Influence factors analysis of facial nerve function after the microsurgical removal of large acoustic neuromas

Objective To study facial function after large acoustic neruomas resections and identify factors which influence these outcomes.Methods A total of 127 cases acoustic neuromas were microsurgically removed via retrosigmoid approach using electromyo-graphy monitoring at neurosurgical department of Xiangya hospital from 2002.1-2008.4.by the senior surgeon(professor Yuan xianrui,MD PHD).A retro-spectively reviewed was performed.Outpatient clinical follow-up every 3 months includes evaluation of facial nerve function.The facial nerve function was assessed using House-Brackmann facial nerve grading system.Results Of 125 cases of complete removal and 2 cases of deliberately partial removal,the facial nerve was anatomically preserved in 126 of 127 cases(99.2%) and preservation is supported by special electrophysiological monitoring.The non-parameter analysis and test for linear trend showed that tumor size(P0.005) and early facial nerve function(P0.0001) correlated with the facial nerve function at 1 year or more postoperatively.Patient age,symptom duration、cystic change,and preoperative hydrocephalus did not influence facial nerve function.Conclusions Resection of acoustic neuroma via retrosigmoid approach using electromyography monitoring is a safe and effective method.The long-term facial nerve function correlates with early facial nerve function(P0.0001) and tumor size(P0.005).