Abstract:

Objective  To investigate the significance of abnormal muscle response (AMR) monitoring during microvascular decompression (MVD) for hemifacial spasm (HFS) in confirming the responsible blood vessel, improving the prognosis and reducing postoperative complications.  Methods  A total of 34 HFS patients underwent AMR monitoring during MVD.  Results  The AMR of mentalis was recorded in all 34 patients by electrically stimulating zygomatic branch of facial nerve before anesthesia.
Compared with preoperation, the AMR latency after operation was significantly longer [(16.12 ± 3.17) ms vs (14.75 ± 3.32) ms, P = 0.015] and amplitude was significantly reduced [(0.11 ± 0.03）mV vs (0.13 ± 0.03) mV, P = 0.027]. AMR was disappeared in 32 cases (94.12% ) after the removal of responsible blood vessel.
There was one patient (2.94%) whose AMR disappeared momentarily after the incision of endocranium and disappeared completely after the removal of responsible blood vessel, while AMR still existed in one case (2.94%) after the removal of responsible blood vessel. Responsible blood vessels included anterior inferior cerebellar artery (N = 30, 88.24%), posterior inferior cerebellar artery (N = 3, 8.82%) and basilar artery (N = 1, 2.94%), which oppressed the root of facial nerve (N = 22, 64.71%), the distal part (N = 8, 23.53%), and both the root and distal part (N = 4, 11.76%). After operation, facial spasm disappeared. Thirty-one cases were cured, 2 cases evidently remitted, and one case inefficacious. The total effective rate was 97.06%.  Conclusions  Continuously intraoperative monitoring of AMR contributes to confirming the responsible blood vessel, completing decompression for facial nerve more thoroughly, improving the prognosis, reducing delayed healing up, at the same time enhancing neurosurgeons' confidence and reducing operation time. 

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摘要：

目的 探讨微血管减压术中持续监测异常肌反应对判断面肌痉挛责任血管、改善预后和减少术后并发症的意义。方法 34 例面肌痉挛患者行微血管减压术，术中持续监测异常肌反应。结果 患者均于麻醉前诱导刺激面神经颧支，并于面神经颏支记录到异常肌反应。与术前相比，术后异常肌反应潜伏期延长［（16.12 ± 3.17）ms 对（14.75 ± 3.32）ms，P = 0.015］、波幅降低［（0.11 ± 0.03）mV 对（0.13 ± 0.03）mV，P = 0.027］。32 例（94.12%）分离责任血管后异常肌反应消失；1 例（2.94%）切开硬脑膜后短暂性消失，至分离责任血管后完全消失；1 例（2.94%）分离责任血管后仍存在。责任血管分别为小脑前下动脉（30 例，88.24%）、小脑后下动脉（3 例，8.82%）和基底动脉（1 例，2.94%），血管压迫面神经根部22 例（64.71%）、远端8 例（23.53%）、同时压迫根部和远端4 例（11.76%）。术后面肌痉挛症状均消失，至随访结束时，治愈31 例、明显缓解2 例、无效1 例，治疗总有效率为97.06%。结论 术中持续监测异常肌反应有助于明确责任血管、更彻底地完成面神经减压、改善预后、减少迟发性愈合，同时可以提高术者信心，减少手术时间。

关键词: 面部肌肉, 痉挛, 显微外科手术, 血管外科手术, 肌电描记术