LONG-TERM EVALUATION OF NERVE REGENERATION IN A BIODEGRADABLE NERVE GUIDE

Nerve regeneration using artificial biodegradable conduits is of incre asing interest. The aim of this study is to evaluate the regeneration and maturation of a nerve after long-term implantation (2 years) of a biodegradable poly-L-lactide/poly-E-caprolactone (PLLA/PCL) copolymeri c nerve guide in the sciatic nerve of the rat. After harvesting, we ev aluated both the regenerated nerves and the controls, using light micr oscopy, transmission electron microscopy, and morphometric techniques. Remnants of biomaterial were still present after 2 years of implantat ion, but the foreign body reaction was very mild at this stage, due to the rounded shapes of the polymer debris. Morphometric analysis showe d significant differences between the regenerated nerve and the normal sciatic nerve: the number of myelinated fibers is higher, and the mea n fiber diameter of the myelinated fibers in the regenerated nerve is smaller. In conclusion, the results demonstrate that the new PLLA/PCL nerve guide can provide optimal conditions for regeneration and matura tion of damaged nerves. (C) 1993 Wiley-Liss, Inc.