Functional recovery after peripheral nerve injury and implantation of a collagen guide

Although surgery techniques improved over the years, the clinical results of peripheral nerve repair remain unsatisfactory. In the present study, we compare the results of a collagen nerve guide conduit to the standard clinical procedure of nerve autografting to promote repair of transected peripheral nerves. We assessed behavioral and functional sensori-motor recovery in a rat model of peroneal nerve transection. A 1 cm segment of the peroneal nerve innervating the Tibialis anterior muscle was removed and immediately replaced by a new biodegradable nerve guide fabricated from highly purified type I + III collagens derived from porcine skin. Four groups of animals were included: control animals (C, n = 12), transected animals grafted with either an autologous nerve graft (Gold Standard; GS, n = 12) or a collagen tube filled with an acellular skeletal muscle matrix (Tube-Muscle; TM, n = 12) or an empty collagen tube (Collagen-Tube; CT, n = 12). We observed that 1) the locomotor recovery pattern, analyzed with kinetic parameters and peroneal functional index, was superior in the GS and CT groups; 2) a muscle contraction was obtained in all groups after stimulation of the proximal nerve but the mechanical muscle properties (twitch and tetanus threshold) parameters indicated a fast to slow fiber transition in all operated groups; 3) the muscular atrophy was greater in animals from TM group; 4) the metabosensitive afferent responses to electrically induced fatigue and to two chemical agents (KCl and lactic acid) was altered in GS, CT and TM groups; 5) the empty collagen tube supported motor axonal regeneration. Altogether, these data indicate that motor axonal regeneration and locomotor recovery can be obtained with the insertion of the collagen tube RevolNerv®. Future studies may include engineered conduits that mimic as closely as possible the internal organization of uninjured nerve.