FIGURE 20-9.

355


FIGURE 20-11

FIGURE 20-1(1

357

.

I IU..LK J U J g C I } - III I M f J ' J l l l l c l

To correct a lop ear surgically, an incision is m a d e

the lateral s u r f a c e of the p i n n a

with a m a r k i n g pen

along the medial e d g e of the helical rim (Fig. 2 0 - 8 C ) .

(Fig. 2 0 - 1 0 / 4 ) . T h e s u r g e o n often can get a clear id a

T h e soft t i s s u e s o n b o t h s i d e s o f t h e " h o o d e d " p i n n a

of

are e l e v a t e d ,

where

the anthelical

fold

should exist by

gerl y

thus exposing the deformed

cartilage.

pressing

Vertical incisions are m a d e d o w n through

the helix

p r o n o u n c e d a n t h e l i c a l fold will a p p e a r o v e r t h e for-

all t h e w a y t o t h e c o n c h a l b o w l , a l l o w i n g t h e f o l d e d

m e r l y flat s u r f a c e o f t h e s c a p h o i d r e g i o n . A 2 2 - g a t g e

cartilage to unfold a n d

flare o u t .

A strut of conchal

the

helical

rim

toward

the

head;

the

un-

n e e d l e is p a s s e d t h r o u g h t h e lateral skin a n d cartilc j;e

bowl cartilage is sutured to the medial surface of the

and into the postauricular incision.

n e w helical rim to give m o r e s u p p o r t (Fig. 20-8D,). If

d y e is t h e n a p p l i e d to t h e n e e d l e tip a n d t h e nee< !a

e n o u g h skin is present,

is withdrawn (Fig. 2 0 - 1 0 6 ) . This marks the m e d al

with

5-0

Vicryl

and

primary closure is obtained

either

6-0

chromic

or

nylon

surface

s u t u r e s ; o t h e r w i s e a p o s t a u r i c u l a r flap like that u s e d

suture

for

repair of pinna

and

The

serves

cartilage

as a

guide

along

the

t tr

med ll

s u r f a c e of t h e p r o p o s e d a n t h e l i c a l fold is s c o r e d wi h a N o . 15 blade through the cartilage, but not throu^ h

nylon suture

the

definition

and

cartilage

sutured

help give

is elevated

the

into place. Small bolsters of cotton s e c u r e d with 4-0 (Fig.

defects

of

placement.

M e t h y l e n e bl ie

to the helical

rim

20-8E).

The

correction

of

prominent

ears

depends

on

w h e t h e r the deformity is overprojection of the concha, the

lack of an anthelical fold, or a combination of two.

both A

Most

prominent ears

have

an

element

of

wooden left

tongue blade ears

on

the

at

the

is

used

start

that s y m m e t r y can be obtained

to

of the (Fig.

measure

the

procedure

so

20-9A).

After

t h e first e a r i s f i n i s h e d , its p r o j e c t i o n i s m a r k e d o n t h e t o n g u e b l a d e a n d u s e d a s a g u i d e for t h e s e c o n d ear.

lateral

If the incisions are

surface

silk

horizontal

(Fig.

21 -

through-and-through,

u n a t t r a c t i v e a n t h e l i c a l fold r e s u l t s . 4-0

mattress

Next,

sutures

e.i

temporar/ are

place i

cartilage, a n d back out the lateral surface, u s i n g th • T e m p o r a r y stay s u t u r e s allov

the s u r g e o n to " a d j u s t " the a n t h e l i c a l fold to obtair s y m m e t r y with t h e o p p o s i t e ear (Fig. 2 0 - 1 0 D ) . W h i t ' 4-0

Ethibond

horizontal

mattress

sutures

are

the

placed on the medial surface of the cartilage through the postauricular incision (Fig.

20-10E). Care must

be taken not to exit t h r o u g h the lateral surface skin W h e n three to four sutures are in place the t e m p o r a r y

A d u m b b e l l - s h a p e d incision is m a d e on the medial s u r f a c e o f t h e p i n n a a n d t h e e l l i p s e o f skin a n d soft

silk sutures are r e m o v e d . f o r m e d (Fig.

An anthelix has n o w been

20-10F).

tissues is r e m o v e d (Fig. 2 0 - 9 8 ) . If there is only slight overprojection

of

the

concha,

conchal-mastoid

su-

With

the ear n o w in

tures of 4-0 white Ethibond are placed in a mattress

a n c e of the cauda

pattern from the mastoid periosteum

11/1,

bowl

perichondrium

(Fig.

20-9C).

to the conchal Extra

correction

B).

