大型听神经瘤术中面神经功能监测及其预后评估

Clinical value of multimodality intraoperative monitoring for facial nerve and prognosis evaluation in large acoustic neuroma

目的研究面神经监测在大型听神经瘤手术中保护面神经的方法和意义,以及术中监测与面神经预后的关系。方法使用美国Nicolet Endeavor-CR16通道的电生理监护仪,术中对26例大型听神经瘤病人术中进行自发和诱发面神经肌电图连续监测,术末以不同强度电流刺激面神经脑干端,观察有无诱发肌电图。术后2周及6-12个月,根据House-Brackmann(H-B)分级方法对面神经功能进行评价。并使用Spearman秩相关检验,对术末电刺激强度与面神经功能分级的关系进行统计分析。结果面神经解剖保留25例(96%),术后6-12个月面神经功能评价,按H-B分级,面神经Ⅰ-Ⅱ级18例(70%)。肿瘤全切后在面神经出脑干端刺激时,电刺激强度与术后6-12个月面神经H-B分级呈正相关(r=0.8,P<0.05)。结论由远及近,由大到小,自发与诱发肌电图结合,可以精确定位面神经,防止面神经损伤;术末电刺激强度越大,面神经H-B分级越高,面神经功能预后越差。

Objective To explore the clinical significance of intraoperative facial nerve monitoring for facial nerve preservation during the acoustic neuroma surgery and its evaluation for prognosis. Methods The Nicolet Endeavor-CR16 facility was used to observe the free-running and stimulus-triggered electromyography of facial nerve in 26 cases of large acoustic neuroma.When the neuroma was cut off,the brainstem of facial nerve was stimulated with various stimulating intensities to observe the trigged EMG.Facial nerve function was assessed using the H-B facial nerve grading system after surgery for two weeks and 6-12 months.Spearman rank correlation test was used to analyze the relationship between stimulating intensity at the end of the surgery and facial nerve function grade. Results The facial nerve was preserved anatomically in 25 cases.According to the H-B facial nerve grading system,facial nerve function was grade Ⅰ-Ⅱ in 18 cases（70%） after surgery for 6-12 months.When stimulating brainstem end after the total resection of tumor,stimulating intensity was positively correlated with H-B score at month 6-12 after surgery. Conclusion Combination of the triggered EMG with free-running EMG when stimulating from the distal to the proximal and from the strong to the weak can help to precisely locate the facial nerve and avoid its injury.The more stimulus intensity is,the high H-B facial nerve grading is,the worse the final facial nerve function is.