Biosurgery is also known as Maggot Debridement Therapy (MDT), the medical use of live maggots (fly larvae) for cleaning non-healing wounds.

The beneficial effects of larvae (maggots) upon the healing of infected wounds have been recognized for hundreds of years. In the main, these larvae found their way into wounds by accident, particularly under battlefield conditions, but it was recorded that when this occurred the wounds tended to heal more quickly and with fewer complications than comparable wounds that had not become infested.

Over fifty years later during the First World War, an orthopedic consultant to American forces in France treated two wounded soldiers who had remained overlooked on the battlefield for a week after the fighting. He found that although their compound fractures and abdominal wounds swarmed with maggots, the wounds had begun to granulate with no evidence of sepsis. Some ten years later, when Clinical Professor of Orthopedic Surgery at the John Hopkins Medical School, Dr. Baer recalled his wartime experiences when trying to treat several cases of intractable osteomyelitis. He obtained a supply of maggots and placed them in the wounds which proceeded to heal within six weeks. Following these experiences the use of larve in wound management became very common in the 1930s, particularly in the USA where larvae of the greenbottle, Lucilia sericata, were produced commercially in large numbers for this purpose by the pharmaceutical company Lederle. The early literature contains many references to the successful use of these larvae in chronic or infected wounds including osteomyelitis, abscesses, burns and sub-acute mastoiditis.

Historically, maggots have been known for centuries to help heal wounds. Many military surgeons noted that soldiers who's wounds became infested with maggots did better --- and had a much lower mortality rate --- than did soldiers with similar but non-infested wounds. William Baer, at Johns Hopkins University in Baltimore, Maryland, was the first physician (an orthopedic surgeon, actually) in the U.S. to actively promote maggot therapy; his results were published posthumously by his colleagues in 1932. MDT was successfully and routinely performed in over 300 hospitals, until the mid-1940's, when its use was supplanted by the new antibiotics and surgical techniques that were believed to be superior to maggot therapy. Maggot therapy was occasionally used during the 1970's and 1980's, when antibiotics, surgery, and other modalities of modern medicine failed. In 1989, physicians at the Veterans Affairs Medical Center in Long Beach, CA, and at the University of California, Irvine, reasoned that if maggot therapy was effective enough to treat patients who otherwise would have lost limbs, despite modern surgical and antibiotic treatment, then we should be using maggot therapy BEFORE the wounds progress that far, and not only as a last resort. Thus was seen the rebirth of maggot debridement therapy, or MDT.

Dr. Ronald A. Sherman’s studies at the Veterans Affairs Medical Center and the University of California, are still underway. Results thus far demonstrate that maggot therapy is more efficient at debriding (cleaning) infected and gangrenous wounds than any other non-surgical treatment prescribed by the hospital's wound care team. Additionally, wounds treated with MDT healed more quickly (by several-fold) than they had been healing prior to initiating MDT.

It is believed that larvae combat wound infection by ingesting microorganisms which are then destroyed in their gut but there is published evidence to suggest that they also secrete chemicals such as allantoin and other agents with with pronounced broad-spectrum antibacterial activity. Studies on the screwworm, however, appear to indicate that this antimicrobial activity may be due to phenylacetic acid and phenylacetaldehyde produced by the bacteria Proteus mirabilis which is a commensal of the larval gut.

To our knowledge, the clinical importance of these antimicrobial agents has never been fully investigated.

In the United States, maggot therapy has been studied in clinical trials since 1989 at the University of California in Irvine and the Veterans Affairs Medical Center in Long Beach, CA. According to Ronald A. Sherman, M.D., of the Maggot Therapy Project at the University of California at Irvine, maggots are especially effective for treating pressure ulcers, diabetic foot wounds, venous stasis ulcers and post-surgical wounds. Studies have revealed that the therapy is more efficient at debriding infected and gangrenous wounds than other non-surgical treatments. The treatment is administered by applying sterilized live maggots to the wound and covering them with a dressing to prevent them from escaping. Maggots are then left to consume the wound's dead and infected tissue. The dressing is removed one to three days later, by which time the maggots have reached maturity and no longer can digest the infected tissue. Depending on the severity of the wound, the procedure may be repeated.

The use of fly larvae in wound management has a sound basis in the literature. It appears to be free of any serious or significant side effects, and may have major advantages over conventional treatments for certain types of wounds.

It is recognised that some patients, and indeed clinicians, may find the presence of 'maggots' in a wound to be unacceptable. However, the results of a survey conducted in the USA published in the American Journal of Surgery in 1935 involving 605 surgeons and 5750 patient treatments, revealed that a favourable opinion on larval therapy was expressed by 552 individuals (91.2%) of those who took part.

Experience gained locally indicates that although some patients and nursing staff may find the use of larvae unacceptable, the technique is much more readily accepted than might have been anticipated.

Provided that a specific patient has no objection to the use of larvae, there appear to be no ethical barriers to their widespread use. A review of the literature has revealed no significant risks or adverse events causally linked with the clinical use of sterile larvae of Lucilia sericata in the above manner.

Excerpted from information provided by Surgical Materials Testing Lab, Ronald A. Sherman, MD, MSc, DTMH, Dept of Pathology, University of California, Irvine, CA 92697-4800 and Suzanne Leigh of the Medical Tribune.