studies about maggots therapy
All About Maggot Therapy
Maggot therapy (also known as maggot debridement therapy [MDT], biotherapy, biosurgery, biodebridement, and larval therapy) is the controlled, therapeutic use of live blow fly larvae ("maggots") to treat skin and soft tissue wounds.
The history of maggot therapy, and the mechanisms by which it works, will be discussed below. But first, some disclosures:
- In the United States, Medical Maggots™ are regulated by the Food and Drug Administration as a prescription only medical device.
- The Medical Maggots™ brand of medicinal maggots are cleared by the FDA for marketing under the following indications: "for debriding chronic wounds such as pressure ulcers, venous stasis ulcers, neuropathic foot ulcers and non-healing traumatic or post surgical wounds."
- This page discusses maggot therapy in general, including recent research. Not all of the claims being made by clinicians or researchers were demonstrated with the Medical Maggots™ brand of medicinal maggots. Monarch Labs does not and can not claim that all of the benefits described in this article or in the published literature apply to the Medical Maggots™ brand of medicinal maggots.
In maggot debridement therapy, germ-free ("disinfected") larvae of therapeutic fly species ("medical grade maggots") are used to treat and manage wounds in a procedure known as "maggot therapy." The maggots are applied to the wound for 2 or 3 days within special dressings to keep the maggots from migrating. Since medicinal maggots can not dissolve or feed on healthy tissue, their natural instinct is to crawl elsewhere as soon as the wounds are clean, or the larvae are satiated.
The scientific literature identifies three primary actions of medical grade maggots on wounds:
- They debride (clean) the wound by dissolving dead and infected tissue with their proteolytic, digestive enzymes;
- They disinfect the wound (kill bacteria) by secreting antimicrobial molecules, by ingesting and killing microbes within their gut, and by dissolving biofilm;
- They stimulate the growth of healthy tissue.
The following topics about maggot therapy are detailed below:
History of Maggot Therapy
Maggots have been known for centuries to help heal wounds. Military surgeons noted that soldiers whose wounds became infested with maggots had better outcomes than those not infested. William Baer, while at Johns Hopkins University in Baltimore, Maryland, may have been the first in the Northern Hemisphere to have intentionally applied larvae to wounds in order to induce wound healing. During the late 1920's, he identified specific species, raised them in the laboratory, and used their larvae to treat several children with osteomyelitis and soft tissue infections. He presented his findings at a surgical conference in 1929. Two years later, after treating 98 children, his findings were published posthumously.
MDT was successfully and routinely performed by thousands of physicians throughout the 1930’s, but soon it was supplanted by the new antibiotics and surgical techniques that came out of World War II. Maggot therapy was occasionally used during the 1970's and 1980's, but only when antibiotics, surgery, and modern wound care failed to control the advancing wound.
The first modern clinical studies of maggot therapy were initiated in 1989, at the Veterans Affairs Medical Center in Long Beach, CA, and at the University of California, Irvine. Controlled clinical studies set out to compare maggot debridement therapy to the standard therapy being prescribed by wound care experts in the treatment of chronic pressure ulcers, diabetic foot ulcers, venous stasis ulcers, post-traumatic wounds, etc. The results of those controlled comparative studies, and the many studies and reports that followed, indicate that MDT is still useful today as a safe and effective treatment tool for some types of wounds. Those studies also demonstrated that there is no reason to withhold MDT until all other modalities have been exhausted, nor use it only as a "last resort." Indeed, while published accounts of "pre-amputation MDT" show a limb salvage rate of over 40%, the success of MDT when used earlier in the course of treatment (say, as a 2nd or 3rd or 4th line treatment) is even more dramatic.
Take a look at some data from just two of the published studies, demonstrating significant debridement in pressure ulcers and diabetic foot ulcers treated with maggot therapy, compared to control therapy.
