A tissue-engineered conduit for peripheral nerve repair

Background: Peripheral nerve repair using autograft material has several shortcomings, including donor site morbidity, inadequate return of function, and aberrant regeneration. Recently, peripheral nerve research has focused on the generation of synthetic nerve guidance conduits that might overcome these phenomena to improve regeneration. In our laboratory, we use the unique chemical and physical properties of synthetic polymers in conjunction with the biological properties of Schwann cells to create a superior prosthesis for the repair of multiply branched peripheral nerves, such as the facial nerve. Objectives: To create a polymeric facial nerve analog approximating the fascicular architecture of the extratemporal facial nerve, to introduce a population of Schwann cells into the analog, and to implant the prosthesis into an animal model for assessment of regeneration. Results: Tubes of poly- L-lactic acid (molecular weight, 100 000) or polylactic-co-glycolic acid copolymer were formed using a dip-molding technique. They were created containing 1, 2, 4, or 5 sublumina, or 'fascicular analogs.' Populations of Schwann cells were isolated, expanded in culture, and plated onto these polymer films, where they demonstrated excellent adherence to the polymer surfaces. Regeneration was demonstrated through several constructs. Conclusions: A tubular nerve guidance conduit possessing the macroarchitecture of a polyfascicular peripheral nerve was created. The establishment of resident Schwann cells onto poly-L-lactic acid and polylactic-coglycolic acid surfaces was demonstrated, and the feasibility of in vivo regeneration through the conduit was shown. It is hypothesized that these tissue-engineered devices, composed of widely used biocompatible, biodegradable polymer materials and adherent Schwann cells, will be useful in promoting both more robust and more precisely directed peripheral nerve regeneration.