The isolated perfused human skin flap: design, perfusion technique, metabolism, and vascular reactivity.

The design, isolated perfusion technique, and reactivity of a novel human skin-flap model are described. A transverse paraumbilical skin flap based on perforator vessels from the deep epigastric system was designed utilizing the tissue usually discarded following abdominal dermolipectomy. Within 3 hours of devascularization, a gassed (95% O2, 5% CO2), 37 degrees C Krebs-Henseleit buffer containing albumin (65 gm/liter) was pumped into the cannulated arterial pedicle of the skin flap and subsequently collected from the venous pedicle. Vascular resistance was continuously monitored and remained stable throughout the 4-hour perfusion. Lactate release was maintained throughout perfusion and was markedly increased by addition of insulin to the perfusate. Addition of norepinephrine to the perfusate resulted in a significant (p less than 0.05) dose-response increase in vascular resistance, and acetylcholine significantly (p less than 0.05) attenuated resistance in flaps preconstricted with norepinephrine. The results of these studies indicate that the isolated perfused human skin flap remained metabolically active with functionally intact vascular endothelium and smooth muscle throughout the 4-hour perfusion. The availability of this technique will, for the first time, permit laboratory study of human skin-flap pathophysiology and pharmacology.