健侧C_7神经根移位术后患肢对应皮层体感诱发电位的变化规律

Study on alterative regularity of somatosensory evoked potential for detecting re-domination process of corresponding cerebral cortex of affected extremity after healthy C_7 nerve root transfer

目的对照已行健侧C7神经根移位术患者与正常人的皮层体感诱发电位(somatosensoryevokedpotential,SEP),了解、分析大脑重塑过程中电生理变化特点。方法12例左侧臂丛神经撕脱伤已行健侧C7→尺神经→正中神经重建患者,其中6例患肢感觉在健侧者为A组,感觉转到患侧者为B组;同时以12位正常人作为对照组。利用SEP技术,刺激左上肢正中神经腕部、肘部,分别记录左右两侧皮层SEP的波形,测定其潜伏期、波幅和腕→肘神经传导速度,并进行统计学比较。结果正常人两侧皮层SEP的潜伏期、波幅之间存在差异,但潜伏期差异无显著性,而波幅差异有显著性。A组患者两侧皮层间SEP潜伏期差异有显著性,波幅差异无显著性。B组患者两侧皮层间SEP潜伏期差异无显著性,而波幅差异则存在显著性。A组与B组患者对侧皮层SEP潜伏期和波幅差异均有显著性。结论健侧C7神经根移位术后,患肢对侧皮层发生功能重塑,两侧皮层记录的SEP潜伏期差值缩短,而波幅差异增大。患侧SEP检测可为患肢对应皮层功能重塑的“再支配”现象提供相应佐证与数据,为临床采取进一步措施促进患者肢体与大脑皮层功能的恢复提供客观依据。

Objective To analyse the alterative characteristics of electrophysiology by detecting somatosensory evoked potential(SEP) during cerebral remodeling after transfer of healthy C7 nerve root both in patients and normal individuals. Methods From 2002 to 2003, 12 cases of the left total brachial plexus nerve root avulsion were surgically treated by transferring healthy C7 nerve root to impaired median nerve through bridged ulnar nerve. The waveform of SEP of bilateral cortical expressions were recorded after stimulating median nerve of impaired upper extremity at the wrist and elbow. Meanwhile, latent period and amplitude of wave of SEP, and nerve conduction velocity from the level of wrist to elbow were exhibited and compared. Results There were differences of the latency and amplitude of SEP in normal individuals between two sides of cerebrum to some extent. In the healthy sides (first group), difference of latency of SEP on two sides of cerebral cortex had no statistical significance but in the reverse for the amplitude of SEP. For the diseased sides(second group), difference of amplitude of SEP for both sides of cerebral cortex between the patients and the nonmal individuals were of statistical significance, but on the contrary for the change of latency of SEP. Conclusion Cerebral cortex dominating affected extremity is able to bring up functional remodeling electrophysiologically after nerve transfer of healthy C7 nerve root. Shortened latency and augmented amplitude discrepancy of SEP recorded on both sides of cerebral cortex were preliminary electrophysiological criterions. After contralateral C7 nerve root transfer, the examination of SEP can offer data of corresponding cortex 'reinnervation', which provides objective evidence for further treatment to promote functional recovery and cortical plasticity.