Composite skin graft: frozen dermal allografts support the engraftment and expansion of autologous epidermis

Abstract

Rapid closure of burn wounds significantly reduces the complications associated with thermal injury. Successful wound coverage, however, is often limited by the lack of suitable autografts. To circumvent this limitation a composite graft was developed which combines the utility and availability of allogeneic skin with the permanence of an autograft. Composite grafts were first employed in a rat wound model and subsequently to treat six patients with thermal injuries. In experiments with rats, full-thickness excised (1") wounds were prepared on thoracic walls, covered with previously frozen allograft skin, dressed, and secured. Five days later, the dead epidermis was removed and trypsin-disaggregated syngeneic epidermal cells applied to the exposed dermal surface. Successful engraftment with complete epidermal coverage could be observed within 7 to 10 days. In eight patients, split-thickness skin bank allografts were placed on full-thickness burn wounds. Four days later the dead epidermis was removed and vacuum blister-prepared sheets of autologous epidermis grafted to the exposed dermal surface. In all eight patients successful engraftment ensued. Increased pigmentation at the site of each original epidermal graft confirmed the stability of underlying allograft dermis. Epidermal expansion ranged from 1:20 to 1:100. All patients were followed from 10 to 12 months with no demonstrated graft loss or significant wound contracture. Composite skin grafts which combine allogeneic dermis and an expanded autologous epidermis can effect rapid wound closure and will remain stable without evidence of rejection or graft breakdown for at least 12 months.