Excess

proper position, the appear-

helix must be assessed (Fig. projection

should

be

removed

20(bv

cutting the Cauda helix) or m o r s c l i / e d (bv scoring) so

can be obtained by removing small disks of conchal

that it lies flatter (Fig. 2 0 - 1 1 C , I ) ) .

b o w l cartilage at the c o n c h a l - m a s t o i d junction (Fig.

lateral surface of the pinna in the region of the c a u d a

2 0 - 9 D ) . A s h a r p No.

helix s h o u l d a l s o b e u n d e r m i n e d , s o that after r e s e c -

disks from

the

c a r e is taken

medial

surface of the conchal

to leave a

chondrium

intact

should

exercised

be

15 b l a d e is u s e d to s h a v e the

on

laver of cartilage a n d

the when

lateral the

surface conchal

The skin on the

bowl,

tion

of

peri-

1 he

postauricular incision is closed

with 4-0 Vicryl

and

6-0

and

Caution bowl

is

the Cauda chromic

helix or

the skin

nvlon

redrapes

sutures,

properly. a

bilateral

m a s t o i d d r e s s i n g i s a p p l i e d . T h e d r e s s i n g c a n b e lefl

brought back into proper position because the ante-

on

rior c o n c h a l b o w l c a r t i l a g e c a n p r o j e c t i n t o t h e e x t e r -

nylon sutures have been used, they can be r e m o v e d

(or o n e w e e k

lo prevent

trauma

to

the ears.

If

n a l a u d i t o r y c a n a l a n d n a r r o w it. I f t h e c a n a l i s m a d e

when

too narrow, this e x c e s s cartilage should be excised.

c a u t i o n e d a g a i n s t e n g a g i n g i n c o n t a c t s p o r t s until six

T h e anthelical fold is c o r r e c t e d through the s a m e i n c i s i o n . T h e p r o p o s e d a n t h e l i c a l fold i s o u t l i n e d o n

SECTION V

t h r o u g h the lateral s u r f a c e of the pinna, t h r o u g h th '. marks m a d e as a guide

deformities.

right and

perichondrium

10C).

the dressing is removed. T h e patient must be

w e e k s after the surgery.

Selected References

Anson

F3J

and

Donaldson

JA:

Surgical

Anatomy

of

the

Temporal

Bone,

3rd

ed.

Philadelphia, WB Saunders Co, 1981. Bailey BJ: Cochlear prosthesis implantation: R e v i e w of the issues (editorial). J A M A 251:3282, 1984. Brackman

DE:

Neurological

Surgery of Ear and

Skull

Base.

New

York,

Raven

Press,

of

Central

1982. Brant-Zawadzki

M

and

Nervous System.

Norman

N e w York,

D:

Raven

Magnetic Press,

Resonance

Imaging

the

1985.

Chakeres EW and LaMasters DL: Paragangliomas of the temporal bone: High resolution CT studies. Radiology 250:749-753, 1984. D a n i e l s D L , M i l l e n S J , M e y e r G A , e t al: M R d e t e c t i o n o f t u m o r i n the i n t e r n a l auditory canal. A J N R 8:249-252, 1987. D o y l e P J : I n d i c a t i o n s for a n d t e c h n i q u e o f e n d a u r a l a n d p o s t a u r i c u l a r i n c i s i o n s . Otolaryngol 6:262-266, 1977. Farrior J B : Incisions in tympanoplasty: A n a t o m i c considerations and indications. Laryngoscope 93:75-86, Fisch

U:

Tympanoplasty

and

1983.

Stapedectomy.

New

York,

Thieme-Stratton,

1980.

F r i e d m a n n 1: Pathology of the Ear. O x f o r d , B l a c k w e l l S c i e n t i f i c P u b l i c a t i o n s , 1 9 7 4 , G a c e k R R : T r a n s e c t i o n o f t h e p o s t e r i o r a m p u l l a r y n e r v e for t h e r e l i e f o f b e n i g n paroxysmal positional vertigo. A n n Otol Rhinol Laryngol 8 3 : 5 9 6 - 6 0 5 , 1974. Gallagher

JC:

Histology

of

the

Human

Temporal

Bone.

American

Registry

of

Pathology. Washington D C , A r m e d Forces Institute of Pathology, 1967. Goodhill

V:

Sudden

deafness

and

round

window

rupture.

Laryngoscope

81:1462-1474, 1971. Griffin C , D e L a P a z R , a n d E n z m a n n D : M R a n d C T correlation o f c h o l e s t e r o l cysts of petrous bone. A J N R 8 : 8 2 5 - 8 2 9 , 1987. House W F : Surgical considerations in cochlear implantation. A n n Otol Rhinol Laryngol 91(Suppl):15-20, 1982. H o u s e W F a n d L u e t j e C M : Acoustic Tumors, V o l s I a n d I I . B a l t i m o r e , U n i v e r s i t y Park Press, 1979. | a n s e n C: Posterior t y m p a n o t o m y : Experience and surgical details. Otolaryngol Clin North Am 5 : 7 9 - 9 6 , 1972. Latack JT,

Kartush J M ,

K e m i n k J L , e t al: E p i d e r m o i d o m a s o f t h e c e r e b e l l o -

pontine angle and temporal bone: CT and MR aspects. Radiology 157:361366, 1985. Lim DJ: H u m a n t y m p a n i c m e m b r a n e . Acta Otolaryngol 7 0 : 1 7 6 - 1 8 6 , 1970. Lim DJ: Functional m o r p h o l o g y of the lining m e m b r a n e of the middle ear and eustachian tube. An overview. A n n Otol Rhinol Laryngol 83(Suppl):5-26, 1974. Marquet

JFE

(ed):

Surgery

and

Pathology

of

the

Middle

Ear.

