Selective Transfer of the C7 Nerve Root: An Experimental Study

The authors present selective C7 nerve root transfer in a rat model. The musculocutaneous nerve was neurotized by various portions of ipsilateral C7. The latent period and maximum amplitude of evoked motor action potential of the biceps, number of regenerating myelinated nerve fibers, cross-sectional area and wet weight of the biceps, and twitch and tetanic tensions of the biceps were measured at four postoperative intervals. In the early postoperative period (1 and 2 months), nerve regeneration in neurotization with the posterior division or the anterior division of C7 was significantly better than that with the anterolateral fascicles of the anterior division or the phrenic nerve. As the postoperative interval prolonged, the parameters of nerve regeneration in the latter two groups approximated those in the former two groups. This indicated that there were enough regenerating nerve fibers in the anterolateral fascicles of the anterior division and a promising potential for nerve regeneration. The clinical significance of the results lies in the design of selective C7 transfer which, using the anterolateral fascicles of the anterior division, could preserve the function of the muscles innervated by the posterior division to the greatest extent, and provide sufficient donor outflow as well. It is therefore a new option for C7 transfer.

KEYWORDS

C7 nerve root - nerve transfer - animal experiment

REFERENCES

• 1 Gu Y D. Microsurgical treatment for brachial plexus root avulsion. In: Gu YD Diagnosis and Treatment of Injuries and Disorders of the Brachial Plexus, 2nd ed. Shanghai; 2001: 49-76
• 2 Gu Y D, Zhang G M, Chen D S et al.. Cervical nerve root transfer from contralateral normal side for treatment of brachial plexus root avulsions.  Chin Med J (Engl). 1991;  104 208-211
• 3 Gu Y D, Zhang G M, Chen D S, Yan J G, Cheng X M, Chen L. Seventh cervical nerve root transfer from the contralateral healthy side for treatment of brachial plexus root avulsion.  J Hand Surg. 1992;  17B 518-521
• 4 Chen L, Gu Y D. An experimental study of contralateral C7 root transfer with vascularized nerve grafting to treat brachial plexus root avulsion.  J Hand Surg. 1994;  19B 60-66
• 5 Gu Y D, Chen D S, Zhang G M et al.. Long-term functional results of contralateral C7 transfer.  J Reconstr Microsurg. 1998;  14 57-59
• 6 Gu Y D, Shen L Y. Electrophysiological changes after severance of the C7 nerve root.  J Hand Surg. 1994;  19B 69-71
• 7 Gu Y D. Distribution of the sensory endings of the C7 nerve root and its clinical significance.  J Hand Surg. 1994;  19B 67-68
• 8 Liu J, Pho R W, Kour A K. Neurologic deficit and recovery in the donor limb following cross-C7 transfer in brachial plexus injury.  J Reconstr Microsurg. 1997;  13 237-242
• 9 Xu J G, Hu S N, Wang H, Gu Y D. Histochemical study on the C7 root and its clinical significance.  Chin J Clin Anat. 1996;  14 243-245
• 10 Xu J G, Gu Y D, Hu S N, Wang H. Comparative study on sensory change after selective C7 root transfer.  Chin J Hand Surg. 1996;  12(suppl) 24-26
• 11 Gu Y D, Ma M K. Nerve transfer for treatment of root avulsion of the brachial plexus: experimental studies in a rat model.  J Reconstr Microsurg. 1991;  7 15-22
• 12 Gu Y D, Wu M M, Zhen Y L et al.. Phrenic nerve transfer for brachial plexus motor neurotization.  Microsurgery. 1989;  10 287-289
• 13 Xu J G, Hu S N, Wang H, Shen L Y, Gu Y D. A study of the clinical application of ipsilateral selective C7 transfer.  Chin J Hand Surg. 1999;  15 151-153
• 14 Gu Y D, Cai P Q, Xu F, Peng F, Chen L. Clinical application of ipsilateral C7 nerve root transfer for treatment of C5 and C6 avulsion of brachial plexus.  Microsurgery. 2003;  23 105-108
• 15 Xu F, Cai P Q, Gu Y D, Chen D S. Influence of ipsilateral nerve root transfer on its innervating muscles: a preliminary report.  Chin J Hand Surg. 2001;  17 133-135