Hearing preservation after acoustic neuroma surgery.

Acoustic neuromas (AN) are benign tumors that arise from the vestibular nerve within the internal auditory canal, where hearing loss is the most common symptom. This retrospective study was done to determine the results of hearing preservation in patients operated for AN at the University of Minnesota, as well as the factors affecting them. One hundred-eighty patients with AN were operated between 1988 and 1998, of whom 91 (50.5%) underwent hearing preservation surgery by either the middle fossa (MF) or the suboccipital (SO) approach. Preoperative and postoperative pure-tone averages (1, 2, and 4 K), speech discrimination scores (SDS), and acoustic reflex thresholds (ART) were noted and classified according to the Shelton's and the Gardner's classifications. The overall rate of hearing preservation was 23.1%. The outcome of hearing results was better with the MF approach compared with the SO approach. Small tumor size and better preoperative hearing levels favored a better postoperative hearing result. The rate of hearing improvement over time was better for the MF patients. Patients for whom intraoperative auditory monitoring was performed seemed to have better hearing outcomes.