Microsurgical evacuation of large acoustic neuromas

Objective To evaluate the safety and efficacy of removing large acoustic neuromas by the retrosigmoid approach.Methods Large acoustic neurinomas were removed from 472 consecutive patients by the retrosigmoid suboccipital approach during 2001 to 2005,114 cases underwent the intraoperative facial nerve monitoring.The long term(1 year for 256 cases) facial nerve function were evaluated with House-Bracman facial nerve grading system.Results Among 256 cases,162 cases(63.3%) had Grade Ⅰ~Ⅱ function,50 cases(19.5%) had Grade Ⅲ~Ⅳ,and 44(17.2%) had Grade Ⅴ~Ⅵ.There were significant difference between EMG group and non-EMG group after operation immediately and one year(χ2 = 7.56,9.12,P 0.05) Conclusions The microsurgery of acoustic neuroma result in a high rate of both anatomical and functional facial nerve preservation,a low incidence of mortality and morbidity.The favourable results can be obtained using the retrosigmoid approach for the removal of large acoustic neurinomas.The intraoperative facial nerve monitoring is useful to improve the facial nerve preservation.