Boston,

Martinus

Nijhoff, 1985. Nager GT and regard

Nager M:

to the blood

Arteries of the h u m a n middle ear, supplies of the auditory ossicles.

with

particular

Ann Otol

Rhinol

Laryngol 62:923-949, 1953. Naumann

HH:

Head and

Neck Surgery.

Vol 3:

Ear.

Philadelphia,

WB

Saunders

Co, 1982. Naunton

RF:

Tympanostomy

tubes:

The

conservative

approach.

Ann

Otol

Rhinol Laryngol 90:529-532, 1981. P a p a r e l l a M M a n d S h u m r i c k D A : Otolaryngology ( V o l s .

1 and 3).

Philadelphia,

WB Saunders Co, 1988. P o r t m a n n M:

The

Ear and

Temporal

Bone.

New York,

Masson,

1979.

362

Selected

References

Index

Proceedings of the second international s y m p o s i u m a n d w o r k s h o p s on surgery ol (he inner ear ( S n n w m a s s , A s p e n , C o l o r a d o ) : Tart 2. Am J Otol 8 : 2 7 1 368, 1987. I'roctor

B:

The

development

of

the

middle

ear

spaces

and

their

surgical

significance. J Laryngol Otol 78:631-648, 1964. Proctor

B

and

Nager

CT:

The

facial

canal:

Normal

anatomy,

variations

and

anomalies. Trans Am Otol Soc 70:49, 1982. Schuknecht

HP:

Stapedectomy.

Schttknecht 1974.

HF:

Pathology

Schuknecht

14F

and

Boston, of

the

Little,

Ear.

Page numbers in italic* indicate illustrations

Brown

Cambridge,

& Co,

1971.

Harvard

University

Press,

Bone

Surgical

A

Implications.

Gulya

Philadelphia,

JA: Lea

Anatomy and

of

Febiger,

S h a m b a u g h C f i J r a n d G l a s s c o c k M E III:

the

Temporal

with

1986.

Surgery o f the Ear, 3 r d e d .

Philadelphia,

W B S a u n d e r s Co, 1980. Shea'

D,

Chole

R,

and

Paparella

MM:

The

considerations. Laryngoscope 89:88-94, Surgical

implantation

t e c h n i q u e for X o m e d

the technique of J. 1986. Swartz Wolff

JD: D,

Imaging Bellucci

Temporal

Bone.

H o u g h ) (pub.

of the Temporal RJ, New

Bone:

and

Eggston

York,

Hafner

endolymphatic

sac:

Anatomical

1979. Audiant Bone Conductor (based on

no. 5 0 - 1 5 0 0 ) . Jacksonville, X o m e d Inc, A

Text-Atlas.

AA:

Surgical

New and

Publishing Co,

York,

Thieme,

Microscopic 1971.

Anatomy

1986. of the

Abscess(es), intracranial, complicating suppurative otitis media, 194, 196 periauricular, complicating suppurative otitis media, 797, 198 Acoustic meatus, external, 5, 6 Acoustic nerve, 21 Acoustic neuromas, translabyrinthine approach for, 331-338. Sec a/so Translabyrinthine approach, for acoustic neuromas Acoustic schwannoma, intracanalicular CT and MR imaging of, 31 Adhesions/tissue, for ossicular chain grafting, 223 Adhesive otitis, tympanoplasty for, 175, 177, 178-180 Aeration lubes, transmeatal permanent, for otitis media, 171-173 Allograft, for total perforation, 233, 234 Ampullae, 20 Amputation of pinna, total, plastic surgery for, 345-347, 348 Anatomy, pertinent, 3-22 Anesthesia, for otologic procedures, 102 Annular ligament, 12 Antibiotics, prophylactic, for otologic procedures, 102 Artery(ies), of external ear, 7, 8 of inner ear, 21 of middle ear, 14, 75 Atelectatic tympanic membrane, histopathologv of, 203 tympanoplasty for, 175, 177, 178-179 Atherosclerosis screening, vascular ultrasounc for, 28, 35 Atresia, congenital. Sec Congenital atresia. Auditory canal, internal, middle fossa approach to, 93, 95-96, 97 translabyrinthine approach to, 87, 89, 90, 91 Auditory nerve, 21 Auditory tube, 12, 14 Auricle, anatomy of, 3 - 6 plastic surgery of, 339-358. See also Plastic surgery of pinna. Auricular artery, posterior, 14 stylomastoid branch of, 8 Auricular branch, of vagus nerve, 8 Auricular nerve, great, 8 Auricular rami, 8 Auriculotemporal branch, of trigeminal nerve, 8

B Basilar membrane, of osseous labyrinth, 19 Biopsv, of externa] auditory canal tumors, 153, 154 Bleeding, complicating total stapedectomy with prosthesis, 257

