Accelerated delay of random flaps in a rat model

Abstract

Random flaps have been supplanted by more immediate and reliable reconstructive methods because the former require two or more procedures and a period of delay. This study was designed to test the hypothesis that a random flap can be elevated, delayed, and safely divided within 4 days. Ninety-two Sprague–Dawley rats were operated by elevating an 8 cm × 4 cm cranially based dorsal flap with its underlying panniculus carnosus muscle. The rats were divided into four groups, one control and three experimental, with 23 rats in each. In the control group, the flap was elevated and its caudal end divided at the same time without delay. In the experimental groups, we tested three delay procedures and all flaps had their caudal end divided 4 days after elevation. The number of flaps showing total viability compared to the flaps showing any amount of necrosis was as follows: control group 1:22, mini delay group 18:5, progressive craniocaudal elevation group 19:4, and the accelerated delay group 22:1. The extent of necrosis, expressed as mean percentage area of necrosis in each group, was as follows: control group 45.9%, in the mini delay group 2.3%, progressive craniocaudal elevation group 2.5%, and the accelerated delay group 0.1%. Delay of this random flap can be accomplished safely in 4 days. In terms of total flap survival and mean percentage necrosis, all three experimental delay procedures were effective in improving total viability and reducing the extent of necrosis significantly. We believe the observed difference in total viability and mean percentage necrosis in the accelerated delay group to be clinically significant.