Hearing preservation and facial nerve outcomes in vestibular schwannoma surgery: total removal using the retrosigmoid approach

BACKGROUND: The present study aims to report the results and the prognostic and technical factors for hearing preservation during removal of vestibular schwannoma by a retrosigmoid approach. METHODS: This was a retrospective study conducting on the 286 vestibular showannomas removal surgeries using retrosigmoid approach during October 2007 to 2011.Preoperative and postoperative clinical, audiometric, and imaging data were collected and analyzed. The mean follow-up period was 3 years. Intraoperative neuromonitoring interventions were done for all patients and the complete excision of tumor was established by post-operative magnetic resonance imaging (MRI). RESULTS: Functional hearing (less than 50 dB PTA and greater than50% speech discrimination) was preserved in 7 of 16 patients (43.7%) with grade II tumors, whereas only 11 of 72 patients (15.3%) with grade III tumors retained their functional hearing. Fifteen out of 16 patients (93.7%) with grade II tumors achieved a House-Brackmann (HB) grade I-III, while 63 of 72 patients (87%) with grade III tumors retained HB I-III facial function. Our result in grade IV tumors was excellence in facial nerve preservation (76%) but hearing preservation in the large tumors was only about 1%. CONCLUSIONS: Findings of the present study showed that hearing preservation depends on the tumor size and using monitoring and other modern instruments and technical skills preservation rate of it could be higher than before. Overall facial nerve preservation was excellent with greater than 90% achieving HB 1 to 3 function at final follow-up. KEYWORDS: Hearing preservation, Facial nerve, Retrosigmoid approach