Short-term And Long-term Outcomes And Some Influential Factors Of Microsurgical Treatment For Vestibular Schwannoma Using The Retrosigmoid Transmeatal Approach:a Report Of416Cases

Objectives:To observe the short-term and long-term outcomes of patients after microsurgical resection of vestibular schwannoma via the retrosigmoid transmeatal approach using electromyography monitoring, and analyze some influential factors. Methods:416patients undergoing vestibular schwannoma operations at neurosurgical department of Xiang Ya Hospital from2002.1-2012.9by the same surgeon(Professor Xianrui Yuan, MD&PHD) were included in this study. A retrospective study was performed on the follow-up results. Results:402tumors were completely removed (96.63%). Anatomic preservation of the facial nerve was achieved in99.04%of the patients, of the cochlear nerve in33.22%and of petrosal vein in83.97%. There were5deaths occurring postoperatively (1.20%).267patients were followed up at least1year, and222of them had H-B grade Ⅰ or Ⅱ facial nerve function (83.15%).144cases had preoperative hearing function,and12cases of them had postoperative useful hearing (grade A or B,8.33%). Long-term facial function was intimately correlated with tumor size and early postoperative facial nerve function through statistical evaluation.Conclusions:1. For all kinds of vestibular schwannomas, the retrosigmoid transmeatal approach is a safe and effective surgical method.2. The law of the postoperative short-term changes of facial nerve function:(1) Patients with H-B grade Ⅰ facial nerve function on the first day after operation, their short-term facial nerve function can stay stable in grade I.(2) Patients with H-B grade Ⅱ or Ⅲ facial nerve function on the first day after operation, their short-term facial nerve function may stay stable or deteriorate, but the conversion time is unknown.3. The law of the postoperative long-term changes of facial nerve function:1week after surgery, postoperative facial nerve function is the worst,3months after operation, the facial nerve function is able to recover gradually, and1year after surgery, facial nerve function can recover steadily. Therefore, the recovery time of facial nerve function is within12months after surgery.4. The main factor affecting the long-term facial nerve function after surgery is the tumor size.Tumor size and early facial nerve function are predictors of long-term facial nerve function.