Atlas of Acoustic Neurinoma Microsurgery Mario Sanna, MD Abdelkader Taibah, MD Professor ofOtolaryngology GruppoOtologico DepartmentofHeadandNeckSurgery CasadiCura“Piacenza” UniversityofChieti PiacenzaandRome,Italy Chieti,Italy GruppoOtologico Maurizio Falcioni, MD PiacenzaandRome,Italy GruppoOtologico CasadiCura“Piacenza” Fernando Mancini, MD PiacenzaandRome,Italy GruppoOtologico CasadiCura“Piacenza” Giuseppe Di Trapani, MD PiacenzaandRome,Italy GruppoOtologico OspedaleKoelleker CasadiCura“Piacenza” Turin,Italy PiacenzaandRome,Italy Alessandra Russo, MD GruppoOtologico CasadiCura“Piacenza” PiacenzaandRome,Italy Withthecollaborationof MasashiHamada,KevinChong,GiuseppeDeDonato,EnricoPiccirillo,AntonioCaruso,LorenzoLauda, GruppoOtologico,Piacenzaand Rome,Italy;RobertoRizzoli,CasadiCura“Piacenza”,PiazenzaandRome,Italy 2nd edition 1007illustrations Thieme Stuttgart·NewYork IV LibraryofCongressCataloging-in-PublicationDataisavailablefromthepub- Importantnote:Medicineisanever-changingscienceundergoingcontinual lisher. development.Researchandclinicalexperiencearecontinuallyexpandingour knowledge,inparticularourknowledgeofpropertreatmentanddrugtherapy. 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ISBN978-3-13-110282-9 123456 V Preface Aspatients’requirementsofthequalityofsurgicalproceduresare only otologists. It is important to note that if two surgeons of increasing,thetechniquesofsurgeryshouldalwaysbeevolvingin different specialties are involved in a team, both of them must ordertoprovidebetteroutcomes.Nowhavingperformedalmost knowhowtoperformallthestepsfromsettingtoclosure.Allthe 3500proceduresonposteriorfossalesionsandmorethan2000 surgeons mustknowalltheapproachesthat can be appropriate onacousticneurinomas,wefeelstronglythatweneedtoupdate for the patient with an acoustic neurinoma. In other words, we the techniques as well as the results obtained with this kind of mustapplythebestproceduretoourpatients,nottheopposite,as surgery. requiredbyatrueindividualizedmanagement. ThesecondeditionofAtlasofAcousticNeurinomaMicrosurgery Webelievethatthisnewbookwillbeofgreathelptoallreaders comestofruition10yearsafterthefirstedition.Duringthepast inbecoming and beingspecialistsand performingexcellentsur- decade we have introduced some technical modifications into geryonpatientswithacousticneurinoma. acoustic neurinoma microsurgery and in this second edition we I would like to acknowledge my gratitude to Dr. Alessandra haveattemptedtodevotemorepagestotheserefinements. Russo,Dr.AbdelkaderTaibah,Dr.MaurizioFalcioni,andDr.Giu- Wehaveaddedtwonewchaptersinresponsetorequeststhat seppe Di Trapani, who have associated with me for many years have been made over that period. Since the role of functional andco-authoredtheelaboratedworkpresentedinthisbook;the surgery has become established, intraoperative monitoring of many discussions and analyses of our work that we shared to- thefacialnerveandthecochlearnerveisnowessentialinremoval getherasateamareacrucialpartofthisedition. of acoustic neurinoma. Great technological advance in implant- I would like to thank Dr. Fernando Mancini for his beautiful able devices(i.e., cochlear and brainstemimplants)hasallowed illustrations,whichhavecontributedsignificantlytothedidactic deafpatientstoregainhearing.Inthelightofthesechanges,we power of this book. My thanks extend to Dr. Masashi Hamada canoffermoretreatmentoptionstopatientswithneurofibroma- from Japan and Dr. Kevin Chong from Singapore, who initially tosistype2andpatientswithneurinomaintheonlyhearingear, started the project. Thanksalsogoto thosewhohavehelped to situations that have long bothered both patients and surgeons. prepare this book: Dr. Giuseppe De Donato, Dr. Enrico Piccirillo, Thesechangeshave,furthermore,introducednewconceptsinthe Dr.AntonioCaruso,andDr.LorenzoLauda,whohavebeenwork- policyoffollow-up,whichhaschangedfromasimplewait-and- ingwithmeinthisgroupformanyyears. scanroute. Throughouttherehavebeenmanyothers,allofmyclinicaland TheinitialmilestoneofskullbasesurgerywaslaidbyWilliam researchcolleagues,whohavemadeinformalcontributions:my House together with William Hitselberger. They pioneered and thankstothemallfortheirresearchprojectsandtheirpersistent systematizedthetechniquesneededforremovalofacousticneu- questioning in thepursuitand gaining ofknowledge.Thanksgo rinomas and made the way for future generations to develop alsototheeditorialstaffofThiemePublishersfortheirexcellent subsequent advances. Acoustic neurinomas nowadays represent