Technology and product reviews T E C H N O L O G Y U P D A T E :


The use of larval therapy in modern wound care


Larval therapy, also known as maggot therapy or biosurgery, is widely used by healthcare professionals for the debridement of sloughy, necrotic wounds. The benefits of this treatment are well-documented and have been widely published in the medical and nursing press[1,2,3]


. Author: Viv Pyatt Useful links


A know-how guide for using larval therapy for wound debridement


Spinal cord injury: using maggots to ease the pressure


This article reviews the evidence for this technique and provides an overview of best practice.


INTRODUCTION For hundreds of years it has been recognised that larvae can have a beneficial effect upon infected wound healing. Originally, it was observed that wounds tended to heal more quickly with fewer complications when larvae found their way into wounds naturally (through flies landing on an area of broken skin and laying their eggs)[4]


. Larvae were claimed References 1. Johnson S. Larval therapy in the


treatment of wounds: a case history. Nurs Res Care 1999; 1(9): 520–21.


2. Sherman RA. Maggot therapy for treating diabetic foot ulcers unresponsive to conventional


therapy. Diabetes Care 2003; 26(2): 446–51.


3. Acton C. A know-how guide to using larval therapy for wound


debridement.Wound Essentials 2 2007; 156–59.


4. Baer WS. The treatment of chronic osteomyelitis with the maggot (larvae of the blowfly). J Bone Joint Surg 1931;13: 438-475.


5.Adams, G.W. Doctors in Blue: The Medical History of the Union Army in the Civil War. Henry Schuman, New York.


6. Pavillard ER, Wright EA. An


antibiotic from maggots. 1957; Nature 180(4592): 916–17.


to accelerate cleansing, combat infection and hasten the removal of necrotic tissue without damaging the healthy tissue beneath. Larvae were deliberately used for debridement in the American Civil War, and the First and Second World Wars[4]


. With the arrival of antibiotics to treat


infection in the 1940s the practice of larval therapy declined, although reports of its benefits continued to appear in literature[5,6]


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The resurgence of interest in their use began in the mid-1990s through a project in Bridgend, South Wales, which bred medicinal quality larvae for clinical use in the UK National Health Service (NHS). As the use of larval therapy for the debridement of wounds has grown in Europe, the US and in the Far East — specifically Japan, Thailand and Malaysia — the commercial availability of larvae has grown[7,8]


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LIFE CYCLE OF THE FLY Medicinal quality larvae are produced from the fly Lucilia sericata, the common green bottle fly. Using this particular fly is beneficial because it lays eggs that are not damaged by the process of disinfection. Disinfection is performed by washing the fly eggs in a solution, which


23 Wounds International Vol 2 | Issue 4 | ©Wounds International 2011


has a high bacterial potency, but a low level toxicity for the eggs. This ensures the removal of any pathogens on the surface of the egg. When hatched, the larvae feed only on dead tissue and slough in the human wound[9]


,


a phenomenon observed by Napoleon's surgeon, Baron Dominique-Jean Larrey, following maggot infestation in wounded soldiers[10]


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The female adult fly will usually lay its eggs on a source of protein so that when the eggs hatch they have an instant food supply and thus ensure their survival. The larvae will hatch within 12–24 hours and are between 1–2mm long. The larvae grow rapidly and will reach their maximum length of 10–12mm in five to seven days. Once maturation is reached, the larvae


stop feeding and begin to pupate. The pupae is formed from the hardened skin of the larvae. Metamorphosis into an adult fly occurs within the pupae. With the right temperature, this takes approximately seven days. The adult fly then emerges from the pupae and, after feeding and mating, is ready to lay eggs.


MODE OF ACTION There are two aspects to the normal feeding action in larvae — mechanical and biochemical. The larvae have a pair of mandibles, or hooks, which form part of the external mouth. These hooks mechanically break down tissue. The larvae produce secretions containing proteolytic enzymes that further break down devitalised tissue into a semi-liquid form that the larvae


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