Wound Care

Gale Encyclopedia of Surgery, (2004) by René A. Jackson, Crystal H. Kaczkowski

In cases where a wound is particularly severe, large, or if it is a third degree burn, cellular wound healing products may be used to close the wound and speed recovery. In some cases (i.e., a third-degree burn), a skin graft will often be used. Although most surgeons prefer to use skin donated from another person (known as cadaver skin, or human allograft), skin donations are not always available. They must rely on more recent products available, such as cellular wound dressings, for the treatment of burns. For skin grafting of full-thickness burn wounds, surgeons use healthy skin from another part of the person's own body (autografting) as a permanent treatment. Surgeons may use cellular wound dressings as a temporary covering when the skin damage is so extensive that there is not enough healthy skin available to graft initially. This helps prevent infection and fluid loss until autografting can be performed.

The survival rate for burn patients has increased considerably through the process of quickly removing dead tissue and immediately covering the wound. Burns covering half the body were routinely fatal 20 years ago but today, even people with extensive and severe burns have a good chance of survival, according to the American Burn Association.

Cellular wound dressings

In recent years, the technology of burn and wound care using cellular wound dressings and grafts are helping to transform the treatment of burns and chronic wounds by decreasing the risk of infection, protecting against fluid loss, requiring fewer skin grafts, and promoting and speeding the healing process. These dressings provide a cover that keeps fluids from evaporating and prevents blood from oozing out once the dead skin has been removed. Some of these products grow in place and expand natural skin when it heals.

Cellular wound dressings may look and feel like skin, but they do not function totally like skin because they are missing hair follicles, sweat glands, melanocytes, and Langerhans' cells. Some cellular wound dressings have a synthetic top layer structured like an epidermis. It peels away over time, or is replaced with healthy skin through skin grafting. How these products are involved in wound repair is a subject of great scientific interest; it is known that they promote a higher rate of healing than does standard wound care.

People with severe wounds, chronic wounds, burns, and ulcers can benefit from cellular wound dressings. Several artificial skin products are available for nonhealing wounds or burns such as: Apligraft® (Norvartis), Demagraft®, Biobrane®, Transcyte® (Advance Tissue Science), Integra® Dermal Regeneration Template® (from Integra Life Sciences Technology), and OrCel®.

Apligraf is a two-layer wound dressing that contains live human skin cells combined with cow collagen. It delivers live cells from a different donor (circumcised infant foreskin). Thousands of pieces of Apligraf are produced in the laboratory from one small patch of cells from a single donor. Dermagraft is made from human cells placed on a dissolvable mesh material. The mesh material is gradually absorbed and the human cells grow and replace the damaged skin after being placed on the wound or ulcer. TransCyte is used as a temporary covering over full thickness and some partial thickness burns until autografting is possible, as well as a temporary covering for some burn wounds that heal without autografting. It consists of human cells from circumcised infant foreskin, and grown on nylon mesh, combined with a synthetic epidermal layer. TransCyte starts with living cells, but these cells die when it is shipped in a frozen state to burn treatment facilities. The product is then thawed and stretched over a burn site. In one to two weeks, the TransCyte starts peeling off, and the surgeon trims it away as it peels. Integra Dermal Regeneration Template is used to treat full thickness and some partial thickness burns. Integra consists of two layers; the bottom layer, made of shark cartilage and collagen from cow tendons, acts as a matrix onto which a person's own cells migrate over two to three weeks. A new dermis is created as the cells gradually absorb the cartilage and collagen. The top layer is a protective silicone sheet that is peeled off after several weeks, while the bottom layer is a permanent cover. A very thin layer of the person's own skin is then grafted onto the neo-dermis. OrCel is also made from circumcised infant foreskin, grown on a cow collagen matrix, and used to treat donor sites in burn patients. It is also used to help treat epidermolysis bullosa, a rare skin condition in children.