Zehr Jackie D, Quadrilatero Joe, Callaghan Jack P
Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, ON, Canada.
Spine (Phila Pa 1976). 2023 May 1;48(9):E122-E129. doi: 10.1097/BRS.0000000000004521. Epub 2022 Nov 2.
In vitro biomechanical study.
This study investigated the incidence of microstructural endplate injuries caused by cyclic compression loading. The covarying effects of joint posture, loading duration, and peak compression variation were assessed.
The endplate is physiologically and functionally important for the maintenance of spine health. Despite the ability to radiographically diagnose and classify macroscopic endplate injuries, the mechanical mechanisms of injury initiation and progression remain largely unknown.
One hundred and fourteen porcine cervical spinal units were examined. All spinal units were exposed to preconditioning tests, followed by cyclic compression testing that differed by posture (flexed, neutral), loading duration (1000, 3000, 5000 cycles), and peak compression variation (10%, 20%, 40%). Microstructural injuries were examined via immunofluorescence staining for collagen I ( i.e. , subchondral bone) and collagen II ( i.e. , hyaline cartilage endplate). From the 678 acquired images, the incidence of node, avulsion, cartilage, and circumferential pore microinjuries were determined. The distribution of microinjuries between postures, spinal levels, and vertebrae were evaluated along with the associations of incidence and size of injuries with loading duration and variation.
The incidence of avulsion injuries was significantly greater in caudal endplates (92%, P =0.006). No other injuries differed between vertebrae ( P ≥0.804) and no significant differences were observed between spinal units ( P ≥0.158). With respect to posture, 100% ( P <0.001) and 90% ( P <0.001) of avulsion and node injuries, respectively, occurred in flexed postures, whereas 82% ( P <0.001) of cartilage microinjuries occurred with neutral postures. Loading duration was significantly associated with microinjury incidence ( P <0.001) and lesion size ( P ≤0.003).
Mechanical factors such as posture did not appreciably affect the incidence of endplate injury, but microinjury types were differently distributed between flexed and neutral postures. The duration of compression was shown to have an important role in the incidence of microinjury and lesion size.
体外生物力学研究。
本研究调查了周期性压缩负荷导致的微观结构终板损伤的发生率。评估了关节姿势、负荷持续时间和峰值压缩变化的协变效应。
终板在维持脊柱健康方面具有生理和功能上的重要性。尽管能够通过影像学诊断和分类宏观终板损伤，但损伤起始和进展的力学机制仍 largely 未知。
检查了114个猪颈椎单元。所有脊柱单元均接受预处理测试，然后进行周期性压缩测试，测试因姿势（屈曲、中立）、负荷持续时间（1000、3000、5000次循环）和峰值压缩变化（10%、20%、40%）而有所不同。通过对I型胶原蛋白（即软骨下骨）和II型胶原蛋白（即透明软骨终板）进行免疫荧光染色来检查微观结构损伤。从获取的678张图像中，确定结节、撕脱、软骨和周向孔隙微观损伤的发生率。评估了姿势、脊柱节段和椎体之间微观损伤的分布情况，以及损伤发生率和大小与负荷持续时间和变化的相关性。
尾端终板撕脱损伤的发生率显著更高（92%，P =0.006）。其他损伤在椎体之间无差异（P≥0.804），在脊柱单元之间也未观察到显著差异（P≥0.158）。关于姿势，分别有100%（P<0.001）和90%（P<0.001）的撕脱和结节损伤发生在屈曲姿势中，而82%（P<0.001）的软骨微观损伤发生在中立姿势中。负荷持续时间与微观损伤发生率（P<0.001）和损伤大小（P≤0.003）显著相关。
姿势等力学因素对终板损伤发生率的影响不明显，但微观损伤类型在屈曲和中立姿势之间的分布有所不同。压缩持续时间在微观损伤发生率和损伤大小方面显示出重要作用。
