Antegrade Venous Drainage in a Reverse-Flow Anterolateral Thigh Flap

Abstract

Sir: The distally based, reverse-flow anterolateral thigh flap variant was described by Zhang in 1990.1 The flow pattern in this flap is well understood and involves communication between the descending branch of the lateral circumflex femoral artery and the lateral superior genicular artery or profunda femoris artery,2 providing pedicled flap coverage of the knee and a satisfactory donor defect. However, venous congestion and edema may compromise the flap (Fig. 1).3,4 We present an innovative method for antegrade augmentation of venous outflow in the reverse-flow anterolateral thigh flap, to improve reliability.Fig. 1.: Although venous congestion subsided within days, the viability of the flap was jeopardized, and it was felt that partial flap loss might occur in the reverse-flow anterolateral thigh flap. Appearance (left) 2 days after flap transfer and (right) 9 days later.The cutaneous perforators are located by means of a Doppler probe and marked. The skin paddle is based over the distal perforator. The medial incision continues down to deep fascia. The perforators are identified in the subfascial plane, lateral to the incision, and are traced to the descending branch of the lateral circumflex femoral artery. If the perforators arise from the transverse branch of the lateral circumflex femoral artery, the flap must be raised as a free flap. The final flap design is then marked and the lateral portion of the flap is elevated. A vascular clamp is applied temporarily to the proximal descending branch of the lateral circumflex femoral artery to confirm adequate flap circulation. The descending branch is then divided proximally, at the junction of descending and transverse branches. The descending branch is dissected distally until an adequate pivot point is reached. The flap is transposed into the recipient site. The great saphenous vein is then transposed anteriorly by open incision or subcutaneous tunnel. The proximal flap pedicle is swung anteriorly and the major concomitant pedicle vein is anastomosed to the great saphenous vein (Fig. 2). The vascular pedicle of the flap is sufficient to reach the great saphenous vein easily. Thus, the flap is drained by the great saphenous vein in an antegrade manner.Fig. 2.: Before anastomosing the major concomitant vein of the proximal flap pedicle to the great saphenous vein, the flap appeared bluish and dusky, and bleeding of dark blood was found at the flap margin.The abundant vasculature around the knee enables various local flap possibilities.5 However, donor-site cosmesis may limit the use of local cutaneous flaps, and regional muscle flaps may produce unacceptable functional and aesthetic deficits. Also, free flap techniques may entail long procedures and changes of patient position. The reverse-flow anterolateral thigh flap provides good wound coverage around the knee. Even in defects involving patellar tendon loss, this flap can also provide fascia lata for one-stage reconstruction.2 However, reports describing the use of the reverse-flow anterolateral thigh flap are scant.1–4 Venous congestion would seem to be the main complication limiting its appeal. In our first three conventional reverse-flow anterolateral thigh flaps, venous congestion occurred in every case and, although subsiding within days, it did jeopardize flap viability, with one episode of partial flap necrosis. In the subsequent case, venous drainage was augmented by anastomosis to the great saphenous vein, as described, allowing physiologic venous drainage from the flap. In this case, congestion did not arise. This technique added approximately 30 minutes to the operating time. Antegrade augmentation of venous drainage in the reverse-flow anterolateral thigh flap by anastomosis of one concomitant vein to the great saphenous vein may improve the reliability of this useful flap. ACKNOWLEDGMENT The authors thank C. P. O'Boyle, M.D., for assistance with the preparation of this article. DISCLOSURE None of the authors has a financial interest to declare in relation to the content of this article. Cheng-Hung Lin, M.D. Chung-Chen Hsu, M.D. Chih-Hung Lin, M.D. Yi-Chieh Chen, M.D. Fu-Chan Wei, M.D. Department of Plastic and Reconstructive Surgery Chang Gung Memorial Hospital Chang Gung Medical College and Chang Gung University Taipei, Taiwan