Medicinal maggots to the rescue
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The goal of the MDT dressing is to keep the maggots on the wound, allow oxygen to reach the maggots, and facilitate drainage of the wound exudate.
The conventional way to accomplish this is to establish a "cage-dressing" over and around the maggots. This is described in the Package Insert (in the next tab), and will be described in greater detail below.
While some therapists still construct their own custom dressings according to the instructions below, most use "pre-assembled" maggot dressings that are now available specifically to confine the maggots on the wound. Monarch Labs has long been a leader in this area, with over 20 years of experience leading to the development of such products as:
The articles listed below describe, in detail, how to construct your own MDT dressing. Custom dressings are particularly useful for unusually large wounds, or wounds in complicated anatomical locations. Contact Monarch Labs if you can not find these articles.
For a pictorial discussion of maggot dressings in horses and other non-human animals, check out our Equine Dressings page.
The ideal maggot dressing should allow the maggots access to the wound bed, but prevent them from crawling away when they are not actively secreting their digestive enzymes. The dressing must also allow fresh air to enter the area (for the maggots are obligate air breathers), and allow the liquefied necrotic tissue to drain freely from the wound.
With the maggots in the wound bed, a porous fabric (i.e., nylon or Dacron chiffon) is affixed (glued or taped) to skin directly, or to a foundation (i.e., hydrocolloid pad) that is itself on the skin. It is advantageous to pre-treat the skin with a protective barrier (skin protectant) to prevent irritation from any drainage or the adhesive itself.
Once the "cage" dressing is applied, a light gauze dressing should be place on top
(for example with two pieces of tape, so as not to occlude air from reaching the maggots within) and then be replaced every 6 hours, or whenever it is soiled.
You do not want the wound drainage to stay on the patient because it can loosen the dressings, or cause skin irritation.
Here is a sequence of photos describing how to make a simple but effective maggot dressing. It comes from the BTER Foundation's educational course materials.
|Gather your supplies in advance. You will need hydrocolloid and cutting supplies, skin barrier or protectant, adhesive, tape (fabric or "pink"), gauze, porous polyester net, and possibly some transparent membrane dressings.|
After cleansing and protecting the peri-wound skin (i.e., with a skin barrier/protectant).
The peri-wound skin is covered with a hydrocolloid pad.
|This can be coated with a liquid or spray adhesive, in preparation for the next layer: the porous fabric top.|
|Place the maggots on the wound at a concentration of 5-10 per sq cm of wound base. Small numbers of larvae can be transferred from the container by wiping them off the sides of the vial with a sterile water- or saline-moistened 2x2 gauze pad. If large numbers of larvae are needed, then the gauze pad in the vial, which harbors most of the maggots, can be cut removed in its entirety, or cut to contain a corresponding number of larvae. For example, if 100-150 larvae are needed, then 1/3 of the gauze pad can be cut off and used, for it will likely harbor 100-150 of the 250-500 larvae in that vial.|
|Add a little light gauze if necessary, to cover the wound; but do not pack the wound with gauze. The maggots will need plenty of room to grow 25 times in volume as they ingest the necrotic and infected wound material as it dissolves away from the wound.
Then quickly cover it all with the porous fabric and affix (with glue and/or tape) to the foundation.
|Top the "cage" dressing with a light absorbent gauze. Do not use a lot of absorbent because it will prevent air entry and suffocate the maggots.
Affix lightly with two pieces of tape or Stockinette.
Too much tape will suffocate the maggots.
Change the top absorbent dressing at least every 6 hours and whenever soiled. Leaving it on for longer periods risks suffocating the maggots, and could also allow the necrotic infected drainage to irritate the patient's skin.
|Wounds that do not have a planar surface will not be able to handle a planar piece of porous fabric without wrinkles, and wrinkles are not good. So many people use nylon stockings to conform to the nature of toe, heel and stump wounds.
This, too, should be topped with a light absorbent gauze top dressing as described above.
|Many of these images were used with permission by the BTER Foundation (www.BTERFoundation.org), which produces educational materials and training programs in maggot therapy and other biotherapeutic procedures.
Register for their training sessions to get more tips, training, or experience with maggot therapy.
(Note: Reportedly, no patients were used or harmed in the making of this video. The actors are just medical students.)
Part 1: The maggot dressings are applied.