In the United States, 70 vials of medical grade maggots are distributed each week to wound care doctors, clinics and hospitals.
Credit: Photo courtesy of Monarch Labs; Irvine, CA
The idea of putting maggots into open flesh may sound repulsive, but such a therapy might be a quick way to clean wounds, a new study from France suggests.
Men in the study, all of whom had wounds that wouldn't heal, were randomly assigned to have dead and unhealthy tissue removed from their lacerations by either standard surgical therapy or maggots (that eat dead tissue).
After about a week, men who received the maggot therapy had less dead tissue in their wounds than men who underwent surgery, the researchers said.
However, after two weeks, the immature insects had lost their advantage: Both groups had about an equal amount of dead tissue in their wounds. And in the end, the maggots did not help the wounds heal faster.
Although the effects of maggot therapy were not dramatic, it may be useful in certain cases, such as in patients with diabetes, whose wounds need rapid control, the researchers said. But continuing the maggot therapy beyond one week is not of benefit, they said.
Medical use of maggots was approved in 2004 by the U.S. Food and Drug Administration. However, only a small minority of patients with unhealing wounds receive the treatment, said Dr. Robert Kirsner, a dermatologist at the University of Miami School of Medicine, who was not involved in the new study.
The study included about 100 men with wounds on their lower limbs. About half received maggot therapy and half received surgical treatment. For the maggot therapy, sterile maggots were placed in a small pouch that was placed on top of the wound. The therapy was applied twice a week for two weeks.
Neither the patients nor the doctor evaluating the wounds knew which therapy a patient received (patients wore a blindfold when their bandages were changed.)
After eight days, the percentage of dead tissue in the wounds of patients who received the maggot therapy was 54.5 percent, compared with 66.5 percent in patients who received surgery. But after 15 days and 30 days, the amount of dead tissue in the wounds was about the same for both groups.
The number of patients who reported feeling a crawling sensation in their wound, and the number reporting pain, was also about the same in both groups, according to the study, which was conducted by researchers at the University Hospital Center of Caen, in France.
Maggots secrete an enzyme that dissolves dead tissue but leaves healthy tissue alone, Kirsner said.
Although there are few risks to the treatment, "there is a gross factor to it," Kirsner said. "Patients have to be very psychologically strong," he said.
Another group of patients that may benefit from the therapy are those who cannot undergo surgery, for instance, if they cannot receive anesthesia, Kirsner said.
Future research should determine whether the effects of maggot therapy can be improved using more maggots, and whether an increase in the number of critters would be painful, the researchers said.
The study is published online today (Dec. 19) in the journal Archives of Dermatology.
Pass it on: Maggots can remove dead tissue from wounds more quickly than standard treatments, but the therapy has no superior benefit beyond one week.