Ex Vivo Delay: A Novel Approach to Increase Prefabricated Flaps Survival Rate.

Background Limited flap survival area is the main disadvantage of prefabricated flaps. To deal with this problem, surgical delay is the common method to achieve a better prognosis. This method requires multiple surgeries with the known associated burdens. We have developed a new strategy, ex vivo delay, utilizing the pathophysiology of surgical delay while avoiding the need for multiple surgeries. Methods We created a rodent animal model utilizing a two-stage operation of a prefabricated abdominal flap. The rats were randomly divided into three groups (n = 6 per group): group A, the control group (no intervention), group B, delayed by the ex-vivo delay device, and group C, delayed using surgical delay technique. Data were collected according to macroscopic analysis, near-infrared fluorescence imaging, and capillary densities. Results According to the macroscopic analysis, groups B and C had a significantly larger flap survival area compared with group A, but group B had a significantly smaller survival area than group C. The near-infrared fluorescence imaging showed the perfusion areas of group B and C to be larger than that of group A. Histologically, groups B and C had a significantly higher capillary density than group A. The vessel caliber in group C was larger than that of groups A and B. Conclusions The ex vivo delay strategy successfully increased flap survival area. This strategy worked by establishing ischemia and enhancing neovascularization. Further improvements in the surgical technique could produce outcomes similar to those seen with surgical delay.