骨质疏松症患者腰椎的年龄和性别相关区域压缩强度特征。

Age- and sex-related regional compressive strength characteristics of human lumbar vertebrae in osteoporosis.

机构信息

Department of Structural Mechanics.

出版信息

J Multidiscip Healthc. 2008 Dec 1;1:105-21. doi: 10.2147/jmdh.s4103.

DOI:10.2147/jmdh.s4103

PMID:21197342

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC3004543/

Abstract

OBJECTIVE

To obtain the compressive load bearing and energy absorption capacity of lumbar vertebrae of osteoporotic elderly for the everyday medical praxis in terms of the simple diagnostic data, like computed tomography (CT), densitometry, age, and sex.

METHODS

Compressive test of 54 osteoporotic cadaver vertebrae L1 and L2, 16 males and 38 females (age range 43-93, mean age 71.6 ± 13.3 years, mean bone mineral density (BMD) 0.377 ± 0.089 g/cm(2), mean T-score -5.57 ± 0.79, Z-score -4.05 ± 0.77) was investigated. Based on the load-displacement diagrams and the measured geometrical parameters of vertebral bodies, proportional, ultimate and yield stresses and strains, Young's modulus, ductility and energy absorption capacity were determined. Three vertebral regions were distinguished: superior, central and inferior regions, but certain parameters were calculated for the upper/ lower intermediate layers, as well. Cross-sectional areas, and certain bone tissue parameters were determined by image analysis of CT pictures of vertebrae. Sex- and age-related decline functions and trends of strength characteristics were determined.

RESULTS

Size-corrected failure load was 15%-25% smaller in women, proportional and ultimate stresses were about 30%-35% smaller for women in any region, and 20%-25% higher in central regions for both sexes. Young's moduli were about 30% smaller in women in any region, and 20%-25% smaller in the central region for both sexes. Small strains were higher in males, large strains were higher in females, namely, proportional strains were about 25% larger in men, yield and ultimate strains were quasi equal for sexes, break strains were 10% higher in women. Ultimate energy absorption capacity was 10%-20% higher in men; the final ductile energy absorption capacity was quasi equal for sexes in all levels. Age-dependence was stronger for men, mainly in central regions (ultimate load, male: r = -0.66, p < 0.01, female: r = -0.52, p < 0.005; ultimate stress, male: r = -0.69, p < 0.01, female: r = -0.50, p < 0.005; Young's modulus, male: r = -0.55, p < 0.05, female: r = -0.52, p < 0.005, ultimate stiffness, male: r = -0.58, p < 0.05, female: r = -0.35, p < 0.03, central ultimate absorbed energy density, male: r = -0.59, p < 0.015, female: r = -0.29, p < 0.08).

CONCLUSIONS

For the strongly osteoporotic population (BMD < 0.4 g/cm(2), T-score < -4) the statical variables (loads, stresses) showed significant correlation; mixed variables (stiffness, Young's modulus, energy) showed moderate correlation; kinematical variables (displacements, strains) showed no correlation with age. The strong correlation of men between BMD and aging (r = -0.82, p < 0.001) and betwen BMD and strength parameters (r = 0.8-0.9, p < 0.001) indicated linear trends in age-related strength loss for men; however, the moderate correlation of women between BMD and aging (r = -0.47, p < 0.005) and between BMD and strength parameters (r = 0.4-0.5, p < 0.005) suggested the need of nonlinear (quadratic) approximation that provided the better fit in age-related strength functions of females modelling postmenopausal disproportionalities.

摘要

目的

通过简单的诊断数据，如计算机断层扫描（CT）、骨密度测定、年龄和性别，获得骨质疏松老年患者腰椎的抗压承载能力和能量吸收能力。

方法

对 54 例骨质疏松性尸体 L1 和 L2 椎体（16 名男性，38 名女性；年龄范围 43-93 岁，平均年龄 71.6 ± 13.3 岁，平均骨密度（BMD）0.377 ± 0.089 g/cm(2)，平均 T 评分-5.57 ± 0.79，Z 评分-4.05 ± 0.77）进行压缩试验。根据载荷-位移图和测量的椎体几何参数，确定比例、极限和屈服应力和应变、杨氏模量、延展性和能量吸收能力。区分了三个椎体区域：上、中、下区域，但某些参数也计算了上下中间层的值。通过对椎体 CT 图像进行图像分析，确定了横截面积和某些骨组织参数。确定了与性别和年龄相关的强度特征下降函数和趋势。

结果

经尺寸校正后的失效载荷女性低 15%-25%，任何区域的女性比例和极限应力低约 30%-35%，两性的中央区域高 20%-25%。杨氏模量在任何区域女性都低约 30%，中央区域两性都低 20%-25%。男性的小应变较高，女性的大应变较高，即男性的比例应变高约 25%，屈服和极限应变大致相等，断裂应变高 10%。男性的极限能量吸收能力高 10%-20%；最终韧性能量吸收能力在所有水平上两性大致相等。男性的年龄相关性更强，主要在中央区域（极限载荷，男性：r = -0.66，p < 0.01，女性：r = -0.52，p < 0.005；极限应力，男性：r = -0.69，p < 0.01，女性：r = -0.50，p < 0.005；杨氏模量，男性：r = -0.55，p < 0.05，女性：r = -0.52，p < 0.005，极限刚度，男性：r = -0.58，p < 0.05，女性：r = -0.35，p < 0.03，中央极限吸收能量密度，男性：r = -0.59，p < 0.015，女性：r = -0.29，p < 0.08）。

结论

对于严重骨质疏松症患者（BMD < 0.4 g/cm(2)，T 评分<-4），静态变量（载荷、应力）显示出显著的相关性；混合变量（刚度、杨氏模量、能量）显示出中等程度的相关性；运动学变量（位移、应变）与年龄无相关性。男性 BMD 与年龄（r = -0.82，p < 0.001）和 BMD 与强度参数（r = 0.8-0.9，p < 0.001）之间的强烈相关性表明了男性与年龄相关的强度损失的线性趋势；然而，女性 BMD 与年龄（r = -0.47，p < 0.005）和 BMD 与强度参数（r = 0.4-0.5，p < 0.005）之间的中度相关性表明需要非线性（二次）逼近，以提供女性绝经后不成比例的年龄相关强度函数建模的更好拟合。