Pressure ulcers develop in immobile patients whose tissues are subjected to continuous pressure from bones on the interior and hard surfaces such as beds or chairs on the exterior. In addition to their immobility, patients at risk for the development of pressure ulcers typically have poor nutritional status, inadequate hydration, and other underlying medical conditions that compromise their ability to heal injuries. Pressure ulcers affect over 1.6 million people in the US and 4.1 million people in the industrialized world as shown in the chart, attached. Estimates of the prevalence of these conditions vary greatly. Estimates as high as 12 million patients have been reported for all types of chronic wounds in the industrialized markets.
Chronic wounds can be of variable sizes and depths.
Partial-thickness ulcers involve a loss of skin that is limited to the epidermis and, potentially, part of the dermis. Full-thickness ulcers involve damage or necrosis of the epidermis, dermis, and subcutaneous tissue, and may extend into the connective tissue below the dermis. The most severe category of ulcer involves injury to the epidermis, dermis, subcutaneous tissue, and muscle, tendon, or bone. The wound healing process is not complete even after the wound has closed. The process of rebuilding normal skin and tissue in a wound can take up to two years after the initial injury.