Institute of Biomechanics, TUHH Hamburg University of Technology, Denickestrasse 15, 21073 Hamburg, Germany.
Ind Health. 2010;48(5):550-6. doi: 10.2486/indhealth.mswbvi-11.
Vibrations have been shown to be an important risk factor for spinal pathologies. The underlying mechanisms are poorly understood and in vivo data scarce and difficult to obtain. Consequently numerical models are used to estimate spinal loading; requiring fatigue strength information, which was obtained in this study for spinal specimens from young and old male donors of working age in vitro. Bone mineral density (BMD) and endplate area were determined using CT scans. Three groups were investigated: young specimens in neutral posture, young in flexed posture, and old in neutral posture. The loading consisted of 300,000 sinusoidal compression cycles of 2 kN, inducing a nucleus pressure peek of approximately 1.4 MPa. No failure of the young specimens in neutral posture was observed, but four specimens from older donors with low BMD failed. The product between endplate area and BMD was shown to be useful to predict fatigue strength for old donors and should therefore be considered with regard to whole body vibration injuries. In flexed posture, two specimens from young donors failed. One failure can be attributed to low BMD following the trend for the old specimens; the other failure could not be explained, leaving the influence of flexion yet unclear.
振动已被证明是脊柱病变的一个重要危险因素。其潜在机制尚不清楚，体内数据稀缺且难以获取。因此，数值模型被用于估计脊柱的加载情况；这需要疲劳强度信息，本研究在体外获得了来自年轻和年老男性工作年龄供体的脊柱标本的疲劳强度信息。使用 CT 扫描确定骨矿物质密度 (BMD) 和终板面积。研究了三组：中立位的年轻标本、弯曲位的年轻标本和中立位的老年标本。加载包括 30 万次 2 kN 的正弦压缩循环，产生大约 1.4 MPa 的核压力峰值。未观察到中立位的年轻标本失效，但 4 个来自低 BMD 老年供体的标本失效。终板面积和 BMD 的乘积对于预测老年供体的疲劳强度非常有用，因此在考虑全身振动损伤时应加以考虑。在弯曲位，2 个年轻供体的标本失效。一个失效可以归因于低 BMD，符合老年标本的趋势；另一个失效无法解释，弯曲的影响尚不清楚。
