Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Otology, Neurotology, and Skull Base SURGERY Clinical Reference Guide Theodore R. McRackan, MD Derald E. Brackmann, MD Contents Foreword by Harold C. Pillsbury, MD xi Introduction xiii Acknowledgmentsxv About the Editors xvi Contributors xvii Section I History of Neurotology 1 Chapter 1 History of Neurotology and Skull Base Surgery Lawrence R. Lustig 3 Section II Embryology Anatomy Physiology 13 Chapter 2 Embryological Development of the Ear Theodore R. McRackan and George B. Wanna 15 Chapter 3 Anatomy and Physiology of the Auditory System Gregory J. Basura and Steven A. Telian 23 Chapter 4 Anatomy and Physiology of the Vestibular System Gregory T. Whitman and Timothy C. Hain 33 Section III Evaluation 45 Chapter 5 The Neurotologic Examination Stanley Pelosi 47 Chapter 6 Hearing Assessment René H. Gifford 55 Chapter 7 Vestibular Testing Yuri Agrawal 67 Chapter 8 Intraoperative Monitoring Christopher K. Giardina and Oliver F. Adunka 75 Section IV Common Otologic Symptoms 83 Chapter 9 Tinnitus Theodore R. McRackan and John C. Goddard 85 v vi Otology, Neurotology, and Skull Base Surgery: Clinical Reference Guide Chapter 10 Otalgia and Temporomandibular Joint Disorders Jason A. Beyea and Aaron C. Moberly 93 Section V Hearing Loss 99 Chapter 11 Congenital and Genetic Hearing Loss Seiji B. Shibata and Richard J. Smith 101 Chapter 12 Otosclerosis Felipe Santos and Michael J. McKenna 111 Chapter 13 Presbycusis Simon I. Angeli 119 Chapter 14 Noise-Induced Hearing Loss Brian S. Chen and William M. Luxford 125 Chapter 15 Traumatic Injuries to the Ear Bradley W. Kesser 131 Chapter 16 Autoimmune Inner Ear Disease M. Jennifer Derebery 141 Chapter 17 Sudden Sensorineural Hearing Loss David S. Haynes and Jacob B. Hunter 149 Chapter 18 Ototoxicity Joseph T. Breen and Jeffrey T. Vrabec 157 Chapter 19 Rare Causes of Hearing Loss Oliver F. Adunka and Craig A. Buchman 169 Section VI Otologic Infections 177 Chapter 20 Otitis Externa Theodore R. McRackan and Marc L. Bennett 179 Chapter 21 Otitis Media Sujana S. Chandrasekhar 187 Chapter 22 Cholesteatoma Brendan P. O’Connell and Ted A. Meyer 197 Chapter 23 Petrous Apicitis and Intracranial Infection Anthony Myint, Joel Lavinsky, John L. Go, and Rick A. Friedman 209 CONTENTS vii Section VII Hearing Rehabilitation 221 Chapter 24 Hearing Aids Monica M. Andriacchi and John W. House 223 Chapter 25 Implantable Hearing Devices Sohit Kanotra and Moises A. Arriaga 233 Chapter 26 Cochlear Implants Robert F. Labadie 247 Chapter 27 Auditory Brainstem Implants Daniel S. Roberts and Eric P. Wilkinson 259 Section VIII Skull Base Disorders 267 Chapter 28 Skull Base and Intracranial Anatomy C. Eduardo Corrales and Robert K. Jackler 269 Chapter 29 Vestibular Schwannoma Theodore R. McRackan and Derald E. Brackmann 281 Chapter 30 Meningiomas Colin L. W. Driscoll 291 Chapter 31 Neurofibromatosis Type II Brian S. Chen and William H. Slattery III 301 Chapter 32 Stereotactic Radiosurgery in Neurotology P. Ashley Wackym, Andrew Y. Kee, and Norman Jed Schroeder 309 Chapter 33 Temporal Bone Malignancy Paul W. Gidley 321 Chapter 34 Jugular Foramen Lesions Theodore R. McRackan and James L. Netterville 331 Chapter 35 Lesions of the Cerebellopontine Angle and Petrous Apex David R. Friedmann, J. Thomas Roland, Jr., and Sean O. McMenomey 341 Chapter 36 Cerebrospinal Fluid Leaks and Encephaloceles Jeffrey D. Sharon and Howard W. Francis 351 viii Otology, Neurotology, and Skull Base Surgery: Clinical Reference Guide Chapter 37 Complications from Neurotologic Surgery Marc S. Schwartz 361 Section IX Vestibular Disorders 371 Chapter 38 Bedside Vestibular Evaluation Evan Graboyes and Joel Goebel 373 Chapter 39 Ménière’s Disease Cameron C. Wick, Maroun T. Semaan, and Cliff A. Megerian 389 Chapter 40 Benign Paroxysmal Positional Vertigo Judith A. White 401 Chapter 41 Superior Semicircular Canal Dehiscence Syndrome 409 Heather M. Weinreich and John P. Carey Chapter 42 Labyrinthitis and Vestibular Neuronitis Edward I. Cho 419 Chapter 43 Vestibular Migraine Michael Thomas Teixido 427 Chapter 44 Nonotologic Causes of Dizziness Timothy C. Hain and Marcello Cherchi 439 Chapter 45 Vestibular Therapy Elizabeth Grace Georgelos 449 Section X Facial Nerve 459 Chapter 46 Embryology and Anatomy of the Facial Nerve Matthew L. Carlson and Alex D. Sweeney 461 Chapter 47 Electrodiagnostic Testing of the Facial Nerve Joseph P. Roche and Marlan R. Hansen 473 Chapter 48 Acute Facial Nerve Palsy Joseph P. Roche and Bruce J. Gantz 481 Chapter 49 Primary Facial Nerve Tumors Alejandro Rivas and Theodore R. McRackan 493 Chapter 50 Facial Nerve Rehabilitation Caroline A. Banks and Tessa A. Hadlock 501 CONTENTS ix Section XI Pediatric Otology 511 Chapter 51 Hearing Loss Syndromes Lourdes Quintanilla-Dieck and Steven Goudy 513 Chapter 52 Congenital Aural