Structural and Functional Regeneration of Muscle-Related Axons After Transection and Repair of the Rat Sciatic Nerve Using Nonvascularized Autologous Fascia as a Barrier Between Tibial and Peroneal Nerve Fascicles

Abstract

Aberrant reinnervation of target organs caused by misdirected axonal growth at the repair site is a major reason for the poor functional outcome usually seen after peripheral nerve transection and repair. This study investigates whether the criss-crossing of regenerating rat sciatic nerve axons between tibial and peroneal nerve fascicles can be reduced by using non-vascularized autologous fascia as a barrier. The left sciatic nerve was transected and repaired at midthigh as follows: epineurialy sutures (Group A); fascicular repair of tibial and peroneal nerve fascicles (Group B); fascicular repair of tibial and peroneal nerve fascicles separating the two fascicles by non-vascularized autologous fascia (Group C). In the control Group D, only the left tibial fascicle was transected and repaired. Five months postoperatively, the outcome of regeneration was evaluated by histology, by retrograde tracing, and by assessment of the contraction force of the gastrocnemius and tibial anterior muscles. The tracing experiments showed that muscle reinnervation was less abnormal in Group C than in Groups A and B. However, muscle contraction force was not better in Group C than in Groups A and B. With respect to the peroneal nerve innervated muscle, the contraction force in Group C was significantly lower than in Group B. The histologic picture indicated that this inferior result in Group C was due to nerve compression caused by fibrotic scar tissue at the site of the fascia graft. Results of this study show that a non-vascularized autologous fascial graft used as a barrier between two sutured nerve fascicles in adjacency reduces criss-crossing of regenerating axons between the fascicles, but causes significant nerve compression.