Fibrin Glue and Conduit Form a Composite Structure in Digital Nerve Repair

Repair of severed nerves without autograft or allograft has included suture, suture with glue alone, suture with conduit and suture with glue augmentation to conduit, where use of conduit is considered for separation of the nerve ends from 5 mm to 3 cm. Repairs must not only serve acutely to provide apposition of nerve ends but must enable the healing of the nerve. Using biological conduit can place suture at the ends of the conduit while fibrin glue alone eliminates suture but with limited strength. The combination of conduit and glue offers the growth guidance of conduit with sufficient strength from the glue to maintain the nerve within the conduit. The role of fibrin glue in the integrity of the repair remains an open question, however. We sought to determine the factors in the strength of a glue-conduit-nerve construct and include consideration of standard suture repair. Fresh-frozen cadaveric digital nerves were repaired with suture alone, with glue alone or with suture and glue together and then loaded to failure. Previously tested specimens with conduit, suture and glue were considered for comparison. The suture alone (2.02 N) and suture with glue (2.24 N) were not statistically different from each other but were statistically stronger than glue alone (0.15 N). When compared to the earlier results of the strength of conduit with glue (0.65 N), these simple results show that the glue and conduit act together. The increased area over which the glue adheres to the nerve and conduit creates a composite structure stronger than either alone.