What Lies Beneath: Why Some Pressure Injuries May Be Unpreventable for Individuals With Spinal Cord Injury.

OBJECTIVE:To investigate intersections between pressure injury (PrI) history, muscle composition, and tissue health responses under physiologically relevant loading conditions for individuals with spinal cord injury (SCI). DESIGN:Repeated measures study design with annual follow-up for up to 3 years. SETTING:Tertiary care center. PARTICIPANTS:Persons with SCI (N=38). Exclusion criteria included having an open pelvic region PrI at the time of recruitment, presence of systemic disease, and/or known sensitivity to contrast. INTERVENTIONS:Not applicable. MAIN OUTCOME MEASURES:Gluteal muscle composition, ischial interface pressures, tissue oxygenation. RESULTS:Ischial region mean interface pressures are the same for individuals with or without a PrI history. Tissue oxygenation is lower during sitting for persons with a PrI history. Individuals with >15% gluteal intramuscular fat were statistically highly significantly (P<.001) more likely to have a history of severe or recurrent PrI. Intramuscular adipose tissue (IMAT) levels within the gluteal muscle may remain low over time or muscle tissue in the gluteal muscle region may be almost entirely replaced by IMAT. In the current study cohort, it was found that muscle composition also continues to change over time even for individuals with long-standing SCI. CONCLUSIONS:Soft-tissue compositional changes, specifically IMAT, provides a reliable indicator of PrI history and may provide a key to personalized PrI risk status for persons with SCI. The current findings confirm that interface pressure mapping alone is a limited indicator for PrI development.