Article

A patient-specific finite element methodology to predict damage accumulation in vertebral bodies under axial compression, sagittal flexion and combined loads.

Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria.
Computer Methods in Biomechanics and Biomedical Engineering (impact factor: 0.85). 08/2008; 11(5):477-87. DOI:10.1080/10255840802078022 pp.477-87
Source: PubMed

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.

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Keywords

axial compression
 
coarsened pQCT images
 
combined loading
 
CT-based finite element
 
cumulated damage
 
damage accumulation
 
damage localised preferentially
 
FE axial stiffness
 
individual compression
 
inherent limitations
 
loading modes
 
novel constitutive law
 
plasticity
 
single loading cases
 
stiffness
 
trabecular compartment
 
use simplistic material behaviour
 
various loading modes
 
vertebral bodies
 
vertebral stiffness