To jump-start the healing of difficult diabetic wounds, US researchers have a suggestion: let maggots do the work.
To allow such wounds to heal, doctors remove infected or dead tissue with scalpels or enzymes, a process they call debridement. But these tools often fail.
"These problem patients with diabetes really need better treatments in order to salvage their limbs," said Lawrence Eron from Kaiser Hospital and the University of Hawaii in Honolulu, who with colleagues presented their findings at a recent scientific meeting in Chicago.
"Maggot debridement treatment is overwhelmingly effective. After just one treatment these wounds start looking better," he told Reuters Health.
The results from Eron's team, which treated 37 diabetics with the maggots, still haven't been vetted by independent researchers.
All of the patients in the study suffered from a type of artery disease that causes poor circulation in the limbs and they all had stubborn wounds, some up to five years old.
The doctors put 50 to 100 maggots, of the species Lucilia sericata, on the wounds and left them there for two days, at which time they applied new ones. They repeated this five times on average.
"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," Eron said.
Maggots secrete substances into wounds that liquefy dead tissue and then ingest the material to further degrade it in their gut. The wounds are cleaned, and other substances contained in the maggot secretions allow the development of granulation tissue, a type of connective tissue that forms during wound healing.
Twenty-one of the patients had successful outcomes, defined as eradication of infection, complete removal of dead tissue, formation of robust connective tissue in the wound and more than three-quarters closure of the wound.
Five wounds were infected with the "superbug" MRSA, but they healed successfully with the maggot therapy. Nine wounds were infected with another bacterium called MSSA, and six of those healed. All 10 cases with infection due to group B streptococci were successfully treated, Eron said.
The treatment failed in some patients. One had excessive inflammation surrounding the wound, two bled too much, and three had problems with infected bones.
Asked how he persuades patients to undergo the treatment, 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.
"After this, we go on to do further treatment with hydrogels, grafts of cell culture tissue, or negative pressure dressings. But to get to the point there these treatments 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."