FEBio finite element model of a pediatric cervical spine

OBJECTIVE The underlying biomechanical differences between the pediatric and adult cervical spine are incompletely understood. Computational spine modeling can address that knowledge gap. Using a computational method known as finite element modeling, the authors describe the creation and evaluation of a complete pediatric cervical spine model. METHODS Using a thin-slice CT scan of the cervical spine from a 5-year-old boy, a 3D model was created for finite element analysis. The material properties and boundary and loading conditions were created and model analysis performed using open-source software. Because the precise material properties of the pediatric cervical spine are not known, a published parametric approach of scaling adult properties by 50%, 25%, and 10% was used. Each scaled finite element model (FEM) underwent two types of simulations for pediatric cadaver testing (axial tension and cardinal ranges of motion [ROMs]) to assess axial stiffness, ROM, and facet joint force (FJF). The authors evaluated the axial stiffness and flexion-extension ROM predicted by the model using previously published experimental measurements obtained from pediatric cadaveric tissues. RESULTS In the axial tension simulation, the model with 50% adult ligamentous and annulus material properties predicted an axial stiffness of 49 N/mm, which corresponded with previously published data from similarly aged cadavers (46.1 ± 9.6 N/mm). In the flexion-extension simulation, the same 50% model predicted an ROM that was within the range of the similarly aged cohort of cadavers. The subaxial FJFs predicted by the model in extension, lateral bending, and axial rotation were in the range of 1–4 N and, as expected, tended to increase as the ligament and disc material properties decreased. CONCLUSIONS A pediatric cervical spine FEM was created that accurately predicts axial tension and flexion-extension ROM when ligamentous and annulus material properties are reduced to 50% of published adult properties. This model shows promise for use in surgical simulation procedures and as a normal comparison for disease-specific FEMs.

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A Three-Dimensional Dynamic Finite Element Model of the Prosthetic Knee Joint: Simulation of Joint Laxity and Kinematics

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/095441105x34437 ◽

2005 ◽

Vol 219 (6) ◽

pp. 415-424 ◽

Cited By ~ 14

Author(s):

M Barink ◽

A van Kampen ◽

M de Waal Malefijt ◽

N Verdonschot

Keyword(s):

Finite Element ◽

Knee Joint ◽

Finite Element Model ◽

Mathematical Formulation ◽

Three Dimensional ◽

Element Model ◽

Joint Kinematics ◽

Published Data ◽

Dynamic Finite Element ◽

Flexion Extension

For testing purposes of prostheses at a preclinical stage, it is very valuable to have a generic modelling tool, which can be used to optimize implant features and to avoid poor designs being launched on to the market. The modelling tool should be fast, efficient, and multipurpose in nature; a finite element model is well suited to the purpose. The question posed in this study was whether it was possible to develop a mathematically fast and stable dynamic finite element model of a knee joint after total knee arthroplasty that would predict data comparable with published data in terms of (a) laxities and ligament behaviour, and (b) joint kinematics. The soft tissue structures were modelled using a relatively simple, but very stable, composite model consisting of a band reinforced with fibres. Ligament recruitment and balancing was tested with laxity simulations. The tibial and patellar kinematics were simulated during flexion-extension. An implicit mathematical formulation was used. Joint kinematics, joint laxities, and ligament recruitment patterns were predicted realistically. The kinematics were very reproducible and stable during consecutive flexion-extension cycles. Hence, the model is suitable for the evaluation of prosthesis design, prosthesis alignment, ligament behaviour, and surgical parameters with respect to the biomechanical behaviour of the knee.

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Development and initial evaluation of a finite element model of the pediatric craniocervical junction

Journal of Neurosurgery Pediatrics ◽

10.3171/2015.8.peds15334 ◽

2016 ◽

Vol 17 (4) ◽

pp. 497-503 ◽

Cited By ~ 6

Author(s):

Rinchen Phuntsok ◽

Marcus D. Mazur ◽

Benjamin J. Ellis ◽

Vijay M. Ravindra ◽

Douglas L. Brockmeyer

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Material Properties ◽

Element Model ◽

Axial Rotation ◽

Craniocervical Junction ◽

Lateral Bending ◽

Fem Method ◽

Flexion Extension ◽

Ligament Stiffness

OBJECT There is a significant deficiency in understanding the biomechanics of the pediatric craniocervical junction (CCJ) (occiput–C2), primarily because of a lack of human pediatric cadaveric tissue and the relatively small number of treated patients. To overcome this deficiency, a finite element model (FEM) of the pediatric CCJ was created using pediatric geometry and parameterized adult material properties. The model was evaluated under the physiological range of motion (ROM) for flexion-extension, axial rotation, and lateral bending and under tensile loading. METHODS This research utilizes the FEM method, which is a numerical solution technique for discretizing and analyzing systems. The FEM method has been widely used in the field of biomechanics. A CT scan of a 13-month-old female patient was used to create the 3D geometry and surfaces of the FEM model, and an open-source FEM software suite was used to apply the material properties and boundary and loading conditions and analyze the model. The published adult ligament properties were reduced to 50%, 25%, and 10% of the original stiffness in various iterations of the model, and the resulting ROMs for flexion-extension, axial rotation, and lateral bending were compared. The flexion-extension ROMs and tensile stiffness that were predicted by the model were evaluated using previously published experimental measurements from pediatric cadaveric tissues. RESULTS The model predicted a ROM within 1 standard deviation of the published pediatric ROM data for flexion-extension at 10% of adult ligament stiffness. The model's response in terms of axial tension also coincided well with published experimental tension characterization data. The model behaved relatively stiffer in extension than in flexion. The axial rotation and lateral bending results showed symmetric ROM, but there are currently no published pediatric experimental data available for comparison. The model predicts a relatively stiffer ROM in both axial rotation and lateral bending in comparison with flexion-extension. As expected, the flexion-extension, axial rotation, and lateral bending ROMs increased with the decrease in ligament stiffness. CONCLUSIONS An FEM of the pediatric CCJ was created that accurately predicts flexion-extension ROM and axial force displacement of occiput–C2 when the ligament material properties are reduced to 10% of the published adult ligament properties. This model gives a reasonable prediction of pediatric cervical spine ligament stiffness, the relationship between flexion-extension ROM, and ligament stiffness at the CCJ. The creation of this model using open-source software means that other researchers will be able to use the model as a starting point for research.

