The Effectiveness of Contralateral C7 Nerve Root Transfer for the Repair of Avulsed C7 Nerve Root in Total Brachial Plexus Injury: An Experimental Study in Rats

Abstract

The aim of this study was to evaluate the feasibility and effectiveness of transferring the contralateral C7 root to repair avulsed C7 nerve root. Thirty rats were randomized into three groups. In group A, rats underwent whole-root avulsion of the left brachial plexus and contralateral C7 root transfer to the avulsed C7 nerve root. In group B, rats underwent whole-root avulsion and contralateral C7 root transfer to the radial nerve. In group C, rats underwent whole-root avulsion of the left brachial plexus without nerve transfer. Functional outcomes were measured by electrophysiological studies, muscle tetanus contraction force, muscle mass, and histology. Six months postoperatively, increased amplitude and shortened latency of compound muscle action potentials, larger maximum tetanic contractile tension, heavier muscle mass, and larger cross-sectional area of the muscle fibers were observed in the triceps, extensor carpi radialis brevis, and extensor digitorum in groups A and B when compared with group C (p < 0.01). There were no significant differences between group A and B (p > 0.05). Contralateral C7 nerve transfer to repair avulsed C7 nerve root was feasible and effective in this rat model. It should be considered as an option for the treatment of brachial plexus injuries.

Keywords

nerve transfer - contralateral C7 - brachial plexus - radial nerve

• References

• 1 Gu YD, Zhang GM, Chen DS, Yan JG, Cheng XM, Chen L. Seventh cervical nerve root transfer from the contralateral healthy side for treatment of brachial plexus root avulsion. J Hand Surg Br 1992; 17 (5) 518-521
• 2 Mcguiness CN, Kay SP. The prespinal route in contralateral C7 nerve root transfer for brachial plexus avulsion injuries. J Hand Surg Br 2002; 27 (2) 159-160
• 3 Terzis JK, Kokkalis ZT. Selective contralateral c7 transfer in posttraumatic brachial plexus injuries: a report of 56 cases. Plast Reconstr Surg 2009; 123 (3) 927-938
• 4 Chen L, Gu YD. An experimental study of contralateral C7 root transfer with vascularized nerve grafting to treat brachial plexus root avulsion. J Hand Surg Br 1994; 19 (1) 60-66
• 5 Song J, Chen L, Gu YD. Functional compensative mechanism of upper limb with root avulsion of C(5)-C(6) of brachial plexus after ipsilateral C(7) transfer. Chin J Traumatol 2008; 11 (4) 232-238
• 6 Wang H, Spinner RJ, Windebank AJ. Quantitative evaluation of movement and strength of the upper limb after transection of the C-7 nerve: is it possible in an animal model?. J Neurosurg Spine 2009; 10 (2) 102-110
• 7 Xu JG, Gu YD, Hu SN, Wang H, Chen L. Electrophysiologic study of influence on C7 innervated muscles after transection of different C7 fascicles. Microsurgery 2004; 24 (2) 147-150
• 8 Vredeveld JW, Blaauw G, Slooff BA, Richards R, Rozeman SC. The findings in paediatric obstetric brachial palsy differ from those in older patients: a suggested explanation. Dev Med Child Neurol 2000; 42 (3) 158-161
• 9 Lu W, Xu JG, Wang DP, Gu YD. Microanatomical study on the functional origin and direction of the thoracodorsal nerve from the trunks of brachial plexus. Clin Anat 2008; 21 (6) 509-513
• 10 Gu YD, Chen DS, Zhang GM , et al. Long-term functional results of contralateral C7 transfer. J Reconstr Microsurg 1998; 14 (1) 57-59
• 11 Gu YD, Xu JG, Chen L, Wang H, Hu SN. Long term outcome of contralateral C7 transfer: a report of 32 cases. Chin Med J (Engl) 2002; 115 (6) 866-868