Bleeding (Continued) jugular bulb, complicating translabyrinthine approach for acoustic neuromas, 337 sinus, complicating translabyrinthine approach for acoustic neuromas, 337 Block method, for temporal bone removal, 39, 40 Blood vessels, of external ear, 7, 8 Bone, cortical, for ossicular chain grafting, 222 skull transcochlear approach to, 90, 92, 93, 94 temporal. See Temporal bone. Bone conduction hearing devices, surgical approach for, 2 8 1 - 2 8 5 . See also Hearing devices, bone conduction, surgical approach for. Bone plug method, for temporal bone removal, 40-41, 43 Bundle of Oort, 22 C Canalplasty, 59, 62, 63, 1 4 9 - 1 5 1 , 152 in exploratory tympanotomy, 127, 129, 130 Caroticotympanic artery, 14 Carotid artery, cervical, atherosclerosis of, vascular ultrasound screening for, 28, 35 external, posterior auricular branch of, 8 Carotid wall, of middle ear, 10 Cartilage, for ossicular chain grafting, 222 Cartilage tympanoplasty, for atrophic tympanic membrane, 173-175, 176 Ceramics, for ossicular chain grafting, 222 Cerebellopontine angle, retrolabyrinthine approach to, 82, 85, 87, 88 with vestibular nerve sectioning, for incapacitating peripheral vertigo, 307, 309, 370-317 Cerebrospinal fluid leak, complicating total stapedectomy with prosthesis, 261 Chemodectoma, of jugular foramen, MR imaging of, 32 Cholesteatoma, CT imaging of, 30 Cholesterol granuloma, of medial petrous apex, MR imaging of, 33 Chorda tympanic branch, of facial nerve, 16 Cleft ear lobe, plastic surgery for, 3 3 9 - 3 4 1 , 342 Closed-cavity tympanomastoidectomy, for otitis media, 181-183, 184 meatoplasty in, 140, 747 Coalescent mastoiditis, complicating suppurative otitis media, 192 Cochlea, 19 Cochlear aqueduct, 19 Cochlear artery, 21 Cochlear division, of vestibulocochlear nerve, 22 Cochlear duct, 20 Cochlear fossa, of middle ear, 10 Cochlear implant(s), 75, 82, 83-84 components of, 286 facial recess approach to, 54, 55-58, 59 surgical approaches for, 286-296 363

364

Index

Index

Cochlear implant(s) (Continued) surgical approaches for, mastuidotomy/ tympanotomy as 2S7

External ear (Continued) vascular supply of, 7, 8 External otitis, intractable, canalplasty for, 151, 112

Gochlcariform p r n a ^ s , in middle e« 1U 22o"'2fi

r

f

f

° ' °

r

t

y

m

p

a

n

i

c

m

^branc.

Computed tomography (CT) imaging, of temporal bone, 28, 2 9 - 3 1 , 34 Congenital atresia, 159-163 histopathology of, 163 surgical technique for, 159-163 Congenital malformations, of pinna, plastic surgery for, 3 5 3 - 3 5 8 Consent, patient, preoperative, 101-102 Cortical bone, for ossicular chain grafting, 222 Cortical mastoidectomy, for otitis media, 181 Cristae, 20 Cupula, 20

Descending artery, H Drainage, petrous, 71, 72 Drills, in operating r o o m , 107 Ductus reuniens, 20 Dura mater exposure, complicating simple mastoidectomy, 135, 137

Earlobe, cleft, plastic surgery for, 3 3 9 - 3 4 1 , 342 Elliptical recess, of osseous labyrinth, 18 Endaural approach, to external ear canal and middle car, 130-132 Endolymphatic duct, 20 Endolymphatic sac, 20 procedures on, for incapacitating peripheral vertigo, 2 9 7 - 2 9 8 , 299-301 surgery on, 47, 49, 50-51 Endosteum, of osseous labyrinth, 19 Epitympanic cells, 17 Epitympanic recess, of tympanic cavity, 9 Epitympanum, 24 Equipment, and procedures in operating room, 102-111 for temporal bone removal, 42, 43 Eustachian tube, 12, 14 Exostosis, canalplasty for, 149, 750, 151 "Exteriorized" mastoid cavity, for otitis media 191 External acoustic meatus, 5, 6 External ear, anatomy of, 3 - 8 auricle of, 3 - 6 bony features and relationships of, 3 canal of, approach to, endaural, 130-132 mastoidotomv as, 137-138 meatoplasty as, 138-140, 141 postauricular, 1 3 2 - 1 3 3 , 134 posterior tympanotomy as, 137 simple mastoidectomy as, 133, 135-137 Thiersch graft in, 140-143 transcanal, 121-127, 128. Sir ahn Transcanal approach, to external ear canal and middle ear. histopathology of, 144-145 procedure on, 149-158 stenotic, canalplasty for, 151 tumors of, 151, 153, 754-155, 156, 157-15$ innervation of, 8, 9