cooperationandcongenialityinhelpinginpreparingthisbook. a specialist field of pathology. Surgeons treating this pathology Finally, Iwould liketothank and dedicatethisbook to allthe mustbespecialists,whetherotolaryngologistsorneurosurgeons. families of the people who have kindly agreed to their photo- Additionally,removalofacousticneurinomaistobeperformedby graphsbeingusedforeducationalpurposes.Theirhelphasmade ateam,inwhichtwoormoresurgeonsshouldbeinvolved.The ourworkpossible. ideal may be a team consisting of one otologist and one neuro- surgeon at minimum, but this is not absolutely necessary – our workdemonstratedherehasbeenachievedbyateamincluding MarioSanna,MD VII Contents 1 GeneralFeaturesofAcousticNeurinomas . . . . . . . . . . . . 1 Drills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Pathogenesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 BipolarCoagulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Epidemiology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Microinstruments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 NaturalHistory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 PostoperativeManagement. . . . . . . . . . . . . . . . . . . . . . . 38 SignsandSymptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 PostoperativeMedication . . . . . . . . . . . . . . . . . . . . . . . . 38 HearingLoss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Discharge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Tinnitus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Disequilibrium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 SurgeryintheCerebellopontineAngle:GeneralConcepts 40 CerebellarDysfunction. . . . . . . . . . . . . . . . . . . . . . . . . . . 2 SurgicalOrientationintheCerebellopontineAngle . . . . . . 40 TrigeminalNerveInvolvement . . . . . . . . . . . . . . . . . . . . . 2 InternalAuditoryCanal. . . . . . . . . . . . . . . . . . . . . . . . . . 40 FacialNerveInvolvement . . . . . . . . . . . . . . . . . . . . . . . . . 2 CerebellopontineAngle. . . . . . . . . . . . . . . . . . . . . . . . . . 41 LowerCranialNerveandBrainstemFindings . . . . . . . . . . . 2 FacialNerve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 HydrocephalusandHeadaches . . . . . . . . . . . . . . . . . . . . . 3 SurgicalTechniquesintheCerebellopontineAngle . . . . . . 44 GeneralGuidelinesforDrilling. . . . . . . . . . . . . . . . . . . . . 44 2 ImagingStudyofAcousticNeurinomas . . . . . . . . . . . . . 4 ManagementofBleeding. . . . . . . . . . . . . . . . . . . . . . . . . 44 TumorAssessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 HowtoDealwithBrainTissueandOther MagneticResonanceImaging . . . . . . . . . . . . . . . . . . . . . . 4 NeurovascularStructures. . . . . . . . . . . . . . . . . . . . . . . . . 45 ComputedTomography . . . . . . . . . . . . . . . . . . . . . . . . . . 15 HowtoObtainBetterAccesstotheTumor . . . . . . . . . . . . 46 DifferentialDiagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 TechniquesofTumorDissectionandRemoval . . . . . . . . . . 47 NeurofibromatosisType2 . . . . . . . . . . . . . . . . . . . . . . . . 15 OtherTumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6 IntraoperativeMonitoring . . . . . . . . . . . . . . . . . . . . . . 52 ResidualTumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 FacialNerveMonitoring . . . . . . . . . . . . . . . . . . . . . . . . . 52 TherapeuticFollow-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 PostoperativeScans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 WaitandScan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 PurposesofIntraoperativeFacialNerveMonitoring. . . . . . 54 3 DecisionMakinginAcousticNeurinomaSurgery. . . . . . . 25 LocalizationoftheFacialNerve(Mapping) . . . . . . . . . . . . 54 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 IdentificationoftheFacialNerve . . . . . . . . . . . . . . . . . . . 54 SurgicalversusNonsurgicalTreatment. . . . . . . . . . . . . . . . 25 MinimizationofNeuralTrauma . . . . . . . . . . . . . . . . . . . . 55 SmallNeurinomas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Artifacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 AcousticNeurinomaintheOnlyHearingEar . . . . . . . . . . . 25 ConfirmationoftheFunctionalIntegrityoftheNerve . . . . 56 AcousticNeurinomainPatientswithPoorGeneral ConcludingConsiderations . . . . . . . . . . . . . . . . . . . . . . . 56 Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 CochlearNerveMonitoring . . . . . . . . . . . . . . . . . . . . . . . 