桥小脑角区肿瘤术中面神经功能监护

Monitoring of facial nerve function during operation for cerebellopontine angle tumors

目的总结桥小脑角区肿瘤术中面神经功能的电生理监测经验。方法对48例桥小脑角区肿瘤病人术中应用肌电图进行连续实时监护,同时进行脑干听觉诱发电位监测。结果术中当接近、触及、牵拉、刺激面神经时,自发肌电图出现突发、双相或多相的高幅电位改变,面神经得以准确定位。脑干听觉诱发电位各波变化中以Ⅴ波潜伏期延长及波幅降低最为显著。肿瘤全切除45例,面神经解剖保留44例,功能保留38例。术后2周House-Brackmann面神经功能分级:Ⅰ￣Ⅱ级38例,Ⅲ￣Ⅳ级8例,Ⅴ级2例;其中Ⅰ￣Ⅱ级的术中刺激值为0.1￣0.2 mA。无死亡及长期昏迷病例。结论突发的双相或多相的高幅肌电图改变,及脑干听觉诱发电位示Ⅴ波潜伏期延长和波幅下降,均为敏感的变化指标;桥小脑角区肿瘤术中实施监护,有助于提高面神经的功能保留率。

Objective To review the experience with electrophysiological monitoring of facial nerve function during cerebellopontine angle （CPA） tumor surgery. Methods Forty-eight patients with tumors in CPA were continuously monitored by electromyography （EMG） and brainstem auditory evoked potential （BAEP） examinations intraoperatively. Results During the surgery of CPA, while the facial nerve was approached, touched, stretched, stimulated, paroxysmal and biphasic or multiphasic high amplitude potential occurred on the EMG, which is very useful to accurately locate the anatomic position of the facial nerve. The most significant changes of BAEP were prolongation of Ⅴ-wave latency and reduction of the wave amplitude. Total tumor removal was achieved in 45 cases, the anatomical preservation of the facial nerve in 44, and the functional preservation in 38. House-Brackmann grade of the facial nerve function 2 weeks after the operation was as follows： grade Ⅰ -Ⅱ in 38 patients,grade Ⅲ-Ⅳ in 8.and grade Ⅴ in 2, while the intraoperative stimulation intensity of patients in grade Ⅰ-Ⅱ was 0.1-0.2 mA. There was no death or long-term coma. Condusion The paroxysmal and biphasic or multiphasic EMG changes, the increase of Ⅴ-wave latency and reduction of the wave amplitude are the sensitive indexes during intra-operative monitoring. The monitoring of them can significantly improve the functional preservation of the facial nerve.