Maggot debridement therapy (MDT) is an approach to wound debridement that has been revived in recent years. MDT offers efficiency, simplicity, cost effectiveness and potential benefits for patients with nonhealing or chronic wounds.1 Research has shown MDT to be a valid and reliable form of treatment, but more study is needed. Further research should examine outcomes compared to surgical debridement; patient tolerance compared to other types of wound debridement; whether MDT is more or less cost effective than surgical debridement or debridement with dressings alone; and whether wound type affects the efficacy of MDT.
History and Effectiveness
The ability of maggots to keep wounds cleaner and prevent disease among soldiers wounded in battle has long been known. From Napoleon to the Civil War and through World War I, military physicians utilized and studied the use of maggots to heal wounds.2 MDT has been gaining momentum since the 1980s, and the U.S. Army even acknowledged the benefits of MDT in today's military medicine and survival techniques.2
A study by Tanyuksel et al found that 10 of 11 study participants who underwent debridement with MDT experienced drastically reduced treatment times in comparison to more conventional therapies.2 Most patients in this study who received MDT had no complaints of discomfort or pain.2 A different study reported increased pain with MDT, but it also found that the pain was generally well controlled with analgesics and that comorbid factors may have played a part in why some patients had more pain than others.3
Provider Preference and Preconceptions
MDT seems counterintuitive to many people because maggots have a negative connotation.4 However, maggots are not dirty and their association with decaying or dead tissue is actually the reason they work. Maggots feed on dead tissue and leave healthy, living tissue untouched to start the healing process. They even promote the healing process of a wound bed by nature of their digestive systems.
Advocates of MDT hope that by familiarizing healthcare providers with the treatment and providing a straightforward algorithm, they will foster a level of comfort and confidence in the therapy. This will permit MDT to be considered more often for the debridement of chronic or infected wounds.5
Provider preference and preconceptions about MDT are areas that have not been thoroughly examined, but the research conducted so far shows that it is rarely the patient who refuses MDT.6 More often it is medical staff, administrative staff and nursing staff who resist MDT use.6 According to the literature, one common reason for not using MDT is the obvious "yuk" factor.7 The "yuk" factor refers to a general distaste for using maggots to clean a wound.4 The same 2005 study by Steenvoorde et al found that patients were agreeable to attempting MDT and that most would recommend it to others due to their overall positive outcomes.7
The main safety concern with MDT stems from its contraindications. Known contraindications to MDT include: allergies to fly larvae, soybean protein or brewer's yeast; a life- or limb-threatening infection that is rapidly advancing due to lack of appropriate wound monitoring; wounds that do not directly open to the outside of the body; coagulopathies (must be used under close supervision); wound around necrotic vessels (could cause rupture of the vessels); and any use in the gastrointestinal tract, the eyes or in the respiratory tract.4
One other contraindication that warrants further description is the use of MDT in infections caused by Pseudomonas aeruginosa. Most bacteria are destroyed in the digestive system of the maggots after they secrete their enzymes into the necrotic wound bed to liquefy the devitalized tissue.8 Types of devitalized tissue include gangrene, slough and necrosis.8 Maggots have difficulty ingesting and destroying Pseudomonas aeruginosa, so patients must also take a systemic antibiotic.
Potential side effects of MDT are bleeding and pain or discomfort.9 An increase in analgesia should counteract these effects.8 Maggots are discarded in the biohazard waste receptacle after being double bagged; they are considered biohazardous waste.
Benefits of MDT
One major advantage of MDT is that it can be used in conjunction with surgery to improve outcomes. In situations when amputation is the next step in care, MDT can show a surgeon where devitalized tissue ends and healthy tissue begins.10 In a recent study of 357 patients, 55 were able to avoid amputation by using MDT to debride the associated wounds.10
A major problem with wound care today is the overuse of antibiotics, which has caused a widespread rise in methicillin-resistant Staphylococcus aureus (MRSA). This knowledge is good motivation to develop or encourage other effective alternative or complementary therapies.11
MDT exhibits impressive advantages in curing bacterial infections within wounds.11 It has long been theorized that maggots produce an anti-infective environment in the wound by releasing proteolytic enzymes. These enzymes have a bacteriostatic effect, but not a bactericidal effect.4 The proteolytic enzymes produced are collagenase and enzymes resembling trypsin and chymotrypsin.12 These enzymes help the maggots absorb the dead tissue and bacteria and destroy the bacteria as it passes through their digestive tract.12 By destroying these bacteria, MDT is able to disrupt the biofilm that forms in or over the necrotic tissue of the wound.13
Once the biofilm has been disrupted, antibiotics are a much more effective tool to use against wound infection because they can effectively fight the bacteria without the biofilm preventing access to the infected wound bed. Therefore, MDT debrides and disinfects wounds well on its own, but adding antibiotics improves the odds of achieving the desired results.8
MDT and antibiotics have been used together with favorable results since they became medical therapies. However, few studies have examined how they work with each other or if they increase each other's efficacy. A study by Aorora et al found that ciprofloxacin (Cipro) activity was enhanced by the secretions of the maggots.11 This study also found that maggots' secretions produced an alkaline pH in the wound, which can promote antibiotic activity.11
Another benefit of MDT is that it is associated with an increased formation of granulation tissue in wounds not treated using MDT. Specifically, Sherman found that "Maggot therapy was . associated with rapid growth of granulation tissue and rapid conversion of necrotic and static ulcers to a healthy wound bed which could appropriately be grafted or surgically closed. The average maggot-treated wound was not only debrided, but covered 60% by healthy granulation tissue within 3 weeks."6
