An electrophysiological study on brain functional reorganization of different operative modes of contralateral C7 transference treating total brachiai plexus avuision in young rats / 中华骨科杂志

ABSTRACT

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.