Yoshimoto H, Abumi K, Ito M, Kanayama M, Kaneda K
Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
J Spinal Disord. 2001 Feb;14(1):21-31. doi: 10.1097/00002517-200102000-00005.
Although range of motion has been considered the best parameter to quantify atlantoaxial instability, no other kinematic parameters have been determined for dynamic quantification. The objectives of this study were to investigate the kinematics of the normal and pathologic atlantoaxial joints by cineradiography and to determine the in-vivo kinematic parameters, if any, for the quantification of atlantoaxial instability. Sagittal plane motion of the atlantoaxial joints was analyzed by cineradiography in 12 healthy volunteers and 15 patients with atlantoaxial subluxation. In both flexion and extension, C1-C2 sagittal rotation and C1 translation in the sagittal plane were measured continuously to determine the time-displacement curves for both parameters. All patients with atlantoaxial subluxation and seven of the volunteers had the sigmoid pattern in their time-displacement curves in sagittal rotation. In these cases, atlantoaxial motion showed different points of the onset of rapid increase in motion in their sigmoid curves between flexion and extension. The discrepancy between these points was more significant in the patients than in the volunteers. In most of the patients who had atlantoaxial instability, subluxation occurred when the atlantoaxial joints were still in a more extended position and they were reduced when they were still in more flexed position. The discrepancy showed characteristics similar to those of the neutral zone observed during in vitro investigations, suggesting that it becomes a good indicator of in vivo atlantoaxial instability.
尽管活动范围一直被认为是量化寰枢椎不稳的最佳参数，但尚未确定其他运动学参数用于动态量化。本研究的目的是通过动态X线摄影术研究正常和病理性寰枢椎关节的运动学，并确定用于量化寰枢椎不稳的体内运动学参数（如果有的话）。通过动态X线摄影术分析了12名健康志愿者和15名寰枢椎半脱位患者的寰枢椎关节矢状面运动。在屈伸过程中，连续测量C1-C2矢状面旋转和C1在矢状面的平移，以确定这两个参数的时间-位移曲线。所有寰枢椎半脱位患者和7名志愿者在矢状面旋转的时间-位移曲线中呈现S形模式。在这些情况下，寰枢椎运动在屈伸过程中的S形曲线中显示出运动快速增加的起始点不同。患者的这些点之间的差异比志愿者更显著。在大多数患有寰枢椎不稳的患者中，寰枢椎半脱位发生在寰枢椎关节仍处于更伸展位置时，而复位发生在仍处于更屈曲位置时。这种差异显示出与体外研究中观察到的中性区相似的特征，表明它成为体内寰枢椎不稳的一个良好指标。
