MANAGEMENT OF VESTIBULAR SCHWANNOMAS (ACOUSTIC NEUROMAS) - AUDITORY AND FACIAL-NERVE FUNCTION AFTER RESECTION OF 120 VESTIBULAR SCHWANNOMASIN PATIENTS WITH NEUROFIBROMATOSIS-2

OBJECTIVE: Vestibular schwannomas (VSs) affect young patients with Neu rofibromatosis 2 (NF-2) and cause very serious problems for hearing, f acial expression, and brain stem function. Our objective was to determ ine a therapy concept for the right timing and indication of neurosurg ical therapy. METHODS: In 1000 consecutive VS resections, 120 tumors i n 82 patients with NF-2 were surgically treated by the same surgeon (M S) at the Department of Neurosurgery at Nordstadt Hospital from 1978 t o 1993, The mean age of the patients was 27.5 years. Sixty tumors were surgically treated in 41 male patients, and 60 tumors were surgically treated in 41 female patients. Bilateral tumor resection was performe d in 38 patients (76 operations, after previous partial surgery in 15 cases elsewhere), and unilateral operations were performed in 44 patie nts, 5 of whom had undergone ipsi- or contralateral surgery that was p erformed elsewhere. The operative and clinical findings are evaluated and compared with the data of patients without NF-2. RESULTS: In 105 c ases, complete tumor resections were achieved. In 15 cases, deliberate subtotal resections were performed. These were for brain stem decompr ession in 4 cases and for hearing preservation in the last hearing ear in 11 cases, with successful preservation in 8 of the 11. Pre- and po stoperative hearing rates were higher in male than in female patients (70% in male versus 65% in female patients before surgery and 40.5 ver sus 31%, respectively, after surgery). Hearing was preserved in 29 of 81 ears (36%),The rate of preservation was 24% in cases of large tumor s and 57% in cases of small tumors (<30 mm). Twenty-one of 82 patients (26%) were bilaterally deaf before surgery. Twenty-five patients had uni- or bilateral hearing after surgery (i.e., 41% of those with preop erative hearing or 30.5% of the whole group). Anatomic facial nerve pr eservation was achieved in 85%. The facial nerve was reconstructed int racranially at the cerebellopontine angle by sural grafting in 17 case s and by hypoglossal-facial reanimation in 5. Two deaths occurred 1 an d 3 months postsurgically as a result of malignant tumor growth with b rain stem dysfunction and respiratory problems, In summary, for patien ts with NF-2, the presentation ages are lower, tumor progression is fa ster, the chances of anatomic and functional nerve preservation are lo wer, the chances of good outcomes are best when surgery is performed e arly and when there is good preoperative hearing function, and the dan ger of sudden hearing loss is higher, The chances and danger often dif fer from side to side among individual patients. CONCLUSION: The indic ation and the timing of tumor resections are in some respects differen t from normal VS handling and are dependent on the tumor extension and related necessity of brain stem decompression and on the auditory fun ction. As an optimal goal, completeness of resection with functional c ochlear nerve preservation is formulated, and as an acceptable comprom ise, subtotal microsurgical resection with functional cochlear nerve p reservation in the last hearing ear is suggested.