56 Radiosurgery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 ManagementofthePatientwithSerious Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 NeurologicalDisorders . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 ConcludingConsiderations . . . . . . . . . . . . . . . . . . . . . . . 59 ManagementofElderlyPatients . . . . . . . . . . . . . . . . . . . . 26 SelectingtheSurgicalApproach . . . . . . . . . . . . . . . . . . . . 27 7 TheTranslabyrinthineApproaches. . . . . . . . . . . . . . . . . 60 TranslabyrinthineversusHearingPreservationSurgeries . . 27 TheEnlargedTranslabyrinthineApproach . . . . . . . . . . . . . 60 TotalversusSubtotalRemoval . . . . . . . . . . . . . . . . . . . . . 29 Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 4 OperatingRoomSetupandPatientCare. . . . . . . . . . . . . 31 Contraindications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 OperationRoomSetup. . . . . . . . . . . . . . . . . . . . . . . . . . . 31 SurgicalAnatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 SurgicalTechnique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Arrangement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 ClinicalApplication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Instruments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 SuctionIrrigation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 VIII Contents EnlargedTranslabyrinthineApproachwithTransapical 10 TranscochlearApproaches . . . . . . . . . . . . . . . . . . . . . . 205 Extension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 TransoticApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 SurgicalAnatomy(RightEar). . . . . . . . . . . . . . . . . . . . . . 94 Contraindications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 SurgicalTechnique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 SurgicalAnatomy(RightEar) . . . . . . . . . . . . . . . . . . . . . . 206 ClinicalApplication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 SurgicalStepsoftheBlind-Sac(Cul-de-Sac)Closure PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 (LeftEar). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 SurgicalTechniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 SpecialConsiderationsintheTranslabyrinthineApproach. . 114 ClinicalApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 AnatomicalVariations. . . . . . . . . . . . . . . . . . . . . . . . . . . 114 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 ManagementofSurgicalMishaps. . . . . . . . . . . . . . . . . . . 123 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 ManagementofNervesandVesselsaroundtheTumor . . . 124 ModifiedTranscochlearApproach . . . . . . . . . . . . . . . . . . . 232 SpecificCharacteristicsoftheTumor . . . . . . . . . . . . . . . . 136 Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 Contraindications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 SurgicalAnatomy(RightEar) . . . . . . . . . . . . . . . . . . . . . . 232 8 CombinedRetrosigmoid–RetrolabyrinthineApproach. . . 142 SurgicalTechnique. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 ClinicalApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236 Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 Contraindications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 SurgicalAnatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 SurgicalDissectionDemonstratingtheCombined Retrosigmoid–RetrolabyrinthineApproach(LeftEar) . . . . . 143 11 ManagementinSpecialSituations . . . . . . . . . . . . . . . . 244 SurgicalTechniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 CurrentStrategyforNeurofibromatosisType2: AccesstotheTumor(RightEar). . . . . . . . . . . . . . . . . . . . 148 TotalRemovalwithaConcomitantCochlearorBrainstem TumorRemoval(LeftEar) . . . . . . . . . . . . . . . . . . . . . . . . 150 Implant. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 ClinicalApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 NeurofibromatosisType2 . . . . . . . . . . . . . . . . . . . . . . . . 244 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 ClinicalDiagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 ClinicalManifestationsofDisease . . . . . . . . . . . . . . . . . . . 245 Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 Disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 DecisionMaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 BrainstemImplantationinNeurofibromatosisType2 . . . . . 