Researchers from Hawaii have a suggestion for how to get granulation going in difficult diabetic wounds - let maggots do the work.
"These problem patients with diabetes really need better treatments in order to salvage their limbs. One of the potential improvements we can make in their treatment is to use a technique, such as maggot debridement therapy, to effectively debride infected or dead tissue to allow their wounds to heal," Dr Lawrence Eron told Reuters Health.
While the usual tools for debridement – scalpels and enzymatic agents – often fail, maggot debridement treatment is overwhelmingly effective," he said in an interview. "After just one treatment these wounds start looking better.
Dr Eron, from Kaiser Hospital and the University of Hawaii in Honolulu, and his colleagues presented their findings this week in Chicago at the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).
They treated 37 diabetics with their maggot debridement approach. The patients all suffered from peripheral vascular disease and had refractory wounds that were up to five years old.
The doctors applied 50 to 100 maggots (Lucilia sericata) to the wounds and left them on for two days, at which time they applied new maggots. This was repeated an average of five times (range, 1 to 30).
"We cage the maggots in a mesh-like material. Nylon panty hose might be used. And then we seal them so they don't get out," Dr Eron explained.
Twenty-one patients (78%) had successful outcomes, which were defined as eradication of infection, complete debridement of devitalized tissue, formation of robust granulation tissue, and greater than a 75% closure of wounds.
Treatment failures were due to excessive inflammation surrounding the wound in one patient, bleeding in two patients, and fistulae from infected bones that closed after a single treatment in three patients.
Antibiotics are often ineffective in such cases. In the current series, five wounds were infected with methicillin-resistant staphylococcus aureus (MRSA) and all were successfully treated with maggot debridement therapy. Nine wounds were infected with methicillin-susceptible S. aureus (MSSA); six of these were successfully treated. All 10 cases with infection due to group B streptococci were successfully treated, Dr Eron reported.
Asked how he persuades patients to undergo the treatment with maggots, Dr Eron said he carefully explains the procedure and then has them sign a consent form.
"A lot of patients might be somewhat wary of having live insects placed into their wounds, so we explain how it works and what possible problems might occur," he said.
Maggots secrete substances into the wounds that liquefy dead tissue and then they ingest the material to further degrade it in their gastrointestinal tract. The wounds are cleaned, and other substances contained in the maggot secretions allow the development of robust granulation tissue, Dr Eron said.
"After this, we go on to do further treatment with hydrogels, grafts of cell culture tissue, or negative pressure dressings. But to get to this point where these techniques will work, you really need to clean up the wound, get rid of dead tissue, and get robust granulation tissue into the wound. And this is where the maggots help."
(Reuters Health, September 2011)