面肌痙攣患者微血管減壓術中側方擴散反應監測對療效的預測作用

焦風，張磊，趙春維，劉波，王棟梁，梁冶矢，劉獻增

(1北京大學人民醫院，北京100044；2烏魯木齊市友誼醫院)

面肌痙攣患者微血管減壓術中側方擴散反應監測對療效的預測作用

焦風1，張磊2，趙春維1，劉波1，王棟梁1，梁冶矢1，劉獻增1

(1北京大學人民醫院，北京100044；2烏魯木齊市友誼醫院)

目的 分析面肌痙攣患者微血管減壓術(MVD)中側方擴散反應(LSR)監測對療效的預測作用。方法 面肌痙攣患者45例，均行MVD術治療，分別于術中微血管減壓前后進行LSR監測。分別于術后第1、7天及術后3個月采用自我評價量表評估手術效果。分析減壓后LSR變化與療效的關系。結果 40例減壓后LSR即刻消失(LSR消失組)；5例LSR未即刻消失(LSR未消失組)，其中1例下降86%、2例下降幅度不足50%、1例無變化、1例因持續自發放電未引出LSR。術后第1天，LSR消失組治愈31例、好轉9例，LSR未消失組治愈1例、好轉1例、無效3例；術后第7天，LSR消失組治愈35例、好轉5例，LSR未消失組治愈1例、好轉2例、無效2例；術后3個月，LSR消失組治愈39例、好轉1例，LSR未消失組治愈1例、好轉2例、無效2例。隨訪3～88個月，LSR消失組全部治愈，LSR未消失組好轉3例、無效2例。術后各觀察時點LSR消失組治愈和好轉比例均高于LSR未消失組，減壓后LSR是否消失與療效存在相關性(P均<0.05)。結論 面肌痙攣患者MVD術中LSR監測結果與療效有關，減壓后LSR消失者治愈及好轉率較高。

面肌痙攣；微血管減壓術；側方擴散反應

面肌痙攣是以一側面神經支配肌肉不自主陣發性抽動為主要癥狀的疾病。目前認為面肌痙攣是由面神經出根區受血管壓迫導致的[1]。微血管減壓術(MVD)是惟一能夠治愈面肌痙攣的方法[2]。側方擴散反應(LSR)為面肌痙攣患者特征性的電生理表現，表現為在痙攣側刺激面神經一個分支，可在其他分支支配的肌肉中記錄到誘發肌電圖。在面神經MVD術中應用LSR監測有助于正確判斷責任血管以保證減壓充分，但學界對LSR監測結果能否作為治療效果的預測因素仍存在爭議[3～5]。為此，本研究分析了面肌痙攣患者MVD術中LSR監測結果對手術療效預測價值，現報告如下。

1 資料與方法

1.1 臨床資料 2009年5月～2016年7月北京大學人民醫院收治的面肌痙攣患者45例，男13例、女32例，年齡28～81歲，病程6個月～20年，左側27例、右側28例。所有患者均通過3.0 T MRI掃描除外腫瘤及血管畸形等繼發原因并采用3D-FIETSTA序列預測面神經出根區有無壓迫、預測責任血管[6]。所有患者均采用MVD術治療。患者取健側臥位，頭向健側旋轉10°、下垂15°，使乳突根部位于最高點；枕下乙狀竇后縱形切口，氣鉆顱骨鉆孔后擴大骨窗直徑約1.5 cm；顯微鏡下釋放腦脊液，仔細分離蛛網膜并輕輕牽拉小腦絨球，顯露面神經出根區；判斷責任血管，小腦前下動脈(AICA)20例、小腦后下動脈(PICA)9例、椎動脈(VA)3例、AICA+PICA 4例、VA+AICA 2例、VA+PICA 6例、靜脈1例，之后充分解剖責任血管與面神經的粘連，以Teflon棉墊開；術中根據LSR監測結果確定減壓是否充分，必要時探查蛛網膜下腔的面神經全長。

