面肌痉挛显微血管减压术中责任血管的解剖分析对手术疗效的影响

目的分析面肌痉挛（hemifacial spasm，HFS）患者颅内责任血管与面神经之间的解剖关系，为HFS显微血管减压术（microsurgical neumvascular decompression，MVD）提供解剖学依据。方法回顾性分析106例经显微血管减压术治疗的面肌痉挛患者的临床资料。术前均行三维时间飞越法磁共振血管造影（3D-TOF-MRA）检查，了解面神经受压迫是否存在责任血管及其来源与走向。采用枕下乙状窦后小脑下外侧入路显露面神经脑干段，仔细观察责任血管及其来源后将其推移，在责任血管与脑干之间放置Teflon减压垫棉。结果3D-TOF-MRA检查显示面神经被微小血管压迫的阳性率达92％。术中发现全部病例均有明确的责任血管，其中小脑前下动脉占66％（70／106）。34例患者中发现面神经根区（root exit zone，REZ）存在明显的压迫切迹。术后104例抽搐症状立即完全消失；2例抽搐症状明显好转，3个月内延迟治愈，总有效率为100％。结论血管压迫可能是面肌痉挛的主要病因。术中REZ的显露、准确判断责任血管、面神经REZ的充分减压，以及垫棉的大小和放置的位置等，是影响手术疗效的重要因素。

Anatomical analysis of offending vessels for hemifacial spasm and the Surgical results of microvascular decompression

Objective To analyze the anatomical relationship between the offending vessels of hemifacial spasm(HFS)and the facial nerve and to provide an anatomical basis for microvascular decompression(MVD)in patients with HFS.Methods The clinical data of 106 patients with HFS treated with MVD from January 2003 to August 2007 were analyzed retrospectively.All patients underwent 3D-TOF-MRA before the operation in order to find out whether the offending vessels existed or not and their origin and running course.During the operation,the root exit zone(REZ)of facial nerve was exposed through the suboccipital retrosigmoid-inferiolateral cerebellum approach.After carefully observing the offending vessels and their origin,a Teflon graft was inserted between the vessels and root exit zone of the facial nerve near the brainstem.Results 3D-TOF-MRA revealed that the positive rate of microvascular compression of facial nerve was 92%.The specific microvascular compression was found in all patients during the operation,and the anterior inferior cerebellar artery accounted for 66%(70/106)in the offending vessels.Apparente vascular impressions were found on the facial nerve at the REZ in 34 patients.The spasm resolved completely immediately after the operation in 104 patients,and the symptoms of spasm improved significantly in 2 patients,and they were cured in three months.The total effective rate was 100%.Conclusions Vascular compression may be the main cause of HFS.Exposing REZ during operation,accurately identifying the offending vessels,fully decompressing of REZ,the size of graft,and location of graft placed are the important factors of influencing surgical efficacy.Skillful microsurgical technique and accurately identifying the offending vessels during the operation,as well as properly decompressing facial nerve are the key factors in improving surgical efficacy and reducing the recurrence of symptoms.