scholarly journals Finite Element and deformation analyses predict pattern of bone failure in loaded zebrafish spines

2019 ◽  
Author(s):  
Elis Newman ◽  
Erika Kague ◽  
Jessye A. Aggleton ◽  
Christianne Fernee ◽  
Kate Robson Brown ◽  
...  
Keyword(s):  
Finite Element ◽  
Disease Process ◽  
Intervertebral Discs ◽  
Vertebral Compression Fractures ◽  
Finite Element Models ◽  
Micro Computed Tomography ◽  
Spinal Motion ◽  
Biomechanical Models ◽  
Testing Stage ◽  
Ultimate Failure

AbstractThe spine is the central skeletal support structure in vertebrates consisting of repeated units of bone, the vertebrae, separated by intervertebral discs that enable the movement of the spine. Spinal pathologies such as idiopathic back pain, vertebral compression fractures and intervertebral disc failure affect millions of people world-wide. Animal models can help us to understand the disease process, and zebrafish are increasingly used as they are highly genetically tractable, their spines are axially loaded like humans, and they show similar pathologies to humans during ageing. However biomechanical models for the zebrafish are largely lacking. Here we describe the results of loading intact zebrafish spinal motion segments on a material testing stage within a micro Computed Tomography machine. We show that vertebrae and their arches show predictable patterns of deformation prior to their ultimate failure, in a pattern dependent on their position within the segment. We further show using geometric morphometrics which regions of the vertebra deform the most during loading, and that Finite Element models of the trunk subjected reflect the real patterns of deformation and strain seen during loading and can therefore be used as a predictive model for biomechanical performance.

scholarly journals Finite element and deformation analyses predict pattern of bone failure in loaded zebrafish spines

2019 ◽  
Vol 16 (160) ◽  
pp. 20190430 ◽  
Author(s):  
Elis Newham ◽  
Erika Kague ◽  
Jessye A. Aggleton ◽  
Christianne Fernee ◽  
Kate Robson Brown ◽  
...  
Keyword(s):  
Finite Element ◽  
Disease Process ◽  
Intervertebral Discs ◽  
Vertebral Compression Fractures ◽  
Finite Element Models ◽  
Micro Computed Tomography ◽  
Spinal Motion ◽  
Biomechanical Models ◽  
Testing Stage ◽  
Ultimate Failure

The spine is the central skeletal support structure in vertebrates consisting of repeated units of bone, the vertebrae, separated by intervertebral discs (IVDs) that enable the movement of the spine. Spinal pathologies such as idiopathic back pain, vertebral compression fractures and IVD failure affect millions of people worldwide. Animal models can help us to understand the disease process, and zebrafish are increasingly used as they are highly genetically tractable, their spines are axially loaded like humans, and they show similar pathologies to humans during ageing. However, biomechanical models for the zebrafish are largely lacking. Here, we describe the results of loading intact zebrafish spinal motion segments on a material testing stage within a micro-computed tomography machine. We show that vertebrae and their arches show predictable patterns of deformation prior to their ultimate failure, in a pattern dependent on their position within the segment. We further show using geometric morphometrics which regions of the vertebra deform the most during loading, and that finite-element models of the trunk subjected reflect the real patterns of deformation and strain seen during loading and can therefore be used as a predictive model for biomechanical performance.

Comparison of four methods to simulate swelling in poroelastic finite element models of intervertebral discs

2011 ◽  
Vol 4 (7) ◽  
pp. 1234-1241 ◽  
Author(s):  
Fabio Galbusera ◽  
Hendrik Schmidt ◽  
Jérôme Noailly ◽  
Andrea Malandrino ◽  
Damien Lacroix ◽  
...  
Keyword(s):  
Finite Element ◽  
Intervertebral Discs ◽  
Finite Element Models

Initial Stress in Biomechanical Models of Atherosclerotic Plaques

2011 ◽  
Author(s):  
L. Speelman ◽  
A. C. Akyildiz ◽  
J. J. Wentzel ◽  
E. H. van Brummelen ◽  
J. Jukema ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Finite Element ◽  
Initial Stress ◽  
Atherosclerotic Plaque ◽  
Initial Stresses ◽  
Atherosclerotic Plaques ◽  
Finite Element Models ◽  
Biomechanical Models ◽  
Fibrous Cap ◽  
Stress Studies

Rupture of the cap of an atherosclerotic plaque is instigated when the stresses in the cap due to the blood pressure exceed the local cap strength. Image based computational finite element models of atherosclerotic plaques are widely used to compute stresses in the fibrous cap. These models are often based on pressurized geometries. The shape of the plaque is determined by the blood pressure at the time of imaging, and thus contains initial stresses (IS) and strains, which are generally ignored in plaque stress studies.

Finite Element Analysis of Fixation System Influence on the Thoracolumbar Spine Stability

2016 ◽  
Vol 821 ◽  
pp. 685-692 ◽  
Author(s):  
Klaudia Szkoda ◽  
Celina Pezowicz
Keyword(s):  
Finite Element ◽  
Sagittal Plane ◽  
Thoracolumbar Spine ◽  
Element Model ◽  
Intervertebral Discs ◽  
Vertebral Compression Fractures ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Transpedicular Fixation ◽  
The Stability

All segments of the spine are characterized by a corresponding curvature in the sagittal plane and different geometrical parameters of vertebrae, which affects the complicated structure of transition between subsequent segments. The aim of the study was to assess changes occurring in the thoracolumbar spine, as a result of application of the transpedicular fixation. The research was conducted on finite element model, which was constructed on the basis of CT images. Five different configurations of the model were analyzed: focusing on vertebral compression fractures and degeneration of intervertebral discs. The analysis showed that the highest displacement occurred for a segment with intervertebral disc degeneration. Transpedicular fixation of injured thoracolumbar spine is given the opportunity to improve the stability and stiffness of the segment under consideration.

