Hearing preservation after acoustic neuroma surgery

Acoustic neuromas (AN) are benign tumors that arise from the vestibular ner ve within the internal auditory canal, where hearing loss is the most commo n symptom. This retrospective study was done to determine the results of he aring preservation in patients operated for AN at 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 p reservation 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 cl assifications. The overall rate of hearing preservation was 23.1%. The outc ome 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 audi tory monitoring was performed seemed to have better hearing outcomes.