脊髓损伤患者双下肢神经肌肉的电生理特征

The electrophysiological changes of lower limbs in subjects with spinal cord injury

目的:采用神经传导测定及肌电图观察脊髓损伤(SCI)患者双下肢神经肌肉电生理变化,为脊髓损伤后双下肢神经肌肉功能判断提供依据。方法:19例脊髓损伤患者,采用常规神经传导检测方法测定双胫、腓总神经运动及感觉传导,分析末端潜伏期、动作电位波幅及传导速度。采用同心圆针电极检测双侧胫前肌、腓肠肌、股四头肌及L4—S1脊旁肌自发肌电活动(SA)。结果:①神经传导特征:94.7%患者运动传导异常,表现为单纯复合肌肉动作电位(CMAP)波幅降低、波幅降低伴潜伏期延长、动作电位缺失三种类型;15.8%的患者同时伴有感觉传导异常,表现为波幅降低、传导速度减慢或动作电位缺失;②胫神经:单纯运动传导异常占47.4%,运动与感觉传导均异常占10.5%;运动传导均表现为双侧异常(动作电位缺失、波幅减低和/或潜伏期延长);感觉传导表现为单侧传导速度减慢和/或波幅降低;③腓总神经:单纯运动异常占78.9%,运动与感觉均受累为15.8%;运动传导双侧异常为84.2%(动作电位缺失和/或波幅降低),单侧异常为10.5%(波幅降低和/或潜伏期延长);感觉传导异常为双侧或单侧动作电位缺失、传导速度降低和波幅降低(15.8%);④胸腰段SCI的胫、腓神经运动传导异常显著高于颈段SCI(腓神经为100%:85.7%,胫神经为66.7%:42.9%)。⑤肌肉自发电活动:所有患者双下肢肌肉及脊旁肌均见不同程度的自发电活动,包括纤颤电位、正锐波。结论:脊髓损伤后双下肢电生理主要表现为运动神经轴索性损害及肌肉异常自发电活动,肌肉异常自发电活动与下肢周围神经电生理改变无关;胸腰段脊髓损伤下肢周围神经传导异常比例高于颈段脊髓损伤。

Objective：To investigate the electrophysiological changes of peripheral nerves and muscles of lower limbs in patients with spinal cord injury（SCI）.Method：Standard sensory and motor nerve conductions examination were performed in tibial nerve,peroneal nerve to analyze distal motor latency,compound muscle action potential（CMAP）,sensory nerve conduction velocity（SNCV） and Sensory nerve action potential（SNAP）.Concentric needle electromyography was used in examination of bilateral tibial anterior,vastus medialis,lateral gastrocnemius and paraspinal musles at L4—S1 level to record spontaneous activities（SA）.Result：①Characteristics of nerve conduction：94.7% patients had abnormal motor nerve conduction with decreased CMAP amplitude,prolonged distal motor latency（DML） and absent response.Abnormal sensory conductions were found in 15.8% patients,including slowed SNCV,low SNAP amplitude and no response.②Tibial nerve：Simple abnormal motor conductions were found in 47.4% patients and abnormal motor and sensory conductions coexisted in 10.5% patients.Abnormal motor conductions were seen in both sides（no response,decreased CMAP amplitude and/or prolonged DML）.The characteristics of sensory conduction were unilaterally slowed SNCV and decreased SNAP amplitude.③Peroneal nerve：Simple abnormal motor conductions were found in 78.9% patients and abnormal motor and sensory conduction coexist in 15.8% patients.84.2% patients had bilaterally abnormal motor conductions with no response and/or decreased CMAP amplitude.Unilaterally abnormal conductions were seen in 10.5% patients with decreased CMAP amplitude and delayed DML.The characteristics of sensory conduction showed slowed SNCV,decreased SNAP amplitude and no response in one or both sides（15.8%）.④Compared to cervical level SCI,the ratio of abnormal conduction of tibial（66.7%：42.9%） and peroneal nerve（100%：85.7%） in thoracolumbar level SCI increased significantly.⑤SA,including fibrillations and positive sharp waves,were noted at variable degrees in all muscles examined.Conclusion：Axonal motor neuropathy and abnormal SA in lower extremities were the main electrophysiological characteristics in patients with SCI.And there was no correlation between SA and the electrophysiological changes of peripheral nerves.The ratio of abnormal nerve conduction of lower extremities with thoracolumbar level SCI was higher than that with cervical level.