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| Maggot vs conservative (control) debridement therapy for pressure ulcers. Average surface area (sq cm) of necrotic tissue for wounds treated with maggot therapy (solid circles; n=43) decreased faster and greater than that seen with conventional therapy (open circles; n=49). Error bars indicate standard error; asterisks indicate significant differences in mean surface area (p<0.05) within 3 weeks. Sherman RA: Wound Repair Regen 2002; 10:208-14 | Maggot vs conservative (control) debridement therapy for diabetic foot ulcers. Average surface area (sq cm) of necrotic tissue for wounds treated with maggot therapy (solid circles; n=14) decreased faster and greater than that seen with conventional therapy (open circles; n=14). Error bars indicate standard error; asterisks indicate significant differences in mean surface area (p<0.05) within 2 weeks.Sherman RA: Diabetes Care 2003; 26:446-51 |
It should be noted the maggots used in these studies were the same species and strain, from the same culture line, as the breeding stock used now for Medical Maggots™ by Monarch Labs.
Current status of maggot therapy
In 1995, only a handful of doctors were using MDT. By 2004, on the basis of clinical and laboratory data like that described above, the U.S. Food and Drug Administration (FDA) cleared Medical Maggots brand of maggots for marketing in the U.S., for the purpose of debriding chronic wounds such as pressure ulcers, venous stasis ulcers, neuropathic foot ulcers and non-healing traumatic or post surgical wounds.
Today, any licensed physician in the U.S. can prescribe maggot therapy. World-wide, approximately 50,000 treatments were applied to wounds in 2011.
Biology of flies and maggots
Maggots are fly larvae, or immature flies, just as caterpillars are butterfly or moth larvae. A diagram of the life cycle of flies and maggots appears below (used with permission of the BTER Foundation).
Not all species of flies are safe and effective as medicinal maggots. There are thousands of species of flies, each with its own habits and life cycle.
Those flies whose larvae feed on dead animals will sometimes lay their eggs on the dead parts (necrotic or gangrenous tissue) of living animals. When maggots are infesting live animals, that condition is called "myiasis." Some of those maggots will feed only on dead tissue, some only on live tissue, and some on live or dead tissue. The flies used most often for the purpose of maggot therapy are "blow flies" (Calliphoridae); and the species used most commonly is Phaenicia (=Lucilia) sericata, the green blow fly. Monarch Labs' Medical Maggots™ are a specific strain of P. sericata that was tested for safety and efficacy over the course of 12 years.
This fly has now been managed in pure culture for over 22 years.
- What do I do with the maggots when they arrive? How do I handle and store them?When the maggots arrive, read the label to make sure that they are for you and not the others in your facility. Remove the packing slip/invoice from the outer box, before it gets lost, and send it to the person responsible for accounts payable. Open the box carefully, so as not to damage the dressings inside. Remove the dressings and bubble-pack or Styrofoam box, which will contains the vial(s) of maggots. Open the bubble-pack or Styrofoam box to check the maggots; this will also provide more air (the vial lid is air-permeable). Inspect the larvae by looking through the vial(s), making sure that the larvae are alive (moving around) and the walls --- which may be moist --- are without slime. If the maggots appear healthy and active, place them back into the bubble-pack or Styrofoam box, seal them, and store at room temperature until use, ideally within 24 hours. Don’t forget to notify the doctors and nurses that the maggots have arrived. Gentle heat (80-90oF) will speed their development and make them slightly larger, sooner. Gentle cooling (45-55o F) will slow their development and prevent them from growing much larger. If the maggots can not be seen or if they are very slow moving, place the vial in a warm incubator to speed their development, and check again in one and two hours. If they still appear dead or immobile, or if they appear infected (slimy or foul smelling), notify Monarch Labs immediately.
- How do I keep the maggots on the wound?Since the maggots’ natural tendency is to wander off before and after they have finished feeding, they must be kept in place by dressings that allow air to enter, allow liquified necrotic tissue to drain out, and still keep the maggots securely over the wound. Instructions and a diagram of the dressing procedures can be found in the package inserts.
Our dressings guidance page has detailed information about applying the maggots, including instructional videos.
Monarch Labs has developed a new dressing, “Le Flap,” which is a pre-fabricated single-piece, two-layered flap-like maggot cage dressing. Use of this dressing can decrease maggot application time to only a few minutes. More information and instructions can be found in the package insert.
