Aetna considers medicinal leech (Hirudo medicinalis) therapy medically necessary for any of the following conditions:
- Poor venous drainage (venous congestion/venous outflow obstruction); or
- Salvage of vascularly compromised flaps (muscle, skin, and fat tissue surgically removed from one part of body to another); or
- Salvage of vascularly compromised replants (limbs or other body parts re-attached after traumatic amputation).
The medicinal leech, Hirudo medicinalis, has been used increasingly for relief of venous congestion, especially for salvage of compromised pedicled flaps and microvascular free-tissue transfer, digital re-implantation, and breast reconstruction. Leech therapy for compromised flaps is best used early since flaps demonstrate significantly decreased survival after 3 hours if venous congestion is not relieved. If venous pooling occurs around a flap or replant, the skin becomes cyanotic, cool, and hard. If capillary refill time (CRT) remains more than 3 seconds the flap or replant will not survive. The objective of leech therapy is for the affected area to become pink and warm, with a CRT of less than 2 seconds.
When leeches begin feeding, they inject salivary components (e.g., hirudin) that inhibit both platelet aggregation and the coagulation cascade. This results in a marked relief of venous congestion. The anti-coagulant causes the bite to ooze for up to 48 hours following detachment, further relieving venous congestion. By feeding for 10 to 60 minutes, leeches consume from 1 to 2 teaspoons of blood. Results from clinical studies showed that the success rate of salvaging tissue with medicinal leech therapy is 70 to 80%. On June 28, 2004, the Food and Drug Administration (FDA) had for the first time cleared the commercial marketing of leeches for medicinal purposes (in skin grafts and reattachment surgery).
Recently, leech therapy has also been suggested to be an effective treatment for rapid reduction of pain associated with osteoarthritis of the knee (Michalsen, et al., 2002). However, its effectiveness in treating osteoarthritis (OA) of the knee needs to be validated in larger randomized controlled studies. In a follow-up randomized controlled study, Michalsen, et al. (2003) evaluated the effectiveness of leech therapy for symptomatic relief of patients with OA of the knee (n = 51). Patients received a single treatment with 4 to 6 locally applied leeches (leech therapy group) or a 28-day topical diclofenac regimen (control group). The primary end point, pain at day 7, was reduced from a mean (+/-SD) of 53.5 +/- 13.7 to 19.3 +/- 12.2 after leech therapy compared with 51.5 +/- 16.8 to 42.4 +/- 19.7 with topical diclofenac. Although the difference between group pain scores was no longer significant after day 7, differences for function, stiffness, and total symptoms remained significant in favor of leech therapy until the end of study and for quality of life until day 28. The authors concluded that leech therapy helps relieve symptoms in patients with OA of the knee. The potential of leech therapy for treating OA and the pharmacological properties of leech saliva remain to be clarified.
In an editorial that accompanied the article by Michalsen, et al., Hochberg (2003) discussed some of the drawbacks of this paper. A lack of blinding of the patients as well as the researchers is a major pitfall because it raises concerns regarding measurement bias, especially since the outcome measures were all subjective. Also, 7 days is a short time frame for measuring the primary outcome measure since OA is a chronic condition. Furthermore, patients in both groups seldom used rescue therapy, suggesting that, despite the observed significant differences in pain scores at day 7, both groups may have been satisfied with their responses to study interventions. Thus, it is still unclear whether leech therapy is effective in treating knee pain in patients with OA.
Medicinal leech therapy is usually carried out for 4 to 5 days for patients with replant; it may be performed for 6 to 10 days for patients with compromised flaps.
A complication of leech therapy is the risk of infection; thus, it is recommended that therapy not be used in the presence of non-viable tissue.
Patients with HIV infection, or individuals taking immunosuppressive medications should not undergo leech therapy because of the risk of overwhelming bacterial sepsis.
The above policy is based on the following references:
- Voge C, Lehnherr SM. Leeches. Nursing. 1999;29(11):46-47.
- Utley DS, Koch RJ, Goode RL. The failing flap in facial plastic and reconstructive surgery: Role of the medicinal leech. Laryngoscope. 1998;108(8 Pt 1):1129-1135.
- de Chalain TM. Exploring the use of the medicinal leech: A clinical risk-benefit analysis. J Reconstr Microsurg. 1996;12(3):165-172.
- Haycox C, Odland PB, Coltrera MD, Raugi GJ. Indications and complications of medicinal leech therapy. J Am Acad Dermatol. 1995;33(6):1053-1055.
- Michalsen A, Moebus S, Spahn G, et al. Leech therapy for symptomatic treatment of knee osteoarthritis: Results and implications of a pilot study. Altern Ther Health Med. 2002;8(5):84-88.
- Michalsen A, Klotz S, Ludtke R, et al. Effectiveness of leech therapy in osteoarthritis of the knee: A randomized, controlled trial. Ann Intern Med. 2003;139(9):724-730.
- Hochberg MC. Multidisciplinary integrative approach to treating knee pain in patients with osteoarthritis. Ann Intern Med. 2003;139(9):781-783.
- U.S. Food and Drug Administration (FDA). FDA clears medicinal leeches for marketing. FDA Talk Paper. T04-19. Rockville, MD: FDA; June 28, 2004. Available at: http://www.fda.gov/bbs/topics/answers/2004/ANS01294.html. Accessed June 30, 2004.
- Frodel JL Jr, Barth P, Wagner J. Salvage of partial facial soft tissue avulsions with medicinal leeches. Otolaryngol Head Neck Surg. 2004;131(6):934-939.
- Whitaker IS, Cheung CK, Chahal CA, et al. By what mechanism do leeches help to salvage ischaemic tissues? A review. Br J Oral Maxillofac Surg. 2005;43(2):155-160.
- Durrant C, Townley WA, Ramkumar S, Khoo CT. Forgotten digital tourniquet: Salvage of an ischaemic finger by application of medicinal leeches. Ann R Coll Surg Engl. 2006;88(5):462-464.
- Knobloch K, Gohritz A, Busch K, et al. Hirudo medicinalis-leech applications in plastic and reconstructive microsurgery--a literature review. Handchir Mikrochir Plast Chir. 2007;39(2):103-107.