Exploring the use of the medicinal leech: a clinical risk-benefit analysis.

The medicinal leech, Hirudo medicinalis, has been used with increasing frequency for salvage of compromised pedicled flaps and microvascular free-tissue transfers. The data pertaining to 18 cases in which flap salvage with leeches was attempted were reviewed and contrasted with the data from 108 published cases from other centers. A further analysis isolated and examined 19 cases in which infection, secondary to leech utilization, supervened. Results suggested that successful salvage of tissue with leeches occurs in 70 to 80 percent of cases. In contrast, the infection rate of most series is between 7 and 20 percent and, when a clinically significant infection occurs, the flap salvage rate drops to 30 percent or less. In addition to infection, the risks of leech therapy include blood loss, which may require replacement transfusion, loss of leeches into body orifices and spaces, allergic reactions, and adverse psychological responses. Clinical indications and contraindications, and strategies to reduce the risks of leech usage, are discussed. Conclusions are that leeches are best used early, and in accordance with an accepted institutional protocol. For each case, the potential risks and benefits must be rigorously assessed and honestly applied.