Large Lytic Defects Produce Kinematic Instability and Loss of Compressive Strength in Human Spines: An in Vitro Study.
Large Lytic Defects Produce Kinematic Instability and Loss of Compressive Strength in Human Spines: An in Vitro Study.
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DOI：
10.2106/jbjs.19.00419
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发表时间：
2021-05-19
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在脊柱转移瘤患者中，运动不稳定被认为是病理性椎体骨折的预测因素。然而，这种运动学不稳定性和脊柱强度损失之间的关系仍然未知。对来自8具女性尸体脊柱（年龄47 - 69岁）的24个3节段胸腰椎节段在轴向压缩（180 N）和轴向压缩屈曲或伸展力矩（7.5 Nm）下进行运动学评估。机械刺激两种溶解性缺损模式：a）椎体缺损（Taneichi模型C，n = 13）和B）模型C+同侧椎弓根和小关节受损（Taneichi模型E，n = 11）。重新测试运动学响应，并测量抗压强度。我们应用双向重复测量分析来测试模型（C，E）对节段运动学响应变化（病变与对照）的影响。我们使用多变量线性回归来测试节段的运动学参数和抗压强度的变化之间的关联。与模型C相比，模型E导致节段伸展（p = 0.0233）和扭转（p = 0.0429）ROM以及伸展力矩下的矢状平移（p <0.001）和屈曲力矩下的矢状平移（p = 0.0452）发生显著更高的变化。中柱破坏（p <0.0001）、屈曲（p = 0.0002）和伸展（p = 0.0021）下较高的轴向平移以及屈曲下矢状平移（p = 0.0009）与下节段的抗压强度呈负相关。严重的脊柱溶解性缺陷影响运动学异常，脊柱压缩强度降低，表明脊柱结构刚度降低。
In patients with spinal metastases, kinematic instability is postulated as a predictor of pathologic vertebral fractures. However, the relationship between this kinematic instability and the loss of spinal strength remains unknown. Twenty-four 3-level thoracic and lumbar segments from eight female cadaver spines, age 47–69 years, were kinematically assessed in axial compression (180N) and axial compression with flexion or extension moment (7.5Nm). Two patterns of lytic defects were mechanically stimulated; a) vertebral body defect (Taneichi model C, n=13) and b) model C + compromise of the ipsilateral pedicle and facet joint (Taneichi model E, n=11). The kinematic response was re-tested, and compression strength was measured. We applied two-way repeated measures analysis to test the model’s (C, E) effect on the change (lesion vs. control) in the segment’s kinematic response. We used multivariable linear regression to test the association between changes in the segment’s kinematic parameters and compressive strength. Compared to model C, model E caused significantly higher changes to the segments extension (p=0.0233) and torsional (p=0.0429) ROM, and sagittal translation (p<0.001) under extension moments and sagittal translations (p=0.0452) under flexion moments. Destruction of the middle column (p<0.0001), higher axial translations under flexion (p=0.0002), and extension (p=0.0021), and sagittal translations under flexion (p=0.0009), were negatively associated with lower segment’s compressive strength. Critical spinal lytic defects affect kinematic abnormality with lower spine compressive strength, suggesting reduced spinal structural rigidity.