The effect of collagen nerve conduits filled with collagen- glycosaminoglycan matrix on peripheral motor nerve regeneration in a rat model

Background: Bioabsorbable unfilled synthetic nerve conduits have been used in the reconstruction of small segmental nerve defects with variable results, especially in motor nerves. We hypothesized that providing a synthetic mimic of the Schwann cell basal lamina in the form of a collagen-glycosaminoglycan (GAG) matrix would improve the bridging of the nerve gap and functional motor recovery. Methods: A unilateral 10-mm sciatic nerve defect was created in eighty-eight male Lewis rats. Animals were randomly divided into four experimental groups: repair with reversed autograft, reconstruction with collagen nerve conduit (1.5-mm NeuraGen, Integra LifeSciences), reconstruction with collagen nerve conduit filled with collagen matrix, and reconstruction with collagen nerve conduit filled with collagen-GAG (chondroitin-6-sulfate) matrix. Nerve regeneration was evaluated at twelve weeks on the basis of the compound muscle action potential, maximum isometric tetanic force, and wet muscle weight of the tibialis anterior muscle, the ankle contracture angle, and nerve histomorphometry. Results: The use of autograft resulted in significantly better motor recovery compared with the other experimental methods. Conduit filled with collagen-GAG matrix demonstrated superior results compared with empty conduit or conduit filled with collagen matrix with respect to all experimental parameters. Axon counts in the conduit filled with collagen-GAG matrix were not significantly different from those in the reversed autograft at twelve weeks after repair. Conclusions: The addition of the synthetic collagen basal-lamina matrix with chondroitin-6-sulfate into the lumen of an entubulation repair significantly improved bridging of the nerve gap and functional motor recovery in a rat model. Clinical Relevance: Use of a nerve conduit filled with collagen-GAG matrix to bridge a motor or mixed nerve defect may result in superior functional motor recovery compared with commercially available empty collagen conduit. However, nerve autograft remains the gold standard for reconstruction of a segmental motor nerve defect.