Although this is compelling data, for this particular study it did not reach statistical significance. Other notable findings, such as those of Jones et al, supported Sherman and others in showing that MDT is vital to the breakdown of necrotic tissue.12 These studies also found that MDT aids in the formulation of new granulating tissue.12
Sterile medical maggots can be purchased from Monarch Labs in Irvine, Calif. Monarch Labs is the only producer or distributor of medical-grade maggots in the United States. Several other countries also have medical-grade maggot distributors.14 The maggots are sterilized and shipped under strict guidelines and can be shipped to areas requiring temperature controlled shipping packaging if needed.15 The maggots come in vials of 250 to 500 and 500 to 1,000 larvae. A vial of 250 to 500 larvae from Monarch Labs is $119.00 and a vial of 500 to 1,000 larvae is $179.00.15
Specific types of dressings and supplies should be used with maggots, and many of them are readily available at most facilities. MDT requires a cage dressing over the maggots and the wound to keep them in place inside the wound. To make the necessary cage dressing, the following are required: a hydrocolloid dressing, medical glue or adhesive, chiffon or mesh, tape or adhesive, and absorbent gauze. A cage dressing must ensure that air can reach the maggots inside the wound, that drainage can escape the wound, and that maggots cannot escape the wound. All of these materials are also available from Monarch Labs.15
Another consideration in using MDT over more traditional debridement therapy is that MDT can work in as few as one or two applications (3 to 6 days of total treatment). Traditional debridement dressings may take months to work, requiring significantly larger amounts of materials and accruing much higher costs for supplies. The retail cost of one box of the traditional hydrogel dressings is $123.13; each box contains five dressings.16 One vial of maggots, plus the dressings, is nearly equal the cost of one box of hydrogel dressings.
Treatment duration and frequency play a large role in cost and must be considered. When one takes into account the number of treatments required to achieve debridement of a wound, MDT is clearly the more cost-effective choice. Results of a study by Wayman et al, as well as multiple studies since, support the comparison between the number of MDT treatments and hydrogel dressings necessary to achieve debridement.17
The "Yuk" Factor
As mentioned earlier, Steenvoorde et al found that patients had no negative feelings toward MDT and would be willing to undergo it again.18 Their study showed that 94% would recommend maggot therapy to others.18 Other sources support these findings. Kitching found that despite their negative preconceptions about "dirty creepy crawlies . inside their wound," five of six patients were pleased with the results of MDT. This includes experiencing little or no pain afterward.18
A less desirable side effect noted by patients was a nonphysical one: societal reaction. One study found that 22% of patients reported negative social interactions related to their MDT.7 An important fact to point out about this study is that 37 out of 38 patients filled out and returned surveys about the MDT care they received.7 This is a significantly high percentage of voluntary participation in a survey, which could be interpreted to show the positive reaction and attitude the patients generally had toward MDT. To remove the stumbling block of negative perception of MDT, healthcare providers need to provide thorough, detailed instruction and education about MDT treatments.
Reconsider This Choice
MDT is not a new concept. Maggots have been used to debride wounds as far back as the French Revolution. MDT has the potential to provide an invaluable service in the area of wound care by debriding and initiating the healing process in infected open wounds and chronic nonhealing wounds that have resisted more conventional treatments. Education and understanding of MDT is vital to allowing MDT to reach its full potential. Providers with open minds, advanced education and willingness to trial MDT can bring new life to an old treatment option for their patients with chronic nonhealing wounds and infected open wounds.
1. Sealby N. The use of maggot therapy in the treatment of a malignant foot wound. Brit J Community Nurs. 2004;9(3):S16-S19.
2. Tanyuksel M, et al. Maggot debridement therapy in the treatment of chronic wounds in a military hospital setup in Turkey. Dermatology. 2005;210(2):115-118.
3. Gilead LL, et al. The use of maggot debridement therapy in the treatment of chronic wounds in hospitalised and ambulatory patients. J Wound Care. 2012;2(2):78,80,82-85.
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6. Sherman RA. Maggot versus conservative debridement therapy for the treatment of
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10. Jones M. An overview of maggot therapy used on chronic wounds in the community. Br J Community Nurs. 2009;14(3):S16,S18,S20.
11. Arora S, et al. Maggot metabolites and their combinatory effects with antibiotic on Staphylococcus aureus. Ann Clin Microbiol Antimicrob. 2011;10:6.
12. Jones J, et al. Maggots and their role in wound care. Brit J Comm Nurs. 2011;16(Suppl 1):24-33.
13. Harris LG, et al. Disruption of Staphylococcus epidermidis biofilms by medicinal maggot Lucilia sericata excretions/secretions. Int J Artif Organs. 2009;32(9):555-564.
14. BioTherapeutics, Education & Research Foundation. Maggot Therapy. http://www.bterfoundation.org/node/19
15. Monarch Labs. http://www.monarchlabs.com/products&services_order.htm
16. Medical Supplies & Equipment Company. Elta Hydrogel Wound Dressing. http://www.medical-supplies-equipment-company.com/product/ppf/id/2623/new_prod_full.asp
17. Wayman J, et al. The cost effectiveness of larval therapy in venous ulcers. J Tissue Viabil. 2000;10(3):91-94.
18. Kitching M. Patients' perceptions and experiences of larval therapy. J Wound
Breanna Paulson is a family nurse practitioner at Elite Health & Fitness in Williston, N.D. Annie Gerhardt is a family nurse practitioner who is an instructor in the program. The authors have completed disclosure statements and report no relationships related to this article.