Alternatives and Adjuncts
The ideal skin substitute should function like natural skin. Moreover, it should provoke a negligible inflammatory response, all while being safe, biocompatible, and carrying no risk of disease transmission.[27,28] Although the best choice for STSG is autologous skin graft, there may be limitations to its use, including pain and scar formation at the harvest site and the ability to perform recurrent harvests; this is classically limited to three or four harvests due to delay in re-epithelization with repeated surgery. Moreover, in the burn patient, the amount of available autologous skin is often limited. Such limitations to autogenous skin have been shown to increase mortality rate and hospital stay. Human skin allograft provides a reasonable alternative to provide a temporary dressing, prevent microbial contamination, and fluid and electrolyte imbalances. These allografts may be prepared by several methods, including lyophilization, a process, in which dehydration occurs to devitalize the cells and destroy cell components and immunologic response. These properties allow the human skin allograft to improve and prepare the granulation tissue of the recipient bed making an appropriate dermal bed for future autogenous STSG.[28,30–35] After its application, an autoimmune response is elicited around 1 week later, increasing the risk of viral and bacterial disease transmission.
A xenograft is a graft that is transferred from an animal of one species to another species. Not unlike allografts, xenografts provide only a temporary covering and require a delayed application of an autograft STSG and elicit an autoimmune response with an increased risk of viral and bacterial disease transmission.[36,37] Most commonly, a porcine xenograft is used due to the many similar physical properties with human skin. However, the porcine xenograft itself remains susceptible to hyperacute rejection due to preformed antibodies to a carbohydrate found on all porcine cells; a knockout gene porcine xenograft has been developed, and early results have shown comparable coverage to allografts. Notwithstanding, porcine xenografts are beset with religious or cultural condemnations of its use. Compared with calcium sodium alginate in the treatment of STSG donor sites, porcine xenograft demonstrated a longer time to healing and worse quality of healed skin with more hypertrophic scar formation. Recently, an acellular fish skin xenograft (Kerecis Omega3 Burn) has been demonstrated to be a reasonable and safe skin substitute. Unlike the porcine xenografts, the acellular fish skin xenograft has been shown to be free of the risk of viral disease transmission and autoimmune reaction risk as well as containing the omega3 fatty acids, eicosapentaenoic and docosahexaenoic acids providing an antimicrobial environment.[36,39,41] Resembling human skin, these fish xenografts have a porous microstructure, which provides an extracellular matrix composed of glycosaminoglycans, proteoglycans, fibronectin, and growth factors.[36,42–46] Advantageously, this xenograft is stored at room temperature, has a shelf life of 3 years, and is marketed as an off-the-shelf product.
J Am Acad Orthop Surg. 2021;29(20):855-861. © 2021 American Academy of Orthopaedic Surgeons