Temple University School of Podiatric Medicine Journal Review Club
Editor's note: This post is part of the Temple University School of Podiatric Medicine (TUSPM) journal review club blog series. In each blog post, a TUSPM student will review a journal article relevant to wound management and related topics and provide their evaluation of the clinical research therein.

Article Title: Effective Wound Bed Preparation Using Maggot Debridement Therapy for Patients With Critical Limb Ischemia
Authors: Nishijima, A, MD; Gosho, M, PHD; Yoshida, R, MD; Yanagibayashi, S, MD, PHD; Takikawa, M, MD, PHD; Nishijima, J, MD; Sekido, M, MD, PHD; Yamamoto, N, MD, PHD
Journal name and issue: Journal of Wound Care 26 Vol. 8 (2017) 483–489
Reviewed by: Thomas Ferrise, Class of 2020 , Temple University School of Podiatric Medicine

Introduction: Wound Bed Preparation With Maggot Debridement in Critical Limb Ischemia

An important factor in wound healing is adequate blood flow; thus patients with critical limb ischemia (CLI) and complex wounds are poor healers. Primary treatment for CLI is revascularization. Wound healing can be prolonged as a consequence of cyclical protease production by necrotic tissue during the inflammatory phase of healing. Debridement of necrotic tissue is therefore necessary to reduce inflammation and progress the healing cycle, as well as to promote epithelialization and reduce risk of infection. Conventional debridement therapy can be difficult in patients with CLI because of limitations in visualizing wound margins and time effectiveness. Maggot debridement therapy (MDT) is a traditional debridement therapy using live, sterilized fly larvae. This study investigated MDT in patients with CLI after midfoot amputation following revascularization by endovascular therapy. The outcomes of wound bed preparation were compared with the outcomes in patients receiving conventional therapy.

Methods

Subjects were selected based on criteria of CLI with revascularization and a wound bed deemed too poor to close after a major lower extremity amputation. Clinical history leading up to the amputation was retrospectively investigated and documented.

The control group was treated with conventional wound bed preparation (the use of sulfadiazine silver or bromelain ointment for debridement and povidone-iodine for cases of maceration). If the ointment provided incomplete debridement, surgical debridement was performed. MDT was indicated for patients in whom conventional therapy failed.

MDT includes removal of ointment and cleansing of the amputated surface. A hydrochloride patch was applied, followed by 10 maggot larvae/cm2 and covered with a nylon sheet. Maggots were replaced every 48 hours. Pain was managed by oral non-steroidal anti-inflammatory drugs and by decreasing the number of maggots.

Successful wound bed preparation was determined by clinical evaluation preceding skin graft and wound closure. Evaluation of wound bed preparation was primarily based on wound healing without major amputation. Secondary parameters were amputation-free survival and capability of ambulation.

Results

A total of 39 patients were observed in this study; 32 were treated using conventional methods, and seven were treated using MDT. The proportion of wound healing that avoided major amputation was significantly higher in the MDT group (86%) versus the control group (38%), whereas amputation-free survival and postoperative ambulation showed no significant differences. Propensity score analysis showed a significantly higher wound healing proportion for the MDT group (86%) versus the control group (38%).

Conclusions

The efficacy of MDT was shown with patients with CLI who underwent angioplasty and midfoot amputation and for whom wound bed preparation by conventional treatment was difficult. Wound healing rates for MDT were higher than after conventional treatment.

In patients with revascularized CLI, wound bed preparation using MDT has four major benefits. First, MDT is highly selective for necrotic tissues, thus making it suitable for irregular margins and deeply penetrating wounds. Second, the technique for MDT is straightforward and easily mastered, minimizing the need for special training. The third major benefit is promotion of granulation tissue formation. Maggot secretions and excretions enhance fibroblast migration, angiogenesis, and production of growth factors within the wound. The fourth benefit is antibacterial action associated with the digestive properties of maggots. Maggots have sterilizing effects against many gram-positive species such as methicillin-resistant Staphylococcus aureus.

Results of this study show that wound healing was more favorable in the MDT group than in the control group. There was no significant difference in amputation-free survival at six months between the two groups. Because CLI is a systemic disease, the definitive factors for prognosis are age (over 75 years), dialysis, reduced cardiac function, and lack of ambulation. When compared with similar studies regarding achievement of ambulation in patients after transmetatarsal amputation, this study reports lower success rates, for reasons that are the major limitations of the study: MDT is not covered by the Japanese national health insurance system, and patients could receive MDT only when conventional treatment yielded unfavorable outcomes.

About the Authors:
Thomas Ferrise is a second year medical student at Temple University School of Podiatric Medicine (TUSPM) in Philadelphia, Pennsylvania. Thomas graduated with honors from the University of North Texas in 2014 with a BA in Biochemistry. Thomas holds a keen interest in reconstructive surgery, diabetic limb salvage, wound care, and sports medicine. He hopes to use his platform as a future Podiatric Physician to improve the health and mobility of his community.

Dr. James McGuire is the director of the Leonard S. Abrams Center for Advanced Wound Healing and an associate professor of the Department of Podiatric Medicine and Orthopedics at the Temple University School of Podiatric Medicine in Philadelphia.