Microvascular transfer of anterior and posterior gracilis muscles in rats.

A microvascular free muscle flap in rats using the anterior and posterior gracilis muscles with femoral vessels as its pedicle is presented. The gracilis muscles form a single unit supplied by the muscular branch artery and vein, averaging 0.3 mm and 0.4 mm in diameter, respectively. These small sizes preclude their use in transplantation. However, the muscular branch vessels in continuity with the femoral vessels can be used for the vascular pedicle in this muscle transplant. This muscle flap was transplanted to the contralateral femoral vessels by end-to-end anastomosis in 15 rats. Thirteen animals survived and 11 flaps were viable at 3 days for a success rate of 85%. The gracilis flaps averaged 674 mg in weight, 1.87 cm X 1.36 cm in size, and 7.23 mm in pedicle length. This free muscle flap model is reliable, relatively easy to perform, and provides adequate muscle bulk for pharmacologic and biochemical studies in transplanted muscle. No lower extremity complications were noted following femoral vessel ligations.