Experimental study on distally based free flap using retrograde arterial flow

Lee, Min Goo; Minn, Kyung Won; Mun, Ku Hyun

Abstract

Microsurgical free-tissue transfer has allowed surgeons to salvage injured limbs but choosing appropriate healthy recipient vessels has proved to be a difficult problem. Retrograde flow flaps are established in island flaps. Retrograde flow anastomosis could prevent the possible kinking and twisting of the arterial anastomosis. By not interrupting the proximal blood flow to the fracture or soft tissue defect site, the compromise of fracture or wound healing might be prevented. We wished to establish an animal model in rat for a retrograde arterial flow based free flap. Nembutal-anesthetized male rats, weighing 250 to 300 gm, were used. The femoral artery and common carotid artery exposed and divided. The systemic and retrograde arterial pressure were quantified by utilizing a paralle tubing system connected with peripheral arterial line. In this study, the retrograde flow was not pulsatile and the retrograde arterial pressure was 64-65 mmHg, with a mean arterial pressure of 106-109 mmHg. An epigastric skin flap, measuring 3x3 cm, was raised with its vascular pedicle. The epigastric free flap was transferred in the same rat from femoral vessels to carotid vessels in end to end fashion. We anastomosed the donor ateries to the distal parts of the divided recipient arteries and the donor veins to the proximal parts of the recipient veins. Twelve experiments were performed and the transplantations succeeded in 75 percent of them. In the remaining 25 percent, the experiments failed due to thrombosis at the site of anastomosis, or other causes. This animal model represents an excellent example of retrograde arterial flow free flap transfer that is reliable.