Multiaxial fatigue characterization of anisotropic bone-implant interfaces

各向异性骨-种植体界面的多轴疲劳表征

• 批准号: RGPIN-2019-04668
• 负责人: McLachlin, Stewart
• 金额: $ 1.97万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=715102
• 关键词: Multiaxial; fatigue; characterization; anisotropic; bone

Metallic implants, used in various types of orthopaedic surgery, are critical to reducing pain and restoring mobility for millions of individuals worldwide. The success of these procedures depends on the mechanical stability of the heterogeneous interface established between the bone tissue and implant, forming the bone-implant system. In spine surgery, for example, pedicle screw instrumentation systems establish rigid stabilization of the spinal column until long-term bony fusion is achieved. However, in the period prior to fusion, these technologies are susceptible to fatigue failure resulting from non-uniform load variations during activities of daily living. This can lead to screw loosening and loss of spinal column stabilization; a significant cause of failure in fusion procedures at a high clinical and societal cost. Yet, the biomechanics of this interface failure mode in the spine are not well understood or properly accounted for in the design and pre-clinical evaluation of implant devices. The proposed research program aims to improve the structural and functional performance of bone-implant systems by advancing our fundamental understanding of the biomechanical factors and implant design considerations that influence the bone-implant interface strength. Through the next five years my team will systematically quantify differences in how, when, and where pedicle screw loosening occurs in comparison of simulated uniaxial and multiaxial cyclic loading modes. The how will identify relevant interactions between loading modes and resulting interface damage using a Design of Experiments approach. When screw loosening occurs will use machine vision and intelligent sensors to measure relative interface movement. Where screw loosening occurs will examine cumulative bone damage using state-of-the-art microscale computed tomography imaging. We will also develop a new, adaptive loading method to improve anisotropic characterization of multiaxial fatigue strength in pedicle screw fixation. This approach will better evaluate interface fatigue strength in the context of bone microstructure variability and build towards new testing standards of the pedicle screw-bone interface. Leveraging outcomes from this research, my team will evaluate design improvements in a 3D printed pedicle screw expansion mechanism based on assessment of multiaxial fatigue strength. Integrating computational topology optimization of the implant design combined with new test methods developed for multiaxial fatigue will establish a new pre-clinical pipeline to evaluate and enhance bone-implant system performance. Ultimately, this research program will improve our understanding of bone-implant interface mechanics and lead to new innovations in spine surgery technologies to help avoid costly revision procedures. This will further strengthen Canada's leadership in producing highly-skilled engineers ready to address global challenges in the medical device industry and beyond.

用于各种类型的骨科手术中的金属植入物对于减轻全球数百万个人的疼痛和恢复流动性至关重要。这些程序的成功取决于骨组织和植入物之间建立的异质界面的机械稳定性，从而形成了骨植入剂系统。例如，在脊柱手术中，椎弓根螺钉仪器系统建立了脊柱的刚性稳定，直到实现了长期的骨融合。但是，在融合之前的那一段时间内，这些技术易受日常生活活动中不均匀负荷变化而导致的疲劳失败。这可能导致螺钉松动和脊柱稳定的丢失；融合程序以高临床和社会成本造成融合程序失败的重要原因。然而，在植入设备的设计和临床前评估中，脊柱中这种接口故障模式的生物力学尚未得到很好的理解或正确解释。 拟议的研究计划旨在通过促进我们对影响骨植入物界面强度的生物力学因素和植入设计考虑因素的基本理解来提高骨植入系统的结构和功能性能。在接下来的五年中，我的团队将系统地量化在模拟的单轴和多轴循环载荷模式的比较时，椎弓根螺钉松动的何时，何时和位置的差异。如何使用实验方法的设计将如何确定加载模式与结果接口损伤之间的相关相互作用。当螺钉松动发生时，将使用机器视觉和智能传感器来测量相对接口的运动。发生螺钉松动的地方将使用最新的微观计算机断层扫描成像检查累积骨损伤。 我们还将开发一种新的自适应加载方法，以改善椎弓根螺钉固定中多轴疲劳强度的各向异性表征。这种方法将在骨微结构变异性的背景下更好地评估界面疲劳强度，并朝着椎弓根螺钉骨接口的新测试标准构建。 利用这项研究的结果，我的团队将根据评估多轴疲劳强度的评估，评估3D印刷椎弓根螺钉扩展机制的设计改进。整合植入物设计的计算拓扑优化与针对多轴疲劳开发的新测试方法结合使用，将建立一条新的临床前管道，以评估和增强骨植入物系统性能。 最终，该研究计划将提高我们对骨骼植物界面力学的理解，并导致脊柱手术技术的新创新，以帮助避免昂贵的修订程序。这将进一步加强加拿大在生产准备应对医疗设备行业及其他地区全球挑战的高技能工程师方面的领导地位。