Nishida Norihiro, Suzuki Hidenori, Tetsu Hanvey, Morishita Yuki, Kumaran Yogesh, Jiang Fei, Funaba Masahiro, Fujimoto Kazuhiro, Ichihara Yusuke, Sakai Takashi, Ohgi Junji
Department of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Faculty of Engineering, Yamaguchi University, Ube, Japan.
Asian Spine J. 2024 Oct;18(5):621-629. doi: 10.31616/asj.2024.0121. Epub 2024 Aug 20.
STUDY DESIGN: Biomechanical study. PURPOSE: To investigate the mechanical characteristics of bone models created from medical images. OVERVIEW OF LITERATURE: Recent advancements in three-dimensional (3D) printing technology have affected its application in surgery. However, a notable gap exists in the analyses of how patient's dimorphism and variations in vertebral body anatomy influence the maximum insertional torque (MIT) and pullout strength (POS) of pedicle screws (PS) in osteoporotic vertebral bone models derived from medical images. METHODS: Male and female patients with computed tomography data were selected. Dimensions of the first thoracic (T1), fourth lumbar (L4), and fifth lumbar (L5) vertebrae were measured, and bone models consisting of the cancellous and cortical bones made from polyurethane foam were created. PS with diameters of 4.5 mm, 5.5 mm, and 6.5 mm were used. T1 PS were 25 mm long, and L4 and L5 PS were 40 mm long. The bone models were secured with cement, and the MIT was measured using a calibrated torque wrench. After MIT testing, the PS head was attached to the machine's crosshead. POS was then calculated at a crosshead speed of 5 mm/min until failure. RESULTS: The L4 and L5 were notably larger in female bone models, whereas the T1 vertebra was larger in male bone models. Consequently, the MIT and POS for L4 and L5 were higher in female bone models across all PS diameters than in male bone models. Conversely, the MIT for T1 was higher in male bone models across all PS; however, no significant differences were observed in the POS values for T1 between sexes. CONCLUSIONS: The mechanical properties of the proposed bone models can vary based on the vertebral structure and size. For accurate 3D surgical and mechanical simulations in the creation of custom-made medical devices, bone models must be constructed from patientspecific medical images.
研究设计:生物力学研究。 目的:研究从医学图像创建的骨模型的力学特性。 文献综述:三维(3D)打印技术的最新进展已影响其在手术中的应用。然而,在分析患者的二态性和椎体解剖结构变化如何影响从医学图像衍生的骨质疏松性椎体骨模型中椎弓根螺钉(PS)的最大插入扭矩(MIT)和拔出强度(POS)方面,存在明显差距。 方法:选择具有计算机断层扫描数据的男性和女性患者。测量第一胸椎(T1)、第四腰椎(L4)和第五腰椎(L5)的尺寸,并创建由聚氨酯泡沫制成的包含松质骨和皮质骨的骨模型。使用直径为4.5毫米、5.5毫米和6.5毫米的PS。T1 PS长25毫米,L4和L5 PS长40毫米。用骨水泥固定骨模型,并用校准的扭矩扳手测量MIT。在MIT测试后,将PS头部连接到机器的十字头上。然后以5毫米/分钟的十字头速度计算POS,直至失效。 结果:女性骨模型中的L4和L5明显更大,而男性骨模型中的T1椎体更大。因此,在所有PS直径下,女性骨模型中L4和L5的MIT和POS均高于男性骨模型。相反,在所有PS中,男性骨模型中T1的MIT更高;然而,两性之间T1的POS值未观察到显著差异。 结论:所提出的骨模型的力学性能可能因椎体结构和大小而异。为了在定制医疗设备的创建中进行准确的3D手术和力学模拟,必须根据患者特定的医学图像构建骨模型。
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