title: A patient-specific finite element methodology to predict damage accumulation in vertebral bodies under axial compression, sagittal flexion and combined loads.
abstract: Due to the inherent limitations of DXA, assessment of the biomechanical properties of vertebral bodies relies increasingly on CT-based finite element (FE) models, but these often use simplistic material behaviour and/or single loading cases. In this study, we applied a novel constitutive law for bone elasticity, plasticity and damage to FE models created from coarsened pQCT images of human vertebrae, and compared vertebral stiffness, strength and damage accumulation for axial compression, anterior flexion and a combination of these two cases. FE axial stiffness and strength correlated with experiments and were linearly related to flexion properties. In all loading modes, damage localised preferentially in the trabecular compartment. Damage for the combined loading was higher than cumulated damage produced by individual compression and flexion. In conclusion, this FE method predicts stiffness and strength of vertebral bodies from CT images with clinical resolution and provides insight into damage accumulation in various loading modes.
authors.affiliation: Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria. yan@ilsb.tuwien.ac.at
authors.forename: Yan
authors.initials: Y
authors.lastname: Chevalier
authors.forename: Mathieu
authors.initials: M
authors.lastname: Charlebois
authors.forename: Dieter
authors.initials: D
authors.lastname: Pahr
authors.forename: Peter
authors.initials: P
authors.lastname: Varga
authors.forename: Paul
authors.initials: P
authors.lastname: Heini
authors.forename: Erich
authors.initials: E
authors.lastname: Schneider
authors.forename: Philippe
authors.initials: P
authors.lastname: Zysset
mesh_terms: D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000503:physiopathology*; D019245:Compressive Strength / Q000502:physiology*; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D008954:Models, Biological; D016103:Spinal Fractures / Q000503:physiopathology; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed / Q000379:methods