Facial canal, 17 facial nerve, avulsion of, complicating translabyrinthine approach for acoustic -neuromas, 337 chorda tympanic branch of, 16 decompression of, transmastoid, 58, 60-67 histopathology of, 324 in temporal bone, 17 paralysis of, complicating suppurative otitis media, 192, 194 surgery on, infratemporal, 315-324 myringotomy as, 315 middle cranial fossa approach to, 3 2 0 - 3 2 4 iranscanal approach to, 317, 379, 320 transmastoid approach to, 315-317, 318 trauma to, complicating simple mastoidectomy, 135 Facial recess approach, to cochlear implant, 54, 55-57. 58, 59 to posterior tympanotomy, 49, 5 2 - 5 3 , 54 Fallopian canal, 17 Fissula ante fenestram, 19 Fistula, perilymphatic, exploratory tympanotomy for, 2 1 0 - 2 1 3 Footplate, floating, complicating total stapedectomy with prosthesis, 260, 261 Foramen of Huschke, 3 Foramen singulare, 21 Foraminifcrous spiral tract, 2] Foreign body reaction, in operating room 104-105 Fossa of incus, 10 Fossub fenestrae cochleae, 10 Fossula fenestrae vestibuli, 10 Fossula post fenestram, 19 Fragments, depressed, complicating total stapedectomy with prosthesis, 260. 261

Gelfoani, for ossicular chain grafting, 2 2 2 - 2 2 7 Geniculate ganglion, 19 Glomus jugulare tumors, infralahyrinthine, infratemporal approach to, 327-331 Glomus tympanicum tumors, 325-327 Glossopharyngeal nerve, tympanic branch of, 14 Clues, for ossicular chain grafting, 223 Graft(s), harvesting of, for total stapedectomy with prosthesis, 249, 252. 253 Thiersch, 140-141 tympanoplasty, classification of, 219 underlay, of tympanic membrane, 62, 63, 64 Grafting, of ossicular chain, 220, 222-223 of tympanic membrane, 220, 221 Granulation tissue, debridement of, from mastoid cavity, for Thiersch graft, 141-143 Granuloma, cholesterol, of medial petrous apex, MR imaging of, 3.3

Hearing devices, bone conduction, surgical approach for, 281-285 aims of, 281 complications of, 285 procedure for, 281, 283-284. 285 Helicotrema, of osseous labyrinth, 19 Helix, spine and tail of, 4 Hematoma of pinna, plastic surgery for, 342, 343-344 Histology, 2 3 - 2 7 Hypotympanic cells, 17

Implant, cochlear, 75, 82, 83-84 facial recess approach to, 54 , 55-5S, 59 IncudomaUeal t, 12 Incus, anatomy of, 12, 13 dislocation of, complicating simple mastoidectomy, 137 complicating total stapedectomy with prosthesis, 257, 259 lesions of, tympanoplasty-ossiculoplasty for, 235, 239. 241 Incustapedial t, 12 Informed consent, preoperative, 101-102 Infralabyrinthine, infratemporal approach to glomus jugulare tumors of, 327-331 Inner ear, anatomy of, 17-22 nerves of, 2 1 - 2 2 sensorj' receptors of, 2 0 - 2 ] tumors of, 3 3 1 - 3 3 8 vascular supply of, 21 Innervation, of external ear, 8, 9 Instruments, for operating room, 105, 107, 109, 770-777 for temporal bone removal, 42, 43 Intact bridge mastoidectomy, 63, 67, 68 Intact-bridge tvmpanomastoidectomy (IBM), for otitis media, 183, 185, 786-190 Intracranial abscess, complicating suppurative otitis media, 194, 796 Intratemporal facial nerve surgery, 3 1 5 - 3 2 4 myringotomy as, 315 lontophoretic anesthesia, 102 Isthmus, 4 Iter chordae tympani posterior, 10

i Jacobson's nerve, 14 Jugular bulb bleeding, complicating translabyrinthine approach to acoustic neuromas, 337 Jugular foramen, chemodectoma of, MR imaging of, 32 Jugular wall, of middle ear, 9 - 1 0

K Keloids, plastic surgery for, 341, 343

L

Hair cells, of spiral organ, 21 l i o n ulus. 19

Labyrinth, of inner ear, 18 membranous, 19-20 osseous. 18-19

365

Labyrinthectomy, 71, 73, 7 4 - 7 5 for incapacitating peripheral vertigo, 302, 305-306, 307, 308 transcanal, 82, 85. 86 Labyrinthine artery, 21 Labyrinthine vein, 21 Labyrinthine wall, of middle ear, 10 Labyrinthitis, complicating suppurative otitis media, 194 Laceration of pinna. with tissue loss, plastic surgery for, 345 without tissue loss, plastic surgery for, 344345 Laserfs), applications of, in middle ear, 276-278 for neurotology, 2 7 8 - 2 8 0 for ossicular problems, 2 7 6 - 2 7 8 for otologic surgery, 272 for stapedotomy, 2 7 3 - 2 7 6 Lidocaine, for anesthesia, 102 Ligament(s), annular, 12 auricle, 6 mallear, 12 Limbus, 19 Lop ears, plastic surgery for, 353, 354, 358

