Chen Hsin-Chang, Wu Jia-Lin, Huang Shou-Chieh, Zhong Zheng-Cheng, Chiu Shiu-Ling, Lai Yu-Shu, Cheng Cheng-Kung
Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; Division of Orthopedics, Taipei City Hospital, Heping Fuyou Branch (Heping), Taipei, Taiwan.
Department of Orthopedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Orthopedics, Taipei Medical University Hospital, Taipei, Taiwan.
Med Eng Phys. 2017 Aug;46:27-32. doi: 10.1016/j.medengphy.2017.05.004. Epub 2017 Jun 15.
Interspinous spacers have been designed to provide a minimally invasive surgical technique for patients with lumbar spinal stenosis or foraminal stenosis. A novel pedicle screw-based interspinous spacer has been developed in this study, and the aim of this finite element experiment was to investigate the biomechanical differences between the pedicle screw-based interspinous spacer (M-rod system) and the typical interspinous spacer (Coflex-F™). A validated finite element model of an intact lumbar spine was used to analyze the insertions of the Coflex-F™, titanium alloy M-rod (M-Ti), and polyetheretherketone M-rod (M-PEEK), independently. The range of motion (ROM) between each vertebrae, stiffness of the implanted level, the peak stress at the intervertebral discs, and the contact forces on spinous process were analyzed. Of all three devices, the Coflex-F™ provided the largest restrictions in extension, flexion and lateral bending. For intervertebral disc, the peak stress at the implanted segment decreased by 81% in the Coflex-F™, 60.2% in the M-Ti and 46.7% in the M-PEEK when compared to the intact model. For the adjacent segments, while the Coflex-F™ caused considerable increases in the ROM and disc stress, the M-PEEK only had small changes.
棘突间撑开器旨在为腰椎管狭窄症或椎间孔狭窄症患者提供一种微创手术技术。本研究开发了一种新型的基于椎弓根螺钉的棘突间撑开器，本有限元实验的目的是研究基于椎弓根螺钉的棘突间撑开器（M型棒系统）与典型棘突间撑开器（Coflex-F™）之间的生物力学差异。使用经过验证的完整腰椎有限元模型分别分析Coflex-F™、钛合金M型棒（M-Ti）和聚醚醚酮M型棒（M-PEEK）的植入情况。分析了每个椎体之间的活动范围（ROM）、植入节段的刚度、椎间盘的峰值应力以及棘突上的接触力。在所有三种装置中，Coflex-F™在伸展、屈曲和侧方弯曲方面提供的限制最大。对于椎间盘，与完整模型相比，Coflex-F™植入节段的峰值应力降低了81%，M-Ti降低了60.2%，M-PEEK降低了46.7%。对于相邻节段，虽然Coflex-F™导致ROM和椎间盘应力显著增加，但M-PEEK仅有微小变化。
