HEARING PRESERVATION IN PATIENTS UNDERGOING VESTIBULAR SCHWANNOMA SURGERY - COMPARISON OF MIDDLE FOSSA AND RETROSIGMOID APPROACHES

Object. The goal of this retrospective study was to evaluate hearing p reservation after surgery for vestibular schwannoma in which the middl e fossa (MF) or retrosigmoid (RS) approaches were used. Hearing preser vation in vestibular schwannoma surgery can be achieved by using eithe r the MR or RS approach. Comparative outcome data between these approa ches are lacking, and, as a result, selection has generally been deter mined by the surgeon's preference. Methods. The authors have compared removal of small vestibular schwannomas via MF and RS approaches with regard to hearing preservation and facial nerve function. The study gr oup was composed of consecutively treated patients with vestibular sch wannoma. 48 of whom underwent operation via an MF approach and 50 of w hom underwent the same number of RS operations. Tumors were divided in to size-matched groups. Hearing results were recorded according to the American Academy of Otolaryngology-Head and Neck Surgery criteria, an d facial nerve outcome was recorded as the House-Brackmann grade. Over all, 26 (52%) of the patients treated via the MF approach achieved a C lass B or better hearing result compared with seven (14%) of the RS gr oup. Some hearing was presented in 32 (64%) of the patients in the MF group and in 17 (34%) of the RS group. The results obtained by using t he MF approach were superior for intracanalicular rumors (p = 0.009. t -test), and for tumors with a cerebellopontine angle (CPA) component m easuring 0.1 to 1 cm (p = 0.006, t-test). For tumors in the CPA that w ere 1.1 to 2 cm in size, our data were inconclusive because of the sma ll sample size. Facial weakness was seen more frequently after MF surg ery in the early postoperative period, but results were equal at 1 yea r. Conclusions. The results of this study have demonstrated a more fav orable hearing outcome for patients with intracanalicular rumors and t umors extending up to 1 cm into the CPA that were removed via the MF w hen compared with the RS approach.