Full-thickness skin loss can occur from burn, trauma, infection, or surgical excision. A skin graft should be considered when the defect cannot be closed primarily or with local tissue flaps and the wound base can adequately support a skin graft. Exposed bone, joint, tendon, blood vessels, and other significant structures are not good candidates for skin grafting and need other methods of reconstruction (pedicled or free flaps). Active infection and poor blood supply to the recipient sites are contraindications. Weight bearing is a relative contraindication for skin grafting, although glabrous skin grafts can sometimes provide an adequate reconstruction.
Skin grafts can be categorized as split thickness or full thickness (figure 1). Full-thickness skin grafts (FTSGs) remove all layers of the skin and create a secondary defect at the donor site, which must be closed primarily or left open to heal secondarily. For this reason, FTSGs are not frequently used for large defects. Split-thickness skin grafts (STSGs) can be of variable thickness, with the amount of dermis taken with the graft the determinant of graft thickness. In general, the thinner the skin graft, the more likely the graft will survive or “take” and quicker the donor site will re-epithelialize. Donor sites heal by epithelial cells in the sweat gland and hair follicles dividing and migrating superficially and then across the donor site until contact inhibition occurs. Thicker skin grafts tend to have better cosmesis because they display less secondary contracture and deformity. In cosmetic areas, including the face and hands, full-thickness grafting is more common because of its better cosmesis.
Because of the large amount of dermis present, the buttock and lateral hip can supply large quantities of STSG when needed (figure 2). The thinner the graft taken, the higher the number of skin grafts that can be harvested from that donor site. The surgeon should be reluctant to use a donor site that will be exposed with normal dress patterns. In the face, color match is important for cosmesis. For this reason, the supraclavicular area, neck, and scalp are better color matches for defects on the face, if available.
In the case of the burn patient, early excision of the burned tissue and skin grafting (within 2 weeks) will limit the amount of hypertrophic scarring and contracture. For all cases of skin grafting, the wound bed must be clean and clear of any evidence of infection. Frequent debridements and dressing changes may be required prior to skin grafting. Negative pressure dressings may help stimulate granulation tissue and prepare the wound bed. Medical issues (including nutritional status) should be optimized.
Generally, local anesthesia can be used for small excisions and skin grafts. Where extensive skin grafting must be carried out, general anesthesia is usually indicated.