The Skin Bridge Is More Important as an Additional Venous Draining Route in a Perforator-Plus Flap

Abstract Background The skin bridge in the perforator-plus flap is considered as an additional source for arterial input and venous drainage apart from the perforator. However, its exact role requires further elucidation. Materials and methods Forty rats that underwent flap elevation with a size of 9 × 3 cm on the dorsum were evenly divided into a perforators-intact group with an intact vascular pedicle, an artery-deficient group with the artery ligated, a vein-deficient group with the vein ligated, and a perforators-deficient group with both vessels ligated. The blood perfusion was measured using a laser Doppler flowmeter. On the seventh day, the necrosis rate of the flaps was calculated and the diameter of vessels in the skin bridge was measured. Results The perfusion pattern was similar between the perforators-intact group and vein-deficient group, as well as between the perforators-deficient group and artery-deficient group. The blood perfusion was much more robust in the perforators-intact and vein-deficient groups. The necrosis rate in the perforators-deficient group (26 ± 1%) was not significantly different from that in the artery-deficient group (29 ± 1%), both of which was significantly larger than that in the perforator-intact (11 ± 3%) and vein-deficient groups (12 ± 4%) ( P ˂ 0.001). The venous network of the skin base in the vein-deficient and perforators-deficient groups dilated dramatically, whereas the arterial network in the artery-deficient and perforators-deficient groups had a very modest expansion. Conclusions The skin base in a perforator-plus flap is much more important as an additional route for vein drainage than for arterial input.