Many treatment schemes have been developed and used to try to treat these nonhealing ulcers. Traditional care consists of debridment and dressing application as well as treatment of the underlying disorder. While this gives the body the opportunity to heal, skin grafts have been developed to enhance the process. There are epidermal replacements (split thickness) as well as epidermal and dermal replacements (full thickness), containing cells and matrix from autologous, heterologous, and xenologous sources. Epidermal replacements may be used when the wound to be treated does not extend deep into the underlying dermal tissue. Epidermal autografts are excised from a donor site on the patient’s body then replanted in the wound. These grafts, as well as full thickness autografts, are good in that they are not rejected by the host and that there is little immune response. However, they create an acute wound at the donor site, which is subject to pain, scarring, and infection. Allografts from cadaver origin can be used as well. There is risk, however, of trasmission of viruses and of immune response. Cultured epidermal cells used as allografts, however, do not contain antigen-presenting Langerhans cells, and so those grafts carry lower risk for rejection. Xenografts, mostly from pigskin, also contain risks of infection and immune system rejection (Kirsner et.al., 1998; Clark et.al., 2000; Balasubramani et.al., 2001; Machens et.al., 2000).

Dermal replacements are often more difficult to develop than epidermal replacements, as they contain both cells and matrix. Dermal substitutes are important, however, to help prevent wound contraction and provide greater stability for the epidermis. Full thickness wounds without dermal replacements do not regenerate normal dermis, rather they form scars (Machens et.al., 2000). Matrices have been developed that contain bovine collagen, glycosaminoglycans, decellularized cadaver skin, and human allograft fibroblasts from cadavers and from neonatal foreskin (Kirsner et.al. 1998; Clark et.al., 2000; Balasubramani et.al., 2001). Dermal replacements contain either no epidermal component, a synthetic polymeric surface, or a cultured stratified epidermis. The newer composite skin grafts contain both dermal and epidermal components, each with cultured dermal fibroblasts in a collagen matrix overlaid with cultured epidermal keratinocytes (Kirsner et.al.1998; Clark et.al., 2000; Balasubramani et.al.,2001; Hutmacher et.al.,2000). These grafts may be combined with a cytokine release system to enhance cellular communication (Tabata, 2001). The goal of these skin grafts is first and foremost to close the wound. When a wound is closed with a graft containing living cells, those cells will then help to accelerate the normal wound healing processes.