Purpose: As alternatives to nerve grafts for peripheral nerve repair, we have synthesized 12 mm long poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (PHEMA-MMA) porous tubes and studied their regenerative capacity for the repair of surgically-created 10 mm rat sciatic nerve gaps. We compared the in vivo regenerative efficacy of these artificial tubes with the gold standard, the nerve autograft.
Methods: Tubes were assessed in vivo for their ability to support nerve regeneration at 4, 8, and 16 weeks post-implantation by histology, electrophysiology, histomorphometry, and reinnervated lateral gastrocnemius (LG) dry muscle mass.
Results: Axonal regeneration within the tubes was observed by 8 weeks, with outcome parameters comparable to autografts. This finding was further supported by the electrophysiological and histomorphometric results. The 16 week tube group had a bimodal response, with 60% of the tubes having a similar response to autografts and the other 40% having significantly lower (p < 0.05) outcome measures in several parameters.
Conclusions: Axonal regeneration in artificial tubes was similar to that in autografts at 8 and 16 weeks, however, a bimodal distribution of regeneration was observed in 16 week tubes.