Measuring the impact of cushion design on buttocks tissue deformation: An MRI approach

Sharon Sonenblum, Jason Ma, Stephen Sprigle, Thomas Hetzel, John Cathcart

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)
486 Downloads (Pure)


Aim: To establish a research approach for describing how different wheelchair cushion designs impact buttocks
tissue deformation during sitting.
Materials and methods: The buttocks of 4 individuals with spinal cord injury and significant atrophy were
scanned sitting in a FONAR Upright MRI. Scans were collected with the individuals' buttocks fully suspended
without pelvic support, and seated on 3 different commercially available wheelchair cushions. Multi-planar
scans were analyzed to provide 3D renderings and measurements of tissue thickness and shape.
Results: Bulk tissue thicknesses at the ischium, which rarely included muscle, were reduced by more than 60%
on enveloping cushion designs studied (i.e., Roho HP and Matrx Vi), and more variably (23–60%) on an orthotic
off-loading design (i.e., Java). Adipose was typically displaced posterior and superior from the unloaded condition,
with more lateral displacement on the Roho HP and Matrx Vi and more medial displacement present on
the Java. Large changes in angle at the sacro-coccygeal joint indicated significant loading on the region.
Deformation at the greater trochanter was more consistent across surfaces. Greater interface pressures tended to
be associated with greater deformation, but the relationship varied by individuals and was highly non-linear.
Conclusions: The buttocks in this study all deformed significantly, but at different locations and in different
manners across all 3 surfaces. Attention needs to be paid to the regions of greatest deformation. A future metric
of shape compliance should consider cushion performance at all high risk regions, and changes to the amount
and shape of tissue in the regions of interest.
Original languageEnglish
Pages (from-to)162-172
Number of pages11
JournalJournal of Tissue Viability
Issue number3
Early online date9 May 2018
Publication statusPublished (in print/issue) - 31 Aug 2018


  • Pressure ulcer
  • Wheelchair cushion
  • MRI
  • Buttocks
  • Multi-planar
  • Tissue deformation


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