Otosurgical aspects in diagnostics and therapy of acoustic neurinomas.

136 acoustic neurinomas were operated upon by otosurgical transtemporal or translabyrinthine interventions. The otosurgical approach was used when a suboccipital craniectomy with a certain retraction of the cerebellum seemed to be avoidable. The pure otosurgical tumour removal was restricted to a tumour extension up to 2.5 cm starting from the fundus of the internal auditory meatus. The transtemporal route was used when hearing was worth saving and the translabyrinthine when the pure tone auditogram showed an average loss of 50 dB or the speech audiogram a discrimination loss of 50% or more. In larger tumours the neurosurgeon removed the intracranial part of the acoustic neurinome preserving the facial nerve and, if possible, the cochlear nerve as well. If parts of the tumour had remained within the internal auditory meatus or if some uncertainty concerning complete tumour removal persisted, an otosurgical second intervention was considered indicated. In 41 patients the cochlear nerve could be preserved at operation. 12 of these patients showed a preservation of their hearing.