健侧C7神经根移位对修复全臂丛根性撕脱伤术后运动皮层重塑的影响

目的 探讨大鼠全臂丛根性撕脱伤行健侧C7神经根移位术后运动皮层重塑的变化,比较不同术式对运动皮层重塑的影响.方法 建立幼年Sprague-Dawley大鼠左侧全臂丛根性撕脱伤模型90只,随机采用三种不同术式健侧C7神经根移位术治疗,包括健侧C7神经根移位至上干前股(A组,30只),移位至正中和肌皮神经(B组,30只)以及移位至正中神经(C组,30只).分别于术后1.5、3、6、9、12个月,以微电极刺激技术检测各组大鼠患肢支配区在双侧大脑运动皮层的分布.另取6只成年SD大鼠为空白对照组.结果 术后1.5个月,各实验组大鼠患肢支配区仅位于同侧运动皮层;术后3和6个月,患肢支配区均位于双侧运动皮层;术后9个月,A组大鼠患肢支配区已达对侧运动皮层;术后12个月,各实验组大鼠患肢支配区均位于对侧运动皮层,B组运动皮层重塑程度优于C组.结论 幼年大鼠健侧C7神经根移位术后运动皮层患肢支配区可实现由同侧皮层到双侧再到对侧皮层的跨大脑半球功能重翅.健侧C7神经根移位术受体神经的类型影响术后运动皮层重塑,移位至臂丛上干前股或同时移位至正中和肌皮神经更有利于实现运动皮层的跨半球重塑.

An electrophysiological study on brain functional reorganization of different operative modes of contralateral C7 transference treating total brachiai plexus avuision in young rats

Objective To detected the motor cortex reorganization and compared the influence on reorganization process as regard to different transfer modes of contralateral seventh cervical nerve root (C7)in young rats model of total brachial plexus root avulsion. Methods The young Sprague-Dawley rats model of total brachial plexus root avulsion was established. The left radix dorsalis and radix ventralis from the fifth cervical nerve root (C5) to the first thoracic nerve root (T1)were exposed and the roots from C5 to T1 were avulsed from the spinal cord. Then, the contralateral C7 transfer operation was performed. Three different operative modes were applied randomly which included contralateral C7 transference to anterior division of the upper trunk (group A, n=30), to both musculocutaneous and median nerves (group B, n=30), or to median nerve (group C, n=30). The movement evocation of motor cortex was measured by intracortical microstimula-tion in both hemispheres, and functional reorganization was assessed dynamically in 1.5, 3, 6, 9 and 12 months after operation. Results After contralateral C7 transference, the ipsilateral motor cortex initially acti- vated the injured limb at 1.5 month, and subsequently the motor cortex of both hemispheres activated the in-jured limb at the 3rd and 6th month. The injured limb was activated mainly by the contralateral motor cortex in group A at the 9th month. The contralateral motor cortex exclusively controlled the injured limb in all three groups at the 12th month after the operation. Meanwhile, the extent of functional reorganization was better in group B than that of group C. Conclusion After contralateral C7 transfer operation, motor cortex in charging injured limb developed a transhemispheric functional reorganization in young rats with total brachial plexus root avulsion. Different operative modes contributed to the functional reorganization of motor cortex. Transferring contralateral C7 to anterior division of the upper trunk or to both musculocutaneous and median nerves provided better functional reorganization than to median nerve.