OBJECTIVESTo evaluate the long-term facial nerve function of patients following microsurgical removal of large and huge acoustic neuroma, and to identify the factors that influence these outcomes.

METHODSA retrospective review was performed which included 176 consecutive patients with a large acoustic neuroma (≥ 30 mm) underwent a retrosigmoid craniotomy for tumor resection between January 2002 to November 2009. House-Brackmann (HB) Scale was used preoperatively and in a long-term follow-up after surgery. Test for linear trend was applied for statistic analysis.

RESULTSComplete resection was achieved in 168 (95.5%) of these 176 patients with a mortality of 1.7%. Anatomic preservation of the facial nerve was attained in 96.0% of the patients. In the series of 96 patients who had at least 1-year follow-up (mean 3.0 years) the facial nerve function preservation (HB grade 1 - 2) was totally attained in 79 patients (82.3%), and 40 of 55 patients (72.7%) who presented huge tumors (diameter > 40 mm) among the 96 patients had facial nerve function preserved. Analysis showed that facial nerve function correlated linearly with tumor sizes (χ(2) = 14.114, ν = 1, P < 0.05).

CONCLUSIONSComplete removal of large and giant acoustic neuroma may be obtained via retrosigmoid approach with facial nerve preservation. Excellent long-term facial function can be expected in the majority of patients who undergo microsurgical removal of vestibular schwannoma via the suboccipital retrosigmoid approach. Tumor size is a significant prognostic parameter for facial nerve function following vestibular schwannoma surgery.