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Ronald Sherman, MD
Director, BTER Foundation (www.BTERFoundation.org)
Clinic Physician, Orange County Health Care Agency |
Those who attended the Superbones West 2012 (Las Vegas) conference in October were fortunate enough to hear experienced clinicians present evidence-based lectures on all topics podiatric. Sometimes, lively audience-inspired discussions followed these presentations. I had the good fortunate to witness - and even participate in – one such discussion: "isn't surgery the proper way to treat osteomyelitis?"
I think it is fair to say that the consensus of the panelists was that surgical resection is generally the treatment of choice. But the panel also admitted that many times surgery is not feasible, or at least is not without very significant risks. In these cases, consideration must be given to non-surgical alternatives. It is within this context that I was asked about maggot debridement therapy (MDT) for osteomyelitis: "why is osteomyelitis a relative contraindication, despite the fact that osteomyelitis used to be one of the primary indications for maggot therapy during the last century?
During the pre-antibiotic years, MDT was commonly used for patients with osteomyelitis (Baer, 1931), often secondary to bacteremias (including tuberculosis). The mainstay of treatment was surgical resection; but after surgery, often the infections would fester or advance. Maggot therapy was used as an adjunct to surgery, usually applied a day or two following the procedure. It would then be continued until healthy granulation tissue formed in the wound bed (demonstrating eradication of the underlying bone infection), or even beyond that, for the purpose of promoting tissue growth (or at least for what we now call: maintenance debridement).
Sometimes, maggot therapy was used alone, such as in patients with chronic osteomyelitis unresponsive to surgical resection, or in patients with early, less advanced infections. Even today, MDT is sometimes used in such situations of osteomyelitis and osteitis.
In order to approve a drug or grant marketing clearance for a specific indication, the U.S. Food and Drug Administration (FDA) must review objective, controlled studies proving efficacy and safety for that indication. Such clinical trials have not yet been done with MDT for osteomyelitis, so osteomyelitis can not be included among the formal indications for maggot therapy. What's more, because I personally believe that surgery is the optimal treatment for bone infection whenever possible, I requested that osteomyelitis be listed as a relative contraindication for using Medical Maggots (the only brand of medicinal maggots to have achieved FDA marketing clearance). In this way, therapists will think twice before choosing maggots over surgery for osteomyelitis.
To this day, many people are still treating osteomyelitis with maggot therapy, when surgical resection is impractical or inadequate (Sherman, Shapiro & Yang, 2007). Maggot therapy has recently been used to help define bone infection (during maggot therapy, as long as bone is exposed, it should be considered infected; once the exposed bone completely covers with healthy granulation tissue, then the osteomyelitis can be considered resolved). However, until someone does a controlled study demonstrating the efficacy and safety of maggot therapy for osteomyelitis, the use of MDT for treating bone infections should remain only a second-line option, for those situations where surgical resection is not clearly the optimal course of action.
Figures 1-3
This 59 year old diabetic man refused amputation, despite absent pedal pulses and osteomyelitis in at least two metatarsal heads (1). Within 2 weeks (3 applications) maggot therapy debrided his wounds (2), although the necrotic big toe still remains at this point, and will soon be surgically removed. The patient healed and one year later still showed no recurrent of infection (3). This case was previously published (Sherman, Shapiro & Yang, 2007). Photos by RA Sherman; used with permission of the Biotherapeutics, Education & Research Foundation.
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Figure 2 |
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LITERATURE CITED:
Baer WS. The treatment of chronic osteomyelitis with the maggot (larva of the blow fly). J Bone Joint Surg 1931; 13:438-75.
Sherman RA, Shapiro CE, Yang RM. Maggot therapy for problematic wounds: uncommon and off-label applications. Adv Skin Wound Care. 2007; 20:602-10.
