Call Evan, Hetzel Thomas, McLean Chad, Burton Joshua N, Oberg Craig
Weber State University, Ogden, UT, USA.
Aspen Seating/Ride Designs, USA.
J Tissue Viability. 2017 Aug;26(3):172-179. doi: 10.1016/j.jtv.2017.05.002. Epub 2017 May 18.
Off-loading or the Orthotic approach to wheelchair seating has been used successfully to provide seating that optimizes tissue protection at the ischial tuberosities (ITs), sacrum and greater trochanters. Recent publications indicate the significance of preventing tissue compression to reduce ulcer formation. Comparative Magnetic Resonance Imaging (MRI) of individuals seated on two cushion types provides direct evidence of tissue unloading resulting in the reduction in tissue compression. Measurement of tissue compression in MRI images provides the cumulative impact of compression and shear resulting in ultimate tissue thickness documented here. In this study's application of MRI to off-loading cushions (OLC), an alternate form of tissue protection was observed. Instead of incorporating immersion and envelopment, loads were transferred from high-risk areas, such as bony prominences, to lower risk soft tissues. This method shows both shearing and compression of load bearing tissues in seated individuals with the OLC in place. Tissue thickness measurements determined by MRI analysis indicate that the OLC provides greater reduction in tissue deformation than the air cell cushion (ACC). Deformation of tissues loaded by the OLC is not significantly different from the deformations seen with the ACC. This research represents the first reported use of MRI to document the comparative off-loading capabilities of two cushions and the resultant tissue compression and ulceration risk. While MRI analysis may not be incorporated in daily cushion prescription, this paper proposes a methodology in which MRI analysis of tissue deformation on comparative cushions allows the determination of best-case cushion selection for reduction of ischial pressure ulcer (PU) risk.
卸载或使用矫形方法进行轮椅座位调整已成功用于提供能优化坐骨结节、骶骨和大转子处组织保护的座位。近期出版物表明预防组织受压对减少溃疡形成的重要性。对坐在两种不同类型坐垫上的个体进行的对比磁共振成像（MRI）提供了组织卸载导致组织受压减轻的直接证据。MRI图像中组织受压的测量记录了此处受压和剪切的累积影响，从而得出最终的组织厚度。在本研究将MRI应用于卸载坐垫（OLC）时，观察到了一种不同形式的组织保护。不是采用浸入和包裹的方式，而是将负荷从高风险区域（如骨突）转移到低风险的软组织。这种方法显示了在使用OLC的坐姿个体中承重组织的剪切和受压情况。通过MRI分析确定的组织厚度测量结果表明，与气室坐垫（ACC）相比，OLC能更大程度地减少组织变形。OLC加载下的组织变形与ACC观察到的变形无显著差异。这项研究是首次报道使用MRI记录两种坐垫的相对卸载能力以及由此产生的组织受压和溃疡风险。虽然MRI分析可能不会纳入日常坐垫处方中，但本文提出了一种方法，即通过对比较坐垫上组织变形的MRI分析来确定降低坐骨压力性溃疡（PU）风险的最佳坐垫选择。
