Retrolabyrinthine approach: technique and newer indications.

Excellent exposure of the cerebellopontine angle is obtained by an approach through the mastoid posterior to the labyrinth. Since the major portion of the dissection is extradural, this approach is associated with a very low morbidity. The retrolabyrinthine approach has been used for several years for selective partial section of the posterior root of the trigeminal nerve in cases of trigeminal neuralgia. Complete relief of pain has been accomplished in 25 of 28 cases, and the other 3 patients had partial relief of pain. The only complications in these patients were partial hearing impairment in 2, and 1 partial abducens nerve paralysis which subsequently recovered completely. Two patients required secondary closure of cerebrospinal fluid leaks. This approach has also been used for exploration and biopsy of cerebellopontine angle tumors and for treatment of other cranial nerve problems. We conclude that the retrolabyrinthine approach is the preferred route to the cerebellopontine angle in a variety of clinical conditions.