Single Versus Double End-to-Side Nerve Grafts in Rats

PurposeAlthough the end-to-side nerve repair technique has been used clinically, it has not yet produced consistent motor and sensory recovery in patients. The aim of this study was to investigate whether end-to-side double nerve grafts display more axonal regeneration compared with a single nerve graft in a rat lower limb preparation.MethodsThe lower limbs of 96 Wister rats were used in experiments comparing single and double end-to-side nerve grafts. Left peroneal nerves were harvested and grafted between the right peroneal and tibial nerves. A single graft was attached end-to-side to the peroneal and tibial nerves through an epineural window (single graft group, n = 24). Two grafts were performed in the same manner in the double graft group (n = 24). The peroneal nerve was exposed in positive controls (n = 24) and no graft was performed in negative controls (n = 24). We recorded action potentials and moist weights of the left tibialis anterior muscle at each time point. Fluoro-Gold-labeled (Fluorochrome, Denver, CO) dorsal root ganglion neurons from L1 to L6 were counted using fluorescence microscopy and compared among the 4 groups.ResultsIn both single and double groups, the amplitude and the tibialis anterior muscle weight increased significantly compared with negative controls but remained lower than those measured in positive controls. There was no significant difference between single and double groups. In Fluoro-Gold-labeled neurons, there was also no significant difference between single and double groups.ConclusionsThe study showed that regeneration of motor and sensory nerve fibers was possible using 2 end-to-side nerve grafts. However, there was no significant difference between single and double grafts. This might suggest a therapeutic limitation of nerve transplants using 2 end-to-side nerve grafts.Clinical relevanceDouble end-to-side repair attracts both motor and sensory axons, and this results in a medium degree of recovery of function; however, double end-to-side nerve grafting does not appear to offer any advantage over a single end-to-side graft.