M Maculae, 20 Magnetic resonance (MR) imaging, of temporal bone, 28, 31-34 Malleal stria, of tympanic membrane, 6 Mallear ligaments, 12 Mallear prominence, of tympanic membrane, 6-7 Malleus, anatomy of, 12, 73 lesions of, tympanoplasty-ossiculoplasty for, 235, 236-238 Malleus-to-ova window prosthesis, for stapes fixation, 263, 266, 267 Mastoid air cells, 17 Mastoid cavitv, exteriorized, for otitis media, 191 granulation tissue from, debridement of, for Thiersch grafts, 141-143 obliteration procedures for, for otitis media, 191-192, 193 skin graft of, 142, 143 Mastoid procedures, for otitis media, 177, 181, 185, 191 Mastoid wall, of middle ear, 10 Mastoidectomy, cortical, for otitis media, 181 intact bridge, 63, 67, 68 radical, 63, 67, 70, 71 modified, 63, 67, 69 for otitis media, 185, 191 simple, 44 -47, 48 as surgical approach, 133. 135-137 Mastoidectomy-tympanotomy approach, to cochlear Implant, 75, 82, 83-84 Mastoiditis, coalescent, complicating suppurative otitis media, 192 Mastoidotomy, 137-138 Mastoidotomy/tympanotomy, for cochlear implants, 287, 2 9 2 - 2 9 6 Maxillary artery, branches of, 8 Meatoplasty, 138 in closed-cavity tympano-mastoldectomy, 140, 141 in open-cavity tympano-mastoidectomy, 138-140 Membranous labyrinth, 19-20 individual components of, 20 Membranous semicircular canals, 20

366

Index

Index

Membranous wall, of middle ear, 9 Meningitis, complicating suppurative otitis media, 194 Meso tympanum, 27 Microscope, operating, 105, 107, 70S, 109 Middle cranial fossa approach, to infratemporal facial nerve surgerv, 320-324 Middle ear, anatomy of, 8 - 1 7 approach to, endaural, 130-132 mastoidotomy as, 137-138 meatoplasty as, 138 closed-cavity tympano-mastoidcctornv as, 140, 141 open-cavitv tympano-mastoidcctornv as, 138-140' postauricular, 132-133, 134 posterior tympanotomy as, 137 simple mastoidectomy in, 133, 135-137 Thiersch graft in, 140-143 transcanal, 121-127, 128. Sir also Transcanal approach, to external ear canal and middle car. auditory tube of, 12-14 dissection of, 75, 76-81 histopathology of, 144-145 laser applications in, 276-278 morphology of, 8 - 1 0 , 11 mucosal lining of, 14 nerves of, 14-16 ossicles of, 10, 12, 13 tumors of, 325-331 glomus jugulare, 327-331 glomus tympanicum as, 3 2 5 - 3 2 7 vascular elements of, 14, 15 Middle fossa approach, to internal auditory canal, 93, 95-96, 97 Modiolus, 19 Mondini's deformity, CI" imaging of, 29 Mucosal lining, of middle ear, 14 Muscle(s), of auricle, 6 Stapedius, 12 tensor tympani. 12 Myringoplasty, tvpe I l\ mp.iriopl.iMv and, 223-213 allograft in, lor total perloration. 233, 234 approach to, 223, 225. 226 for small central perforation, 225. 227-22$ overlay technique of, for central perforation. 22^. 22 K 230 underlay graft in. Un large .interim perforation, 230, 232. 231

Neurectomy, singular, for incapacitating peripheral vertigo, 302, 304 lympanic, exploratory tympanotomy for, 211, 213, 214 Neuromas, acoustic, translabyrinthine approach lor, 331 - 3 3 8 . See also Translabyrinthine approach for acoustic neuromas. Neurotology, lasers for, 278-280

O Occipital artery, 14 Open-cavity tympano-mastoidectomy, meatoplasty in, 138-140 Operating microscope. 105, 107, 108. 109 Operating room, 101-111. Sec a I fin Surgery, equipment and procedures in, 102-111 foreign body reaction in, 104-105 instruments in, 105, 107, U0-1U positioning of surgical team in, 105, /06 record of operation in, 109, 111, 111-120 skin preparation in, 103-104 surgical time in, \ \ \ Operating room cards, for instruments and materials, 109 Organ of Corti, 20 Osseous labyrinth, 18-19 Osseous spiral lamina. 19 Ossicles, anatomy of, 10, 12, 13 for ossicular chain grafting, 222 laser applications in, 276-278 problems of, combined, tympanoplastyossiculoplasty for, 240, 241, 243 Ossiculoplasty, 62, 63, 65-66 in tympanoplasty, 233, 235-243. S,v also Tympanoplasty-ossiculoplasty. Otitis, external, intractable, canalplasty for, m , 152 Otitis media. IM -2(N cartilage Ivmpanopla-l\ loi atropine IVIUCMOIC membrane lor. 173 175, J7c exleriuri/ed mastoid civilv lor, I9| lnsiop.uhology oh JW-20«î mastoid oblitération procedure lor 191-142

l

for posterior perforation in atrophic membrane. 231). 231 Myringotomy and tubes, for otitis- media, 164-171 aim of, 164 complications of, 170-171 incisions for, 165, 166-167, 168 indications for, 1 6 4 - 1 6 5 instruments for, 165 tubes in, 1 6 8 - 1 7 0 for intratempora! facial nerve surgery, 315

