Outcomes of end-to-end nerve repairs are more successful compared with outcomes of repairs bridged by nerve grafts. However, end-to-end repairs are not always possible for large nerve gaps, as excessive tension may cause catastrophic failure. In this study, we built on previous nerve-lengthening studies to test the hypotheses that gradual lengthening of the proximal stump across a large nerve gap enables an end-to-end repair and such a repair results in more favourable regenerative outcomes than autografts, which represent the gold standard in bridging nerve gaps. To test these, we compared structural and functional outcomes in Lewis rats after repair of sciatic nerve gaps using either autografts or a novel compact internal fixator device, which was used to lengthen proximal nerve stumps towards the distal stump over 2 weeks, prior to end-to-end repair. Twelve weeks after the initial injury, outcomes following nerve lengthening/end-to-end repair were either comparable or superior in every measure compared with repair by autografting. The sciatic functional index was not significantly different between groups at 12 weeks. However, we observed a reduced rate of contracture and corresponding significant increase in paw length in the lengthening group. This functional improvement was consistent with structural regeneration; axonal growth distal to the injury was denser and more evenly distributed compared with the autograft group, suggesting substantial regeneration into both tibial and peroneal branches of the sciatic nerve. Our findings show that end-to-end repairs following nerve lengthening are possible for large gaps and that this strategy may be superior to graft-based repairs.

中文翻译：

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与自体移植大鼠坐骨神经缺损相比，神经延长和随后的端到端修复产生了更好的结果。

与通过神经移植桥接的修复结果相比，端对端神经修复的结果更为成功。但是，由于神经张力过大可能会导致灾难性的故障，因此对于大的神经间隙而言，端对端修复并不总是可能的。在这项研究中，我们建立在以前的神经延长研究的基础上，以检验以下假设：跨大神经间隙逐渐延长近端树桩能够进行端到端修复，并且这种修复所产生的再生结果比自体移植更为有利。代表弥合神经间隙的金标准。为了测试这些结果，我们比较了使用自体移植物或新型紧凑型内部固定器装置修复坐骨神经间隙后在Lewis大鼠中的结构和功能结局，该装置用于在2周内将近端神经残端向远端残端延长，在进行端到端修复之前。初始损伤后十二周，与自体移植修复相比，神经延长/端对端修复后的各项结果在各方面均具有可比性或优越性。各组在12周时的坐骨神经功能指数无显着差异。但是，我们观察到拉长组的挛缩率降低，爪长显着增加。这种功能上的改进与结构再生是一致的。与自体移植组相比，损伤远端的轴突生长更密集且分布更均匀，这表明坐骨神经的胫骨和腓骨分支均大量再生。