Prefabrication of a free peripheral nerve graft following implantation on an arteriovenous pedicle

Extensive nerve injuries frequently necessitate the use of long autografts, and sources of expendable donor nerves are limited. It is for these cases that nerve transplantation would have its greatest potential. However, regeneration in the rejected allograft fails because of a lack of the positive neurotropic and neurotrophic influences physiologically provided by viable Schwann cells. This report aims to show the feasibility of vascularization of the peripheral nerve by prefabrication. The study was designed to vascularize an autogenous nerve graft segment by using an arteriovenous bundle in the rabbit. A 3.5-cm segment of sciatic nerve was harvested and implanted in between the femoral vessels, and was isolated from secondary revascularization by a custom-made tube. A peripheral nerve graft was prefabricated by implantation on the vascular pedicle, and neovascularization was evaluated by microangiography and histology. The graft exhibited early neovascularization on day 2, and numerous new capillaries were noted to restore primarily perineurial blood flow on day 7, then all along the graft on day 14. The viability of the Schwann cells was preserved, and the structural integrity of the graft was maintained. This is a preliminary report on secondary vascularization of a segment of an autogenous nerve to maintain the viability of Schwann cells and the integrity of the conduit. In the future, with the concomitant use of host immunosuppression or with more advanced pre-treatment methods, nerve allografts could be revascularized by vascular bundles. The current tempo of medical research will hopefully enable the use of fresh nerve allografts that are rendered less immunogenic by more refined techniques.