Use of weight-bearing MRI for evaluating wheelchair cushions based on internal soft-tissue deformations under ischial tuberosities

作者：Shabshin Nogah; Zoizner Gil; Herman Amir; Ougortsin Vlad; Gefen Amit^*

来源：Journal of Rehabilitation Research and Development, 2010, 47(1): 31-42.

DOI：10.1682/JRRD.2009.07.0105

• bedsores
• decubitus
• deep tissue injury
• foam
• open MRI
• pressure sores
• pressure ulcer
• rehabilitation
• sitting pressures
• viscoelastic

Deep tissue injury (DTI) is a severe type of pressure ulcer, in which damage initiates under intact skin, in soft tissues that are mechanically deformed by load-bearing bony prominences. Sitting-acquired DTI typically occurs in the gluteus muscles that could sustain deformations by the weight-bearing ischial tuberosities (ITs). No clinical method currently exists for measuring internal tissue deformations; so design and selection of wheelchair cushions are based mostly on measuring sitting pressures. Our objective was to evaluate the influence of different commercial cushions on internal soft-tissue deformations under the ITs, using weight-bearing magnetic resonance imaging (MRI). We specifically compared muscle, superficial fat, and effective (muscle and fat together) tissue deformations while subjects (n = 10) sat on four cushions (two viscoelastic and two foam) and directly on a rigid support. Deformations were maximal in muscle tissue (mean 70%), twice more the amount than in fat (similar to 30%). Effective soft-tissue deformations were similar to 50% to similar to 60%. Although cushions mildly reduced muscle deformations in the order of 10%, theoretically, our interpretation suggests that this deformation level adds safe sitting time. This study demonstrated that weight-bearing MRI is applicable for evaluating wheelchair cushions and, in the future, may be a tool to systematically support cushion design and selection.

• 出版日期2010