Use of Silicone Materials to Simulate Tissue Biomechanics as Related to Deep Tissue Injury
Use of Silicone Materials to Simulate Tissue Biomechanics as Related to Deep Tissue Injury
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DOI：
10.1097/01.asw.0000460127.47415.6e
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发表时间：
2015-02-01
影响因子：
2.4
通讯作者：
Conner-Kerr, Teresa A.
中科院分区：
文献类型：
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作者：
Sparks, Jessica L.;Vavalle, Nicholas A.;Conner-Kerr, Teresa A.
目的：深部组织损伤（DTI）是由长时间的机械负荷导致血流中断和代谢清除受阻引起的。一种模拟DTI起始的生物力学方面、深部肌肉组织中的应力和应变的患者模拟器，作为减压技术的培训工具以及减压产品的测试平台可能是有用的。作为朝着这个目标迈出的一步，本研究评估了硅酮材料在集中载荷下模拟肌肉组织中应力分布的能力。
方法：为了量化候选硅酮材料的力学性能，对3种硅酮配方（Ecoflex 0030、Ecoflex 0010和Dragon Skin；Smooth - On公司，宾夕法尼亚州伊斯顿）进行了无侧限压缩实验。将结果拟合到奥格登超弹性材料模型中，并将所得的剪切模量（G）与已发表的生物组织数值进行比较。然后对Ecoflex 0030和猪肌肉进行压痕试验，以研究硅酮模拟肌肉在集中载荷下所呈现的非均匀应力分布的能力。创建了有限元模型以量化整个组织深度的应力。最后，构建了一个初步的患者模拟器原型，并记录了深部和浅表“组织”压力以检查应力分布。
结果：压痕试验显示肌肉和Ecoflex 0030中应力分布趋势相似，但Ecoflex 0030中的应力大小高于猪肌肉。所有3种硅酮配方的剪切模量都在已发表的生物组织数值范围内。在本研究报告的实验条件下，Ecoflex 0030比猪肌肉表现出更大的刚度。
结论：压痕试验和患者模拟器原型试验显示出相似的趋势，即靠近骨隆突处压力较高，朝着界面表面压力大小逐渐降低。从定性上看，硅酮模拟了在集中载荷下肌肉中观察到的非均匀应力现象。尽管剪切模量在生物范围内，但应力和刚度值超过了猪肌肉。这项研究是朝着开发一种模拟深部肌肉中应力和应变的生物力学条件的临床前模型迈出的第一步，因为局部生物力学因素被认为在DTI的起始中起作用。未来需要进行研究以完善临床前模型模拟通常介于骨骼和支撑表面之间的肌肉、脂肪、真皮和表皮等连续组织层的生物力学参数的能力，针对有DTI风险的身体部位。
OBJECTIVE: Deep tissue injury (DTI) is caused by prolonged mechanical loading that disrupts blood flow and metabolic clearance. A patient simulator that mimics the biomechanical aspects of DTI initiation, stress and strain in deep muscle tissue, would be potentially useful as a training tool for pressure-relief techniques and testing platform for pressure-mitigating products. As a step toward this goal, this study evaluates the ability of silicone materials to mimic the distribution of stress in muscle tissue under concentrated loading.METHODS: To quantify the mechanical properties of candidate silicone materials, unconfined compression experiments were conducted on 3 silicone formulations (Ecoflex 0030, Ecoflex 0010, and Dragon Skin; Smooth-On, Inc, Easton, Pennsylvania). Results were fit to an Ogden hyperelastic material model, and the resulting shear moduli (G) were compared with published values for biological tissues. Indentation tests were then conducted on Ecoflex 0030 and porcine muscle to investigate silicone's ability to mimic the nonuniform stress distribution muscle demonstrates under concentrated loading. Finite element models were created to quantify stresses throughout tissue depth. Finally, a preliminary patient simulator prototype was constructed, and both deep and superficial "tissue'' pressures were recorded to examine stress distribution.RESULTS: Indentation tests showed similar stress distribution trends in muscle and Ecoflex 0030, but stress magnitudes were higher in Ecoflex 0030 than in porcine muscle. All 3 silicone formulations demonstrated shear moduli within the range of published values for biological tissue. For the experimental conditions reported in this work, Ecoflex 0030 exhibited greater stiffness than porcine muscle.CONCLUSION: Indentation tests and the prototype patient simulator trial demonstrated similar trends with high pressures closest to the bony prominence with decreasing magnitude toward the interfacial surface. Qualitatively, silicone mimicked the phenomenon observed in muscle of nonuniform stress under concentrated loading. Although shear moduli were within biological ranges, stress and stiffness values exceeded those of porcine muscle. This research represents a first step toward development of a preclinical model simulating the biomechanical conditions of stress and strain in deep muscle, since local biomechanical factors are acknowledged to play a role in DTI initiation. Future research is needed to refine the capacity of preclinical models to simulate biomechanical parameters in successive tissue layers of muscle, fat, dermis, and epidermis typically intervening between bone and support surfaces, for body regions at risk for DTI.