Thursday, March 27, 2008

Medical Leech Use

The 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 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

  • Removing tight dressings and sutures
  • Increasing the elevation to promote venous drainage via gravity
  • Leeches are effective for treating venous congestion in replantation
  • 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).
  • 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

  • anesthetizing the wound area (a local anesthetic substance)
  • dilate the blood vessels to increase blood flow (a histamine-like vasodilator that promotes local bleeding)
  • 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

BioPharm Leeches--a supplier who is on "the biting edge of science". Their site is full of useful information regarding applying leeches, post-leech wound care, etc.

UCLA Louise M Darling Biomedical Library; History & Special Collections--very nice online exhibit on Bloodletting

12 comments:

Femail doc said...

Gad, Demi Moore must be nuts.

There's an interesting study that used medical leeches for pain control in osteoarthritis of the knee:
http://www.annals.org/cgi/content/full/139/9/I-22

rlbates said...

I wish they had explained "how" it worked. Maybe it's the local anesthesia effect from the leech saliva.

sterileeye said...

Bloodletting is the last thing I would think would be revived. Maybe to much black bile in her body...

Sid Schwab said...

This topic sucks.

(It's a joke: leech/suck.)

rlbates said...

You are so right Dr Sid! (and it needed a good joke)

Chrysalis Angel said...

I've never heard of them used for detoxing the blood, ridiculous. Where do they get those ideas?

Interesting post though.

dr said...

Suture,
This post has been chosen as the winner of the weekly Scrubby Award by redscrubs.com. Along with this award comes a free pair of red scrubs, courtesy of NW Scrubs.

rlbates said...

Thanks, dr!

Dreaming again said...

I don't have the nerve to read this post *grin* or should that be grimace?

Midwife with a Knife said...

I must say, leeches do seem like they'd be creepy (kind of like maggot debridement), but at the same time, if it would save a finger, I'd be all for it. EW!

rlbates said...

MWWK, when it would save a finger or an ear, etc, I would be for it.

storkdok said...

This brings back memories! Way back in the mid90's when I was a resident on the surgical ICU rotation for a couple of months, I admitted a urology patient. He had gotten drunk, then tried to repair his round saw in his garage. He forgot to unplug it, and when he repaired the wires, it started. It zipped into his groin where it cut off his penis and one testicle. The urologists reattached his penis, and we used leeches for the congestion. The ICU nurses, a funny bunch, named them Fluffy and Muffy. They actually gave them a little ceremonial goodbye when they went to the "biohazard in the sky".

It was funny on the first morning of rounds, the head nurse took a look at the patient and said, you look familiar? Have you ever been a patient here before? The guy blushed and admitted he had, that he had gotten drunk the previous winter and tried to walk home in a snowstorm. He lost several toes that time. Head nurse said, "Might want to stop drinking."