scholarly journals Biomechanical Analysis of the Spine in Diffuse Idiopathic Skeletal Hyperostosis: Finite Element Analysis

2021 ◽  
Vol 11 (19) ◽  
pp. 8944
Author(s):  
Norihiro Nishida ◽  
Fei Jiang ◽  
Junji Ohgi ◽  
Masahiro Fuchida ◽  
Rei Kitazumi ◽  
...  
Keyword(s):  
Finite Element ◽  
Diffuse Idiopathic Skeletal Hyperostosis ◽  
Three Dimensional ◽  
Intervertebral Discs ◽  
Biomechanical Analysis ◽  
Radius Of Curvature ◽  
Minor Trauma ◽  
Element Analysis ◽  
Spine Model ◽  
External Forces

Patients with diffuse idiopathic skeletal hyperostosis (DISH) develop fractures of the vertebral bodies, even in minor trauma, because of the loss of flexibility, which causes difficulties in fusing vertebrae; therefore, the diagnosis of spine injuries may be delayed. We used the three-dimensional finite element method to add data on ossification to the healthy vertebral model in order to investigate how stress in intervertebral discs changes with bone shape and whether these changes present any risk factors. A healthy spine model and a DISH flat model (T8–sacrum) were generated from medical images. As an ossified hypertrophic model, T11–T12 was cross-linked with hypertrophic ossification, and hypertrophy was found to be 5 and 10 mm. An ossifying hypertrophic groove model (5 and 10 mm) was created at T11–T12 and T11–L1. A groove was created at the center of T12, and the radius of curvature of the groove was set to 1 and 2.5 mm. An extension force and flexion force were applied to the upper part of T8, assuming that external forces in the direction of flexion and extension were applied to the spine. Stresses were greater in the DISH flat model than in the healthy model. In the hypertrophic ossification model, the stress on the vertebral body was similar to greater ossification in extension and flexion. In the ossified hypertrophic groove model, the stress at the center of the groove increased. In DISH, vertebrae are more susceptible to stress. Furthermore, depending on the morphology of ossification, stresses on the vertebrae and intervertebral discs differed even with similar loads. An examination of ossification geometry may help surgeons decide the thoracolumbar spine’s stress elevated position in patients with DISH, thereby contributing to the understanding of the pathogenesis of pain.

scholarly journals Finite element and biomechanical analysis of risk factors for implant failure during tension band plating

2020 ◽  
Vol 48 (11) ◽  
pp. 030006052097207
Author(s):  
Jing Ding ◽  
Fei Wang ◽  
Fangchun Jin ◽  
Zhen-kai Wu ◽  
Pin-quan Shen
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Biomechanical Model ◽  
Element Model ◽  
Tension Band ◽  
Biomechanical Analysis ◽  
Implant Failure ◽  
Element Analysis

Objective Tension band plating has recently gained widespread acceptance as a method of correcting angular limb deformities in skeletally immature patients. We examined the role of biomechanics in procedural failure and devised a new method of reducing the rate of implant failure. Methods In the biomechanical model, afterload (static or cyclic) was applied to each specimen. The residual stress of the screw combined with different screw sizes and configurations were measured and compared by X-ray diffraction. With regard to static load and similar conditions, the stress distribution was analyzed according to a three-dimensional finite element model. Results The residual stress was close to zero in the static tension group, whereas it was very high in the cyclic load group. The residual stress of screws was significantly lower in the convergent group and parallel group than in the divergent group. The finite element model showed similar results. Conclusions In both the finite element analysis and biomechanical tests, the maximum stress of the screw was concentrated at the position where the screws enter the cortex. Cyclic loading is the primary cause of implant failure.

