Finite element analysis predicts experimental failure patterns in vertebral bodies loaded via intervertebral discs up to large deformation.
Vertebral compression fractures are becoming increasingly common. Patient-specific nonlinear finite element (FE) models have shown promise in predicting yield strength and damage pattern but have not been experimentally validated for clinically relevant vertebral fractures, which involve loading through intervertebral discs with varying degrees of degeneration up to large compressive strains. Therefore, stepwise axial compression was applied in vitro on segments and performed in silico on their FE equivalents using a nonlocal damage-plastic model including densification at large compression for bone and a time-independent hyperelastic model for the disc. The ability of the nonlinear FE models to predict the failure pattern in large compression was evaluated for three boundary conditions: healthy and degenerated intervertebral discs and embedded endplates. Bone compaction and fracture patterns were predicted using the local volume change as an indicator and the best correspondence was obtained for the healthy intervertebral discs. These preliminary results show that nonlinear finite element models enable prediction of bone localisation and compaction. To the best of our knowledge, this is the first study to predict the collapse of osteoporotic vertebral bodies up to large compression using realistic loading via the intervertebral discs.
Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland. Electronic address: allison.clouthier@queensu.ca.
Allison L
AL
Clouthier
Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland. Electronic address: hadi.seyed@istb.unibe.ch.
Hadi S
HS
Hosseini
Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland. Electronic address: ghislain.maquer@istb.unibe.ch.
Ghislain
G
Maquer
Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland. Electronic address: philippe.zysset@istb.unibe.ch.
Philippe K
PK
Zysset
D001696:Biomechanical Phenomena; D004548:Elasticity; D020342:Finite Element Analysis; D050815:Fractures, Compression / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D007403:Intervertebral Disc / Q000503:physiopathology*; D055959:Intervertebral Disc Degeneration / Q000503:physiopathology; D008954:Models, Biological; D017711:Nonlinear Dynamics; D019904:Polymethyl Methacrylate; D011379:Prognosis
D019904:Polymethyl Methacrylate
Boundary conditions; Disc degeneration; Finite element analysis; Large deformations; Spine segment; Vertebral fracture