Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, 15203, USA.
Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, 15203, USA.
Sci Rep. 2019 Oct 29;9(1):15490. doi: 10.1038/s41598-019-51871-w.
Intervertebral discs are important structural components of the spine but also are significant sources of morbidity, especially for the "low back" lumbar region. Mechanical damage to, or degeneration of, the lumbar discs can diminish their structural integrity and elicit debilitating low back pain. Advancement of reparative or regenerative means to treat damaged or degenerated discs is hindered by a lack of basic understanding of the disc load-deformation characteristics in vivo. The current study presents an in vivo analysis of the morphometry and deformation of lumbar (L2-S1) intervertebral discs in 10 healthy participants while performing a common lifting act, using novel dynamic radiographic imaging of the lumbar vertebral body motion. Data analyses show uniquely different (p < 0.05) characteristics in morphometry, normal and shear strain patterns of the L5S1 discs, while the rest of lumbar discs exhibit great similarity. In particular shear strains in L2-L5 discs exhibited stronger linear correlations (R ≥ 0.80) between strain changes and amount of lumbar flexion-extension motion compared to L5S1 (R ≤ 0.5). The study therefore advances the state of knowledge on in vivo mechanical responses of the lumbar intervertebral discs during functional tasks.
椎间盘是脊柱的重要结构组成部分，但也是发病率的重要来源，特别是“下背部”腰椎区域。腰椎间盘的机械损伤或退变会降低其结构完整性，并引起使人衰弱的下背部疼痛。由于缺乏对椎间盘在体负载-变形特性的基本了解，修复或再生手段的进展受到阻碍。本研究采用新型腰椎椎体运动动态放射影像学方法，对 10 名健康参与者进行常见举升动作时，对腰椎（L2-S1）椎间盘的形态和变形进行了在体分析。数据分析显示，L5S1 椎间盘的形态、正常和剪切应变模式具有独特的不同（p < 0.05）特征，而其余腰椎间盘则表现出很大的相似性。特别是 L2-L5 椎间盘的剪切应变与腰椎屈伸运动的变化量之间的线性相关性更强（R ≥ 0.80），而 L5S1 椎间盘的相关性较弱（R ≤ 0.5）。因此，该研究推进了在体条件下腰椎间盘在功能任务中力学响应的知识状态。
