Total brachial plexus injury: contralateral C7 root transfer to the lower trunk versus the median nerve
Ye Jiang, PhD, Huashan Hospital, Shanghai, China
Introduction：A rat model for the treatment of total brachial plexus injury (tBPI) has been established. In this model, contralateral C7 (cC7) was transferred to lower trunk via the prespinal route. A quantitative assessment is needed to evaluate the improvement of this new surgical model over the existing ones. The purpose of the experimental study is to compare the efficacy of finger flexion after cC7 transfer to either lower trunk via the prespinal route or median nerve bridged by vascularized ulnar nerve graft via subcutaneous tunnel for repair of tBPI in a rat model.
Materials & Methods：Ninety adult Sprague-Dawley rats were randomly assigned to three groups with 30 each, including group A (cC7 transfer to lower trunk), group B (cC7 transfer to median nerve), and group C (healthy control). Postoperative reanimation of finger flexion in the two experimental groups was evaluated by the grasping test, electrophysiological study, myophysiologic test, wet muscle weight, muscle fiber cross-sectional area measurements and myelinated nerve fiber counts.
Results：After the operations, the function of forearm flexor muscles in both experimental groups recovered gradually. We did not observe complete restoration by the end of the 12-week observation. Finger flexion was observed at 8 weeks postoperatively. The muscle wet weight maintaining rate of forearm flexor muscles in group A was greater than that in group B at 4, 8 and 12 weeks postoperatively (P< 0.05). The results of grasping test and myophysiologic test of group A were better than those in group B at 8 and 12 weeks postoperatively (P<0.05). There were no significant differences between group A and B in electrophysiological evaluation, cross-sectional area of the flexor digitorum superficialis muscle and myelinated nerve fiber counts of median nerve at every postoperative interval.
Conclusions： For finger flexion reconstruction in rats with tBPI, it is more effective to transfer cC7 to lower trunk via the prespinal route than to median nerve bridged by vascularized ulnar nerve graft via subcutaneous tunnel. Therefore, it can yet be regarded as an alternative method.
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