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.