Byrne Ryan M, Zhou Yu, Zheng Liying, Chowdhury Suman K, Aiyangar Ameet, Zhang Xudong
Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15203, USA.
Department of Industrial & Systems Engineering, Texas A&M University, College Station, TX 77843, USA.
J Biomech. 2018 Mar 21;70:88-95. doi: 10.1016/j.jbiomech.2017.09.026. Epub 2017 Oct 19.
The lumbar facet joint (FJ) is often associated with pathogenesis in the spine, but quantification of normal FJ motion remains limited to in vitro studies or static imaging of non-functional poses. The purpose of this study was to quantify lumbar FJ kinematics in healthy individuals during functional activity with dynamic stereo radiography (DSX) imaging. Ten asymptomatic participants lifted three known weights starting from a trunk-flexed (∼75°) position to an upright position while being imaged within the DSX system. High resolution computed tomography (CT) scan-derived 3D models of their lumbar vertebrae (L2-S1) were registered to the biplane 2D radiographs using a markerless model-based tracking technique providing instantaneous 3D vertebral kinematics throughout the lifting tasks. Effects of segment level and weight lifted were assessed using mixed-effect repeated measures ANOVA. Superior-inferior (SI) translation dominated FJ translation, with L5S1 showing significantly less translation magnitudes (Median (Md) = 3.5 mm, p < 0.0001) than L2L3, L3L4, and L4L5 segments (Md = 5.9 mm, 6.3 mm and 6.6 mm respectively). Linear regression-based slopes of continuous facet translations revealed strong linearity for SI translation (r > 0.94), reasonably high linearity for sideways sliding (Z-) (r > 0.8), but much less linearity for facet gap change (X-) (r ∼ 0.5). Caudal segments (L4-S1), particularly L5S1, displayed greater coupling compared to cranial (L2-L4) segments, revealing distinct differences overall in FJ translation trends at L5S1. No significant effect of weight lifted on FJ translations was detected. The study presents a hitherto unavailable and highly precise baseline dataset of facet translations measured during a functional, dynamic lifting task.
腰椎小关节（FJ）常与脊柱发病机制相关，但对正常FJ运动的量化仍局限于体外研究或非功能性姿势的静态成像。本研究的目的是通过动态立体放射成像（DSX）对健康个体在功能活动期间的腰椎FJ运动学进行量化。10名无症状参与者在DSX系统内成像时，从躯干屈曲（约75°）位置开始提起三个已知重量的物体至直立位置。使用基于无标记模型的跟踪技术，将其腰椎（L2-S1）的高分辨率计算机断层扫描（CT）扫描衍生的三维模型与双平面二维X线片配准，以提供整个提起任务中的瞬时三维椎体运动学。使用混合效应重复测量方差分析评估节段水平和提起重量的影响。上下（SI）平移主导FJ平移，L5S1的平移幅度（中位数（Md）=3.5mm，p<0.0001）显著小于L2L3、L3L4和L4L5节段（分别为Md=5.9mm、6.3mm和6.6mm）。基于线性回归的连续小关节平移斜率显示SI平移具有强线性（r>0.94），侧向滑动（Z-）具有较高线性（r>0.8），但小关节间隙变化（X-）的线性较低（r～0.5）。与上位（L2-L4）节段相比，下位节段（L4-S1），特别是L5S1，表现出更大的耦合，揭示了L5S1处FJ平移趋势的总体明显差异。未检测到提起重量对FJ平移有显著影响。该研究提供了一个迄今为止无法获得的、高度精确的在功能性动态提起任务中测量的小关节平移基线数据集。
