BLOOD-FLOW CONTRIBUTIONS BY THE SUPERIOR AND INFERIOR EPIGASTRIC ARTERIAL SYSTEMS IN TRAM FLAPS, BASED ON LASER-DOPPLER FLOWMETRY

This study was designed to quantify the relative contribution of the inferior and superior epigastric systems to infraumbilical TRAM flap skin blood flow, using laser Doppler flowmetry. In twelve flaps (11 patients), blood-flow measurements were obtained during routine elevation of the TRAM flap for breast reconstruction. Baseline readings were obtained and recorded after stabilization of blood flow. The deep inferior epigastric artery and vein (IEA) were clamped and measurements were obtained. An atraumatic aortic clamp was then placed across the superior strip of rectus abdominis muscle, occluding the superior epigastric system (SEA) and all collateral branches from the superior circulation, and readings obtained. IEA occlusion produced a reduction in skin flap blood flow which averaged 23 +/- 21 percent of baseline. When the SEA system was occluded, no significant decrease was noted. In fact, skin blood flow increased to 136 +/-69 percent of baseline. When both the SEA system and IEA were clamped, skin blood flow averaged 10 +/- 9 percent of baseline, representing random movement of erythrocytes. The present study quantitatively documents the overwhelming dominance of the IEA system to supply the skin of the infraumbilical TRAM flap.