There are some more unusual techniques used in medicine, and they can also be a little gruesome. The thought of maggots crawling around on your skin is pretty unpleasant, but it does apparently have some therapeutic basis...

Imagine going to a doctor for a leg wound that just won't heal. Instead of prescribing antibiotics, the doctor suggests a treatment of maggots. Sounds horrible? You may have read stories with concentrated close ups of huge numbers of scary and non- sterile looking creatures and wondered why anyone would even consider such a treatment. But, disgusting as it sounds, scientific research has shown that, in some cases, such creepy crawlies may heal a wound more quickly and efficiently than modern medicine. "Biosurgery" using larvae such as maggots for treatment of difficult wounds is now becoming an established discipline in the management of difficult wounds.

VOLKER STEGER/SPL

Maggots

Maggot therapy (placing live sterile maggots on a wound, also known as larval therapy), in combination with surgery, was used during the early decades of the 20th century for treating osteomyelitis and purulent infections of the soft tissue.¹ We have known for hundreds of years that soldiers whose wounds become infected with maggots are less likely to die from septicaemia than those who did not.² Since the 1940s, when antibiotics became widely available, maggot therapy was used only as a last resort. But maggots have more recently again been used successfully in the treatment of various chronic soft tissue wounds, including neurovascular ulcers, venous stasis wounds, pressure ulcers, traumatic and surgical wounds, burns, and necrotic tumours.^1­6 Larval therapy is currently being used in over 350 hospitals and institutions in the United Kingdom.⁷

The year 1995 remains a landmark in the history of maggot therapy when the first controlled prospective trial showed a significant improvement in the rate of healing associated with maggot therapy for treating pressure ulcers in patients with injuries to their spinal cord.⁷ The International Biotherapy Society was also formed in 1996 (www.homestead.
com/biotherapy/), which supports research and clinical use of maggot therapy and other biological therapeutics.

Mode of action

Maggot therapy by three main actions: debridement, or by liquefaction of necrotic tissue; elimination of infection; and hastened wound healing. These mechanisms are currently being investigated by several laboratories around the world. Debridement and healing has been noted in diabetic foot ulcers, venous stasis ulcers, and other chronic wounds where two or more conventional treatments had previously failed.^{1 2}

Moving over the surface of wounds, maggots secrete a rich mixture of proteolyic enzymes, which liquidises dead tissue. Maggots then ingest this and, by raising the pH of wounds and secreting chemicals, can prevent the growth of some bacteria. Normal tissue is not removed because the enzymes are neutralised when they come into contact with it.²

It is important to select the appropriate wound for treatment with maggots. A moist exudating wound with adequate oxygen supply is a prerequisite for maggot therapy. Dry wounds and open wounds of body cavities are a contraindication. The maggots used for medical purposes do not burrow under patients' skin. They also do not multiply because a mature larva must leave a wound to pupate or it will die. A doctor using this procedure simply flushes the maggots out of a wound after several days (often removed after 3-5 days). Practical problems associated with maggot therapy include keeping the wound bed moist and the larvae from escaping the wound. Moving larvae can also cause a tickling sensation reported by some patients. These problems may be solved by applying dressings whereby the maggots are completely contained in their own cage, separated from, but in contact with, the patient. This can be done by placing the maggots on a hydrocolloid sheet under a net on the surface of wounds.²

Most of the literature on maggot therapy is anecdotal. More studies are needed to evaluate further the role of maggots in clinical practice. Maggots are still viewed as the antithesis of health and cleanliness. The aesthetic and psychological disadvantages of maggot therapy can, however, be overcome with adequate information and support to both patient and clinical staff.

Maggot therapy may prove to be a cost effective and useful aid in the management of selected cases of difficult wounds and ulcers. It is also important to consider maggot therapy in individuals in whom antibiotics or surgery are ineffective, associated with high risk, or unavailable. Maggot debridement will be of particular benefit to communities with poor resources, which have endemic, chronic, and intractable wound problems such as those in tropical and developing countries.

GEOFF TOMPKINSON/SPL

Leeches

Another folk remedy handed down through the ages is the use of leeches. The first use of medicinal leeches occurred about 2500 years ago in Egypt, when they were applied to treat all kinds of ailments from headaches to stomach aches. It was thought that leeches would drain "impure blood" from the body, thereby curing illness.⁸

Leeches belong to a class of legless invertebrates called annelids. Over 650 species of leeches are known. Their multiple curative effects are due to the components of their saliva. Hirudin is the principal anticoagulant in leech saliva. Hirudin is now produced by recombinant DNA technology and is administered to patients undergoing coronary angioplasty and for the treatment of deep venous thrombosis. Other properties of this saliva are that it is antithrombotic, thrombolytic, hypotensive, anti-inflammatory, bacteriostatic, and analgesic.⁹

Medicinal leeches were used for bloodletting and have been applied to congested or inflamed parts of the human body for over 2000 years. Today, leeches are used mostly in plastic and reconstructive surgery. The main indication for their use is for treatment of venous insufficiency in salvageable tissue with intact arterial perfusion. The anticoagulant effect of the secretions produced by leeches helps to relieve venous congestion and improve blood flow to compromised free tissue flaps.¹⁰ The procedures in surgery that may benefit from leech therapy include replanted digits after traumatic avulsion or amputation, and compromised skin flaps after successful arterial revascularisation but suffering from venous congestion and haematomas.^{11 12}

In cases of venous congestion where re-establishing the flow of blood is essential, leeches have great therapeutic value because, as they consume their meal of blood, they promote blood flow through the tissue. Even after a leech is full of blood and detaches from the body, the anticoagulants it secretes into the tissue allow the wound to ooze blood for hours afterwards. The oozing promoted by the leech's natural anticoagulants also allows blood to continue flowing through the tissue. Meanwhile, during leech therapy (for example, two per day for a finger replant), which can typically last for up to five days, new veins may grow into the reconstructed region from surrounding healthy tissue and help re-establish adequate blood drainage.^9­11

Leeches obviously have their drawbacks, not the least of which is patients' squeamishness about having them attached to their bodies. They can sometimes slip off patients and reattach themselves to other parts of the body not in need of therapy.¹⁰ Moreover Leeches are not sterile and can cause bacterial infections mainly due to Aeromonas hydrophila. Leech therapy may also be complicated by excessive blood loss requiring additional treatment.

Don't overlook creepy crawlies

Despite their somewhat unconventional nature, leeches and maggots have been shown to be effective in many different areas of medicine. Perhaps more of us who have been sceptical about such treatments up to now should start regarding them as a serious option.