N Neoplasms of pinna, plastic surgery for, 347 349-353 Nerve(s), facial, decompression of, transmastoid, 58, 60-61 of externa] ear, 8, 9 Of inner ear, 21-22 of middle early, 14, 16

inaMoid procedure- in. 177. 1st. IS".. I'll m.iMoidei limn (>>i u.rtie.il | K 1 radical. I'M modilied. 1X5, I'M mucoid, histopathology of. 199 myringotomy and tubes for. 164-171. Sec al
P Pain, complicating total stapedectomy with prosthesis, 257 Paraganglioma, MR imaging of, 32 Paralysis, inlratemporal facial nerve, surgery for, 3 1 5 - 3 2 4 myringotomy as, 315 Pars fiaccida, 7 Pars tensa, 7 Patient consent, preoperative, 101-102 Periauricular abscess, complicating suppurative otitis media, 197, 198 Perilymphatic fistula, exploratory tympanotomy for, 210-213 Periosteum, of osseous labyrinth, 19 Peripheral vertigo, incapacitating, surgery for, 297-314 Petrosal artery, superficial, 14 Petrosal nerve, lesser, 16 Petrositis, complicating suppurative otitis media, 194, 195 Petrotympanic sutures, 3 Petrous apex, cells of, 17 medial, cholesterol granuloma, MR imaging of, 33 Petrous drainage, 71, 72 Petrous portion, of external ear, 3 Phalangeal cells, 20 Pharyngotympanic tube, 12, 14 Plastic surgery of pinna, 3 3 9 - 3 5 8 for amputation of pinna, total, 345-347, 348 for cleft car lobe, 3 3 9 - 3 4 1 , 342 for congenital malformations, 353-358 for hematoma, 342, 343-344 for keloids, 341, 343 for laceration with tissue loss, 345 without tissue loss, 344-345 for neoplasms, 347, 349-353 Plastics, for ossicular chain grafting. 222 Plastipore. for ossicular chain grafting. 222 Pneumati/ation, of temporal bone, lh-17 Portmann technique, for Iransmeatal permanent aeration lube insertion, 171, 172 I'osljuncular approach, to external ear canal and middle ear, 132-133, 134 Preoperative otologic evaluation, 101 Prominence, of facial canal, Ul ut lateral semicircular canal, 10 Prominent ears, plastic surgery for, 353, 355-357. 358 Promontory of middle ear, 8 prominent, complicating total stapedectomy with prosthesis, 257, 259 Prosthesis, malleus-to-oval window, for stapes fixation, 263, 266, 267 partial ossicular replacement, for malleus lesion, 235 total ossicular replacement, for combined ossicular problems, 240, 241-243 total stapedectomy with, 2 4 9 - 2 6 1 . Sec also Stapedectomy, total, with prosthesis. Pyramidal eminence, of middle ear, 10

R Radical mastoidectomy, modified, 63, 67, 69 Record of operation, 109, 111, 711-120

367

Rctrolabyrinthine approach, to cerebellopontine angle, 82, 85, 87, 88 and vestibular nerve sectioning, for incapacitating peripheral vertigo, 307, 309, 310-311 Round window, 19 Round window niche, of middle ear, 10

Saccular duct, 20 Saccule, 20 procedures on, for incapacitating peripheral vertigo, 302, 303 Scala tympani, 19 Scala vestibuli, 19 Schuknecht's method, of temporal bone removal, 39, 40-41, 43 Schwannoma, acoustic, intracanalicular CT and MR imaging of, 37 seventh nerve, MR imaging of, 34 Scutum, 9 Semicanal, for tensor tympani muscle, 10 Semicircular canals, drilling of, complicating simple mastoidectomy, 137 membranous, 20 of osseous labyrinth, 18-19 Sensory receptors, of inner ear, 20-21 Sigmoid sinus, damage to, complicating simple mastoidectomy, 137 thrombophlebitis of, complicating suppurative otitis media, 194, 196-197, 198 Silastic for ossicular chain grafting, 222 Sinus, bleeding in, complicating translabyrinthine approach for acoustic neuromas, 337 posterior, of middle ear, 10 Skin grafts, for tympanic membrane, 220, 221 preparation of, in operating room, 103-104 thin, harvesting, for Thiersch grafts, 142, 143 Skull bone, transcochlear approach to, 90, 92, 93. 94 Spherical recess, of osseous labyrinth, 18 Spine of helix, 4 Spiral ganglion, 22 Spiral ligament, of osseous labyrinth, 19 Spiral organ, 20 Spiral sulcus, internal, of osseous labyrinth, 19 Squamolympanic sutures, 3 Squamous portion, of external ear, 3 Stapedectomy, harvesting, grafts in, 249, 252, 253 making prosthesis in, 253, 254-255 problems and variations during, 257, 259-260, 261 procedure in, 253, 256, 257, 258 total, with prosthesis, 249-261 Stapedius muscle, 12 Stapedotomy, 261 laser. 2 7 3 - 2 7 6 Stapes, anatomy of, 12, 73 fixation of, in obliterative otosclerosis, 261, 262 interposition procedure for, 261, 263, 264 malleus-to-oval window prosthesis for, 263, 266, 267 stapedotomy for, 261 surgery for, 247-271 total stapedectomy with prosthesis for, 2 4 9 - 2 6 1 . Sec also Stapedectomy, total, with prosthesis, histopathology of, 268-271 lesions of, tympanoplasty-ossiculoplasty for, 240, 241

