Contoured Foam Cushions Cannot Provide Long-term Protection Against Pressure-Ulcers for Individuals with a Spinal Cord Injury: Modeling Studies.

OBJECTIVE

To determine changes in internal soft-tissue loads in the buttocks of individuals with a spinal cord injury (SCI), who undergo pathoanatomical changes during the first months and years following the occurrence of the SCI, while sitting on a contoured foam cushion (CFC) that has been fitted close to the time of the injury but has not been replaced in subsequent years.

DESIGN

Internal tissue loads in variant buttocks anatomies on a CFC were analyzed by means of finite element computer simulations. The pathoanatomical changes that are characteristic to SCI and were simulated here are: increase in fat tissue mass, intramuscular fat infiltration, muscle atrophy, and combinations of these conditions.

SETTING

Computational biomechanical modeling.

MAIN

RESULTS

Simulating the aforementioned pathoanatomical changes consistently resulted in greater mechanical strain and stress magnitudes and more inhomogeneity in the loading state of muscle and fat tissues, with a more profound effect in fat. The simulations further indicated a clear trend of exacerbation in tissue exposure to loads as the pathoanatomical changes progress chronologically and the CFC is not replaced.

CONCLUSIONS

A CFC that has been fitted at a time close to the SCI, but has not been replaced in subsequent years, substantially loses its efficacy in protecting patients from developing pressure ulcers and deep tissue injury in particular.