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CAWC’s Christine Pearson appears in the April 2010 edition of Canadian Nurse
Posted
Friday, May 07, 2010
Red tape holds up wound-healing wonders
In 2009, Health Canada changed the classification of medical maggots from a medical device to a drug. That decision made the wound-cleaning critters harder to come by and has led many clinicians to abandon a safe and effective treatment for patients whose wounds are not healing.
“Before, we could order the maggots from the supplier and have them within 24 hours,” says Christine Pearson, a wound clinician at Vancouver Coastal Health and a strong supporter of maggot therapy. “Now, it can take weeks just to process the paperwork. I haven’t used maggots for the last year; it’s too onerous trying to get that done.”
Medical-grade maggots are produced in a sterile lab where the eggs are washed in antiseptic solution and kept alive with a food source of brewer’s yeast and soy until they are transported.You need an import permit from the Canadian Food Inspection Agency and a broker at the border to deal with customs, Pearson explains, because only one lab in North America, located in Irvine, Calif., produces medical-grade maggots. “Some clinicians in the hospital are still using them, but access to the maggots is slow and that delays wound healing.”
Maggot therapy isn’t new. During the First World War, military surgeons discovered that soldiers on the battlefield whose wounds were infested with maggots had clean, healthy flesh growing underneath. That brought renewed interest in the treatment until the 1930s, when antibiotics were introduced and use of the maggots fell out of favour.
Live medical-grade larvae of the green blow fly are used to digest dead tissue, or slough, from chronic wounds such as pressure ulcers, surgical wounds and diabetes-related tissue damage. (“Some people can’t get white blood cells and enzymes stimulated in their body and their wounds go on for months with no progress,” says Pearson. “You can send them to the hospital and have a surgeon clean the wounds out, but that is really expensive.”) Maggots are especially effective with infected wounds; they eat bacteria and excrete substances with anti-microbial properties. They also produce substances that stimulate the growth of new tissue.
Five to 10 maggots are applied for each centimetre of the wound base and left in the wound for two to three days, until they are “full.”Maggots can be applied loose or in a teabag-like sac. Pearson prefers the free-crawling ones, adding that they don’t go anywhere they shouldn’t and don’t damage anything that is healthy. The maggots are covered with a secure but breathable dressing — they need air to breathe, and an outer dressing of gauze is applied to absorb any excess drainage. After two or three days, the maggots are flushed out with a saline solution and discarded.
Depending on the size of the wound and the amount of slough, it could take up to five treatments to clean the wound completely. “But 99 per cent of the people I put them on don’t even feel them,” she says.
A recent British study — one of only two randomized controlled trials on the therapy — found that although maggots took significantly less time to remove debris from the wound, they didn’t shorten the amount of time it took to heal or lessen the level of bacteria compared to a topical medication (the standard treatment). The patients who were treated with maggots also reported more pain.
Pearson responds that the researchers looked at only one type of wound (venous ulcers) and that topical medications don’t get rid of slough — an important step in the healing process.
“Nurses might balk at applying maggots if they have phobias, but they usually come around when they see how effective the treatment is,” she says. “I tell them not to think of them as squirmy little worms but as an active dressing.”
Despite the “yuck” factor, Pearson says she has never had a patient refuse the treatment. In fact, patients are taught to maintain the dressing at home: “And if a couple of maggots get loose, you just squish them.”
Keeping the critters contained isn’t what’s on Pearson’s mind. She sits on the board of the Canadian Association of Wound Care, a group that wrote to Health Canada explaining why medical-grade maggots should be available closer to home. “There are hundreds of papers from all over the world proving how effective a treatment this is, yet ours is one of the few countries that aren’t producing their own supply.”
So far, Health Canada has refused to give approval for a lab. “Dr. Chris Harvey-Clark, director of the Animal Care Centre at the University of British Columbia, is willing to give us space and produce medical-grade maggots, but Health Canada said we’d have to do multi-centre clinical trials,” says Pearson. “Our group looked into it and found out that the trials would cost over $100,000. If there is no drug company involved, it’s virtually impossible to fund something like that.”