Deep tissue injury: how deep is our understanding?

Area of Science:

• Biomedical Engineering
• Tissue Mechanics
• Cellular Physiology

Background:

• Deep pressure ulcers involve deep tissue injury (DTI) originating in muscle layers near bony prominences due to sustained loading.
• DTI is serious as it starts internally, often undetected until advanced, complicating treatment.
• Understanding DTI mechanisms is crucial for developing effective preventive measures.

Purpose of the Study:

• To investigate the underlying mechanisms of deep tissue injury (DTI) in skeletal muscle.
• To differentiate the roles of mechanical deformation and ischemia in DTI.
• To propose a sequence of events leading to cell necrosis in DTI.

Main Methods:

• Utilized a hierarchical research approach combining in vivo animal models and in vitro muscle models.
• In vivo: Studied effects of combined ischemia and deformation, and ischemia alone.
• In vitro: Examined isolated effects of deformation, hypoxia, glucose depletion, and acidification.

Main Results:

• Deformation exceeding a threshold can cause rapid, persistent tissue damage.
• Ischemia, driven by glucose depletion and acidification, induces damage more gradually.
• A sequence of events leading to skeletal muscle cell necrosis was proposed based on experimental findings.

Conclusions:

• Mechanical deformation and ischemic factors contribute distinctly to DTI.
• The proposed sequence of events provides insight into DTI pathogenesis.
• Findings support the development of targeted preventive strategies for deep pressure ulcers.