[Facial nerve preservation following microsurgical removal of large and huge acoustic neuroma].

Objectives: To 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.

Methods: A 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.

Results: Complete 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).

Conclusions: Complete 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.