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Finite element analysis of middle cervical spine

10.32920/ryerson.14660517 ◽

2021 ◽

Author(s):

Noushin Bahramshahi

Keyword(s):

Spinal Cord ◽

Finite Element ◽

Cervical Spine ◽

Three Dimensional ◽

Spinal Column ◽

Element Model ◽

Published Data ◽

Element Analysis ◽

Flexion Extension ◽

Disc Bulge

The spinal cord may be injured through various spinal column injury patterns. However, the relationship between column injury pattern and cord damage is not well understood. This investigation was conducted to develop a detailed, asymmetric three-dimensional finite element model of the C3-C5 cervical spine. The model was validated by comparing the simulation results obtained in this study with experimental published data. Upon validation of the model, the spinal cord was included into the model the simulation were performed. The disc bulge in the model with spinal cord were measured and compared with the results of the model without spinal cord. The results showed that inclusion of the spinal cord reduced the amount of lateral disc bulged. The results of the analysis of the model with spinal cord showed that in compression, the anterior surface of spinal cord sees more displacement, stress and strain that posterior surface and vice versa for flexion/extension.

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Finite element analysis of middle cervical spine

10.32920/ryerson.14660517.v1 ◽

2021 ◽

Author(s):

Noushin Bahramshahi

Keyword(s):

Spinal Cord ◽

Finite Element ◽

Cervical Spine ◽

Three Dimensional ◽

Spinal Column ◽

Element Model ◽

Published Data ◽

Element Analysis ◽

Flexion Extension ◽

Disc Bulge

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Development and validation of a C0-C7 cervical spine finite element model

MATEC Web of Conferences ◽

10.1051/matecconf/201710813007 ◽

2017 ◽

Vol 108 ◽

pp. 13007

Author(s):

Wei Wei ◽

Yin Liu ◽

Xianping Du ◽

Na Li

Keyword(s):

Finite Element ◽

Cervical Spine ◽

Finite Element Model ◽

Element Model ◽

Development And Validation

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Biomechanical Effect of Lumbar Disc Degeneration Under Flexion/Extension: A Finite Element Model Study

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-176190 ◽

2007 ◽

Author(s):

Lissette M. Ruberté ◽

Raghu Natarajan ◽

Gunnar B. J. Andersson

Keyword(s):

Finite Element ◽

Lumbar Spine ◽

Finite Element Model ◽

Disc Degeneration ◽

Pathological Condition ◽

Lumbar Disc ◽

Element Model ◽

Adjacent Segment ◽

Lumbar Disc Degeneration ◽

Flexion Extension

Degenerative disc disease (DDD) is a progressive pathological condition observed in 60 to 80% of the population [1]. It involves changes in both the biochemistry and morphology of the intervertebral disc and is associated with chronic low back pain, sciatica and adult scoliosis [2,3]. The most accepted theory of the effects of DDD on the kinematics of the spine is that proposed by Kirkaldy-Willis and Farfan which states that the condition initiates as a temporary dysfunction, followed by instability and then re-stabilization as the disease progresses [4]. Although there is no clear relationship between disc degeneration and the mechanical behavior of the lumbar spine, abnormal motion patterns either in the form of increased motion or erratic motion have been reported from studies on human cadaveric motion segments [5,6]. To date however no study has looked at how disc degeneration affects the adjacent segment mechanics. IN vivo testing is difficult for these purposes given that specimens are generally obtained from people at the later stages of life and consequently often display multiple pathologies. A finite element model is a viable alternative to study the mechanics of the segments adjacent to the diseased disc. It is hypothesized that moderate degeneration at one level will alter the kinematics of the whole lumbar spine.

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Finite Element Model of the Human Knee Joint to Study Tibio-Femoral Contact Mechanics

10.1115/imece2000-2562 ◽

2000 ◽

Author(s):

Tammy Haut Donahue ◽

Maury L. Hull ◽

Mark M. Rashid ◽

Christopher R. Jacobs

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Degrees Of Freedom ◽

Soft Tissues ◽

Element Model ◽

Human Knee ◽

Human Knee Joint ◽

Solid Models ◽

Flexion Extension ◽

A New Technique

Abstract A finite element model of the tibio-femoral joint in the human knee was created using a new technique for developing accurate solid models of soft tissues (i.e. cartilage and menisci). The model was used to demonstrate that constraining rotational degrees of freedom other than flexion/extension when the joint is loaded in compression markedly affects the load distribution between the medial and lateral sides of the joint. The model also was used to validate the assumption that the bones can be treated as rigid.

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