Study of microcirculation of rat femoral nerve and development of a new vascularized nerve graft model.

This study was designed to investigate the microcirculation of the rat femoral nerve and to develop a vascularized nerve graft (VNG) model which is reliable, consistent, and simple. The rat was chosen for considerations of cost and simplicity of the model. One and 2 cm long femoral nerve segments were transected proximally and distally and left attached to the femoral artery and vein in all animals. Experimental groups included the following procedures: 1) the femoral artery and vein were ligated distally and an arteriovenous (AV) fistula just proximal to the ligature was constructed; 2) distal ligation only of the femoral artery and vein was done; 3) ligation of the femoral artery and vein was done both distally and proximally; 4) control: no ligation or construction of an AV fistula were done. Neurovascular segments in all groups were wrapped with a thin silicone sheath to prevent neurovascularization from the surrounding tissues. At seven days postoperatively, viability of the segments was assessed by fluorescein dye and microangiography studies, followed by histologic evaluation. Results showed that a 1- or 2-cm long femoral nerve segment, when left attached to distally ligated femoral vessels and an intact neurovascular sheath, is a simple design to reproduce and can serve reliably as a VNG model in the rat.