248 ClinicalApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 ManagementofAcousticNeurinomainthe 9 EnlargedMiddleCranialFossaApproach . . . . . . . . . . . . 176 OnlyHearingEar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 ClinicalApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 Contraindications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 SummaryofAuditoryBrainstemImplants . . . . . . . . . . . . . 266 SurgicalAnatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 TechniqueforIdentificationoftheInternalAuditoryCanal . 178 House’sMethod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 Fisch’sMethod(MeatalPlaneApproach). . . . . . . . . . . . . . 178 12 FacialNerveReanimation . . . . . . . . . . . . . . . . . . . . . . 268 Garcia-Ibanez’sMethod. . . . . . . . . . . . . . . . . . . . . . . . . . 179 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 OurMethod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 SurgicalDissectionDemonstratingtheMiddleCranial End-to-EndAnastomosis . . . . . . . . . . . . . . . . . . . . . . . . . . 268 FossaApproach(LeftEar) . . . . . . . . . . . . . . . . . . . . . . . . 180 KeystoSuccessfulResults . . . . . . . . . . . . . . . . . . . . . . . . 268 SurgicalTechniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 InterpositionGraft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 SpecialPositioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 ClinicalApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 SurgicalStepsuptotheInternalAuditoryCanal(RightEar). 184 HarvestingtheSuralNerveGraft. . . . . . . . . . . . . . . . . . . . 282 ExposureoftheInternalAuditoryCanal(RightEar). . . . . . 187 HypoglossofacialNerveAnastomosis. . . . . . . . . . . . . . . . . 283 TumorRemoval(RightEar) . . . . . . . . . . . . . . . . . . . . . . . 189 AnatomyoftheHypoglossalNerve . . . . . . . . . . . . . . . . . . 283 Closure(RightEar) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 SurgicalApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 ClinicalApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 PearlsandPitfalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Contents IX 13 TheRoleofEndoscopyinAcousticNeurinomaSurgery . 286 CerebrospinalFluidLeakage . . . . . . . . . . . . . . . . . . . . . . 298 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 Meningitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 BrainEdema. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Sterilization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 CranialNerveDefects . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 EndoscopicSurgicalAnatomy . . . . . . . . . . . . . . . . . . . . . . 286 Ataxia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 FromthePosteriorAspectoftheTemporalBone: Hydrocephalus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 RetrosigmoidApproach . . . . . . . . . . . . . . . . . . . . . . . . . . 286 AirEmbolism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 ThroughtheSuperiorSurfaceoftheTemporalBone: Pneumocephalus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 MiddleFossaApproach . . . . . . . . . . . . . . . . . . . . . . . . . . 288 Headaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 TheTechniqueofEndoscopy . . . . . . . . . . . . . . . . . . . . . . . 289 PostoperativeUnsteadiness . . . . . . . . . . . . . . . . . . . . . . . 300 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 Tinnitus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 TranslabyrinthineApproach . . . . . . . . . . . . . . . . . . . . . . . 289 NonspecificComplications . . . . . . . . . . . . . . . . . . . . . . . . 300 RetrosigmoidApproach . . . . . . . . . . . . . . . . . . . . . . . . . . 293 AtelectasisandPneumonia . . . . . . . . . . . . . . . . . . . . . . . 300 EnlargedMiddleFossaApproach. . . . . . . . . . . . . . . . . . . . 293 DeepVenousThrombosisandPulmonaryEmbolism . . . . . 301 RisksofCerebellopontineAngleEndoscopy . . . . . . . . . . . . 294 WoundInfectionandHematoma . . . . . . . . . . . . . . . . . . . 301 Transfusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 14 ComplicationsandManagement . . . . . . . . . . . . . . . . . 295 Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 PostoperativeComplicationsSpecifictoCerebellopontine AngleSurgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 Hemorrhage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 Infarction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296