A review of the literature suggests an estimated 1% to 2% of the population will be affected by leg or foot ulceration, which often is associated with diabetes mellitus or venous disease.1 Such ulcers can become chronic wounds when they do not heal in an orderly and timely manner.2 In addition to reducing quality of life, chronic wounds result in significant health care expenditures.3-7 The incidence of chronic wounds in the population is likely to increase with the increasing prevalence of obesity and diabetes.8-10
Using the 2005–2008 National Health and Nutrition Examination Survey, the 2007–2009 National Health Interview Survey, 2009 Indian Health service data, and 2010 US resident population estimates, the United States Centers for Disease Control and Prevention11 estimates 6.0% of the US adult population (more than 18 million people) have been diagnosed with diabetes and an additional 7 million live with undiagnosed diabetes. Diabetic neuropathy and impaired blood circulation, common complications of diabetes, contribute to foot deformities and ulcers.12 More than 12% of adults with diabetes have a history of foot ulcers, which is associated with an increased risk for lower extremity amputation (LEA).13 In 2006–2008, the yearly prevalence of DFUs among the Medicare population with diabetes was estimated to be 8.0% and the yearly prevalence of LEA in the same population was estimated to be 1.8%.14
DFUs add to the already high cost of diabetes care.15 The results of a prevalence-based study using the 2012 US population showed the incremental cost of treating DFUs is $11,700 to $16,883 per patient (2012 US$), between $9 to $13 billion annually in the US.7
Venous leg ulcers (VLUs) may result from venous incompetence and venous hypertension.16 Primary risk factors for VLUs are increasing age, obesity, previous leg injuries, deep venous thrombosis, and phlebitis.17 In 2011–2012, the prevalence of adult obesity in the US reached 35%.18 Results of a retrospective, cohort study19 using data from 1988–1996 suggest the estimated annual prevalence rate of VLUs among persons age 65 is 1.69%, with an annual incidence rate of 1.13 to 1.20 per 100 persons. A comprehensive review20 reported prevalence estimates of active or healed venous ulcers in the general population range from <1% to 5%, depending on sampling methods and the population studied. Health care costs generated in the treatment of VLUs are high. Although newer estimates are wanting, a 1997 retrospective cohort study6 estimated VLU treatment costs at $9,600 per patient in the US; after 2013 Medical-CPI adjustments,21 that amount is $17,000 per patient.
Standard wound care for DFUs typically includes debridement, management of moisture balance, and offloading to relieve pressure. If needed, advanced treatments such as therapeutic growth factors, bioengineered tissues, hyperbaric oxygen therapy, or negative pressure wound therapy (NPWT) can be employed.22 VLUs are typically treated with compression therapy and moisture-retentive dressings as well as the advanced treatments noted for use with DFUs when wound healing does not progress.16,17
Effective treatments for chronic wounds are needed to ease the high patient and health care cost burdens. A growing body of evidence from retrospective studies, randomized prospective studies, and case studies suggests the application of human skin allograft in the form of cryopreserved cadaveric skin may improve healing of chronic wounds compared to standard wound care or bioengineered skin substitutes.23-27
AlloSkin™ (AlloSource®, Centennial, CO), hereafter referred to as AHSA, is a meshed, partial-thickness, cryopreserved human skin allograft processed from donated cadaveric tissue. The donated tissue undergoes extensive serological and microbiological testing for specific micro-organisms and fungal contaminants and is evaluated to ensure graft acceptability. AHSA has been found through proteomic analysis28 to contain extracellular matrix proteins, glycosamnoglycans, cytokines, collagens, and other natural compounds. Collagen is known to aid in wound healing by guiding fibroblasts that migrate along the connective tissue matrix; the collagen fibers attract fibrogenic cells that are essential to wound healing.
AHSA is regulated by the US Food and Drug Administration (FDA) as a Human Cell, Tissue, and Cellular Tissue Based Product (HCT/P) under Code of Federal Regulations Title 21 Parts 1270 and 127129 for use in the care of adequately debrided wounds that are free of infection, including burn wounds and nonburn acute and chronic wounds. After thawing in sterile isotonic solution for a minimum of 1–5 minutes, AHSA is temporarily secured on the wound bed with adhesive strips, surgical glue, or tacking with sutures. According to the manufacturer,30 the allograft tissue generally sloughs in 7–14 days as granulation tissue develops. Additional applications are used if satisfactory granulation tissue formation has not been achieved with the initial application.
Human skin allograft is standard therapy for patients with extensive burns.23,31 It functions as a protective barrier and provides collagen and structure to the wound bed, factors that may facilitate healing of other types of wounds. A recent retrospective review27 described the use of allograft as a biologic dressing for chronic ulcers, DFUs, necrotizing fasciitis, and acute traumatic wounds; histological analysis showed evidence of tissue repair in the migration of epithelia from the patient’s skin to the surface of the allograft and the presence of granulation tissue at the base of the allograft.
The purpose of this retrospective descriptive study was to evaluate wound care outcomes and the safety of using AHSA in the care of patients with chronic DFU, VLU, surgical, or traumatic wounds.