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Maggot Debridement Therapy: A Suitable Treatment Option for Chronic Wound Care EMILIA M. KOOIENGA; JEROME GODDARD, PHD
Abstract Chronic, non-healing wounds due to burns, diabetes, and other injuries cost United States patients about 50 billion dollars each year. Traditionally, treatment has involved surgical debridement of necrotic tissue and frequent cleaning and changing of the wound and dressings to manage infection risk and promote healing. In the 1920s, a new method of wound debridement called maggot debridement therapy or MDT emerged and has continually developed into an effective treatment strategy. Sterile, live blow fly larvae are either placed into the wound and sealed in by gauze or held in place by a mesh bag in the wound. Secretions of the larvae kill bacteria, dissolve necrotic tissue, and stimulate healthy tissue formation. Studies have shown that MDT has the power to debride and contribute to wound healing as early as four weeks, compared to conventional therapy. With multiple benefits and few side-effects, MDT is a well-supported and increasingly accessible tool for physicians in chronic-wound treatments. Introduction Chronic wounds affect about 2% of the population of the United States, with a total cost of about 50 billion dollars annually.1 The cost of care increases in those patients with co-morbidities, complications, or other conditions related to their wounds. Traditional therapies for chronic wound care consist of surgical debridement of necrotic tissues supplemented by antibiotics. Maggot Debridement Therapy (MDT) is an alternative method of debridement in wound care that warrants further exploration. The use of maggots in wound care was first noted by William Baer at Johns Hopkins hospital in the 1920s as having a positive impact on healing soldiers’ wounds;2 however, post-World War II, maggot therapies were mostly replaced with antibiotic therapy and surgical techniques.2 In this paper, we explore traditional therapies used in debriding wounds and compare them with the merits, uses, and efficacy of MDT. Myiasis The infestation of living vertebrates with dipterous larvae is called myiasis and can be either facultative (opportunistic) or obligate. Obligate myiasis constitutes true parasitism and is a complex
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issue. The subject of this paper is facultative myiasis and how it can be used in clinical medicine. Flies, particularly those in the family Calliphoridae, lay eggs on dead animals that the developing larvae consume. Unfortunately, sometimes the adult flies mix up what is dead or alive and may lay their eggs in malodorous, pus-filled wounds on people and animals. This is sometimes termed cutaneous myiasis where fly larvae enter an open wound, feeding upon dead tissue in the wound. They do not subsequently enter into living tissue. While there are stories of people stranded outdoors after an accident with maggots in their lesions (supposedly helping prevent infection), these infestations may lead to secondary infection of the wound.3 “Wild” or naturally occurring flies and their larvae may transport a host of pathogens into the wound. For example, Staphylococcus aureus and other Group B Streptococcus organisms have been isolated from myiasis patients’ wounds.3 Types of Chronic Wounds Chronic wound care typically refers to those slow- or non-healing ulcer-like sores most often found on bedridden patients or diabetics.4 Pressure ulcers are common among bedridden patients in long-term inpatient care or who are afflicted with medical conditions that limit or prevent movement of the body.5 These ulcers develop on the less padded areas of the body with more delicate skin and less fat. In comatose patients, for example, ulcers are commonly found on the back, hips, heels and ankles.5 Patients who rely on the daily use of a wheelchair often find developing ulcers on their shoulder blades, tailbone, and back from both pressure and friction. Diabetic patients, as well as other patients with vascular diseases, are also at risk of developing pressure non-healing ulcer wounds. Decreased blood flow and nerve damage from diabetes complications mean the area, once pressure is applied, gets even less blood. This leads to tissue death as nutrition and hydration are withheld from the area. Nerve damage in the ulcer-forming area means that the patient may not feel the excess pressure or friction and will not be aware of the need to change body position to prevent injury. Complicating matters, secondary infections often occur in persistent open wounds. Methicillin-resistant Staphylococcus aureus (MRSA), in particular, is a notable concern for those with chronic wounds.
