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 th at has shown greater efficacy in alleviating venous congestion and promotin g skin flap survival than previously described clinical therapies. Abdomina l skin flaps (3 x 6 cm) were raised on Sprague-Dawley rats and were subject ed to two ischemic events that simulated clinical venous congestion. The an imals received two treatments with the device prototype during 7-day experi ment (N = 9). Flap perfusion was monitored with a scanning laser Doppler im ager (LDI) and was normalized to adjacent skin perfusion. Photographic imag es of flaps at 7 days were assessed for areas of nonnecrotic tissue, and LD I data consisted of perfusion measurements at nine time points during the 7 -day experiment. The device prototype was able to promote an average surviv al 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%) tha t did not receive any treatment, but was a significant increase over the sa me treatment schedule with clinically used leeches (34.6 +/- 7.3%). At 7 da ys, LDI data showed flap perfusion to be 65.6 +/- 7% of adjacent skin perfu sion, a significant increase over this level at the end of the second ische mic event (21 1%; p < 0.05). These results suggest that this device could b e used clinically to alleviate venous congestion and to promote flap surviv al. The device could also be useful for prophylactic treatments and to mini mize treatment delays because its long shelf-life permits immediate availab ility when a treatment decision is made.