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 / 中华骨科杂志

ABSTRACT

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.