USE OF MAGGOTS IN ORTHOPAEDIC INFECTION

Abstract

Introduction and Aim: In 1995, sterile maggots (blow fly larvae) became available commercially for the first time since the mid-1930s. We have used them in managing ‘problem wounds’ in an orthopaedic unit. We have re-assessed the value of maggot debridement therapy (MDT) in present-day orthopaedics.

Method and Results: To date 95 patients have been treated. (Average age 62; range 16–91). Eighty-five percent of cases involved the lower limb. The remainder were upper limb, apart from one spinal lesion and one sacral sore. Twenty percent of patients had diabetes; six amputation stumps were treated. In 60% of cases a single application was used, the larvae being left in-situ for three to five days. Some wounds required up to three applications. The dressing technique is easily learnt and is ideal for outpatient clinics. The most appropriate wounds are those with a wide opening, extensive slough, and natural drainage. The greatest benefit follows infection with gram-positive cocci, and anaerobes. In eight cases, MRSA infection was cured or controlled.

Larvae provide optimal wound healing conditions, by literally eating pus and bacteria, and also by stimulating granulation tissue to form. However, they cannot produce wound healing if a major sequestrum or implant is present. In general, patient acceptance was good, but five patients requested early removal of maggots. Since 2001, the maggots have been available in sachet form (the so-called ‘Bio-bag’) and this packaged application has made the treatment more readily acceptable, and easier.

Overall we judged that MDT had produced healing or improvement in 80% of infected wounds. Unusual wounds, such as animal bites, a sea -urchin lesion, and infected gout produced some of the most striking cures.

Conclusion: Maggot therapy uniquely minimises both the need for surgical debridement and antibiotics. We therefore recommend its continued use.