Nonsurgical delay of skin flaps: effect of a suture delay technique on blood flow and survival.

Surgical delay is the only clinical means of improving survival of skin flap tissue, but it has inherent risks and costs of a surgical procedure. This study tested the hypothesis that any method of disrupting the circulation at the distal perimeter of a planned skin flap would induce collateral circulation from the base of the flap and thereby improve flap survival. The suture delay technique was performed on rats, and two outcome measures were used: blood flow patterns and skin flap survival. Blood flow patterns were tested before and after the suture technique by means of the base occlusion test. Flap survival in the suture delay group was compared with survival in acute and surgical delay control groups. Flap survival in the suture delay group (95.6% +/- 0.6%, n = 22) was significantly greater than in the acute control group (85.7% +/- 1.6%, n = 22) and was not different from that in the surgical delay model (95.2% +/- 0.5%, n = 21). Laser Doppler studies demonstrated a change in blood flow patterns. This study supports the theory that the mechanism of the delay phenomenon is the development of collateral blood from the base of the flap and suggests that the benefits of delay can be achieved with minimal surgical trauma.