Surgery of the internal acoustic meatus and the cerebello-pontine angle.

Tumoral and functional surgery of the cerebellopontine angle and the internal acoustic meatus has been performed in our department for more than 20 years. Acoustic neurinomas (700 cases operated to date) represent the great bulk of this surgery. Since 1985, we have drastically modified our approach to these tumors (220 cases). Large tumors are now dealt with, regardless of the patient's hearing, through a widened translabyrinthine approach. Small tumors with normal hearing are operated on through a suboccipital or a retrolabyrinthine approach depending on the tumoral extension in the internal acoustic meatus. The facial nerve function was preserved in 83% of the cases. Hearing was saved only 6 times in 45 attempts, despite 23 cases of apparent anatomical conservation of the cochlear nerve. Vestibular neurectomy, carried out through a middle cranial fossa or through a retrolabyrinthine approach, ameliorated vertigo in 95% of cases. The major operative risks are regressive facial paresis and secondary total deafness (10% of cases). Surgical treatment of facial hemispasm by neurovascular decompression is very effective, but not without risk. We now prefer to use botulin toxin therapy.