异常肌反应刺激阈值变化在面肌痉挛显微血管减压术中的意义

Significance of threshold change of abnormal muscle response in microvascular decompression for hemifacial spasm

目的研究异常肌反应（AMR）刺激阈值在面肌痉挛（HFS）显微血管减压术（MVD）中的变化及其与术后疗效的关系。方法回顾性纳入2015年6月至2016年3月在沈阳军区总医院神经外科行MVD的67例HFS患者，术中均行AMR监测，分析减压前后AMR刺激阈值变化对预后的影响。结果67例患者切开皮肤前AMR阈值为0．1—32．0mA，中位数为3．6mA。减压术后AMR完全消失43例，未消失24例。AMR未消失者减压后AMR阈值为2．2～84．0mA，中位数为18．7mA，其中较切开皮肤前AMR阈值提高〈1倍者9例，提高≥1倍者15例。术后1年随访，治愈60例（89．6％），未治愈7例（10．4％）。AMR消失组43例患者中，42例（97．7％）治愈，其中40例（93．0％）术后即刻症状消失。AMR未消失组24例患者中，18例（75．0％）治愈，其中10例术后即刻症状消失，8例在术后10d至11个月治愈，中位数为2．5个月。AMR消失组与未消失组比较，术后即刻和术后1年治愈率差异均有统计学意义（均P〈0．05）。在AMR未消失组中，术后AMR刺激阈值较切开皮肤前提高≥1倍者的治愈比例高于提高〈1倍者（分别为14／15、4／9），差异有统计学意义（P=0．015）。结论MVD治疗HFS，术后AMR消失者预后较好；AMR未消失者更易于出现延迟治愈，术后AMR刺激阈值较切开皮肤前提高≥1倍者的预后相对较好。

Objective To investigate the intraoperative threshold change of abnormal muscle response （AMR） and its relationship to clinical outcome in microvascular decompression （MVD） for hemifacial spasm （HFS）. Methods A retrospective analysis was conducted on 67 HFS patients who underwent AMR monitoring during MVD at Neurosurgery Department, General Hospital of Shenyang Military Command, from June 2015 to March 2016. The clinical efficacy was evaluated at two time points： immediately following operation and 1 year post surgery. Threshold change of AMR from pre-decompression to decompression was documented and its relationship to clinical outcomes was analyzed. Results The AMR threshold in 67 cases before skin incision was 0. t - 19.0 mA （median： 3.6 mA）. The AMR disappeared completely in 43 cases after decompression and remained in 24 cases. The threshold of remaining AMR after decompression was 2. 2 - 84. 0 mA （ median： 18.7 mA）. The threshold increased less than 1 time in 9 cases and at least 1 time in 15 cases. All patients were followed up for 1 year and 60 cases （89.6%） were cured and 7 cases （ 10.4% ） were not. Out of 43 cases with disappearance of AMR, 42 （97.7%） were cured which included 40 （93.0%） with immediate remission post surgery. Among the 24 cases whose AMR did not disappear after decompression, 18 （75. 0% ） were cured including 10 with immediate remission and 8 with delayed effect from 10 day to 11 months （median： 2.5 months） post surgery. Immediate and 1-year postoperative clinical outcomes were significantly different between the group with AMR disappearance and that without AMR disappearance （both P 〈 0. 05）. In the group with remaining AMR, the curing rate was higher in cases with threshold increase of AMR of at least 1 time compared with that in those with threshold elevation of less than 1 time, which were 14/15 and 4/9, respectively. The difference was statistically significant （P =0. 015）. Conclusions During MVD for HFS, the disappearance of AMR seems to be associated with better outcome and delayed remission is more likely to occur in those without AMR disappearance. The threshold increase of at least 1 time post decompression compared with preoperative （prior to skin incision） level might be related to better clinical outcome.