Three-Dimensional Elastic-Plastic Finite-Element Analysis of the Flattening of Wire Between Plain Rolls*

2000 ◽  
Vol 123 (3) ◽  
pp. 397-404 ◽  
Author(s):  
H. Utsunomiya ◽  
P. Hartley ◽  
I. Pillinger
Keyword(s):  
Finite Element ◽  
Elastic Recovery ◽  
Three Dimensional ◽  
Lateral Spread ◽  
Radius Of Curvature ◽  
Forming Process ◽  
Empirical Formulas ◽  
Element Analysis ◽  
Finite Element Program ◽  
Elastic Plastic

It is normal industrial practice to roll round edged flat wires from round circular wires using plain rolls. Although this is not a complex type of metal forming process, the internal deformation is highly three-dimensional. It is important to be able to determine the lateral spread, elongation and final profile precisely. In this paper, this process has been analyzed using an elastic-plastic finite element program. Firstly, algorithms for integrating the constitutive equations, i.e., return mapping algorithms, are evaluated to determine the most accurate technique. Then, the influences of friction and reduction in thickness on the deformation characteristics are investigated. The lateral spread and the radius of curvature of the free surface are quantitatively in reasonable agreement with those obtained from empirical formulas. The lateral spread increases with friction and with reduction. The variation of elongation in the roll bite is investigated in detail. It is found that the elongation is not uniformly distributed across the cross section. After passing the roll gap, the distribution is compensated by the elastic recovery of wire, otherwise it may cause edge waves.

scholarly journals Evaluation of Useful Biomechanical Parameters On Scoliosis Using Finite Element Method

2020 ◽  
Vol 7 (2) ◽  
pp. 71-80
Author(s):  
Midiya Khademi ◽  
Ali Nikoo
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Cobb Angle ◽  
Vertebral Column ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Spine Model ◽  
Patient Model ◽  
The One ◽  
External Forces

Background: Scoliosis is a deformity of the vertebral column, and shape-changing and deformation of the spine are some critical factors that can cause this abnormality. This condition causes some problems like deflection of the spine in the coronal plane toward medial or lateral. Cobb angle is a measurement for the investigation of the severity of this condition. There are several effective therapies suggested for the reduction of the Cobb angle for patients who has this abnormality. It has suggested that before applying external forces to correct this condition, biomechanical evaluation of this deformity, can be useful during diagnosis. Methods: The purpose of this study is the evaluation of Cobb angle correction using external forces. For this aim first, the dimensional data of the patient’s vertebrae are extracted from CT-scan images using Mimics software, and the vertebral column modeled in Catia software for finite element analysis (FEA). Afterward, the model was imported into Abaqus software to evaluate the effect of forces on the spine model. The study was done by assuming two cases for the spine, one-piece (without a nucleus) and two-piece (with a nucleus) intervertebral disc. Results: After studying the results of this simulation, it concluded that after applying gravity force to these two cases, the percentage of Cobb angle’s reduction was about 0.05 for a two-piece disc and about -0.18 for the one-piece disc. Therefore, the two-piece disc assumption was better for analyzing this parameter. The results of maximum displacement and von misses stress show that the two-piece disc is accurate. Conclusion: In order to investigate which analysis is appropriate to be selected, choosing a twopiece intervertebral disc model is superlative. Whether our goal is only to examine the stress which is present in the patient model, choosing a one-piece disc is a more optimal duo to take much less time.

2-D Finite Element Analysis of Engineering Components

1995 ◽  
Author(s):  
Ajay Garg
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Elements ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Radius Of Curvature ◽  
Element Analysis ◽  
Element Mesh ◽  
Require Time ◽  
Simple Boundary

Abstract Design and analysis of engineering components can be categorized under the theory of continuum mechanics, plates/shells or beams. Closed form solutions for determining deformations and stresses are available for simple structures with simple boundary conditions. In the cases of complex structures, boundary conditions and loads, analytical solutions are not readily available. Finite element analysis (FEA) can be performed to resolve the simulation barrier of these analytically indeterminate structures. Similar to analytical approach, FEA can simulate the components through solid, plate/shell or beam elements. Finite element analysis through 3-D solid elements is costly and may require time in weeks, which may not be at the disposal of an analyst. Axi-symmetric components and components with an infinite radius of curvature (flat surfaces), but with complex cross sections can be modeled by 2-D axi-symmetric and plate elements, respectively. Two dimensional finite elements require less time and hardware support than three-dimensional elements. Two development cases of successful application of 2-D finite elements instead of 3-D finite elements are discussed. Experimental and analytical verification of FEA results, and guidelines for checking finite element mesh discretization error are presented.

