Development of a clinically useful mechanical leech device that promotes flap survival in an animal model of venous-congested skin flaps.

The authors describe the design and testing of a mechanical leech device that has shown greater efficacy in alleviating venous congestion and promoting skin flap survival than previously described clinical therapies. Abdominal skin flaps (3 x 6 cm) were raised on Sprague-Dawley rats and were subjected to two ischemic events that simulated clinical venous congestion. The animals received two treatments with the device prototype during 7-day experiment (N = 9). Flap perfusion was monitored with a scanning laser Doppler imager (LDI) and was normalized to adjacent skin perfusion. Photographic images of flaps at 7 days were assessed for areas of nonnecrotic tissue, and LDI data consisted of perfusion measurements at nine time points during the 7-day experiment. The device prototype was able to promote an average survival area in the flap of 60.0 +/- 3.5%, which was not only a significant (p < 0.05) increase over previously published control groups (8.0 +/- 5.0%) that did not receive any treatment, but was a significant increase over the same treatment schedule with clinically used leeches (34.6 +/- 7.3%). At 7 days, LDI data showed flap perfusion to be 65.6 +/- 7% of adjacent skin perfusion, a significant increase over this level at the end of the second ischemic event (21 +/- 1%; p < 0.05). These results suggest that this device could be used clinically to alleviate venous congestion and to promote flap survival. The device could also be useful for prophylactic treatments and to minimize treatment delays because its long shelf-life permits immediate availability when a treatment decision is made.