听神经瘤术中面神经电生理监测的问题与对策

目的 探讨听神经瘤术中面神经电生理监测技术的常见问题与对策,提高面神经解剖保留率,并对解剖保留的面神经进行功能评价.方法 25例听神经瘤患者手术时均在面神经电生理监测下进行,全部采用枕下乙状窦后入路,显微外科切除肿瘤,肿瘤切除后对面神经功能进行评价.结果 肿瘤全切除25例(100%),无手术死亡;面神经解剖保留23例,占92%.面神经功能状态H-B分级Ⅰ、Ⅱ级19例,Ⅲ、Ⅳ级5例,Ⅴ级1例.术末刺激强度越小,术后面神经功能越好;低于0.5 mA同时面肌肌电波幅大于100 μV,面神经功能可达Ⅰ～Ⅱ级;术末刺激强度大于2 mA波幅反应不明显时,术后面神经功能恢复不理想.结论 术中自发或诱发式神经电生理监测技术的灵活应用可明显提高面神经解剖保留率和功能保留率,对其定量分析有助于术后面神经功能的判断.

Problems and solutions of intraoperative facial nerve electrophysiologic monitoring for acoustic neuroma

Objective To explore the solutions to some problems of intraoperative facial nerve monitoring during operation for acoustic neuroma and evaluate the function of anatomically preserved facial nerve. Methods The tumors were resected with suboccipital retrosigmoid approaches under microscope in 25 cases. Intraoperative monitoring was used to protect facial nerve and evaluated its function. Results Total removal was achieved in 25 patients( 100% ). The facial nerve was preserved anatomically in 23 cases(92% ),H - B Grade Ⅰ～Ⅱ in 19 cases, Grade Ⅲ～Ⅳ in 5, Grade Ⅴ～Ⅵ in 1. Stimulative intensity at the end of tumor resection was related to the function of facial nerve, and the lower was the better. The function of facial nerve might be Ⅰ～Ⅱ grade when stimulative intensity was lower than 0. 5 mA, and facial electromyograph response amplitudes was greater than 100 μV. The function of facial nerve was not ideal when stimilative intensity was above 2 mA and response amplitude was not clear. Conclusions Skilled technique of intraoperative facial nerve electrophysiologic monitoring can obviously increase the rate of anatomical and functional preservation of facial nerve, and quantitative analysis of electromyogram may help to evaluate its postoperative function.