Effect of venous superdrainage on a four-territory skin flap survival in rats

BACKGROUND: In a previous report, the authors demonstrated that distal arterial supercharging is more effective at increasing flap survival. There is no doubt of the benefit of arterial augmentation in flap surgery, but the effect of venous superdrainage is still controversial. The purpose of this study was to investigate how venous augmentation could generate larger flap survival areas with different superdrainage positions in rats. METHODS: A four-territory skin flap, developed by the authors, was used. Forty rats were divided into four groups, as follows: group 1, flaps based only on the deep circumflex iliac artery and vein; group 2, flaps superdrained with the ipsilateral superficial inferior epigastric vein; group 3, flaps superdrained with the contralateral superficial inferior epigastric vein; and group 4, flaps superdrained with the contralateral deep circumflex iliac vein. On the fourth postoperative day, the flaps were assessed by measurements of necrosis and survival areas. Vascular changes produced by venous augmentation were evaluated angiographically. RESULTS: Compared with group 1 (mean flap survival, 37.8 ± 5.0 percent), the flap survival areas were significantly greater in the superdrainage flap groups (group 2, 57.4 ± 6.5 percent, p < 0.001; group 3, 72.4 ± 21.3 percent, p < 0.001, and group 4, 89.2 ± 18.8 percent; p < 0.001). Angiographic assessment of the flaps revealed dilatation of the choke vein between the territories and reorientation of dilated veins along the long axes of the flaps. CONCLUSIONS: This study demonstrates that venous augmentation is also effective for increasing flap survival, and the distal procedure is more effective than the proximal procedure in arterial supercharging.