Atresia Paul R. Lambert 525 Section XII Other Otologic Considerations 531 Chapter 53 Otologic Manifestations of Systemic Disorders J. Eric Lupo 533 Chapter 54 External Auditory Canal Lesions Elliott D. Kozin and Daniel J. Lee 545 Chapter 55 On the Horizon Justin S. Golub and Ravi N. Samy 553 Index 563 Foreword This remarkable text, edited by Drs. McRackan and Brackmann, is a significant addition to our armamentarium of references in the field of otology, neurotology, and skull base surgery. The chapters are well-written and encompass the scope of the subspecialty. Each author is a well-recognized expert in their field and the format of the chapters by outline is extremely easy to follow. It is an outstanding reference for residents, fellows, and practicing otolaryngologists as well as neurotologists. The text is simplistic and easily addresses any question that may arise in the mind of the reader. This is clearly a reference guide. No attempts have been made to increase the prose to describe the topics, but that is not to say that the key issues are hard to assess using the format. The editors are to be commended in formulating a text that is extremely user-friendly to the reader. In these days where the majority of information we seek is available on the Internet, this particular book will be a completely different offering that will be a welcome addition to anyone’s library. I look forward to receiving my copy!!! — Harold C. Pillsbury, MD Professor and Chief Otolaryngology-Head and Neck Surgery The University of North Carolina at Chapel Hill xi Chapter 29 Vestibular Schwannoma Theodore R. McRackan and Derald E. Brackmann Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282 Epidemiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282 Pathophysiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282 Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 Diagnosis and Evaluation . . . . . . . . . . . . . . . . . . . . . . 284 Natural History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 Observation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 Microsurgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 Radiosurgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 281 282 Otology, Neurotology, and Skull Base Surgery: Clinical Reference Guide Nomenclature • Virchow named lesion neuroma due to parallel fibers on histology appear to be axons • Initially thought to be cochlear origin due to associated hearing loss • Murrey and Stout discovered origin cell to be Schwann cell • Preferred name is currently vestibular schwannoma (VS) although acoustic neuroma is still widely used Epidemiology • Represent approximately 6% of all intracranial tumors • Prospective Denmark database estimate approximately 20 VS per 1 million population • Incidence increasing due to awareness and improved imaging access and quality 1. 7.8 VS/million 1976 to peak 23 VS/million year 2004 • Tumor size at time of diagnosis has decreased from 30 mm in mid1970s to current 10 mm • Mean age at diagnosis has also decreased from 58 years to 49 years Pathophysiology • Arise from vestibular division of eighth cranial nerve 1. More commonly the inferior vestibular nerve • VS do not likely arise from Obersteiner-Redlich transition zone (glialschwannian junction) as initially thought 1. Most tumors form lateral to the Obersteiner-Redlich transition zone; oligodendrocytes produce myelin medial to junction and Schwann cells lateral 2. Greatest density of Schwann cells lies at Scarpa’s ganglion; VS likely arise from Schwann cell population associated with the Scarpa’s (vestibular) ganglion; like VS, Scarpa’s ganglion can lie near junction but also at various locations • Understanding of genetic origins of sporadic VS is still uncertain; tumor biology is mostly understood through studying Neurofibromatosis type II (see Chapter 31) • There are two histological patterns; Antoni A are densely packed cells with an organized whirled appearance (Verocay body); Antoni B are more loosely packed collection of vacuolated pleomorphic cells; Antoni B may occur more frequently in large tumors 1. Stain positive for S-100 CHAPTER 29 Vestibular Schwannoma 283 Presentation • Hearing loss is most common presenting symptom and present in 95% of patients 1. Typically gradual onset unilateral sensorineural hearing loss 2. During clinical course up to 26% of patients report sudden onset SNHL 3. Normal hearing patients are more likely to have tumors <1 cm • AAO-HNS has standardized hearing reporting in VS (Table 29–1) • Vertigo/dysequilibrium is most common presentation in patients with normal hearing 1. Occurs in 20–50% of patients 2. Vertigo typically occurs relatively early in symptomology due to peripheral nerve disturbance but can spontaneously resolve 3. Dysequilibrium typically occurs late in course due to