Rehabilitation Engineering and Applied Research Laboratory, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Atlantic Dr. Office 026 Atlanta, 30332-0280, Georgia.
Rehabilitation Engineering and Applied Research Laboratory, College of Design and the George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Atlantic Dr. Lab 027 Atlanta, 30332-0280 , Georgia.
J Tissue Viability. 2018 Aug;27(3):162-172. doi: 10.1016/j.jtv.2018.04.001. Epub 2018 May 9.
To establish a research approach for describing how different wheelchair cushion designs impact buttocks tissue deformation during sitting.
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.
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.
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.
建立一种研究方法，描述不同轮椅坐垫设计如何影响坐姿时臀部组织的变形。
对 4 名脊髓损伤且臀部严重萎缩的个体进行了扫描，让他们坐在 FONAR 直立式 MRI 中。扫描时，个体的臀部完全悬空，没有骨盆支撑，分别坐在 3 种不同的市售轮椅坐垫上。对多平面扫描进行了分析，提供了组织厚度和形状的 3D 渲染和测量。
在研究的包裹式坐垫设计（即 Roho HP 和 Matrx Vi）上，坐骨处的大块组织厚度减少了 60%以上（即很少包含肌肉），而在矫形减压设计（即 Java）上则变化更大（23-60%）。脂肪通常从未负重状态向后和上方移位，在 Roho HP 和 Matrx Vi 上的横向移位更大，在 Java 上的内侧移位更大。骶尾关节角度的较大变化表明该区域存在明显的负荷。大转子处的变形在各表面上较为一致。界面压力越大，变形越大，但个体间的关系是非线性的。
本研究中所有臀部都发生了明显的变形，但在所有 3 个表面上的位置和方式都不同。需要注意变形最大的区域。未来的形状顺应性指标应考虑坐垫在所有高风险区域的性能，以及感兴趣区域中组织数量和形状的变化。
