Wednesday, January 14, 2009

Maggot Therapy

Recently read a new article (the sixth one in the references below) on “maggot therapy” and couldn’t resist updating the one I first did in October 2007.

 

When I was a general surgery resident, we had a couple of patients come in with maggots in their wounds--both with venous stasis ulcers on their legs. As "icky" as it was to clean the maggots out of the wounds, it was down right impressive how clean the wounds were (and yes it was my job to do the cleaning). Those maggots sure had done a wonderful job of removing the necrotic tissue and leaving behind healthy granulation tissue. (photo credit)

Maggot therapy waxes and wanes in popularity throughout time. Ambroise Pare (1509-1590) is generally given credit for first noting the beneficial effects of maggots in suppurative wounds. Napoleon's famous military surgeon, Baron D. J. Larrey (1766-1842) noted larvae of the blue fly in the wounds of soldiers in Syria during the Egyptian expedition. He noted that the maggots only attacked putrefying substances rather than living tissues and that they promoted their cicatrization.

W. W. Keen commented on the presence of maggots in wounds during the Civil War, saying that the maggots were disgusting but did no apparent harm. The first scientific study of the use of maggots was done by Dr. William S. Baer of Baltimore, Maryland. He first mentioned this "viable antiseptic" for the treatment of chronic osteomyelitis in a discussion following an article by Bitting that appeared in 1921. Baer commented on the clean wound of two soldiers with neglected compound femur fractures and abdominal wounds who had lain neglected for 7 days on the battlefields of World War I in 1917. Inspection of the wounds showed that they were infected with thousands of maggots, but had healthy granulation tissue beneath. At that time, the mortality from such wounds with the best medical care was close to 75%, and therefore the maggots made a profound impression. He went on to study maggots in detail.

Maggots, by definition, are fly larvae, just as caterpillars are butterfly or moth larvae. Phaenicia sericata (green blow fly) larvae is the one used in maggot therapy.

A drawing of the life cycle of this fly appears below. (photo credit)

One-day-old larvae are only about 2 mm in length, and almost transparent. By the time the maggots are 3 or 4 days old, they have grown to about 1 cm (1/2 inch) long. (photo credit)

Maggot Therapy

Maggots may be used intentionally as biological debriding agents. They are an effective alternative to surgical debridement in patients who cannot go to the operating room for medical reasons.

It is the larvae of the green blowfly (Phaenicia sericata) that is used. This larvae is sterilized with radiation before being used so that they will not be able to convert from the larvae to the pupae stage. They secrete enzymes that dissolve the necrotic tissue and the biofilm that surrounds bacteria. This forms a nutrient-rich liquid that larvae can feed on. Thirty larvae can consume 1 gram of tissue per day.

They are placed on wounds and covered with a semipermeable dressing. The debridement is painless, but the sensate patient can feel the larvae moving. More importantly, maggots help to sterilize wounds, because they consume all bacteria regardless of their resistance to antibiotics (including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus).

Maggots have to be replaced every 2 to 3 days. Maggot therapy can be administered on an outpatient basis, provided that visiting nurses are familiar with their use. This is a good technique for painlessly removing necrotic tissue and destroying antibiotic-resistant bacteria in patients who cannot undergo surgical debridement for medical reasons. They work well in infected and gangrenous wounds, with the best results reported in diabetic wounds.

Maggots must be disposed of as infectious waste in a biohazard bag when finished.  It is best to double-bag and seal the removed maggots.

 

From the sixth reference article regarding use of maggots in the United States:

Maggots are available only by prescription.

The Food and Drug Administration regulates the use of medical maggots, as not all species are therapeutic or safe.

Approved use currently exists for the debridement of non-healing necrotic skin and soft tissue wounds that include pressure ulcers, venous ulcers, neuropathic foot ulcers, and non-healing traumatic or postsurgical wounds.

In the United States, the supplier of Medical Maggots is Monarch Labs in Irvine, California. A vial of 250 to 500 larvae costs approximately $88 plus shipping and handling.  The number of vials needed will be determined by the wound size and duration of therapy. Many wounds require only 1 to 2 applications over a 3- to 7-day period.

 

Medical grade larvae are available from Zoobiotic Ltd and Monarch Labs.

