Larvotherapy for wound care

As the name suggests, larvotherapy or maggot therapy is a natural wound care technique that involves the use of small live larvae. This ancient method gives convincing results on wounds that are struggling to heal. Less painful than a conventional treatment performed with a scalpel by a health professional, larvotherapy is increasingly used in the medical field. Their use regularly makes it possible to avoid a more serious and painful surgery.

Christian Riesen, a nurse specialising in wound care and healing, introduced the technique at the ASSAL Centre in 2018. He explains in more detail what it involves.

What is larvotherapy and how can maggots heal wounds?

The larvae of the fly Lucilia sericata have been used in forensic medicine for many years. They use dead bodies to lay their eggs so that they can feed as soon as they hatch. Then, in the wild, they leave the place of their birth to move to a dry place and transform into a cocoon and then a fly. The different stages of their evolution make it possible to assess the date of death of their host.

As far as wound treatment is concerned, they are used from birth and for the first 4-5 days of their life during which they feed in order to reach their "adult" size.

They secrete an enzyme that will "liquefy" devitalized tissue (extracorporeal digestion) and then absorb it. At the same time, they secrete a form of "natural antibiotic" to avoid poisoning themselves with the germs present in the dead tissue.

It is thanks to this natural process that we use the larvae of the Lucilia sericata fly to wash and heal wounds.

When we talk about larvae or maggots, we usually think of something unhygienic. Are the larvae used the same as those found in our waste?

No, they are fly larvae that are raised and produced only in a sterile environment and monitored by the Entomos company based in Oberentfelden in the canton of Aargau. The larvae are produced under strict hygienic conditions and are intended for medical use only. The process is monitored and meets federal standards.

The larvae are recognised as a wound treatment aid (in the same way as a plaster or ointment) and the therapy is listed and referenced in the LiMA (list of aids and appliances). As a result, this therapy is recognised and reimbursed by insurance companies.

On what type of wounds is larvotherapy used?

Technically, we can use it on any type of wound, except for a few restrictions related to particular cases (tumours, visible arteries or risk of bleeding, dry necroses).

However, the wounds must be "clean" wounds, as the larvae are not used on clean, progressing wounds.

There are no known contraindications or adverse side effects.

Are the maggots deposited directly on the wound? Is there no risk of them escaping?

There are 2 possible methods:

- Bagged maggots: the wound is measured (length x width) and we receive a sealed bag corresponding to the surface area of the wound from a minimum of 2x2cm to a maximum of 10x10cm.

- Free maggots: the same measurement is made and we receive the free maggots and make a special dressing

In both cases there is, as a general rule, no "escape" possible and no health risk.

How do patients feel about this method?

There is no "general rule". As with any therapy, the advantages and disadvantages of the proposed therapy must be discussed with the patient and alternatives given. If the patient's situation lends itself to the use of larvae, then I do not hesitate to offer this option.

Some patients are indeed reluctant, while others are curious and ask many questions. In general, many patients are enthusiastic about the fact that we can open up to a natural and alternative therapy.

Patients who have used this method are generally satisfied with the process and would do it again if necessary.

Is it a painful technique?

As with any therapy, there is an unknown factor in the patient's reaction and it depends on the situation.

As explained earlier, the larvae perform extracorporeal digestion with enzymes, so they allow only dead tissue to be destroyed and removed in a gentle and selective way. They do not "nibble" at the wound, so the patient does not feel a "bite".

Some patients feel the movement of the larvae in the dressing but without pain. This sensation is not particularly intense and does not prevent them from living normally.

In retrospect, based on the many treatments carried out in our Centre, we can say that, on the whole, the therapy was well tolerated by our patients. In some cases, an adaptation of the pain medication was necessary (e.g. introduction of a Dafalgan-type painkiller).

Overall, patients say that this technique is less painful than a scalpel debridement for example.

How long does a larvae treatment last and can the patient continue to walk during this time?

The larvae are usually applied on Tuesday and removed on Friday (4-5 days of treatment). Another session can be scheduled for the following Tuesday and so on. As long as the wound is not completely cleaned, the treatment can be repeated.

However, the activity of the larvae leads to an increase in discharge and sometimes requires more frequent treatment/check-ups at the practice.

For the patient, there are few instructions, but the main one is to respect the complete discharge of the treated area. Indeed, maggots are alive and if the patient presses/knocks strongly on the area, it will simply kill the larvae and the treatment will not be effective anymore.

It is particularly important when resting/sleeping not to lie on the treated area. That said, most patients have no difficulty in doing this: even if there are no larvae, leaning on a wound is not pleasant.

It is best to avoid using this method on heavy areas, such as the heel, unless the area can be guaranteed to be relieved.

What happens to the larvae once they have done their job?

The larvae are disposed of in the medical waste stream, as they sometimes come into contact with infected wounds.