Mixed arterio-venous insufficiency in random skin flaps in the rat: is the application of medicinal leeches beneficial?
BACKGROUND
Leeches are commonly used in reconstructive surgery for the treatment of venous congestion in flaps. Documented mechanisms of action are (1) injection of the anticoagulant hirudin; (2) active suction of blood; and (3) passive oozing of the bite wound. Even though the benefits of leeches in venous congestion are widely accepted, little is known about their effects in mixed arterio-venous insufficiency.


METHODS
Thirty Wistar rats were randomized into three groups (n = 10 each), and 9 x 3 cm ischemic random skin flaps were elevated on the rat dorsum. Group 1 served as controls. In group 2, one leech was applied to the distal part of the flap and in group 3, three leeches were applied, one at a time, at 8 h intervals. Postoperatively, flap survival and perfusion were quantitated by daily planimetry and laser-Doppler imaging.


RESULTS
The application of a single leech on postoperative day 7 did not lead to any statistically significant changes in total flap survival or tissue perfusion. Triple leech application, however, caused a significant decrease in flap survival of 6.6% at day 7 (3x leech versus control: 45.8% +/- 8.5% versus 52.4% +/- 8.5%, respectively) (P < 0.01) and a decline in flap perfusion of 13% (3x leech versus control: 71.3% +/- 16.6% versus 84.3% +/- 9.3%, respectively) (P < 0.01).


CONCLUSIONS
The data demonstrate that the application of leeches in the setting of mixed arterio-venous insufficiency can be hazardous to flap viability. Pure venous congestion with an adequate arterial supply remains the only indication for controlled leech application in the clinical setting.
Schlaudraff
Kai Uwe
KU
Plastic and Reconstructive Surgery Unit, Department of Surgery, University Hospitals of Geneva, Geneva, Switzerland.
Bezzola
Thierry
T
Montandon
Denys
D
Pepper
Michael S
MS
Pittet
Brigitte
B
D000818:Animals; D047709:Hirudo medicinalis; D017078:Laser-Doppler Flowmetry; D008297:Male; D016491:Peripheral Vascular Diseases / Q000473:pathology / Q000628:therapy*; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000098:blood supply* / Q000473:pathology; D014022:Tissue Survival