STABILITY OF HEARING PRESERVATION FOLLOWING ACOUSTIC NEUROMA SURGERY

Identification of small acoustic neuromas has become commonplace. Freq uently, affected individuals are identified prior to the development o f significant hearing loss. Whereas many studies have focused on heari ng preservation surgery, few have reported on stability of hearing res ults after resection of acoustic neuroma. Between 1985 and 1991, 36 pa tients underwent resection of an acoustic neuroma via a retrosigmoid, internal auditory canal approach with attempted hearing preservation. Hearing was preserved in 24 patients; 17 were available for testing fo r the present study. Follow-up ranged from 1.5 to 8 years. All patient s underwent complete audiologic assessment; most patients also underwe nt auditory brainstem response testing. There was an average 6 dB incr ease in pure-tone average between early (1 month) postoperative and lo ng-term postoperative test results. A binomial single subject statisti c was used to assess for significant changes in speech recognition sco res over time. In two subjects there was a significant decrease; howev er, speech recognition also improved significantly in two subjects. Fi ve of the 17 subjects demonstrated either a significant (at least 15 d B) increase in pure-tone average or a significant decrease in speech r ecognition over the time-course of the study. All patients maintained usable hearing. We conclude that long-term hearing preservation is a r ealistic goal in selected acoustic neuroma operations.