Multiphase Poroelastic Finite Element Models for Soft Tissue Structures

1992 ◽  
Vol 45 (6) ◽  
pp. 191-218 ◽  
Author(s):  
Bruce R. Simon
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Material Behavior ◽  
Constitutive Law ◽  
Finite Strains ◽  
Finite Element Models ◽  
Tissue Fluid ◽  
Biomechanical Models ◽  
Highly Nonlinear ◽  
Tissue Structures

During the last two decades, biological structures with soft tissue components have been modeled using poroelastic or mixture-based constitutive laws, i.e., the material is viewed as a deformable (porous) solid matrix that is saturated by mobile tissue fluid. These structures exhibit a highly nonlinear, history-dependent material behavior; undergo finite strains; and may swell or shrink when tissue ionic concentrations are altered. Given the geometric and material complexity of soft tissue structures and that they are subjected to complicated initial and boundary conditions, finite element models (FEMs) have been very useful for quantitative structural analyses. This paper surveys recent applications of poroelastic and mixture-based theories and the associated FEMs for the study of the biomechanics of soft tissues, and indicates future directions for research in this area. Equivalent finite-strain poroelastic and mixture continuum biomechanical models are presented. Special attention is given to the identification of material properties using a porohyperelastic constitutive law and a total Lagrangian view for the formulation. The associated FEMs are then formulated to include this porohyperelastic material response and finite strains. Extensions of the theory are suggested in order to include inherent viscoelasticity, transport phenomena, and swelling in soft tissue structures. A number of biomechanical research areas are identified, and possible applications of the porohyperelastic and mixture-based FEMs are suggested.

Development of specimen-specific finite element models of human vertebrae for the analysis of vertebroplasty

2008 ◽  
Vol 222 (2) ◽  
pp. 221-228 ◽  
Author(s):  
V N Wijayathunga ◽  
A C Jones ◽  
R J Oakland ◽  
N R Furtado ◽  
R M Hall ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Bulk Material ◽  
Image Data ◽  
Finite Element Models ◽  
Micro Computed Tomography ◽  
Bone Material ◽  
Automated Methods ◽  
Pmma Cement ◽  
Good Agreement

The aim of this study was to determine the accuracy of specimen-specific finite element models of untreated and cement-augmented vertebrae by direct comparison with experimental results. Eleven single cadaveric vertebrae were imaged using micro computed tomography (mCT) and tested to failure in axial compression in the laboratory. Four of the specimens were first augmented with PMMA cement to simulate a prophylactic vertebroplasty. Specimen-specific finite element models were then generated using semi-automated methods. An initial set of three untreated models was used to determine the optimum conversion factors from the image data to the bone material properties. Using these factors, the predicted stiffness and strength were determined for the remaining specimens (four untreated, four augmented). The model predictions were compared with the corresponding experimental data. Good agreement was found with the non-augmented specimens in terms of stiffness (root-mean-square (r.m.s.) error 12.9 per cent) and strength (r.m.s. error 14.4 per cent). With the augmented specimens, the models consistently overestimated both stiffness and strength (r.m.s. errors 65 and 68 per cent). The results indicate that this method has the potential to provide accurate predictions of vertebral behaviour prior to augmentation. However, modelling the augmented bone with bulk material properties is inadequate, and more detailed modelling of the cement region is required to capture the bone—cement interactions if the models are to be used to predict the behaviour following vertebroplasty.

scholarly journals Finite element models can reproduce the effect of nucleotomy on the multi-axial compliance of human intervertebral discs

2020 ◽  
Vol 23 (13) ◽  
pp. 934-944
Author(s):  
Marc A. Stadelmann ◽  
Roland Stocker ◽  
Ghislain Maquer ◽  
Sven Hoppe ◽  
Peter Vermathen ◽  
...  
Keyword(s):  
Finite Element ◽  
Intervertebral Discs ◽  
Finite Element Models

scholarly journals The Verification of Human Lumbar Vertebrae and Intervertebral Disc Finite Element Models under Mechanical Forces

2021 ◽  
Vol 15 ◽  
pp. 1-10
Author(s):  
Mohankumar Palaniswamy ◽  
Anis Suhaila Shuib ◽  
Khai Ching Ng ◽  
Shajan Koshy
Keyword(s):  
Finite Element ◽  
Lumbar Vertebrae ◽  
Well Being ◽  
Intervertebral Discs ◽  
Finite Element Models ◽  
Geometrical Analysis ◽  
Total Deformation ◽  
Element Analysis ◽  
Significant Difference ◽  
Validation Procedure

Bone, being nonhomogeneous in nature need a complicated and time-consuming process to undergo computed simulation like finite element analysis. To overcome this hurdle, assuming a nonhomogeneous model as homogeneous could be a solution. The objective of this study is to focus on developing a homogeneous human lumbar finite element models and verify them under mechanical force by measuring disc stress, disc strain, disc deformation, total strain, and total deformation. Experimental and geometrical analysis were performed before verifying the lumbar model. To verify the models’ reliability, nonhomogeneous lumbar models were also developed. Five different static structural simulations were performed on four lumbar segments, and twenty parameters were measured. Numerically, out of twenty, eighteen parameters showed very less or no significant difference between homogeneous and nonhomogeneous models of the intervertebral discs and lumbar vertebrae. At the same time, proper caution to be provided while examining the results. With this validation procedure, researchers can process artifact images to get more information which enables them to contribute to the patient’s well-being.

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