THE MICROVENOUS VALVULAR ANATOMY OF THE HUMAN DORSAL THORACIC FASCIA

The use of free scapular fasciocutaneous flaps for reconstruction of r ecalcitrant grade 6 venous stasis ulcers has shown excellent early suc cess rates. Venous refilling times measured postoperatively over the f laps by photoplethysmography have noted improvements to normal levels. Preliminary anatomic studies have demonstrated valves in the circumfl ex scapular veins of flaps used in reconstruction. The purpose of this study was to investigate and document the number, morphology, size, a nd location of valves in the human dorsal thoracic fascia. Ten scapula r flaps were obtained from unembalmed cadavers and injected with methy l methacrylate. Each flap cast was divided into four parts: proximal, right and left, and distal, right and left. We reduced the size of spe cimens (the largest being 24 x 11 mm) and studied them in a scanning e lectron microscope. We identified all valves, estimated the diameter o f the corresponding vein, calculated the depth of the valvular sinus, and related it to the corresponding venous size. Light microscopy and transmission electron microscopy were used as assisting tools applied to glutaraldehyde-fixed specimens. Analysis of injected specimens show ed that valves were most abundant in veins with a luminal diameter of 30 to 120 mu m (59.3 percent of 905 valves). The depth of valves becam e larger with increasing venous diameter. The sizes of valve sinuses w ere not different for individual valves. Except for veins larger than 1000 mu m in diameter, there was no significant difference between the number of valves in different parts of an individual flap, nor were t here significant differences between the valve numbers in different fl aps. Most valves were bicuspid; only in the vein category of 30 to 120 mu m were unicuspid valves encountered. Valves sometimes were located in series in a short segment of a vein; occasionally, they were found at the merging site of two veins. Transmission electron microscopy sh owed that valve leaflets had collagen fibers that ascended toward the tip of the leaflet and occasionally were accompanied by elastic fibers . Myofibroblasts were regularly present in the valve leaflets. These d ata show that fasciocutaneous flaps from the scapular region have nume rous valves (90 valves on average in each flap) in the venous microcir culation. The microvenous valves in the dorsal thoracic fascia appear to be structurally similar to valves in larger veins. These valves may play a role in the improved hemodynamics and promising clinical outco me of patients with chronic venous insufficiency who have undergone fr ee scapular flap reconstruction.