368

Index

Stapes footplate, 25 Stapes interposition, 261, 263, 264 Statoacoustic nerve, 21 Statoconic membrane, 20 Stenotic canal, canalplasty for, 15] Stria vascularis, 20 Stylomastoid branch, of posterior auricular artery, 8, 14 Subiculum, of middle ear, 10 Suction, in operating room, 107, 109 Suppurative otitis media, complications of coalescent mastoiditis as, 192 facial nerve paralysis as, 192, 194 intracranial abscess as, 194, 196 labyrinthitis as, 194 meningitis as, 194 periauricular abscess as, 197, 198 petrositis as, 194, 195 sigmoid sinus thrombophlebitis as, 194, •796-197, 198 surgery for, 192, 194-198 Suprameatal spine, 3 Suprameatal triangle, 3 Surgery, anesthesia for, 102 antibiotics for, 102 evaluation for, 101 patient consent for, 101-102 record of, 109, 111, 7 1 7 - 7 2 0 Surgical team, positioning of, in operating room, 105, 106 Surgical time, in operating room, 11]

T Tail of helix, 4 Tectorial membrane, 20 Teflon, for ossicular chain grafting, 222 Tegmen tympani, 9 Tegmental wall, of middle ear, 9 Temporal bone, dissection of, 3 7 - 9 7 procedures for, 4 4 - 9 7 canalplasty as, 59, 62, 63 cochlear implants as, 54, 5 5 - 5 5 , 59, 75. 82, 83-S4 endolymphatic sac surgery as, 47, 49, 50-57 facial recess approach to posterior tympanotomy as. 49, 5 2 - 5 3 , >-l intact bridge mastoidectomy as, 63, 67, 68 labyrinthectomy as, 71, 73 . 7 4 - 7 5 middle ear dissection as. 75, 76-81 middle fossa approach to internal auditor,' canal as, 93, 95-96, 97 ossiculoplasty as, 62, 63, 65-66 petrous drainage as, 71, 72 radical mastoidectomy as, 63, 67, 70, 71 modified, 63, 67, 69 retrolabyrinthine approach to cerebellopontine angle as, 82, 85, 87, 88 Simple mastoidectomy as, 4 4 - 4 7 , 48 transcanal'labyrinthectomy as, 82, 85, 86 transcochlear approach to skull bone as, 90, 92, 93, 94 translabyrinthine approach to internal auditory canal as. 87, 89, 90, 91 transmastoid facial nerve decompression as, 59, 60-67 underlay graft of tympanic membrane as, 62, 63, 64 facial nerve in, 17

Temporal bone (Continual) histology of, 2 3 2 7 imaging of by computed tomography, 28, 29-31, 34 by magnetic resonance, 28, 3 7 - 3 4 high resolution, 2 8 - 3 5 paraganglioma of, MR imaging of, 32 pneumatizaHon of, 16-17 removal of, 3 9 - 4 3 resection of, subtotal, 153, 755, 156 total, 136, 157-75S Tensor tympanic muscle, 12 Terminal incisure, 4 Thiersch graft, 140-143 debridement of granulation tissue from mastoid cavity for, 141-143 harvesting thin skin for, 742, 143 of mastoid cavity, 142, 143 Thrombophlebitis, sigmoid sinus, complicating suppurative otitis media, 194, 196-197, 198 Tissue adhesions, for ossicular chain grafting, 223 Transcanal approach, to external ear canal and middle car, 121-127, 128 closure in, 125 I evaluation of flaps in, 123, 124, 125 exposure of middle ear in, 125, 726 highlights of, 121 incisions in. 123, 124 injection of local anesthetic in, 123, 724 inspection and cleansing in, 121, 123 packing in, 127, 728 pitfalls in, 121 revisions in, 125, 127 to intra temporal facial nerve surgery, 317, 379, 320 to labyrinthectomy, for incapacitating peripheral vertigo, 302, 306 Transcanal labyrinthectomy, 82, 85. 86 Transcochlear approach, to skull bone, 90, 92, 93, 94 Translabyrinthine approach, to acoustic neuromas, 331-338 aim of, 331 highlights of, 331 intraoperative complications or problems with, 3 3 7 - 3 3 8 pitfalls of, 331 procedure for, 331-337 to internal auditory canal, 87, 89, 90, 9? Transmastoid approach, to infratemporal facial nerve surgery, 315-317, 378 to labyrinthectomy, for incapacitating peripheral vertigo, 307, 308 Transmastoid labyrinthine dissection, 71, 73, 74-75 r

Transmeatal permanent aeration tubes, for otitis media, 171-173 Transmoid facial nerve decompression, 59, 60-61 Transverse crest of fundus, 21 Trigeminal nerve, auriculotemporal branch of, 8 Tumor(s), external auditory canal, 151, 153, 754-155, 156. 757-758' inner ear, 331-338 middle ear, 325-331 glomus tympanicum, 325-327 glomus jugulare, 327-331 of pinna, total, plastic surgerv for, 347, 349-353 Tympanic artery. 14

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