5 1960 Mortality rate in California: 43.5% Olivecrona (Sweden)：414 cases small tumors: 4.5%large tumors: 22.5%Facial paralysis: 50%
6 Dr. W. House （1961-） Middle fossa approach (1961) Traslab approach (1962)
7 OriginDevelopment in the internal acoustic meatus from the schwann cells of the vestibular ganglion (Sterkers JM et al., Acta Otolaryngol., 1987)Arachnoid sheet enveloping the tumour during its expansion to the CPA.
8 Epidemiology 6 to 8 % of all intracranial tumours The most frequent (80 to 90%) of the CPA tumoursSporadic, and solitary in 95 % of casesAssociated with NF2 in 5 % of casesEstimated incidence in USA and Western Europe: 1 for 100,000 individuals per year (Kurlan et al., J neurosurg, 1958 ; Nestor JJ et al., Arch Otlaryngol Head Neck Surg, 1988)
9 REASON FOR CONSULTATION Moffat et al., 1998n = 473.Expected symptom: %(progressive HL,tinnitus,unsteadiness)Sudden hearing loss: 9.6 %Atypical presentation: 10 %..
10 MRI diagnosis Isosignal on T1, and variable aspect en T2 views Constant gadolinium enhancementIntratumoral cysts in large neurinomesNo adjascent meningeal enhancementEnlarged IAMExtension predominantly posterior to IAM
11 Differential diagnosis Other neurinomas in the CPA: 5th, 7th, or caudal cranial nerve neurinomasOther lesions:Most frequent:MeningiomasCholesteatomasRare lesions :lipomas, metastases, hemangiomas, medulloblastomas etc…..
12 Unilateral or asymetrical audio-vestibular signs : Hearing loss, vestibular syndrome, tinnitusNeurotological examinationAudiometry+ABR+VNGNormal ABR and VNGAbnormalityAge< 60 years> 60 yearsMRI + GadoliniumMRI + GadoliniumFollow-upAudio-vestibular work-upIn 6 months
13 Decisionnal factorsTumor volumeAgeHearing function
14 Therapeutic options Conservative managament Radiotherapy Surgery Varaiable tumor growthAccording to age and tumor size < 1,5 cmMRI in 6 months and then once a yearConservative managamentRadiotherapyGamma-knife, LINACVolume stabilisationHearing loss and facial paresisUnder evaluationSurgery
15 Goals of the surgery 1- Minimal vital and neurological risks 2- Total removal3- Facial function preservation4- Hearing preservation
27 Translabyrinthine removal of VS after radiosurgery 5 cases；Difficult in facial nerve dissection；Results：total removal in all casesfacial function: grade II in 1 casegrade III in 2 casesgrade IV in 2 casesgrade VI in 1 case
28 Transotic removal of VS with chronic middle ear infection 3 cases；Results：total removal in all casesfacial function: all with gradeI-IIno postoperative infection