title: Contoured Foam Cushions Cannot Provide Long-term Protection Against Pressure-Ulcers for Individuals with a Spinal Cord Injury: Modeling Studies.
abstract: 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.
  
  
  METHODS
  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.
  
  
  METHODS
  Computational biomechanical modeling.
  
  
  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.
authors.affiliation: Naama Shoham, MSc, and Ayelet Levy, MSc, are doctoral students in the Department of Biomedical Engineering at Tel Aviv University in Tel Aviv, Israel. Kara Kopplin, BSc, is the Senior Director of Efficacy Research, Standards, and Compliance at the ROHO Group, Belleville, Illinois. Amit Gefen, PhD, is a Professor of Biomedical Engineering at Tel Aviv University. Ms Shoham, Ms Levy, and Dr Gefen have disclosed that they received research funding from ROHO, Inc, for investigating the effects of cushioning materials and designs on buttocks tissues during weight bearing. The authors disclose that this support is, however, irrelevant to the data that were presented and the conclusions that were made here. Dr Gefen is the Chair of the Scientific Advisory Board of ROHO. Ms Kopplin has no financial relationships related to this article.
authors.forename: Naama
authors.initials: N
authors.lastname: Shoham
authors.forename: Ayelet
authors.initials: A
authors.lastname: Levy
authors.forename: Kara
authors.initials: K
authors.lastname: Kopplin
authors.forename: Amit
authors.initials: A
authors.lastname: Gefen
mesh_terms: D001696:Biomechanical Phenomena; D001835:Body Weight; D002081:Buttocks; D003198:Computer Simulation; D004867:Equipment Design; D006801:Humans; D008954:Models, Biological; D003668:Pressure Ulcer / Q000209:etiology / Q000517:prevention & control*; D011482:Protective Devices; D013119:Spinal Cord Injuries / Q000150:complications*; D013314:Stress, Mechanical; D013997:Time Factors