 

REFERENCES

1.  Maggot Therapy: The Surgical Metamorphosis; Plastic & Reconstructive Surgery. 72(4):567-570, October 1983; Pechter, Edward A. M.D.; Sherman, Ronald A. B.S.

2.  From the Bible to Biosurgery: Lucilia sericata--Plastic Surgeon's Assistant in the 21st Century; Plastic & Reconstructive Surgery. 117(5):1670-1671, April 15, 2006; Whitaker, Iain S. M.A.Cantab., M.R.C.S.; Welck, Matthew M.B.Ch.B.; Whitaker, Michael J. M.A.Cantab.; Conroy, Frank J. M.R.C.S.

3.  Maggot Debridement Therapy; Plastic & Reconstructive Surgery. 120(6):1738-1739, November 2007; Mumcuoglu, Kosta Y. Ph.D.

4.  Clinical Approach to Wounds: Debridement and Wound Bed Preparation Including the Use of Dressings and Wound-Healing Adjuvants; Plastic & Reconstructive Surgery. Current Concepts in Wound Healing. 117(7S) SUPPLEMENT:72S-109S, June 2006 ; Attinger, Christopher E. M.D.; Janis, Jeffrey E. M.D.; Steinberg, John D.P.M.; Schwartz, Jaime M.D.; Al-Attar, Ali M.D.; Couch, Kara M.S., C.R.N.P., C.W.S.

5.  Maggot Therapy Project

6.  Maggot Therapy for Wound Management; Advances in Skin & Wound Care:Vol 22(1),Jan 2009, pp 25-27; Hunter, Susan RN, MSN; Langemo, Diane PhD, RN, FAAN; Thompson, Patricia RN, MS; Hanson, Darlene RN, MS; Anderson, Julie PhD, RN, CCRC

7.  Maggots Are Enough to Gag Superbugs; Wall Street Journal Article August 8, 2008;  by Scott Hensley (Don’t watch the video in the article if you are squeamish.)

 

My Old Blog Posts

Maggot Therapy, October 31, 2007

Maggot Therapy Revisited, August 11, 2008

 

 

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5 comments:

Trauma Junkie said...

What an interesting post.

I've always thought maggot therapy was pretty neat, albeit pretty gross. What's most interesting about it is that you still sometimes see it done and it dates back to the Medieval days (perhaps sooner).

Bongi said...

i hate the smell of maggots in a wound. i have actually gaged at the smell before.

WhiteCoat said...

Very cool.
Don't see these types of patients too often, but they always evoke a very strong reaction when they show up.
The last time, about half the hospital showed up in the ED for some lame excuse and then asked "where's the guy with the maggots on his leg?"

Jabulani said...

I used to be friendly with a woman (sadly now demised) who had ulcers on both legs just above the inner ankle. She'd stoically put up with them for 20 years by simply dressing them and then changing the gooey dressing a couple of days later.

After I'd heard about maggot treatment, I asked her why she didn't consider it. She felt she couldn't cope with the "creepy crawly" feeling. She'd rather have the gooey bandages and inconvenience of having to wear trousers all the time to hide the dressings.

On a trip to New Zealand one year, one of her ulcers became badly infected and she visited a doctor out there. He prescribed some ointment for her and told her where she could obtain same in the UK. This turned out to be a magical treatment, because the ulcers suddenly dried up and healed. She was left with nasty scars but at least was able to wear skirts. It totally changed her life.
However, I've always wondered if she couldn't possibly have had that pleasure 5 years earlier had she gone for the maggot treatment. I'll never know ...

medrecgal said...

Wow, that's kind of gross, but in a peculiarly interesting way. As someone who survived a nasty tangle with MRSA that led to a lengthy (at least by today's standards) hospitalization, it was a curiosity that maggots can even help in the treatment of that nasty critter and its equally virulent relative VRE.

Too bad they couldn't find some kind of substance that would do the same thing (like a chemical debridement) without the "ick factor" of the actual maggots, particularly since dealing with large wounds that heal slowly is a tough haul even for those of us who are otherwise healthy. I'd certainly see the benefit for things like infected diabetic ulcers or venous stasis ulcers.