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: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=737774
• 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.

金属植入物，用于各种类型的骨科手术，是至关重要的，以减少疼痛和恢复全球数百万人的流动性。这些手术的成功取决于在骨组织和植入物之间建立的异质界面的机械稳定性，形成骨-植入物系统。例如，在脊柱手术中，椎弓根螺钉器械系统建立脊柱的刚性稳定，直到实现长期骨融合。然而，在融合之前的时期，这些技术容易因日常生活活动期间的非均匀载荷变化而疲劳失效。这可能导致螺钉松动和脊柱稳定性丧失;这是融合手术失败的重要原因，临床和社会成本很高。然而，在植入物器械的设计和临床前评价中，尚未充分理解或正确解释脊柱中这种界面失效模式的生物力学。拟议的研究计划旨在通过推进我们对影响骨-种植体界面强度的生物力学因素和种植体设计考虑因素的基本理解，改善骨-种植体系统的结构和功能性能。在接下来的五年里，我的团队将系统地量化椎弓根螺钉松动的方式、时间和位置的差异，以比较模拟单轴和多轴循环加载模式。如何将识别相关的相互作用之间的加载模式和由此产生的界面损伤，使用实验设计的方法。当发生螺钉松动时，将使用机器视觉和智能传感器测量相对界面运动。在螺钉松动发生的部位，将使用最先进的微型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。这种方法将更好地评估骨微结构变异性背景下的界面疲劳强度，并建立椎弓根螺钉-骨界面的新测试标准。 利用这项研究的结果，我的团队将根据多轴疲劳强度评估评估3D打印椎弓根螺钉扩张机制的设计改进。将种植体设计的计算拓扑优化与针对多轴疲劳开发的新测试方法相结合，将建立一种新的临床前管道，以评估和增强骨-种植体系统的性能。最终，这项研究计划将提高我们对骨-植入物界面力学的理解，并导致脊柱外科技术的新创新，以帮助避免昂贵的翻修手术。这将进一步加强加拿大在培养高技能工程师方面的领导地位，以应对医疗器械行业及其他领域的全球挑战。