Establishment and validation of finite element model of ossification of cervical posterior longitudinal ligament with intervertebral fusion

2020 ◽  
Author(s):  
Li Hui ◽  
Liu Huiqing ◽  
Zhang Yaning
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Posterior Longitudinal Ligament ◽  
Intervertebral Discs ◽  
Biomechanical Analysis ◽  
Intervertebral Fusion ◽  
Dimensional Finite Element

Abstract [Background ]: To establish a three-dimensional finite element model of ossification of the posterior longitudinal ligament of the cervical spine with intervertebral fusion and verify its effectiveness, and provide a platform for finite element calculation and biomechanical analysis in the later stage.[Method]: Select the Department of Spinal Surgery, Linfen People's Hospital A volunteer imported 719 DICOM format images of cervical spine CT scans into Mimics modeling software to build a preliminary 3D model in the stl format, and used Geomagic Studio 2013 software to refine and refine the 3D model to smooth out noise and generate NURBS surfaces The model was then imported into the finite element analysis software Ansys workbench 15.0, adding ligaments and intervertebral discs, meshing, assigning material properties, and simulating 6 activities of the human cervical spine, and comparing them with references.[Results]: A total of 7 Cervical vertebral body, 1 thoracic vertebral body, 5 intervertebral discs and ligaments, etc., with a total of 320512 nodes and 180905 units. It has a realistic appearance, high degree of detail reduction, and ossification of the cervical longitudinal longitudinal ligament with good geometric similarity Incorporate a three-dimensional finite element model of intervertebral fusion. In flexion and extension, left and right lateral flexion, and axial rotation activity compared with references, there is not much difference.[Conclusion]: OPLL merger interbody fusion dimensional finite element model has good mechanical and geometric similarity after similarity cervical established in this study, the model can provide a platform for the latter to further biomechanical analysis.

scholarly journals The Effects of Physiological Biomechanical Loading on Intradiscal Pressure and Annulus Stress in Lumbar Spine: A Finite Element Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Siti Nurfaezah Zahari ◽  
Mohd Juzaila Abd Latif ◽  
Nor Raihanah Abdull Rahim ◽  
Mohammed Rafiq Abdul Kadir ◽  
Tunku Kamarul
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Three Dimensional ◽  
Element Model ◽  
Intervertebral Discs ◽  
Intradiscal Pressure ◽  
Element Analysis ◽  
Physiological Loading ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The present study was conducted to examine the effects of body weight on intradiscal pressure (IDP) and annulus stress of intervertebral discs at lumbar spine. Three-dimensional finite element model of osseoligamentous lumbar spine was developed subjected to follower load of 500 N, 800 N, and 1200 N which represent the loads for individuals who are normal and overweight with the pure moments at 7.5 Nm in flexion and extension motions. It was observed that the maximum IDP was 1.26 MPa at L1-L2 vertebral segment. However, the highest increment of IDP was found at L4-L5 segment where the IDP was increased to 30% in flexion and it was more severe at extension motion reaching to 80%. Furthermore, the maximum annulus stress also occurred at the L1-L2 segment with 3.9 MPa in extension motion. However, the highest increment was also found at L4-L5 where the annulus stress increased to 17% in extension motion. Based on these results, the increase of physiological loading could be an important factor to the increment of intradiscal pressure and annulus fibrosis stress at all intervertebral discs at the lumbar spine which may lead to early intervertebral disc damage.

scholarly journals A comparative biomechanical analysis of suprapectineal and infrapectineal fixation on acetabular anterior column fracture by finite element modeling

2019 ◽  
Author(s):  
MEHMET YÜCENS ◽  
KADİR BAHADIR ALEMDAROĞLU ◽  
AHMET ÖZMERİÇ ◽  
SERKAN İLTAR ◽  
AHMET ÖZGÜR YILDIRIM ◽  
...  
Keyword(s):  
Finite Element ◽  
Plate Fixation ◽  
Three Dimensional ◽  
Fracture Line ◽  
Biomechanical Analysis ◽  
Vertical Shear ◽  
Anterior Column ◽  
Fixation Method ◽  
Stable Fixation ◽  
Element Analysis

