March 19, 2009 -- Maggot therapy -- using live maggots to eat away dead tissue -- is more painful and does not lead to faster healing of leg ulcers than standard treatment.
Maggot therapy uses the larvae of the green bottle fly, also known as the green blowfly. Maggots eat only dead tissue without harming living tissue. That makes maggot therapy an efficient way for doctors to rid wounds of dead and decaying tissue, a procedure called debridement.
People with poor circulation in their legs often develop difficult-to-treat leg ulcers. Standard treatments for these ulcers employs various kinds of hydrogels -- wet dressings that pull dead tissue from the ulcers.
With hydrogels, but not with maggot therapy, a compression dressing can be used to cover the wound and ease patients' pain.
But because debridement is an important part of wound management, maggot therapy (also called larval therapy) is on the rise.
Yet there have been few randomized, controlled clinical trials of maggot therapy, note Jo C. Dumville, PhD, of the University of York, Enlgand, and colleagues. To remedy the situation, they enrolled 267 patients with leg ulcers and at least 25% wound coverage with dead tissue.
Patients were treated either with loose maggots, maggots contained in a net bag, or a hydrogel product.
Maggot therapy did indeed remove dead tissues better than standard therapy. Yet patients treated with either form of maggot therapy did not heal significantly more quickly than those given the standard treatment.
However, patients who received maggot therapy reported twice as much pain prior to healing as did patients who received standard treatment.
"We found no evidence to recommend the routine use of larval therapy on sloughy leg ulcers to speed up healing or reduce bacterial load," Dumville and colleagues conclude. "If debridement in itself is a goal of treatment ... then larval therapy should be considered; however, it is associated with significantly more pain than hydrogel."
Dumville and colleagues report their findings in the March 19 Online First edition of BMJ.