A successful neurotization of two different muscles using a single intact motor nerve: experimental study on rats

The development of microsurgical techniques and better understanding of nerve biology has resulted in significant improvement in the results of nerve repair. Some problems are still present. What would be the method of choice if 2 transected nerves were to be coapted and only one neighboring intact nerve was available? We performed neurotization of 2 different muscles by a single intact nerve, using only one nerve graft by reverse end-to-side coaptation that has already been introduced into the literature. We assessed the results histomorphologically and functionally. Twenty-four adult rats were used in the present study and equally divided into 4 groups. Group 1 (n = 6): Control group; Group 2 (n = 6): Unrepaired nerve damage group; Group 3 (n = 6): End-to-end repair group. The peroneal branch of the sciatic nerve was excised to obtain an approximate size of 2 cm-graft, which was subsequently divided into 2 equal pieces to obtain 2 pieces of grafts each 1 cm long. Then, the tibial branch of the sciatic nerve was also cut to produce a nerve defect. End-to-end coaptation was obtained. A “V” shape was obtained. Group 4 (n = 6): Reverse end-to-side repair group. The peroneal branch of the sciatic nerve was excised as a graft approximately 2-cm in length. Subsequently a defect was produced by cutting the tibial branch of the sciatic nerve. Coaptation was performed by suturing the dissected proximal end of the tibial nerve by reverse end-to-side coaptation. A “U” shape resembling a horse shoe was obtained. The success of Group 4 was demonstrated when both peek-to-peek and latency timing of extensor digitorum and gastrocnemius muscles, determined as the target organ, were evaluated. Besides, an equal distribution was observed in Group 4 when number of myelinated (P = 0.596) and unmyelinated (P = 0.936) axons in both legs of grafts were compared with each other. However, myelinated axons were not equally distributed between the legs of the nerve graft in Group 3 (P = 0.027). In conclusion, reverse end-to-side coaptation is a useful technique for 2 different muscle neurotization via a single nerve graft and a single nerve coaptation with a donor nerve.