The effect of intravertebral heterogeneity in microstructure on vertebral strength and failure patterns

• Published in: Osteoporosis international 2013-03, Vol.24 (3), p.979-989
• Main Authors: Hussein, A. I., Morgan, E. F.
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Anisotropy; Bone density; Bone Density - physiology; Compressive Strength - physiology; Computed tomography; Elasticity - physiology; Endocrinology; Female; Humans; Male; Mechanical properties; Medicine; Medicine & Public Health; Microstructure; Original Article; Orthopedics; Osteoporosis; Rheumatology; Shear Strength - physiology; Spine; Stress, Mechanical; Thoracic Vertebrae - diagnostic imaging; Thoracic Vertebrae - physiology; Thoracic Vertebrae - ultrastructure; Thorax; Tomography; Vertebrae; X-Ray Microtomography - methods
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-012-2039-1

Summary The goal of this study was to determine the influence of intravertebral heterogeneity in microstructure on vertebral failure. Results show that noninvasive assessments of the intravertebral heterogeneity in density improve predictions of vertebral strength and that local variations in microstructure are associated with locations of failure in the vertebral body. Introduction The overall goal of this study was to determine the influence of intravertebral heterogeneity in microstructure on vertebral failure. Methods Trabecular density and microarchitecture were quantified for 32 thoracic vertebrae using micro-computed tomography (μCT)-based analyses of 4.81 mm, contiguous cubes throughout the centrum. Intravertebral heterogeneity in density was defined as the interquartile range and quartile coefficient of variation of the cube densities. The vertebrae were compressed to failure to measure stiffness, strength, and toughness. Pre- and post-compression μCT images were analyzed using digital volume correlation to quantify failure patterns in the vertebrae, as defined by the distributions of residual strain. Results Failure patterns consisted of large deformations in the midtransverse plane with concomitant endplate biconcavity and were linked to the intravertebral distribution of bone tissue. Low values of connectivity density and trabecular number, and high values of trabecular separation, were associated with high strains. However, local microstructural properties were not the sole determinants of failure. For instance, the midtransverse plane experienced the highest strain ( p