Skrzypiec Daniel M, Nagel Katrin, Sellenschloh Kay, Klein Anke, Püschel Klaus, Morlock Michael M, Huber Gerd
Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, U.K.
Ind Health. 2016 Aug 5;54(4):308-14. doi: 10.2486/indhealth.2015-0162. Epub 2016 Jan 30.
An in-vitro experiment was designed to investigate the mode of failure following shear fatigue loading of lumbar motion-segments. Human male lumbar motion-segments (age 32-42 years, n=6) were immersed in Ringer solution at 37°C and repeatedly loaded, using a modified materials testing machine. Fatigue loading consisted of a sinusoidal shear load from 0 N to 1,500 N (750 N±750 N) applied to the upper vertebra of the motion-segment, at a frequency of 5 Hz. During fatigue experiments, several failure events were observed in the dynamic creep curves. Post-test x-ray, CT and dissection revealed that all specimens had delamination of the intervertebral disc. Anterior shear fatigue predominantly resulted in fracture of the apophyseal processes of the upper vertebrae (n=4). Exposure to the anterior shear fatigue loading caused motion-segment instability and resulted in vertebral slip corresponding to grade I and 'mild' grade II spondylolisthesis, as observed clinically.
设计了一项体外实验，以研究腰椎运动节段在剪切疲劳载荷作用下的失效模式。将人类男性腰椎运动节段（年龄32 - 42岁，n = 6）浸入37°C的林格溶液中，并使用改良的材料试验机进行反复加载。疲劳载荷包括以5 Hz的频率向运动节段的上位椎体施加从0 N到1500 N（750 N±750 N）的正弦剪切载荷。在疲劳实验过程中，在动态蠕变曲线中观察到了几次失效事件。测试后的X射线、CT和解剖显示，所有标本均出现椎间盘分层。前向剪切疲劳主要导致上位椎体的关节突骨折（n = 4）。如临床观察到的那样，暴露于前向剪切疲劳载荷会导致运动节段不稳定，并导致对应于I级和“轻度”II级椎体滑脱的椎体滑移。