Clinical Answers
- What is maggot therapy?Maggot therapy (also known as maggot debridement therapy [MDT], larval therapy, larva therapy, larvae therapy, biodebridement or biosurgery) is a special treatment for wounds in which the therapist places medical grade fly larvae onto a wound, within a special dressing.
- What types of wounds might benefit from maggot therapy?Medical Maggots™ are indicated for debriding non-healing necrotic skin and soft tissue wounds, including pressure ulcers, venous stasis ulcers, neuropathic foot ulcers and non-healing traumatic or post surgical wounds.
- What are the advantages of maggot therapy?A. Efficacy, as demonstrated in several controlled clinical studies.
B. Excellent safety record.
C. Simple enough that non-surgeons can use it to provide thorough debridement when surgery is not available or is not the optimal choice for other medical reasons. This means that it is also possible to provide surgical quality debridement as an outpatient or in the home.
D. Low cost of treatment. - Is maggot therapy regulated by the FDA?Yes, production and marketing of Medical Maggots™ is regulated by the Food and Drug Administration as a prescription only medical device. In January 2004, the U.S. Food and Drug Administration granted permission to Dr. Ronald Sherman to produce and market Medical Maggots brand of medicinal maggots, for the following indications: "Debriding non-healing necrotic skin and soft tissue wounds, including pressure ulcers, venous stasis ulcers, neuropathic foot ulcers, and non-healing traumatic or post surgical wounds."
- Will maggot therapy hurt?Maggots do not bite. They do not have teeth. They do have modified mandibles though, called “mouth hooks,” and they have some rough bumps around their body which scratch and poke the dead tissue, one of the mechanisms that debrides the wound. It is similar to a surgeons “rasper,” but on a microscopic scale.
The maggots are so small when applied that they can not even be felt within the wound. Those patients who already have wound pain before beginning maggot therapy, perhaps due to exposed nerves or other reasons, may have some pain during maggot therapy when the maggots become large enough to be felt crawling over those nerves (usually at about 24 hours). Those patients should be given access to pain medications (analgesics); but if pain medication is inadequate to relieve the discomfort, the maggots can be removed early. Once the dressings are removed, the maggots will crawl out and the pain should cease immediately. If further debridement is necessary, another MDT dressing can always be applied later, but it should be used only for a brief period, again, until the patient is uncomfortable. - Can anyone order Medical Maggots™? Is it necessary to have a doctor’s prescription?Medical Maggots™ are regulated by the Food and Drug Administration (FDA) as a Prescription Only medical device. This means that they must be ordered or prescribed by a licensed medical or veterinary therapist. They can not be released without a prescription or an order to do so by an appropriately licensed health care provider.
- Can anyone do maggot therapy?Maggot therapy is simple enough that the procedure can be performed by physicians and veterinarians, nurses and physical therapists, health care assistants . . . sometimes even by patients and their families. Of course, experience and training helps! Whoever applies the maggot dressings should read all packaging and relevant information thoroughly, making sure they understand the procedure, and that they have all of the necessary supplies at hand.
- Do I need special training or certification to do maggot therapy?Special training or certification in maggot therapy is not required by law; but it certainly is helpful. Definitely read all relevant package inserts before applying the maggots (and preferably before ordering, which is why we have posted them for you in the next tab.
Our Maggot Dressings Guidance Page has written, pictorial, and video instructions to help you construct the best maggot dressings. Additionally, our customers have access to our on-call clinical consultant (Dr. Ronald Sherman) to assist therapists with their clinical questions. - Where can I find training to do maggot therapy?Several training courses and workshops are available. The BioTherapeutics, Education & Research (BTER) Foundation produces training workshops, and has many other educational resources posted on its website, including Policies & Procedures, lecture slides, and a patient information booklet.
