VASCULAR DELAY IN SKELETAL-MUSCLE - A MODEL FOR MICROCIRCULATORY STUDIES

Dynamic myoplasty is a relatively new use for muscle flaps and has led us to revisit the mechanisms of vascular delay as a means of optimizi ng blood supply to muscle flaps. Despite the well-documented effective ness of vascular delay in skin flaps, vascular delay in muscle flaps h as not been widely reported. Regardless of the many mechanisms postula ted in the literature as contributors to the delay effect in skin, the one element common to all these hypotheses is the importance placed o n changes in the microcirculation. Based on this factor, in the presen t study we developed and validated an animal model in which delay-indu ced microvascular changes could be measured in skeletal muscle flaps. We used the hairless mouse latissimus dorsi muscle flap because its va scular distribution is similar to that of humans and its thin structur e will enable us in future studies to directly view and measure its mi crovasculature using videomicroscopy. In 12 animals, we found that del ay significantly (p < 0.01) reduced necrosis of the distal part of the muscle from 57 +/- 9 percent in nondelayed flaps (n = 7) to 22 +/- 3 percent in delayed (n = 5) flaps. In these studies, we also determined that the hairless mouse latissimus dorsi muscle flap will serve as an excellent model for defining microvascular changes throughout delay.