1.2 LSR監測方法 于術中微血管減壓前后進行LSR監測。監測LSR時，應用去極化型肌松藥進行麻醉插管后不再應用肌松類藥物，以異丙酚和芬太尼維持麻醉[7]。監測設備為CADWELL 32通道術中神經電生理監測儀。記錄電極位置包括患側面神經支配的額肌、眼輪匝肌、口輪匝肌、頦肌及三叉神經支配的咬肌，有一支插入肌腹并與另一支距離0.5 cm。刺激電極位于面神經分支的顳支，陰極位于患側耳屏與外眥連線中點、陽極位于距陰極1 cm處。地線位于FPz點(根據國際10-20系統電極定位)。刺激顳支，額肌及眼輪匝肌有肌電圖表現為直接刺激反應；觀察患側口輪匝肌及頦肌有無肌電圖反應。初始刺激強度從5 mA開始，逐漸增加至20 mA，若仍未引出LSR則認為其消失；若初始刺激強度未引出LSR，但隨著刺激強度增加、LSR重現，則認為LSR未消失，需重新探查面神經全程以保證充分減壓[8]。

1.3 療效評估方法 分別于術后第1、7天及術后3個月評估手術效果。患者以自我評價量表描述面肌痙攣癥狀改善的程度，改善100%為治愈，改善50%～90%為好轉，0～50%無效。

1.4 統計學方法 采用SPSS16.0軟件進行統計學分析。計數資料以頻數表示，組間比較采用Fisher確切概率法。P<0.05為差異有統計學意義。

2 結果

40例減壓后LSR即刻消失(LSR消失組)；5例LSR未即刻消失(LSR未消失組)，1例下降86%、2例下降幅度不足50%、1例無變化、1例因持續自發放電未引出LSR。術后第1天，LSR消失組治愈31例、好轉9例，LSR未消失組治愈1例、好轉1例、無效3例；術后第7天，LSR消失組治愈35例、好轉5例，LSR未消失組治愈1例、好轉2例、無效2例；術后3個月，LSR消失組治愈39例、好轉1例，LSR未消失組治愈1例、好轉2例、無效2例。隨訪3～88個月，LSR消失組全部治愈，LSR未消失組好轉3例、無效2例。術后各觀察時點LSR消失組治愈和好轉比例均高于LSR未消失組，減壓后LSR是否消失與療效存在相關性(P均<0.05)。

3 討論

面肌痙攣發病機制有兩種學說：外周性學說認為面神經出腦干區覆蓋的中樞性髓鞘受損，導致暴露的神經軸突互相接觸，進而引發神經纖維之間跨突觸傳遞的異位沖動;中樞性學說則認為各種原因引起面神經運動核興奮性異常增高，進而導致面肌痙攣[9]。目前MVD已成為治療面肌痙攣的最有效方法。術中準確找到責任血管并將面神經根出根區與責任血管充分墊開是手術成功的關鍵。LSR為面肌痙攣患者特征性的電生理表現[10]。

在臨床實踐中我們發現，當將責任血管從面神經根出根區分離開后，多數病例(40例)LSR即刻消失，部分病例反應幅度明顯降低。究其原因我們考慮在解除血管對神經的壓迫后，運動神經元的興奮性隨之降低并逐漸恢復正常。LSR可反映面神經傳導通路的興奮性，排除干擾后，LSR消失表明興奮性恢復正常[11～13]。通過本組病例研究我們體會，術中應用LSR監測對正確判斷責任血管和保證減壓效果有很大幫助。部分病例在初步判定責任血管并減壓后，LSR并未消失，其主要原因為術中對責任血管判斷不正確或遺漏、對神經減壓不充分、墊入Teflon棉位置不正確、遠端血管壓迫等。本組3例患者存在上述情況，經過調整顯微鏡角度重新探查發現另有其他壓迫血管[14]。另外，有些責任血管游離不徹底，致使墊入的Telfon棉與面神經仍有緊密接觸，調整墊棉后LSR消失。因此，通過術中LSR監測，可保障充分游離責任血管，并將Telfon棉墊入責任血管與腦干之間以改變責任血管的行程，完全解除其對面神經的壓迫。

