Biomechanical Effects of Chiropractic-Based Distraction Therapy on the Behavior of Healthy and Degenerated Cervical Discs: A Finite Element Model Analysis

2009 ◽  
Author(s):  
Mozammil Hussain ◽  
Ralph E. Gay ◽  
Kai-Nan An ◽  
Rodger Tepe
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Neck Pain ◽  
Finite Element Model ◽  
Disc Degeneration ◽  
Element Model ◽  
Model Analysis ◽  
Biochemical Changes ◽  
Tissue Properties ◽  
Disc Tissue

Many neck pain complaints are associated with degenerated discs in cervical spine. Disc degeneration (DD) consists of cascading stages of events with complex changes in disc tissue properties. This results in deterioration of the ability of the disc to perform its function normally. Several biomechanical and biochemical changes occur in the disc with degeneration. Increase in motion segment stiffness and peak stresses in the posterior annulus are some of the gross changes that occur in the disc with degeneration.

Incomplete Fibers Affect Disc Biomechanics Higher Than the Fibers With Laxity: A Finite Element Model Analysis

2011 ◽  
Author(s):  
Mozammil Hussain
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Load Transfer ◽  
Element Model ◽  
Model Analysis ◽  
Main Function ◽  
Stress Distributions ◽  
Disc Tissue ◽  
Tissue Matrix ◽  
Stress Patterns

Disc morphological disruptions — incomplete length and laxity in annular fibers — affect the behavior of the disc tissues in different ways. These changes in fibers alter the main function of the disc — inter-segmental load transfer along the spine — by affecting the surrounding extracellular disc tissue matrix. Tissues surrounding the altered fibers experience variations in stress distributions and the biomechanical reasoning behind variations in stress patterns may be multifactorial. While incomplete fibers are found in both healthy and aged discs with higher occurrences in the later ones [1], laxity in fibers is a progressive degenerative property [2]. How much the fiber incompleteness relative to the laxity in fibers contributes to the disc biomechanics remains to be clearly quantified?

Corpectomy versus discectomy for the treatment of multilevel cervical spine pathology: a finite element model analysis

2012 ◽  
Vol 12 (5) ◽  
pp. 401-408 ◽  
Author(s):  
Mozammil Hussain ◽  
Ahmad Nassr ◽  
Raghu N. Natarajan ◽  
Howard S. An ◽  
Gunnar B.J. Andersson
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Finite Element Model ◽  
Element Model ◽  
Model Analysis ◽  
Spine Pathology

FEBio finite element model of a pediatric cervical spine

2021 ◽  
pp. 1-7
Author(s):  
Sean M. Finley ◽  
J. Harley Astin ◽  
Evan Joyce ◽  
Andrew T. Dailey ◽  
Douglas L. Brockmeyer ◽  
...  
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Finite Element Model ◽  
Material Properties ◽  
Surgical Simulation ◽  
Element Model ◽  
Axial Stiffness ◽  
Published Data ◽  
Axial Tension ◽  
Flexion Extension

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.

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

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.

scholarly journals Computer Simulation of Female Urinary Incontinence

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Yingchun Zhang ◽  
Gerald W. Timm ◽  
Arthur G. Erdman
Keyword(s):  
Finite Element ◽  
Urinary Incontinence ◽  
Finite Element Model ◽  
Element Model ◽  
Physical Activities ◽  
Sample Population ◽  
Force Level ◽  
Female Pelvis ◽  
Tissue Properties ◽  
Mechanical Tissue

Objectives: The purpose of this study is to establish pressure, distension and other parameters involved that produce tissue injury during vigorous physical activities in women, so that superior methods and devices for diagnosing and treating urinary incontinence (UI) can be created. Background: A higher prevalence of daily UI in a female athlete population was found compared to that of a randomly selected and age matched sample population, but the mechanism of UI is not clearly understood. Methods: Mechanical tissue properties of affected organ structures were determined by using specimens from cadavers. A realistic geometric model of the female pelvis was developed from patients’ specific CT images. The finite element model was built by combining the mechanical tissue properties and the geometry of organs involved, and the finite element analysis (FEA) was then performed using ABAQUS 6.7 to simulate the biomechanical response of the female pelvis during physical activities. Results: Tissue specimens from 11 cadavers were tested which included specimens of the bladder, uterus, pelvic muscle, vagina and urethra. A finite element model was built with approximately 500,000 tetrahedral elements. The force level and resulting organ displacements in the female pelvis during physical activities were investigated successfully by using the FEA method. Discussion: The knowledge of force level and organ displacements during physical activities helps to understand the mechanisms of UI occurring during physical activities.

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