[An experimental study on outcome of ipsilateral C7 nerve root transfer to repair the root avulsion of the brachial plexus].

OBJECTIVE

To experimentally compare the treatment outcome of the injured upper limb of the root avulsion of C5 and C6 of the brachial plexus repaired by ipsilateral C7 nerve root transfer and other three multiple nerve transfers.

METHODS

One hundred and twenty SD rats of simulated C5 and C6 root avulsion randomly divided into 4 groups, and 30 each underwent various combined nerve transfers. Group A: the ipsilateral C7 root transferred to the upper trunk of brachial plexus and the spinal accessory nerve to the suprascapular nerve; Group B: partial fascicles of the ulnar nerve transferred to the biceps branch (Oberlin's procedure), the spinal accessory to the suprascapular and branches to the triceps long head to the axillary nerve; Group C: the phrenic transferred to the musculocutaneous, cervical plexus motor branches to the lower trunk (axillary nerve) of brachial plexus and the spinal accessory nerve to the suprascapular nerve; Group D: the phrenic transferred to the musculocutaneous and the spinal accessory nerve to the suprascapular nerve. Neurotization outcomes were evaluated at 3, 6 and 12 weeks postoperatively by comparing changes of behavioral tests (Ochiai clinical scores, Barth Foot-fault test and Terzis grooming test), neurophysiological investigations and muscular histology.

RESULTS

At 3 weeks after operation, no significant difference was found between Group A and other three control groups in the three behavioral evaluations. Neurophysiologic investigations of the axillary nerve showed that Group A was superior to the other three groups. Muscular histological outcome of the axillary nerve and deltoid muscle showed that Group A was superior to the Group C and D, while no significant difference was found between Group A and B. Except that the thruput of regenerating medullated musculocutaneous nerve fibers of Group A was superior to Group C, neurophysiological and histological outcome of the musculocutaneous nerve and biceps showed that no significant difference was found between Group A and other three groups. At 12 weeks postoperatively, nearly all the behavioral, neurophysiological and histological determination showed that Group A was superior to the other three groups.

CONCLUSIONS

Ipsilateral C7 transfer to the upper trunk of brachial plexus combined with the spinal accessory nerve to the suprascapular nerve is found to be significantly effective on treatment of the root avulsion of C5 and C6 of the brachial plexus.