[Surgery of large neurinomas of the acoustic nerve performed only by the translabyrinthine approach. Apropos of 50 cases].

A combined otoneurosurgical team has operated upon 68 patients with acoustic nerve neurinomas over a period of 13 months (Sept. 1982-Oct. 1983). Exploration and operation in this homogeneous series were carried out under the same conditions, and a CT scan was performed in each patient before and after surgery. The size of the neuroma was less than 2 cm in diameter in 18 cases, between 2 and 3 cm in 28 cases, between 3 and 4 cm in 10 and 4 cm or more in 12. This report relates to the 50 neurinomas over 2 cm in diameter, these requiring multidisciplinary co-operation during surgical removal. The translabyrinthine approach was used exclusively in 48 cases, and was combined with a retrosigmoid approach in the other 2 cases. Total tumoral excision was possible in 46 cases (92%) and partial removal in 4 patients (8%). Complications included one death (bilateral giant neurinomas), resolving purulent meningitis (2 cases), 3 patients with cerebrospinal fluid fistulae which healed after lumbar drainage, and 1 case of postoperative hematoma in the ponto-cerebellar angle requiring further surgery. The facial nerve was undamaged in 48 cases (96%). Postoperative facial palsy developed in 39 cases, and 15 have recovered subnormal motility. Follow up is insufficient in the other 17 patients. It is suggested that the translabyrinthine approach enables ablation of neurinomas of whatever size. This approach is reliable since it avoids injury to neighboring nerve structures. The facial nerve is detected immediately and can be protected throughout operation. The latter is, however, a long and difficult procedure, and otoneurosurgical collaboration is advisable.