Metamorphosis is a change in the nature or form of a thing or living creature. Maggot debridement therapy (MDT) takes advantage of the immature form of the green bottle fly (Lucilia sericata) and its exponential growth cycle prior to its transformation into an adult fly. The larvae grow with their tiny external spicules scraping across the wound debris. Their excretions and secretions1 act as proteolytic enzymes to debride dead and devitalized tissue, transforming an eschar-covered wound bed into one with healthy granulation tissue. This synergistic, paired metamorphosis requires the appropriate wound bed preparation and proper handling of the medicinal MDT for optimal outcomes.

This issue's continuing education article examines the Advantages of Maggot Debridement Therapy for Chronic Wounds. The bibliographic review concludes that MDT is an effective debridement technique that is often quicker than the autolytic debridement from hydrogels with comparable healing time to conventional therapy. Four of five cited reviews identified a significant increase in antimicrobial-free days for wounds treated with maggots.

To translate this theoretical framework to practice, the editors paired our European academic review authors with the MDT clinical experience of Dr Ronald Sherman, which enhanced the review's continuing education value. The FDA indications for MDT include debriding of nonhealing necrotic skin and soft-tissue wounds including pressure injuries, venous stasis ulcers, neuropathic foot ulcers, and nonhealing traumatic or postsurgical wounds. Successes have been achieved with case series on amputation prevention and treatment as the last resort for nonhealing wounds, provided the cause has been corrected and there is adequate blood supply to heal.2 Contraindications to medical MDT include untreated deep and surrounding infection, closed internal cavities or abscesses, and wounds with exposed large vessels.

The clinician applying maggot therapy for the first time should read the product monograph and watch an instructional video or talk to an MDT-experienced clinician. Wound bed preparation prior to maggot application is important. The wound with a dry eschar should be softened while waiting for maggot delivery with a hydrocolloid dressing, hydrogel, enzymatic debriding drug, or surgical debridement of the thick eschar. Pseudomonas should ideally be reduced with antiseptics on the surface before applying maggots.

Maggots are obligate aerobes that require oxygen diffusion between the moisture layers on the wound surface; supersaturated wounds can drown maggots. Inadequate surface moisture on dry surface eschar can kill young maggots, which can be covered with saline gauze or other breathable moisture retaining surfaces.

Whether maggots are best in a sealed net bag or free range with direct wound contact is up for debate. While some reports have documented that free-range maggots can debride the wound faster,3 the contained net pouch is probably best around sensitive areas including the mouth and eyes. Even though sealed net bags are slower and more expensive, they may bring comfort to the clinician and the patient to overcome the psychological "ick factor."

Healthcare system limitations are one of the main reasons that maggot therapy is less popular in North America compared to the European continent where costs are often absorbed in global budgets. Medicinal maggot costs in North America are often greater than reimbursement from government healthcare fees.

Accidental maggots from the environment, which are not sterile and can spread disease, may also pose a problem. Some maggot species eat healthy tissue, unlike the green bottle fly that restricts its digestive actions to devitalized tissue.

Maggot therapy offers an alternate debridement technique to surgical techniques, autolytic debridement, mechanical debridement, and enzyme methods. We would appreciate your comments and observations from clinical experience to further the dialogue and knowledge base related to medical MDT.

R. Gary Sibbald, MD, DSc (Hons), MEd, BSc, FRCPC (Med Derm), FAAD, MAPWCA, JM

Elizabeth A. Ayello, PhD, MS, BSN, RN, CWON, ETN, MAPWCA, FAAN

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