肱三头肌及指总伸肌电生理支配权重分析在同侧C_7神经根移位术中的临床意义

CLINICAL SIGNIFICANCE OF ELECTROPHYSIOLOGICAL DOMINANCE ANALYSIS OF TRICEPS BRACHII MUSCLE/EXTENSOR DIGITORUM COMMUNIS MUSCLE INNERVATION IN IPSILATERAL C_7 TRANSFER

目的分析在健侧C7神经根移位术中得出的臂丛神经各干对肱三头肌/指总伸肌的电生理支配权重,推断其对于同侧C7神经根移位术的影响,为探讨其安全性和适应证提供电生理依据。方法随机选择2007年8月-2007年10月15例全臂丛神经根性撕脱伤,行健侧C7神经根移位的患者。男13例,女2例;年龄18～49岁,平均28岁。致伤原因:坠落伤1例,压砸伤2例,余均为车祸伤。左侧8例,右侧7例。术中依次刺激健侧臂丛神经上、中、下干,于肱三头肌/指总伸肌记录复合肌肉动作电位(compound muscle action potential,CMAP),比较各干的CMAP波幅所占百分比,确定臂丛神经各干对肱三头肌/指总伸肌的电生理支配权重。术后6个月内随访肱三头肌/指总伸肌肌力,并复查肌电图了解其自发电活动和主动募集反应情况。结果15例患者均获随访6个月。肱三头肌的电生理支配权重:上中干型3例(20%),中下干型3例(20%),全干型7例(47%),中干型2例(13%);指总伸肌:中下干型3例(20%),全干型10例(67%),下干型2例(13%)。肱三头肌:术后1个月,2例出现肱三头肌肌力4级,募集反应单纯相,至术后3个月恢复正常。余患者术后1个月肌力均达5级,募集反应单纯混合相或混合相。指总伸肌:术后1个月,患者肌力及募集反应均恢复正常。结论对于各种电生理支配权重的患者,C7神经根的切取均不会造成肱三头肌和指总伸肌的实质性损害,同侧C7神经根移位术是安全可行的;但对于中干支配权重高的患者,采用同侧C7神经根全干移位应慎重,有可能造成肱三头肌短期内的肌力下降。

Objective To analysis the electrophysiological dominance weight of the triceps brachii muscle/extensor digitorum communis muscle innervated by brachial plexus and to conclude its effect on the ipsilateral C7 transfer so as to offer electrophysiological data for the safety and indication of ipsilateral C7 transfer. Methods From August 2007 to October 2007, 15 patients with complete brachial plexus nerve root avulsion received contralateral C7 transfer. There were 13 males and 2 females aged 18-49 years （28 years on average）. Injury was caused by falling in 1 case, by crush in 2 cases and by traffic accident in 12 cases, involving left side in 8 cases and right side in 7 cases. The upper, middle and lower trunk of the brachial plexus were stimulated respectively, the compound muscle action potential （CMAP） at the triceps brachii muscle/extensor digitorum communis muscle was recorded, and then the electrophysiological dominance weight of the triceps brachii muscle/extensor digitorum communis muscle innervated by brachial plexus was confirmed according to the comparison of the amplitude percentage of the CMAP by three trunks. The muscle strength of triceps brachii muscle/extensor digitorum communis muscle was evaluated and the electromyogram was taken 6 months after operation. Results All patients were followed up for 6 months. Concerning the electrophysiological dominance weight, the triceps brachii muscle was mainly innervated by upper- middle trunk in 3 cases （20%o）, by middle-lower trunk in 3 cases （20%）, by whole trunk in 7 cases （47%） and by middle trunk in 2 cases （13%）. While the extensor digitorum communis muscle was mainly innervated by middle-lower trunk in 3 cases （20%）, by whole trunk in 10 cases （67%） and by lower trunk in 2 cases （13%）. Concerning the triceps brachii muscle, 2 patients got the muscle strength of 4 grade with recruitment simple phase at 1 month after operation and returned to normal at 3 month after operation, while 13 patients got the muscle strength of 5 grade with recruitment simple or mixed phase at t month after operation. Concerning the extensor digitorum communis muscle, the muscle strength and the recruitment phase of all 15 patients recovered to normal at 1 month after operation. Conclusion To patients with various kinds of electrophysiological dominance weight, the cutting of C7 does not substantially damage the triceps brachii muscle or extensor digitorum communis muscle, indicating that the ipsilateral C7 transfer is safe and feasible. However, it should be applied prudently for the patients with high dominance weight since it may result in the short-term decrease of triceps brachii muscle strength.