Nerve Re-innervations by an End-to-side Neurorrhaphy of Myocutaneous Transplantation in Rats

End-to-side (terminolateral) neurorrhaphy was first documented in the 19(superscript th) century, but it hasnt been routinely practiced. The purpose of this study is to evaluate nerve reinnervation after isogeneic or allogeneic end-to-side neurorrhaphy in a novel rat myocutaneous model. The obturator nerve with a gracilis muscle island flap from the donor was sutured end-to-side to the obturator nerve of the recipient through an epineurial window. The obturator nerves of the recipients distal to the neurorrhaphy site were either intact or severed. The evaluation of nerve reinnervation was dependent on the stimuli-induced muscle contraction, the histological and morphological observations, and the counting of nerve axons in a cross section. Results revealed that nerve reinnervation crossing the end-to-side neurorrhaphy sites was significant in all experimental groups. The axon counts of the receiving nerves distal to the neurorrhaphy sites were not statistically different between groups with transection and without transection of the distal nerve, and neither iso-transplantation nor allotransplantation exhibited difference. Functional recovery could be observed after both iso-and allotransplantations. In addition, immunosuppression did not affect the end-to-side nerve reinnervation in the allograft group. This result indicates that nerve reinnervation and functional recovery could be restored by the end-to-side neurorrhaphy of receiving either iso-or allo-transplantation.