有研究表明MVD術中LSR消失或幅度較減壓前明顯下降預示著比較樂觀的手術效果，極有可能完全緩解或大部分緩解面肌痙攣癥狀。本研究結果顯示，術后第1、7天及術后術后3個月LSR消失組治愈和好轉比例均高于LSR未消失組，且隨訪3～88個月也得到相同結果，認為減壓后LSR是否消失與療效存在相關性。這表明在充分減壓后面神經核的興奮性逐漸降至正常，進而面肌痙攣癥狀緩解。影響MVD術后緩解率的因素多種多樣且比較復雜，術者經驗也是影響手術效果的重要因素。LSR監測可幫助準確判斷責任血管及減壓是否充分，這對于經驗不足的年輕神經外科醫生或剛剛開展此類手術的神經外科單位有重要參考價值。LSR監測不但能減少尋找責任血管的時間，減少不必要的過分牽拉，起到保護面神經、聽神經功能的作用；而且能夠幫助判斷減壓是否充分，尤其是有多根責任血管時，可防止發生遺漏[15，16]。

由于術中LSR消失與否和術后療效之間存在明顯相關，因此，根據LSR監測結果制定不同的減壓策略，盡可能減少責任血管遺漏，做到對面神經進行充分減壓，有助于提高術后療效。

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Prognostic value of intraoperative lateral spread response monitoring during microvascular decompression in patients with hemifacial spasm

JIAOFeng1,ZHANGLei,ZHAOChunwei,LIUBo,WANGDongliang,LIANGYeshi,LIUXianzeng

(1People'sHospitalofPekingUniversity,Beijing100044,China)

Objective To investigate the prognostic value of intraoperative lateral spread response (LSR) monitoring in the treatment of hemifacial spasm (HFS) by microvascular decompression (MVD). Methods Forty-five patients with primary HFS treated by MVD. During operations, we performed LSR monitoring before and after MVD respectively. All patients were assessed after operation on day 1 and 7, and at 3 month after surgery by self-assessment scale. We analyzed the relationship between the change of LSR and prognosis. Results In 40 patients, the LSR disappeared immediately after decompression (LSR disappeared group). In the remaining 5 patients, the LSR did not vanish immediately after decompression (LSR non vanishing group), one patient's LSR decreased 86%, 2 patients' LSR decreased above 50%, 1 patient had no change, and in 1 patient, LSR was not detected from the start. On day 1 after operation, in the LSR disappeared group, HFS was relieved totally in 31 patients, 9 patients described improvement; in the LSR non vanishing group, 1 patient totally relieved, 1 patient improved, and 3 patients failed. On day 7, in the LSR disappeared group, HFS was relieved totally in 35 patients, 5 patients described improvement; in the LSR non vanishing group, 1 patient totally relieved, 2 patient improved, and 2 patients failed. After 3 month, in the LSR disappeared group, HFS was relieved totally in 39 patients, 1 patients described improvement; in the LSR non vanishing group, 3 patient improved, and 2 patients failed. After 3-month to 88-month follow-up, in the LSR disappeared group, all the 40 patients cured, in the LSR non vanishing group, 3 patients improved and 2 patients failed. At all the postoperative observing time, the proportion of cure and improvement of the LSR disappeared group was higher than that of the LSR non vanishing group. Statistical analysis found a significant correlation between the relief of LSR and clinical outcome (allP<0.05). Conclusion LSR monitoring of HFS patients in MVD is correlated with the curative effect, and the rate of cure and improvement is higher in patients with disappeared LSR after decompression.

hemifacial spasm; microvascular decompression; lateral spread response

10.3969/j.issn.1002-266X.2017.15.021

R745.1

B

1002-266X(2017)15-0071-03

2016-12-08)