The therapy involves the use of larvae of the greenbottle fly, which are introduced into a wound to remove necrotic, sloughy and/or infected tissue. Larvae can also be used to maintain a clean wound after debridement if a particular wound is considered prone to resloughing.
The technique, which has been used for centuries, has been reintroduced into modern medicine by doctors and wound care specialists who have found that larvae are able to cleanse wounds much more rapidly than conventional dressings.
Whilst larvae should not be regarded as a cure for all types of wounds, by removing dead tissue and any associated bacteria, in most instances they will improve the condition of a wound and allow the process of healing to begin.
How does Larval Therapy work?
The processes by which larvae clean wounds are very complex, but in simple terms they physically feed on dead tissue by releasing a mixture of natural enzymes and components into the wound, these enzymes break down dead tissue into a liquid form that the larvae can then easily remove and digest. During this process the actively feeding larvae also take up bacteria, which are then destroyed within their gut. This process is so effective that larvae can often clean a wound within a few days.
How big are the larvae?
The larvae that are applied to your wound are only a few millimetres in length, smaller than a grain of rice. During the treatment time they will increase in size as they clean the wound, to a maximum of 12mm.
How are the larvae applied?
There are two methods of application:
- BioBag Dressing: The larvae are sealed within a dressing which is a finely woven net pouch containing a small piece, or pieces of foam, which aid the growth of the larvae. The BioBag Dressings come in varying sizes and are applied according to the nature and size of the wound being treated. The larvae remain sealed within the dressing throughout the treatment.
- Loose Larvae: The larvae are applied directly onto the wound and retained within a special dressing system. The exact nature of this is determined by the size and location of the area to be treated.
How long does the treatment last?
This can vary with each treatment of larvae and the method of application being used. BioBag Dressings can be left in place for up to four days; it is possible for the dressing to be removed and reapplied on a daily basis to allow inspection of the wound site. ‘Free Range’ larvae are generally left in place for up to three days before being removed from the wound site.
With both application methods, it is impossible to predict how long a course of treatment will take. Sometimes a wound is completely cleansed by a single application of larvae but other wounds may require two or more treatments to achieve the desired effect.
Will I notice anything different during larval therapy?
During larval therapy you may notice some changes in the wound:
- The wound may become a little wetter than usual or show the presence of a dark red or pink discharge. This is due to the action of the larvae breaking down the dead tissue.
- Sometimes a wound that contains a lot of dead tissue will develop a characteristic smell during treatment. This is nothing to worry about, it is just due to the activity of the larvae and should disappear when the dressing is changed.
- Most people are unaware of the larvae’s presence, although a small number of patients claim that they can feel the larvae moving but only describe this as a tickling sensation.
- Some patients, particularly those with poor circulation report that their wounds become more painful during larval therapy but this can generally be controlled with medication.
- Some patients have found that the pain associated with infected wounds is reduced following larval therapy.
Will larvae burrow into healthy tissue?
The larvae used in wound management will not attack or burrow into healthy tissue, they only remove dead tissue.
Will the larvae multiply in my wound?
Only adult flies can lay eggs, so the larvae cannot reproduce or multiply within the wound.
Where do the larvae come from?
Larvae are produced in a special unit by highly trained staff at BioMonde, a company with many years experience in wound management.
Are there any activities that should be avoided during treatment?
Although it is possible for the patient to carry out most normal activities whilst undergoing larval therapy, they should ideally not bathe or immerse the wound in water. It is also not a good idea to sit with the wound too close to a source of heat e.g. fire or radiator, as the larvae may dry out. Similarly, sitting or walking on a wound treated with larvae should also be avoided as much as possible.
Why use larval therapy instead of a conventional dressing?
Clinical experience with larvae has shown that they can clean wounds in a fraction of the time taken by more conventional dressings, which could potentially speed up healing times. They are also useful in the management of infected wounds containing bacteria that are difficult to kill with more conventional treatments. Larvae have also been shown to be successful at eliminating MRSA from wounds.