The bypass flap: an innovative technique of distal revascularization--anatomical study and clinical application.

Combined surgery for placement of a distal venous bypass and a free flap enables successful treatment of tissue loss caused by ischemia. This complex surgery has limited indications. The multiple anastomoses on the same arterial axis increase the risk of thrombosis and a certain number of venous grafts are likely to undergo mid-term deterioration. Because of these difficulties, we propose a new concept: the bypass flap (BF), which is based on the harvesting of an arterial axis to provide an arterial graft and a free flap supplied by a collateral branch of the graft. The aim of the anatomic part of this study was to evaluate the length and diameter of the arterial graft and its tissue branch and to study the feasibility of the BF. Thirty-two anatomic preparations were made by intraarterial injection of Rhodosil in 16 cadavers. The arterial graft included the subscapular artery and the thoracodorsal artery. The flap consisted of the anterior serrate muscle supplied by the branch of that graft. The distribution, length, and diameter of the arteries were examined. The mean length of the arterial graft line maintaining diameter above 2 mm was 12.5 cm (8.5-15.5). Three clinical applications of the BF based on the thoracodorsal artery axis were performed on three patients with tissue loss caused by severe ischemia of the lower limb. No occlusion of the BF occurred and healing of the tissue loss was achieved after 4, 7, and 10 months, respectively. This technique has the advantage of decreasing vascular distal resistance, which may contribute to improvement of vessel reconstruction patency. It is simpler because the anastomoses are fewer and it presents the advantage of requiring only autologous arterial material of an appropriate diameter.