Evaluation of clinically applicable exsanguination treatments to alleviate venous congestion in an animal skin flap model

This study compares the effectiveness of alleviating venous congestion with mechanically-made outlets or leech therapy in promoting skin flap survival. Free flaps of abdominal skin (3 x 6 cm) were raised on Sprague-Dawley rats and subjected to ischemic events, simulating venous congestion. Animals received 1) no treatment: 2) two treatments involving two 18-gauge needle-puncture outlets: or 3) two sessions of leech therapy. Flap perfusion was monitored with a scanning laser Doppler flowmeter. Photographic images of flaps at 7 days were assessed for areas of normal tissue (n = 15), and laser Doppler flowmeter data consisted of control (n = 6), outlet (n = 6), and leech (n = 7). Both the needle-puncture outlet (40.0% +/- 9.24%) and leech treated (34.6% +/- 7.34%) groups had a significantly greater surviving skin area than untreated control flaps (8.0% +/- 5.0%), with 2 of 15 flaps receiving mechanical outlets exhibiting >90% surviving area. After 7 days, laser Doppler flowmeter data showed greater mean perfusion in the outlet (71.7% +/- 16.8%) and leech (92.6% +/- 17.2%) treated groups, compared to controls (15.2% +/- 10.2%). There was a significant increase in perfusion in the outlet (13.3% +/- 6.2%) and leech (9.1% +/- 1.1%) treated groups from the end of secondary ischemia to day 7 (p < 0.05) compared to controls. The results suggest that two spatially separated outlets are as effective as one leech in increasing the area of surviving skin in venous congested flaps.