Skin Grafting

A wound that will accept a skin graft must be free of infection, free of devitalized tissue, and must have an adequate blood supply. Skin grafts are classified as either split thickness or full thickness and are selected depending on the size of the defect to be covered and the thickness of coverage that is desired for a particular area. Split-thickness skin grafts (STSGs) are typically used to cover defects when cosmesis is not of primary concern and when the size of the defect is too expansive to be covered by a full-thickness skin graft (FTSG). During the harvesting of an STSG, a thin layer of epidermis and dermis is excised using either a dermatome or the Humby knife at a thickness that is predetermined by the adjustable setting that is selected. STSG are often meshed to expand the surface area of the graft, thereby minimizing the size of the necessary donor site while providing drainage holes for blood or serum. FTSGs are usually used to cover a smaller surface area and require primary closure of the donor site. In the harvesting of an FTSG, an ellipse is made around the defect pattern, which is then incised and undercut. The donor site is then closed primarily; or alternatively, if there is too much tension, an STSG may be used to cover the donor site. The effective healing of an STSG depends on the presence of a well-vascularized recipient site, close apposition of the graft to the recipient bed, and appropriate immobilization of the graft to foster development of nascent vascular connections. The 2 basic factors affecting graft take are the ability of the graft to receive nutrients and the presence of vascular ingrowth from the recipient bed. Factors that will negatively impact the healing of a skin graft include patient smoking, radiation, chemotherapeutic or immunomodulating drugs, and malnutrition. Complications of skin grafting include primary and secondary graft contracture, altered function, sensation and hair growth of donor skin, and pigmentation mismatch.