Study of the delay phenomenon in the rat TRAM flap model.

Partial flap necrosis is frequently associated with the pedicled TRAM flap in the clinical setting. We created a TRAM flap model in rats (one control group and four delay groups; n = 8 in each group) and used a variety of flap delay techniques and vascular manipulations in an effort to increase the surviving area of the flap. The areas of surviving skin paddles in the five groups ranged from 4.4 cm2 in the control group to 9.9 cm2 in one of the delay groups. Analysis of variance and Tukey's pairwise comparisons indicated that delay groups II, III, and IV differed significantly from the control group (ANOVA F = 15.99, p < 0.001; Tukey experimental ER = 0.05, individual ER = 0.0068; critical value = 4.07). Ligation of the superficial inferior epigastric vessels and deep superior epigastric vessels (dominant pedicle) 1 week before TRAM flap surgery increased the area of survival of the skin paddle significantly in the rat model. The procedure is relatively easy to perform, and our laboratory findings should be readily reproducible in clinical practice.