UJF-Grenoble1/CNRS/TIMC-IMAG UMR 5525, Grenoble F-38041, France.
UJF-Grenoble1/CNRS/TIMC-IMAG UMR 5525, Grenoble F-38041, France.
J Biomech. 2014 Jul 18;47(10):2231-6. doi: 10.1016/j.jbiomech.2014.05.004. Epub 2014 May 14.
With 300,000 paraplegic persons only in France, ischial pressure ulcers represent a major public health issue. They result from the buttocks׳ soft tissues compression by the bony prominences. Unfortunately, the current clinical techniques, with - in the best case - embedded pressure sensor mats, are insufficient to prevent them because most are due to high internal strains which can occur even with low pressures at the skin surface. Therefore, improving prevention requires using a biomechanical model to estimate internal strains from skin surface pressures. However, the buttocks׳ soft tissues׳ stiffness is still unknown. This paper provides a stiffness sensitivity analysis using a finite element model. Different layers with distinct Neo Hookean materials simulate the skin, fat and muscles. With Young moduli in the range [100-500 kPa], [25-35 kPa], and [80-140 kPa] for the skin, fat, and muscles, respectively, maximum internal strains reach realistic 50 to 60% values. The fat and muscle stiffnesses have an important influence on the strain variations, while skin stiffness is less influent. Simulating different sitting postures and changing the muscle thickness also result in a variation in the internal strains.
在法国，仅有 30 万截瘫患者，但坐骨压力溃疡却是一个主要的公共卫生问题。它们是由臀部软组织受到骨突的压迫而引起的。不幸的是，目前的临床技术，即使使用嵌入式压力传感器垫，也不足以预防它们，因为大多数压力溃疡是由于内部高应变引起的，即使在皮肤表面的压力较低的情况下也可能发生。因此，改善预防措施需要使用生物力学模型来估计内部应变从皮肤表面压力。然而，臀部软组织的刚度仍然未知。本文使用有限元模型进行了刚度灵敏度分析。不同的层采用不同的Neo Hookean 材料模拟皮肤、脂肪和肌肉。皮肤、脂肪和肌肉的杨氏模量分别在[100-500 kPa]、[25-35 kPa]和[80-140 kPa]范围内，最大内部应变达到了现实的 50%到 60%。脂肪和肌肉的刚度对应变变化有重要影响，而皮肤的刚度影响较小。模拟不同的坐姿和改变肌肉厚度也会导致内部应变的变化。
