Verification of a Free Vascularized Nerve Graft Model in the Rat with Application to the Peripheral Nerve Allograft

We report a vascularized sciatic nerve graft in the rat, based upon the femoral popliteal superior muscular artery pedicle. The pedicle may be raised from the common femoral artery via the popliteal artery, with accompanying venous drainage to the femoral vein. We have characterized two vessels: the middle tibial artery to the posterior tibial nerve and the arteria comitas nervus peroneus to the peroneal nerve. Plastic monomer and Evans blue labeled albumin injections established the anatomic model. The graft was reliably perfused at the time of isolation and 24 hours post-transplantation. The model was used to evaluate regeneration across allogeneic (ACI to Lewis, n = 12) versus syngeneic (Lewis to Lewis, n = 6) nerve grafts. Electrophysiologic and histomorphometric assessments demonstrated that the vascularized immunosuppressed allograft was similar to the vascularized syngeneic graft. Both were superior to the vascularized allograft without immunosuppression.