Deep, unequivocally full-thickness burns may be excised to the level of the investing fascia using a scalpel, an electrocautery device, or even a laser. The excised wound must be covered with a skin graft to prevent desiccation of the exposed tissue and to effect definitive closure.
Tangential excision is commonly employed in the treatment of partial-thickness burns. Successive thin layers of nonviable tissue are removed until a wound bed of viable tissue, characterized by uniformly dense capillary bleeding, is developed. If the full thickness of the skin is involved, the excision should extend until normal fatty tissue is encountered. The wound is closed with a split-thickness skin graft. Blood loss associated with tangential excision, which can be prodigious, can be minimized by the application of gauzes soaked in a thrombin solution; by subcutaneous injection of ornithine vasopressin; or, if the burn is on a limb, by use of a tourniquet.
In patients with extensive burns but limited donor sites, the use of meshed grafts increases the area of burn wound that can be covered with the skin harvested from a donor site of given size. Although the expansion ratio of meshed grafts can be as great as 9 : 1, such large grafts are associated with a prolonged time of epithelialization of the interstices and increased scarring. Therefore, expansion should be limited to the commonly used ratios of 2 : 1 or 3 : 1. When donor sites are inadequate because of extensive burns, any of several synthetic or biologic dressings can be used for temporary coverage of the wound. Viable cutaneous allograft is the gold standard of biologic dressings and when obtained through reputable sources such as the American Association of Tissue Banks the risk of disease transmission has been decreased significantly. Cutaneous xenografts (commonly porcine) are alternatives to cadaver allografts, and synthetic products such as Biobrane, a silicone membrane on nylon fabric coated with dermal porcine collagen, and Transcyte, which is Biobrane and cultured newborn human fibroblasts, may also be used for temporary wound coverage.
The benefits of burn wound excision are realized at specific physiologic costs: blood loss, pulmonary effects of anesthesia and surgery, and sacrifice of any partial-thickness burn within the area of a full-thickness burn. Along with physiologic fluid resuscitation, improved ventilatory support, and effective control of infection, excision has greatly helped survival in burn patients. Improvements in functional and cosmetic therapies further facilitate rehabilitation of patients.
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