Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada.
Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada.
Eur Spine J. 2022 Jun;31(6):1501-1507. doi: 10.1007/s00586-022-07196-w. Epub 2022 Apr 4.
Previous studies have shown that the posterior elements/facet joints provide strength to the overall functional spine unit (FSU) by taking 3-25% of vertical compressive load off the intervertebral disc (IVD). However, little is known regarding whether this offloading has a protective effect against endplate fracture. Therefore, the purpose of this study was to investigate if the posterior elements provide a protective role to the endplate in porcine cervical spines under fracture-inducing conditions. Twenty-two cervical porcine FSUs (C5/6 level) were randomized into two groups: 1) a control group which had their posterior elements left intact (n = 11); 2) an experimental group which had the posterior elements removed (n = 11). Each FSU underwent a previously reported rapid IVD pressurization protocol in order to create endplate fractures. Briefly, hydraulic fluid was rapidly injected into the IVD via a standard inflation needle inserted through the anterior annulus which was connected to a hydraulic pump and pressure transducer. Post pressurization, each FSU was dissected to determine the presence and size of endplate fracture. Peak pressurization and rate of pressurization were not found to differ between intact and cut specimens (p = 0.313 and 0.101, respectively). In contrast, significantly, more cut FSUs sustained an endplate fracture (11/11) compared to intact FSUs (5/11); p = 0.012. Further, cut FSUs resulted in a fracture area 1.91 times greater in size compared to the fractures seen in the intact FSUs (p = 0.011). Therefore, posterior elements appear to decrease the risk and severity of endplate fracture.
先前的研究表明，后部结构/关节突关节通过分担 3-25%的垂直压缩负荷来为整体功能脊柱单位（FSU）提供强度，从而减轻椎间盘（IVD）的负荷。然而，对于这种卸载是否对终板骨折具有保护作用，人们知之甚少。因此，本研究旨在探讨在致骨折条件下，猪颈椎后部结构是否对终板起到保护作用。22 个猪颈椎 FSU（C5/6 水平）随机分为两组：1）对照组，后部结构完整（n=11）；2）实验组，后部结构切除（n=11）。每个 FSU 都进行了先前报道的快速 IVD 加压方案，以产生终板骨折。简而言之，通过插入前环的标准充气针将液压流体快速注入 IVD，该针与液压泵和压力传感器相连。加压后，每个 FSU 都进行解剖以确定终板骨折的存在和大小。完整和切除标本的加压峰值和加压速率没有差异（p=0.313 和 0.101）。相比之下，显著的是，更多的切除 FSU（11/11）比完整 FSU（5/11）更能维持终板骨折；p=0.012。此外，与完整 FSU 相比，切除 FSU 的骨折面积大 1.91 倍（p=0.011）。因此，后部结构似乎降低了终板骨折的风险和严重程度。