Monarch Labs periodically sponsors training sessions, produced by the BTER Foundation. So does the Wound Care Education Institute, Wild on Wounds Conference, and the University of California, Riverside, Extension. You can evenhost a maggot therapy workshop in your town by contacting the BTER Foundation (www.BTERFoundation.org). - Where can I find a therapist who will prescribe and/or do maggot therapy?The closest therapist may be your own! Ask your doctor about maggot therapy. Monarch Labs and many other organizations provide training, in case s/he has never done it before (don’t worry, the maggots know exactly what to do, even if your doctor doesn’t!).
If you need a referral, the BTER Foundation maintains a therapist referral list. You can look up therapists by name or by city and state.
If you still can not find a therapist near you, call or e-mail us. Monarch Labs is not able to post our clients’ names or contact information, but we can give you a private referral to a few doctors in your area, if it is OK with those doctors. We can also provide your current doctor with a list of therapists to whom s/he can refer you and other patients. - How are maggots applied to a wound?Maggots are confined within a cage-like dressing over the wound for two to three days. The maggots are usually allowed to move freely within that cage, with the wound floor acting as the bottom of the cage ("confinement dressing"). Sometimes, the maggots are contained within a sealed pouch, placed on top of the wound ("containment dressing"). The dressing must be kept air permeable because maggots require oxygen to live. When maggots are satiated, they are larger and seek to leave the site of a wound. The dressing must be secure enough to prevent their escape until the therapist can remove the dressing and dispose of the maggots and dressings properly. Multiple two-day courses ("cycles") of maggot therapy may be necessary, depending on the severity of the wound and the extent of the necrotic tissue.
Therapists can use pre-manufactured dressings (i.e., Monarch Labs' “Le Flap"; seepackage insert) or they can construct their own dressings, using commonly available dressing materials (see package inserts or our written and pictographicdressings guidance page).
On our dressings guidance page, you can see, step-by-step how to apply maggots to a variety of wounds, and even watch an instructional video showing how to make your own dressings out of readily available materials. That video was produced by the BTER Foundation and publicly posted. - How many maggots are applied (what is the dose)?The dose is 5 - 8 larvae per cm2 of wound surface area.
- How do you get all of the maggots out?The maggot dressing is removed as soon as the maggots have finished secreting their proteolytic (tissue-dissolving) enzymes (within 48-72 hours). At that time, their natural instinct is to leave the wound and crawl away as quickly as possible. So when the dressing is opened, the maggots will be “at the gate,” eagerly awaiting their release. If any slow growing larvae remain, they can be removed with a simple wipe, wash, or irrigation. If they are hiding within a crevice, simply cover the wound with saline-moistened gauze, and replace it three time/day; the remaining maggots will leave the wound within the next 24 hours (as soon as they feel it is safe), and bury themselves in the gauze. More about dressing removal can be found on ourdressings guidance page
- How many treatment cycles are necessary?The duration of one course ("cycle") of treatment is 2 - 3 days. The number of treatment cycles depends on the size of the wound and the extent of necrotic tissue. The number of cycles can range from one to ten or more; the average is 3 cycles. Examine the wound after each treatment cycle (and 24 hours later, if possible), to determine if another cycle of treatment is necessary.
- How do I dispose of the maggot dressings after they are removed?Maggots are germ-free when applied, but become contaminated when they come into contact with the patient’s wound flora. MDT dressings should be handled like all other infectious dressing waste: placed in an appropriate bag and autoclaved or incinerated by the waste management department. Place the maggot dressings in a plastic bag and seal the bag completely. Then place the sealed bag into a second plastic bag and seal completely. Place the bag with the other infectious dressing waste, which should be disposed of (usually it is autoclaved or incinerated) within 24 hours.
- How do I dispose of the unused medicinal maggots?Unused maggots are germ-free and not a biohazard. They may be discarded in regular trash bins. Make sure the vial is Sealed securely so that they can not escape.
- What is the usage of maggot therapy in the United States?There are over 2,000 health care centers in the United States that have utilized maggot therapy.
- Are other countries using maggot therapy?Yes, over 4,000 therapists are using maggot therapy in more than 20 countries. Approximately 50,000 treatments were applied to wounds last year.