cerebellar involvement 4. Due to slow rate of tumor growth, majority of patients compensate • Tinnitus reported in 53–70% of patients 1. Variable in nature 2. Asymmetric tinnitus without hearing loss should warrant investigation for retrocochlear pathology • Trigeminal nerve symptoms occur in approximately 20% of patients 1. Most commonly malar hypesthesia or parasthesia a. Can result in absent or decreased corneal reflexes b. Very rare in tumors <1 cm, but occurs in 20% of patients with 1–3 cm tumors and 50% in tumors larger than 3 cm 2. Given high prevalence of headache in general popular, hard to establish association with acoustic neuromas; vestibular schwannoma-related headaches are likely dull with mild to moderate intensity Table 29–1. American Academy of Otolaryngology-Head and Neck Surgery Hearing Classification after VS Surgery Hearing Class PTA SDS A ≤30 ≥70% B 31–50 50–71% C >50 >50% D Any <50% Note. PTA = pure-tone average; SDS = speech discrimination score. 284 Otology, Neurotology, and Skull Base Surgery: Clinical Reference Guide • Facial nerve (FN) dysfunction is relatively uncommon (<10% of patients) 1. Can present as facial twitching or paralysis/paresis 2. Either symptom should raise concern for primary facial nerve tumor • Late symptoms are much less common today due to early detection 1. Increased intracranial pressure from hydrocephalus can result in nausea/emesis, diplopia, papilledema, and lethargy to obtundation 2. Lower cranial nerve symptoms of hoarseness, dysphagia, and dysarthria are rare in modern era Diagnosis and Evaluation • Audiologic evaluation 1. Pure-tone audiogram (PTA) and speech discrimination scores (SDS) show wide variability from normal to no response 2. Rollover (worsened SDS with increasingly loud presentation) and acoustic reflex decay (acoustic reflex fades during prolonged presentation of signal) were once thought to be good markers for retrocochlear pathology; over time these have been found to be poorly reliable • Auditory brainstem response (ABR) testing 1. Attractive as screening tool because it is noninvasive, inexpensive, and rapid 2. The interaural wave I to V latency difference (IT5) is most reliable screening measure for VS; latency of 0.2 ms or more is considered abnormal 3. Sensitivity ranges from 63–95% a. Highest sensitivity with tumors larger than 2 cm (100%) b. Decreased to 60% with tumors less than 1 cm 4. Stacked ABR increases sensitivity to 95% for all tumors • Electronsytagmography 1. Abnormal results in 98% of superior vestibular tumors and 60% inferior vestibular nerve tumors 2. Reduced ipsilateral caloric response and spontaneous nystagmus to contralateral side are common findings 3. Wide variety of findings in larger tumors including: abnormal saccadic pursuit, bilateral horizontal gaze nystagmus, and failed fixation suppression 4. Can be used to help identify vestibular nerve of origin in planning for hearing preservation surgery for middle cranial fossa surgery (discussed later) CHAPTER 29 Vestibular Schwannoma 285 • Magnetic Resonance Imaging 1. Isotense or hypotense on T1 and T2, but enhance with gadolinium 2. VS are centered on IAC, have spherical shape without dural attachment or hyperostotic adjacent bone 3. Up to 100% sensitivity and specificity in modern era with gadolinium 4. Able to accurately display size, location, depth of penetrance into IAC (discussed later for hearing preservation surgery) 5. Heavily T2 weighted fast spin-echo series can help identify location of facial nerve (FN) nerve with regard to the VS a. This series can also identify VS with 98–100% sensitivity and 99.5–100% specificity without gadolinium Natural History • Determination of tumor growth varies based on study; some define intracanalicular tumor growth as growth to extrameatal tumor whereas others simply define tumor growth as growth in any dimension by 2 mm; most precise gauge is volumetric analysis • Difficult to determine true VS growth rates as larger tumors are intervened upon and not included in natural history studies; therefore, there is an inherent bias toward decreased growth rates • Collected data in meta-analyses show approximately 50% of VS grow (data ranges from 6–73% in literature) • Mean growth rates in all VS 1–2 mm/year; this rate increases to 2–4 mm/year in those tumors with proven growth • Majority of studies show no relationship between gender, age, duration of symptoms, initial hearing level, and laterality and likelihood of VS growth 1. Multiple studies have shown that VS larger than 2 cm have increased propensity to grow 2. Some evidence exists for increased growth rates of extrameatal compared to intrameatal tumors Treatment • Overall goal is to maintain patient quality of life and intervene when the decrease in quality of life from treatment outweighs the effects of further tumor growth