Effect of hyperbaric oxygen and medicinal leeching on survival of axial skin flaps subjected to total venous occlusion

This study evaluates the effect of hyperbaric oxygen and medicinal leeching on axial skin flaps subjected to total venous occlusion. Axial epigastric skin flaps (3 X 6 cm) were elevated on their vascular pedicles in 40 male W istar rats. Total venous occlusion was achieved by division of all veins dr aining the skin flap. Arterial inflow was left intact. Animals were randoml y assigned to one of five groups: sham (n = 8); control, total venous occlu sion only (n = 8); occlusion with hyperbaric oxygen (n = 8); occlusion with leeching (n = 8); occlusion with leeching and hyperbaric oxygen (n = 8). T he hyperbaric oxygen protocol consisted of 90-minute treatments, twice dail y, with 100% O-2 at 2.5 atmospheres absolute for 4 days. The leeching proto col consisted of placing medicinal leeches on the congested flaps for 15 mi nutes, once daily, for 4 days. Laser Doppler measurements of flap perfusion were recorded preoperatively, postoperatively, and on postoperative days 1 and 3. The percentage of flap necrosis was evaluated. on postoperative day 3. Mean percentage necrosis and mean laser Doppler readings were compared between both groups. The flaps in the sham group demonstrated 99 percent su rvival, whereas the flaps in the occlusion-only group demonstrated 100 perc ent necrosis. The flaps in the occlusion with oxygen, the occlusion with le eching, and the occlusion with oxygen and leeching groups demonstrated 1, 2 5, and 67 percent survival, respectively. Sham laser Doppler readings remai ned within normal limits. Laser Doppler readings in the occlusion- only and the occlusion with oxygen groups decreased to negligible levels on postope rative day 1, and on postoperative day 3 no perfusion was demonstrated. In both the occlusion with leeching and the occlusion with leeching and oxygen groups, there was also a significant decrease in laser Doppler measurement s after surgery, but perfusion remained stable throughout the remainder of the study. This study demonstrates that hyperbaric oxygen alone is not an e ffective treatment for skin flaps compromised by total venous occlusion. Th e combination of leeching and hyperbaric oxygen treatment of total venous o cclusion results in a significant increase in flap survival above that foun d with leeching alone. It appears that hyperbaric oxygen is effective becau se of the venous out-flow provided by leeching as demonstrated by laser Dop pler flow readings.