- Can you do maggot therapy on animals?Yes, veterinarians can request Medical Maggots™ for use in animals. Several studies and references are listed on our Veterinarian web pages,and on our support & reference pages.
Discussion about how to make maggot dressings for animals appears on our equine dressings page, which you can open in the next tab.
Financial Answers
- How does reimbursement work?The last time AMA and CMS (Center for Medicare & Medicaid)issued coding recommendations for maggot therapy was in 2008. Until AMA issues a new, MDT-specific procedure code, their basic advice still holds: code separately for the procedure (using a debridement code) and for the maggots & supplies (using text descriptions, or HCPCS codes, where they exist).
For the procedure code, consider using the debridement code: 97602 ("Non-excisional debridement"). For the supply code, they suggested using CPT® supply code 99070 ("Supplies and materials provided by the physician over and above those usually included with the office visit or other services rendered"), followed by a written list of every specific product used.
If you use ABC codes, then the maggots can be coded using ABC code for maggots (EAACT) or the HCPCS code for misc. devices (A9270).
Remember: insurance claims are first reviewed by a screener who's job is to eliminate as many claims as possible. If they are unfamiliar with maggot therapy, their preliminary determination may be that maggot therapy is not a covered service. This is usually incorrect, and a thorough appeal will nearly always be accepted, if the treatment was consistent with official (FDA-sanctioned) indications.
The BTER Foundation will assist with appeals. For those without insurance or other financial resources, Monarch Labs and the BTER Foundation also provide Patient Assistance Grants. Additional information can be found on our Reimbursement page. - Can I still get maggots and maggot therapy even if I do not have insurance or a lot of money?Of course! We at Monarch Labs are dedicated to the proposition that medical care should not be rationed on the basis of ability to pay. Besides, if you haven’t noticed the price sheets, take a look . . . the cost of Medical Maggots is a lot less expensive than most other similar products. Even so, it can be hard to come up with the money to pay for them, so here are some solutions:
For those without insurance or other financial resources, Monarch Labs and theBTER Foundation also provide Patient Assistance Grants. Additional information can be found on our Reimbursement page.
Remember: Never postpone your medical treatment just because you do not have the money yet. Monarch Labs can send the treatments ordered, and bill you later, if you want. Delaying treatment can lead to progression of the underlying infection, circulatory compromise, or other problems, which in turn can leave you with a larger, more difficult-to-treat wound, a worse prognosis, and a need for more costly treatment.
Website Answers
- How do I notify you if I find an error or problem on the website, or simply want to comment?We want to hear about any problems with our website or our products. Contact us by phone, fax, e-mail or post. You can get these numbers from our Contact Page
- How do I notify you if your website is not displaying on my browser?We want to hear about any problems with our website or our products.Contact us by phone, fax, e-mail or post. You can get these numbers from ourContact Page
Other Answers
- Can the maggots reproduce in my wound during maggot therapy?No, all larvae are immature, and can not reproduce until reaching adulthood.
- Will the maggots turn into flies in my wound?No, the immature larvae are removed after just 2 or 3 days and discarded. If not discarded, it would take 2 or 3 weeks for them to turn into flies. If any maggot escapes without re-capture, then it may be possible for it to hide for a couple weeks, pupate, mature, and emerge as an adult fly several weeks later. Indoors, these flies will generally die before having a chance to reproduce or make larvae of their own.
- Who supplies maggots for maggot therapy in the United States?In the United States, Monarch Labs (www.monarchlabs.com) in Irvine, California, is the exclusive supplier of Medical Maggots™ (disinfected Phaenicia sericata larvae) for maggot debridement therapy.
- Where can I find more information?Check out these links:
A. BioTherapeutics, Education & Research Foundation at www.BTERFoundation.org.
B. Wound Care Education Network.
C. Arrange to attend or sponsor a Maggot Therapy Lecture or Workshop. - Where I can hear from patients whom have tried maggot therapy?The BTER Foundation Has recorded and posted several patient interviews. You can find links to these interviews on our Support - Video nterviews Page.
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