Moment Prediction for Evaluating Stability of the Upper Cervical Spine Fixed with Wires Using Finite Element Analysis

2006 ◽  
Vol 321-323 ◽  
pp. 1098-1102
Author(s):  
Hyo Shin Kim ◽  
Youn Soo Kim ◽  
Joung H. Mun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cervical Spine ◽  
High Rate ◽  
Posterior Fixation ◽  
Upper Cervical Spine ◽  
Element Analysis ◽  
Surgical Methods ◽  
Upper Cervical ◽  
The Moment

This study was aimed at predicting moments with respect to diameters of wires for evaluating stability of the upper cervical spine fixed with wires based on the finite element analysis. In case of the severe atlanto-axial instability, several surgical methods have been tried and the posterior fixation using wires has been widely used because of the sufficient stability and high rate of bony adhesion. The diameters of wires applied in this study were 0.7 mm, 0.9 mm and 1.25 mm. 1.5 Nm is the moment for the normal physiological range of motion of the upper cervical spine in cadaver models. However, if this moment is applied to the occiput, an excessive load occurs at the occipito-atlantal joint and clinical problems can break out realistically. Thus, it is necessary to predict moments for evaluating stability with respect to diameters of wires. The results showed that 0.7 mm wire allowed the biggest moment while 1.25 mm wire allowed the smallest moment. In addition, the upper cervical spine fused with wires was stabilized effectively as the load increased.

Investigation of Upper Cervical Spine Injury due to Frontal and Rear Impact Loading Using Finite Element Analysis

2014 ◽  
Author(s):  
Tanvir Mustafy ◽  
Kodjo Moglo ◽  
Samer Adeeb ◽  
Marwan El-Rich
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Motor Vehicle ◽  
Spine Injury ◽  
Upper Cervical Spine ◽  
Fe Model ◽  
Facet Joints ◽  
Element Analysis ◽  
Effective Prevention ◽  
Upper Cervical

Predicting neck response and injury resulting from motor vehicle crashes is essential for improving occupant protection, effective prevention, and in the evaluation and treatment of spinal injuries. Injury mechanism of upper cervical spine due to frontal/rear-end impacts was studied using Finite Element (FE) analyses. A FE model of ligamentous (devoid of muscles) occipito-C3 cervical spine was developed. Time and rate-dependent material laws were used for assessing bone and ligament failure. Frontal and rear-end impact loads at two rates of 5G and 10G accelerations were applied to analyze the model response in terms of stress distribution, intradiscal pressure change, and contact pressure in facet joints. Failure occurrence and initiation instants were investigated. Frontal and rear-end impacts increased stresses significantly producing failure in most components for both rates. However, transverse ligament and C2-vertebral endplate only failed under rear-end impact. No failure occurred in cortical bone, dens, disc, anterior or posterior longitudinal ligaments. The spine is more prone to injury under rear-end impact as most of the spinal components failed and failure started earlier. Ligaments and facet joints are the most vulnerable components of the upper cervical spine when subjected to frontal/rear end impacts and injury may occur at small ranges of displacement/rotation.

Biomechanics of a posture-controlling cervical artificial disc: mechanical, in vitro, and finite-element analysis

2010 ◽  
Vol 28 (6) ◽  
pp. E11 ◽  
Author(s):  
Neil R. Crawford ◽  
Jeffery D. Arnett ◽  
Joshua A. Butters ◽  
Lisa A. Ferrara ◽  
Nikhil Kulkarni ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cervical Spine ◽  
Postural Control ◽  
Range Of Motion ◽  
Computer Modeling ◽  
Mechanical Testing ◽  
Artificial Disc ◽  
Element Analysis

Different methods have been described by numerous investigators for experimentally assessing the kinematics of cervical artificial discs. However, in addition to understanding how artificial discs affect range of motion, it is also clinically relevant to understand how artificial discs affect segmental posture. The purpose of this paper is to describe novel considerations and methods for experimentally assessing cervical spine postural control in the laboratory. These methods, which include mechanical testing, cadaveric testing, and computer modeling studies, are applied in comparing postural biomechanics of a novel postural control arthroplasty (PCA) device versus standard ball-and-socket (BS) and ball-in-trough (BT) arthroplasty devices. The overall body of evidence from this group of tests supports the conclusion that the PCA device does control posture to a particular lordotic position, whereas BS and BT devices move freely through their ranges of motion.

Incorporating ligament laxity in a finite element model for the upper cervical spine

2017 ◽  
Vol 17 (11) ◽  
pp. 1755-1764 ◽  
Author(s):  
Timothy L. Lasswell ◽  
Duane S. Cronin ◽  
John B. Medley ◽  
Parham Rasoulinejad
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Finite Element Model ◽  
Element Model ◽  
Upper Cervical Spine ◽  
Upper Cervical ◽  
Ligament Laxity

INFLUENCE OF THE CONSTITUTIVE MATERIAL BEHAVIOR MODEL ASSIGNED TO THE ANNULUS FIBROSUS AND THE NUCLEUS PULPOSUS ON THE BIOMECHANICAL PERFORMANCE OF A MODEL OF THE CERVICAL SPINE: A FINITE ELEMENT ANALYSIS STUDY

2010 ◽  
Vol 10 (01) ◽  
pp. 151-166 ◽  
Author(s):  
YUAN LI ◽  
GLADIUS LEWIS
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cervical Spine ◽  
Annulus Fibrosus ◽  
Constitutive Models ◽  
Material Behavior ◽  
Elastic Behavior ◽  
Behavior Model ◽  
Element Analysis ◽  
Constitutive Material

One feature of the literature on finite element analysis of models of cervical spine segment(s) is that an assortment of constitutive models has been used for the elastic behavior of the annulus fibrosus (AF) and the nucleus pulposus (NF). The extent to which the model assigned to each of these tissues affects the values of the biomechanical parameters of interest of the model is lacking. This issue was the subject of the present study. We used a three-dimensional solid model of the C4–C6 motion segment units (which comprised the vertebral bodies, the bony posterior elements (transverse processes, pedicles, laminae, spinous processes, and facet joints), the intervertebral discs (IVDs), the endplates, and the five major ligaments) and eight combinations of constitutive models. It was found that (1) the influence of the constitutive material models used depended on the tissue considered, with some, such as the posterior endplate of C5 and the cancellous bone of C6, showing marked sensitivity, while others, such as the cancellous bone of C4 and the cortical bone of C5, were moderately affected; and (2) the biomechanical performance of the spine model is more sensitive to the material behavior model used for the AF than it is to that used for the NF. These results suggest that experimental and computational efforts expended in obtaining the most appropriate constitutive model for the elastic behavior of the two parts of the IVD, in particular the AF, are justified.

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