Background: The aim of this study is to compare the stability and implant stresses of suprapectineal plate with infrapectineal plate in three subconfigurations of the screw types. Methods: The stabilities of different fixation methods were compared by finite-element analysis on six models. Three infrapectineal models and three suprapectineal models each with locked, unlocked or combined screws were employed. Three-dimensional finite element stress analysis was performed by using isotropic materials with a load of 2.3 kN applied at standing positions. Motion at the fracture line was measured on four different points that are located at pubic and iliac side of the fracture line. Results: Infrapectineal plate fixation with unlocked screws was found to be the most stable fixation method with 0.006 mm displacement of fragments in all axes at standing positions. Suprapectineal unlocked method was found to be the most unstable in standing positions with maximum distraction values of 0.46 mm vertical shear movement in x-axis, -0.14 mm distraction in y-axis and -0.33 mm lateral shear in z-axis. Conclusions: To our results infrapectineal unlocked plate supplies the most stable fixation with least implant stress in contrary to the suprapectineal unlocked plate, which has the lowest stability and highest implant stresses. Keywords: Acetabular fracture; anterior column; suprapectineal; infrapectineal; fixation; finite element.

Three-Dimensional Finite Element Analysis of Dental Implant Threads

2018 ◽  
Vol 876 ◽  
pp. 138-146
Author(s):  
Aswin Yodrux ◽  
Nantakrit Yodpijit ◽  
Manutchanok Jongprasithporn
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dental Implant ◽  
Three Dimensional ◽  
Biomechanical Analysis ◽  
3D Fem ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
States Patent

This paper presents the use of Three-Dimensional Finite Element Method (3D-FEM) for biomechanical analysis on dental implant prosthetics. This research focuses on three patents of threads of dental implant systems from United States Patent and Trademark Office (USPTO) and two new conceptual design models. The three-dimensional finite element analysis is performed on dental implant models, with compressive forces of 50, 100, and 150 N, and a shear force of 20 N with the force angle of 60 degrees with the normal line respectively. The Stress and displacement analysis is conducted at four different areas (abutment, implant, cortical bone, and cancellous bone). Findings from this research provide guidelines for new product design of dental implant prosthetics with stress distribution and displacement characteristics.

scholarly journals Bone Stress-Strain State Evaluation Using CT Based FEM

2021 ◽  
Vol 7 ◽  
Author(s):  
Oleg V. Gerasimov ◽  
Nikita V. Kharin ◽  
Artur O. Fedyanin ◽  
Pavel V. Bolshakov ◽  
Maxim E. Baltin ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Numerical Modeling ◽  
Three Dimensional ◽  
Physical Experiment ◽  
Qualitative Assessment ◽  
Element Analysis ◽  
Crack Location ◽  
External Forces ◽  
Tomography Data

Nowadays, the use of a digital prototype in numerical modeling is one of the main approaches to calculating the elements of an inhomogeneous structure under the influence of external forces. The article considers a finite element analysis method based on computed tomography data. The calculations used a three-dimensional isoparametric finite element of a continuous medium developed by the authors with a linear approximation, based on weighted integration of the local stiffness matrix. The purpose of this study is to describe a general algorithm for constructing a numerical model that allows static calculation of objects with a porous structure according to its computed tomography data. Numerical modeling was carried out using kinematic boundary conditions. To evaluate the results obtained, computational and postprocessor grids were introduced. The qualitative assessment of the modeling data was based on the normalized error. Three-point bending of bone specimens of the pig forelimbs was considered as a model problem. The numerical simulation results were compared with the data obtained from a physical experiment. The relative error ranged from 3 to 15%, and the crack location, determined by the physical experiment, corresponded to the area where the ultimate strength values were exceeded, determined by numerical modeling. The results obtained reflect not only the effectiveness of the proposed approach, but also the agreement with experimental data. This method turned out to be relatively non-resource-intensive and time-efficient.

Sign in / Sign up

Export Citation Format

Share Document