The Incidence of Positive Modifications to Nerve Conduits in Rodent Nerve Repair Models

摘要

Biological and nonbiological conduits have become a common tool for overcoming short gaps in peripheral nerve repair. While avoiding the increased surgical time and morbidity associated with harvesting of autograft, they offer an efficient and convenient method for avoiding tension in situations of minimal nerve loss or nerve retraction.13,14 There are clinical and experimental data to support this clinical usage; however, results are often unpredictable, particularly with gaps greater than a few centimeters and in larger diameter nerves.13,14,27 These limitations have motivated research aimed at evolving and improving current conduit design.Current conduit designs create a relative protected microenvironment within nerve tubes allowing neurotrophic factors to accumulate and a fibrin clot forms between the nerve ends.3,17 This clot, which becomes progressively unstable with increasing lengths, acts as a scaffold to allow Schwann cells and subsequently axons to migrate across the gap.3,8,22,25 As researchers move toward the next generation of nerve conduits, common areas of “enhancement” include intraluminal fillers, alterations in conduit wall materials, and the addition of various growth and neurotrophic factors. With such a myriad of potential enhancements, the best single or even combined approach is difficult to predict.2 Small animal nerve regeneration models theoretically provide a research tool that could help unravel this complex question. However, when reviewing the animal literature on nerve conduits to discern what modifications may be of therapeutic benefit, it is often confusing as it seems that all modifications seem to do well. To verify and better understand this observation, we systematically reviewed the available scientific literature with the hypothesis that almost all published rodent conduit repair studies will show positive results, regardless of specific modifying strategy suggesting an underlying bias in the literature.