Age- and direction-related adaptations of lumbar vertebral trabecular bone with respect to apparent stiffness and tissue level stress distribution  

作　　者：He Gong Yubo Fan Ming Zhang Ling Qin 

机构地区：[1]Department of Health Technology and Informatics,The Hong Kong Polytechnic University, Hong Kong, China [2]Department of Mechanics,Jilin University, 130025 Changchun, China [3]Department of Bioengineering,Beihang University, 100083 Beijing, China [4]Department of Orthopaedics and Traumatology,The Chinese University of Hong Kong, Hong Kong, China

出　　处：《Acta Mechanica Sinica》2009年第1期121-129,共9页力学学报（英文版）

基　　金：The project supported by the Hong Kong Polytechnic University Research Grants(G-U273); the National Natural Science Foundation of China(10502021 and 10529202)

摘　　要：The objective of this study was to study the age-related adaptation of lumbar vertebral trabecular bone at the apparent level, as well as the tissue level in three orthogonal directions. Ninety trabecular specimens were obtained from six normal L4 vertebral bodies of six male cadavers in two age groups, three aged 62 years and three aged 69 years, and were scanned using a high-resolution micro-computed tomography （micro-CT） system, then converted to micro- finite element models to do micro-finite element analyses. The relationship between apparent stiffness and bone volume fraction, and the tissue level yon Mises stress distribution for each trabecular specimen when compressed separately in the longitudinal direction, medial-lateral and anterior-posterior directions （transverse directions） were derived and compared between two age groups. The results showed that at the apparent level, trabecular bones from 69-year group had stiffer bone structure relative to their volume fractions in all three directions, and in both age groups, changes in bone volume fraction could explain more variations in apparent stiffness in the longitudinal direction than the transverse directions; at the tissue level, aging had little effect on the tissue von Mises stress distributions for the compressions in all the three directions. The novelty of the present study was that it provided quantitative assessments on the age and direction- related adaptation of Chinese male lumbar vertebral trabecular bone from two different levels： stiffness at the apparent level and stress distribution at the tissue level. It may help to understand the failure mechanisms and fracture risks of vertebral body associated with aging and direction for the prevention of fracture risks in elder individuals.The objective of this study was to study the age-related adaptation of lumbar vertebral trabecular bone at the apparent level, as well as the tissue level in three orthogonal directions. Ninety trabecular specimens were obtained from six normal L4 vertebral bodies of six male cadavers in two age groups, three aged 62 years and three aged 69 years, and were scanned using a high-resolution micro-computed tomography （micro-CT） system, then converted to micro- finite element models to do micro-finite element analyses. The relationship between apparent stiffness and bone volume fraction, and the tissue level yon Mises stress distribution for each trabecular specimen when compressed separately in the longitudinal direction, medial-lateral and anterior-posterior directions （transverse directions） were derived and compared between two age groups. The results showed that at the apparent level, trabecular bones from 69-year group had stiffer bone structure relative to their volume fractions in all three directions, and in both age groups, changes in bone volume fraction could explain more variations in apparent stiffness in the longitudinal direction than the transverse directions; at the tissue level, aging had little effect on the tissue von Mises stress distributions for the compressions in all the three directions. The novelty of the present study was that it provided quantitative assessments on the age and direction- related adaptation of Chinese male lumbar vertebral trabecular bone from two different levels： stiffness at the apparent level and stress distribution at the tissue level. It may help to understand the failure mechanisms and fracture risks of vertebral body associated with aging and direction for the prevention of fracture risks in elder individuals.

关 键 词：Vertebral body Trabecular bone Micro-finite element analysis Apparent stiffness Tissuevon Mises stress 

分 类 号：O34[理学—固体力学] TB301[理学—力学]