VASCULAR FILLING AND PROTEIN EXTRAVASATION IN 3 VARIETIES OF VASCULARIZED VENOUS NERVE GRAFTS

The purpose of this study was to compare the microcirculation perfusio n and plasma-protein extravasation in varieties of venous nerve grafts . Venous nerve grafts were created from the left median nerve and brac hial vein of the rabbit. The vein was interposed between (a) brachial artery to brachial artery (AVA); or (b) brachial artery to proximal ce phalic vein (AVV); or (c) brachial vein to brachial vein (VVV). A stan dard, vascularized, nerve graft was created in the opposite limb, to s erve as a control, and the untouched sciatic nerve served as a second control. Microcirculation perfusion and permeability of endoneurial ve ssels were evaluated using intravenously-injected albumin labelled wit h Evans blue dye (EBA) as a fluorescent tracer within 1 hr after surge ry. Six hours after surgery, the nerves were removed and evaluated for tracer content and distribution. Extravasation of EBA was extensive i n both AVA and AVV forms of the venous nerve graft, suggesting good pe rfusion but showing significant protein leakage and edema. VVV, on the other hand, had only slight extravasation, comparable to untouched sc iatic nerves. Although the number of vessels filled with blood in the VVV was 69 percent of the vascularized nerve graft, the lack of marked extravasation may make it the venous nerve graft of choice.