THE INFLUENCE OF NERVE CONDUITS DIAMETER IN MOTOR NERVE RECOVERY AFTER SEGMENTAL NERVE REPAIR

Many conduits have demonstrated potential to substitute nerve autografts; however, the influence of conduit inner diameter (ID) has never been studied as a separate parameter. This experimental study compared motor recovery after segmental nerve repair with two different ID collagen conduits: 1.5 and 2.0 mm. In addition, the conduits were analyzed in vitro to determine the variations of ID before and after hydration. Thirty rats were divided into three groups: 2.0 mm ID, 1.5 mm ID, and a control group autograft. After 12 weeks, the 1.5 mm ID group demonstrated significant increase in force (P<0.0001) and weight (P<0.0001) of the tibialis anterior muscle and better histomorphometry results of the peroneal nerve (P<0.05) compared to 2.0 mm ID group; nevertheless, autograft results outperformed both conduits (P<0.0001). Conduits ID were somewhat smaller than advertised, measuring 1.59 +/- 0.03 mm and 1.25 +/- 0.0 mm. Only the larger conduit showed a 6% increase in ID after hydration, changing to 1.69 +/- 0.02 mm. Although autografts perform best, an improvement in motor recovery can be achieved with collagen conduits when a better size match conduit is being used. Minimal changes in collagen conduits ID can be expected after implantation. (c) 2014 Wiley Periodicals, Inc. Microsurgery 34:646-652, 2014.