Shen Hangkai, Fogel Guy R, Zhu Jia, Liao Zhenhua, Liu Weiqiang
Department of Mechanical Engineering, Tsinghua University, Beijing, China; Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen, China.
Spine Pain Begone Clinic, San Antonio, Texas, USA.
World Neurosurg. 2019 Jul;127:e1112-e1119. doi: 10.1016/j.wneu.2019.04.051. Epub 2019 Apr 10.
Recently, interspinous stabilization with the interspinous process device (IPD) has become an alternative to treat lumbar spinal stenosis. The biomechanical influence of different design features of IPDs on intradiscal pressure (IDP) and facet joint force (FJF) has not been fully understood. The aim of this study was to investigate the biomechanical performance of different IPDs using finite element (FE) method.
A FE model of the L1-5 segments was developed and validated. Four surgical FE models were constructed by inserting different implants at the L3-4 segment (Coflex-F, DIAM, Wallis, and pedicle screw system). The 4 motion modes were simulated.
The IPDs decreased range of motion (ROM) at the surgical level substantially in flexion and extension, but little influence was found in lateral bending and torsion. Compared with the DIAM and Wallis devices, the Coflex-F device showed advantages in stabilizing the surgical level, especially in flexion and extension, while it increased FJF at adjacent levels by 26%-27% in extension. Among the 3 IPDs, the DIAM device exhibited the most comparable ROM, IDP, and FJF at adjacent levels compared with the intact lumbar spine. The influence of the Wallis device was between that of the Coflex-F and DIAM devices.
Compared with rigid fixation, the IPDs demonstrated less compensation at adjacent levels in terms of ROM, IDP, and FJF, which may lower the incidence of adjacent segment degeneration in the long term.
最近，使用棘突间装置（IPD）进行棘突间稳定术已成为治疗腰椎管狭窄症的一种替代方法。IPD不同设计特征对椎间盘内压力（IDP）和小关节力（FJF）的生物力学影响尚未完全明确。本研究的目的是使用有限元（FE）方法研究不同IPD的生物力学性能。
建立并验证了L1-5节段的有限元模型。通过在L3-4节段植入不同的植入物（Coflex-F、DIAM、Wallis和椎弓根螺钉系统）构建了四个手术有限元模型。模拟了四种运动模式。
IPD在手术节段显著降低了屈伸时的活动范围（ROM），但在侧屈和扭转时影响较小。与DIAM和Wallis装置相比，Coflex-F装置在稳定手术节段方面具有优势，尤其是在屈伸时，而在伸展时它使相邻节段的FJF增加了26%-27%。在这三种IPD中，与完整腰椎相比，DIAM装置在相邻节段的ROM、IDP和FJF方面表现出最相近的数值。Wallis装置的影响介于Coflex-F和DIAM装置之间。
与刚性固定相比，IPD在ROM、IDP和FJF方面在相邻节段表现出较少的代偿，从长期来看这可能会降低相邻节段退变的发生率。
