No Difference in Outcomes Detected Between Decellular Nerve Allograft and Cable Autograft in Rat Sciatic Nerve Defects

BACKGROUND: Nerve injuries with a gap/defect represent a clinical challenge without a clear solution. Reconstruction with cable autografts is a common treatment technique, and repair with decellular nerve allograft is a newer option. The purpose of this study was to compare the functional outcomes of reconstruction with cable autografts with those of matched-diameter decellular nerve allografts to evaluate the relative importance of diameter as well as the autograft-versus-allograft nature of the reconstruction. METHODS: A unilateral 10-mm sciatic nerve defect was created in 81 genetically identical male Lewis rats and then repaired with a reverse autograft, 4 or 5 sural nerve cable autografts, or a matched-diameter decellular nerve allograft. In each group, at each time point (12, 16, and 20 weeks), all 9 animals underwent functional testing and 5 of the 9 underwent histologic analysis. Functional testing included bilateral measurements of the isometric tetanic force of the tibialis anterior (primary outcome), the weight of the tibialis anterior, and the gastrocnemius compound muscle action potential (CMAP) latency. Histologic evaluation included an axon count as well as measurement of the axon density, fiber diameter, myelin thickness, and G-ratio. RESULTS: The repair groups did not differ significantly in terms of isometric tetanic force, muscle weight, or CMAP latency, but these measurements did differ significantly according to the time after surgery (p < 0.05). The isometric tetanic force percent recovery (width of the 95% confidence interval) for the reverse autograft, cable autograft, and decellular nerve allograft was 57.7% (15.6%), 57.0% (23.4%), and 56.0% (19.7%), respectively, at 12 weeks; 69.1% (14.7%), 65.6% (18.5%), and 65.9% (29.1%) at 16 weeks; and 72.5% (18.2%), 73.7% (25.6%), and 71.8% (22.4%) at 20 weeks. Isometric tetanic force and muscle weight recovery were greater and CMAP latency was shorter at 20 and 16 weeks after surgery than they were at 12 weeks. The treatment type did not affect any of the histologic outcomes. CONCLUSIONS: In this animal study, we found that matched-diameter decellular nerve allograft was not significantly different from reverse autograft or cable graft reconstruction in terms of function and histologic outcomes. These findings support decellular nerve allograft as a viable treatment option for nerve reconstruction. CLINICAL RELEVANCE: This study showed that decellular nerve allograft was no different from cable or reverse autograft in terms of outcome measures in a rat sciatic nerve defect model. If these results are applicable clinically, it would obviate the need for autograft nerve harvest and its ensuing donor site morbidity.