Conclusion: The retrosigmoid approach for small vestibular schwannomas (VS) yields a high rate of facial function preservation. Hearing preservation rates depend on tumor size and preoperative hearing.
Objectives: To report the results and to investigate the prognostic factors for hearing preservation after removal of small VS by a retrosigmoid approach.
Patients and methods: From October 1994 to July 2005, 110 VS removed through a retrosigmoid approach were included in this retrospective study. Preoperative and postoperative clinical, audiometric, videonystagmographic, and imaging data were collected. The mean follow-up period was 23+/-20.7 months (range 1-110).
Results: The preservation of a good facial function (House and Brackmann grade 1-2) was achieved in 91% of patients at 1-2 years after surgery. Among patients with a preoperative class A or B (n=99), a postoperative serviceable hearing (AAO-HNS classes A and B) was preserved in 36% and a useful hearing (classes A, B, and C) in 44%. Hearing preservation appeared to be influenced by tumor size and preoperative hearing. Multiple regression analysis of the preoperative factors influencing the hearing outcome showed that preoperative high frequency pure tone thresholds associated with tumor size were better correlated to postoperative pure tone average (PTA) than preoperative low frequencies.