Leech Therapy

The leeches comeback in modern surgery

Medical leech use

T

he leech was indispensable in 19th Century medicine for bloodletting. Bloodletting is a practice believed to be a cure for anything from headaches to gout. It is what Demi Moore recently received to "detoxify" her blood. Bloodletting was abandoned by the medical community long ago in favor of scientific medical advances.

Use of leeches underwent a renaissance of sorts in the area of modern plastic reconstructive surgery and particularly in microsurgery transplantation. Credit for this renewed interest in leeches is given to two Slovenian surgeons, M. Derganc and F. Zdravic, who described their use to prevent venous congestion of skin-flap transplants in an article in the British Journal of Plastic Surgery in 1960. These surgeons credit their own use of leeches to a Parisian surgeon, one Philippe-Frédéric, who reported in 1836 that he had used leeches to restore circulation following reconstruction of a nose.

Leeches are most used following reattachment or transplantation surgery (fingers, toes, ears, etc) and in flap surgery when the venous outflow is poor - hence venous congestion. Many flaps and reattachment fail due to venous congestion rather than the arterial blood supply. It is much easier to attach the two ends of the arteries as arteries are thick-walled and relatively easy to suture. The veins, however, are thin-walled and especially difficult to suture, especially if the tissue is badly damaged. It is not uncommon to get blood to flow in the reattached arteries but not veins. When that happens, the venous circulation is severely compromised. The blood going into (arterial) the reattached finger/flap becomes congested, or stagnant due to the poor outflow (venous). The reattached portion turns blue and lifeless and is at serious risk of being lost. This is when the leech comes in handy.

Treatment of venous congestion includes

1. Removing tight dressings and sutures
2. Increasing the elevation to promote venous drainage via gravity
3. Leeches are effective for treating venous congestion in replantation
4. Nail plate removal and the application of a heparin-soaked sponge to the nail bed has been described for distal replantations (fingers or toes) when a vein could not be repaired and the patient refused leeches (Gordon, 1985).
5. Finally, operative revision can be considered. This is less successful for salvaging a failing replant because of venous congestion rather than arterial insufficiency.

So how do leeches work? The rationale behind the use of leeches in surgical procedures is fairly straightforward. The key to success is the exploitation of a unique property of the leech bite - the creation of a puncture wound that bleeds literally for hours. The leech's saliva contains substances that

1. anesthetize the wound area (a local anesthetic substance)
2. dilate the blood vessels to increase blood flow (a histamine-like vasodilator that promotes local bleeding)
3. prevent the blood from clotting - 1) Hirudin, a direct thrombin inhibitor and 2) Hyaluronidase, which increases the local spread of leech saliva through human tissue at the site of the wound and also has antibiotic properties.

Complications of Leech Therapy

Aeromonas hydrophila infections are a recognized complication of postoperative leech application, with reported incidences ranging from 2.4% to 20%. Prophylactic antibiotics are often recommended. In the event infection develops, early diagnosis and immediate initiation of an empirical intravenous antibiotic therapy are essential.

Another major concern in the use of leeches is their migration from the surgical site, possibly into the body or the wound itself. It has been suggested that you attach one end of a surgical suture to the leech and tie the free end to a firm object or dressing.

Leech therapy or bloodletting will not detoxify your body. Blood loss is not how the body detoxifies itself. Our bodies use the kidneys and liver for "detoxifying" or "filtering" the blood. I would politely suggest that if Demi thinks that bloodletting detoxifies her body, maybe she could donate blood so someone will truly benefit from it.

references

• Alternative Treatments for Wounds: Leeches, Maggots, and Bees; Medscape Article, Nov 8, 2007; Karen Dente, MD
• Hand, Amputations and Replantation; eMedicine Article, June 28, 2006; Bradon J Wilhelmi MD
• When Modern Medicine Needs Some Help - Jack McClintock (PDF file)
• (Gordon L, Leitner DW, Buncke HJ, Alpert BS. Partial nail plate removal after digital replantation as an alternative method of venous drainage. J Hand Surg [Am]. May 1985;10(3):360-4. [Medline]
• Salvage of Partial Facial Soft Tissue Avulsions with Medicinal Leeches; Otolaryngol Head Neck Surg, 2004; 131 (6):934-9; Frodel JL, Barth P, Wagner J (abstract)
• Beyond Bloodletting: FDA Gives Leeches a Medical Makeover; FDA Consumer Magazine, Sept-Oct 2004 Issue; Carol Rados
• UCLA Louise M Darling Biomedical Library; History & Special Collections - very nice online exhibit on Bloodletting

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