Effect of the delay phenomenon on survival of rat island skin flaps with total venous occlusion.

Necrosis is an inevitable result in flaps with total venous occlusion even if arterial flow is sufficient. The purpose of this study was to investigate the effect of surgical delay on rat island skin flaps with total venous occlusion, using 20 Swiss albino rats. Two epigastric island flaps were elevated in each rat. Flaps of experimental and control groups were elevated in the same animal. In the experimental group (n=20), flap boundaries were incised down to the fascia and the incisions were sutured as a delay procedure at the first stage. After 7 days, the 3×6-cm epigastric island flap was elevated, the inferior epigastric vein was ligated, and was cut under X60 magnification. Then, all flaps were sutured back to their original beds. In the control group (n=20), the same surgical procedure as in the experimental group was repeated without a delay procedure. Viability was assessed at postoperative days 1, 3, and 7. At the end of day 7, all flaps in the control group were totally necrosed; however flaps in the experimental group survived partially. The surviving area ranged between 24 and 74 percent (mean: 60±15 percent). The differences between the two groups were found to be statistically significant, using Student's t-test (p<0.005). Surgical delay could not completely save a flap with totally interrupted venous return. Nevertheless, a 60±15 percent portion of these flaps could survive with the help of a simple delay procedure.