Revascularization of nerve grafts: A qualitative and quantitative study of the soft-tissue bed contributions to blood flow in canine nerve grafts

Blood flow to canine saphenous nerve grafts either in contact with a healthy soft-tissue bed or isolated from the soft-tissue bed by entubulation was quantitated at 3, 7, 14, and 28 days after surgery with radionuclide-labeled microspheres and evaluated histomorphometrically. At 3 days there was no statistical difference between the 2 techniques in regard to nerve graft blood flow, and neither group had blood flow in the middle portion of the graft. In contrast, analysis at 7, 14, and 28 days found blood flow in the middle segments of the nonisolated conventional nerve grafts to exceed that of entubulated nerve grafts with evidence in these segments of both lateral and longitudinal revascularization. The results of this investigation support an important role for the soft-tissue bed in nerve graft revascularization and suggest that neovascularization from the soft-tissue bed is the primary mechanism for restoration of blood flow in such grafts.