Technique of hearing preservation in small acoustic neuromas.

The ideal operation for acoustic neurinoma would not only provide total excision without injury to the brain stem and with preservation of facial nerve function, but would also allow retention of useful hearing in those patients who come to operation with intact hearing function. Documented preservation of useful hearing in the rather extensive literature concerning acoustic neurinomas is rare. An operative technique has been developed utilizing a retromastoid approach, brain stem auditory-evoked potentials and direct auditory monitoring, facial nerve electromyography, and microsurgical techniques that have enabled us to preserve useful hearing in three and some hearing in two of six consecutive patients who had preoperative hearing. Rules regarding preservation and criteria regarding documentation of hearing preservation are outlined.