Prajapati Arvind Kumar, Harikrishna Varma Parimanathukovilakom Ramavarma, Saravana Kumar Gurunathan, Muraleedharan Chirathody Vayalappil, Divakar Ganesh
Bio-Medical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India.
Department of Engineering Design, Indian Institute of Technology Madras, Chennai, India.
Asian Spine J. 2024 Dec;18(6):765-776. doi: 10.31616/asj.2024.0220. Epub 2024 Oct 22.
Basic study.
This study aimed to utilize finite element (FE) analysis and design of experiment (DoE) techniques to propose and optimize a novel pedicle screw design and compare its pull-out force with that of a control device.
Pedicle screw-based fixation is the gold-standard treatment for spine diseases, particularly in fusion procedures. However, pedicle screw loosening and breakage still occur in osteoporotic and non-osteoporotic patients. This research investigates screw design modifications to enhance screw-bone interface strength and reduce the likelihood of loosening.
We conceptualized a novel pedicle screw considering vertebral bone morphology and strength differences. A validated FE model was developed and used in conjunction with DoE to determine the screw՚s optimum geometrical parameters. The FE model was validated through simulation and laboratory experiments using the control device. The optimized thread profiles for cortical bone and cancellous bone were determined, with pull-out force as the primary factor for screw design evaluation.
FE analysis results for the control device closely matched experimental results, with less than 5% difference. The chosen unique pitch/depth ratio showed maximum pull-out force for cortical bone, while DoE enabled the optimization of design parameters for cancellous bone. The optimized pedicle screw exhibited a 15% increase in pull-out force compared to the control device.
The study proposes a novel pedicle screw design with better pull-out strength than the control device. Combining FE analysis with DoE is an effective approach for screw design optimization, reducing the need for extensive prototyping tests. A two-variable analysis suffices for optimizing cortical bone design parameters, while a multi-variable analysis is more effective for optimizing cancellous bone design parameters.
基础研究。
本研究旨在利用有限元（FE）分析和实验设计（DoE）技术，提出并优化一种新型椎弓根螺钉设计，并将其拔出力与对照装置进行比较。
基于椎弓根螺钉的固定术是脊柱疾病的金标准治疗方法，尤其是在融合手术中。然而，在骨质疏松和非骨质疏松患者中，椎弓根螺钉松动和断裂仍会发生。本研究调查螺钉设计的改进，以增强螺钉与骨的界面强度并降低松动的可能性。
我们结合椎骨形态和强度差异，构思了一种新型椎弓根螺钉。开发了一个经过验证的有限元模型，并与实验设计一起用于确定螺钉的最佳几何参数。通过使用对照装置的模拟和实验室实验对有限元模型进行验证。确定了皮质骨和松质骨的优化螺纹轮廓，将拔出力作为螺钉设计评估的主要因素。
对照装置的有限元分析结果与实验结果密切匹配，差异小于5%。所选的独特螺距/深度比在皮质骨中显示出最大拔出力，而实验设计能够优化松质骨的设计参数。与对照装置相比，优化后的椎弓根螺钉拔出力提高了15%。
本研究提出了一种新型椎弓根螺钉设计，其拔出强度优于对照装置。将有限元分析与实验设计相结合是螺钉设计优化的有效方法，减少了大量原型测试的需求。双变量分析足以优化皮质骨设计参数，而多变量分析在优化松质骨设计参数方面更有效。
