A Theoretical Analysis of Damage Evolution in Skeletal Muscle Tissue With Reference to Pressure Ulcer Development

Soft tissues are sensitive to prolonged compressive loading, eventually leading to tissue necrosis in the form of pressure ulcers, Pressure ulcers can occur in situations where people are subjected to sustained mechanical loads, such as when bedridden, sitting in a wheelchair or from wearing prostheses. Pressure ulcers severely affect the patient's quality of life, since the ulcers are painful, difficult to heal and often prolong hospitalization periods. Despite considerable attempts to prevent pressure ulcers, prevalence figures remain unacceptably high. In a prevalence study involving more than 16,000 patients in the Netherlands, a mean prevalence of 23.1% in health care institutions was reported. Pressure ulcers are often classified in four different stages, ranging from discoloration of intact skin (Stage I) to full thickness skin loss involving tissue damage that extends to underlying bone involving both fat and muscle tissues (Stage IV). Although this classification is widely used in clinical practice, it does not necessarily relate to the origin of the ulcers. Depending on the nature of loading, pressure ulcers can either initiate superficially at the skin, or initiate in deeper layers such as muscle tissue. The present study focuses on deep pressure ulcers that initiate in muscle tissue, since deeper ulcers are more harmful and show more extensive ulceration. In addition, muscle tissue is more susceptible to the development of pressure ulcers and, hence, deep ulcers develop at a faster rate than superficial ulcers, making them particularly dangerous. Yet, these deep ulcers are difficult to prevent and identify, since they are rarely visible at the skin surface at the time of initiation. As such, the four stage classification scheme can be misleading, since it does not represent an ordinal scale.