Prediction of Biomechanical Parameters in the Lumbar Spine During Static Sagittal Plane Lifting

1998 ◽  
Vol 120 (2) ◽  
pp. 273-280 ◽  
Author(s):  
W. Z. Kong ◽  
V. K. Goel ◽  
L. G. Gilbertson
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Sagittal Plane ◽  
Thoracolumbar Spine ◽  
Force Model ◽  
Shear Stresses ◽  
Lumbar Region ◽  
Facet Joints ◽  
Vertebral Bodies ◽  
Biomechanical Parameters

A combined approach involving optimization and the finite element technique was used to predict biomechanical parameters in the lumbar spine during static lifting in the sagittal plane. Forces in muscle fascicles of the lumbar region were first predicted using an optimization-based force model including the entire lumbar spine. These muscle forces as well as the distributed upper body weight and the lifted load were then applied to a three-dimensional finite element model of the thoracolumbar spine and rib cage to predict deformation, the intradiskal pressure, strains, stresses, and load transfer paths in the spine. The predicted intradiskal pressures in the L3-4 disk at the most deviated from the in vivo measurements by 8.2 percent for the four lifting cases analyzed. The lumbosacral joint flexed, while the other lumbar joints extended for all of the four lifting cases studied (rotation of a joint is the relative rotation between its two vertebral bodies). High stresses were predicted in the posterolateral regions of the endplates and at the junctions of the pedicles and vertebral bodies. High interlaminar shear stresses were found in the posterolateral regions of the lumbar disks. While the facet joints of the upper two lumbar segments did not transmit any load, the facet joints of the lower two lumbar segments experienced significant loads. The ligaments of all lumbar motion segments except the lumbosacral junction provided only marginal moments. The limitations of the current model and possible improvements are discussed.

scholarly journals MDCT-Based Finite Element Analyses: Are Measurements at the Lumbar Spine Associated with the Biomechanical Strength of Functional Spinal Units of Incidental Osteoporotic Fractures along the Thoracolumbar Spine?

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 455
Author(s):  
Nico Sollmann ◽  
Nithin Manohar Rayudu ◽  
Long Yu Yeung ◽  
Anjany Sekuboyina ◽  
Egon Burian ◽  
...  
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Fracture Risk ◽  
Thoracolumbar Spine ◽  
Areal Bone Mineral Density ◽  
Mineral Density ◽  
Osteoporotic Vertebral Fractures ◽  
The Mean ◽  
Biomechanical Strength

Assessment of osteoporosis-associated fracture risk during clinical routine is based on the evaluation of clinical risk factors and T-scores, as derived from measurements of areal bone mineral density (aBMD). However, these parameters are limited in their ability to identify patients at high fracture risk. Finite element models (FEMs) have shown to improve bone strength prediction beyond aBMD. This study aims to investigate whether FEM measurements at the lumbar spine can predict the biomechanical strength of functional spinal units (FSUs) with incidental osteoporotic vertebral fractures (VFs) along the thoracolumbar spine. Multi-detector computed tomography (MDCT) data of 11 patients (5 females and 6 males, median age: 67 years) who underwent MDCT twice (median interval between baseline and follow-up MDCT: 18 months) and sustained an incidental osteoporotic VF between baseline and follow-up scanning were used. Based on baseline MDCT data, two FSUs consisting of vertebral bodies and intervertebral discs (IVDs) were modeled: one standardly capturing L1-IVD–L2-IVD–L3 (FSU_L1–L3) and one modeling the incidentally fractured vertebral body at the center of the FSU (FSU_F). Furthermore, volumetric BMD (vBMD) derived from MDCT, FEM-based displacement, and FEM-based load of the single vertebrae L1 to L3 were determined. Statistically significant correlations (adjusted for a BMD ratio of fracture/L1–L3 segments) were revealed between the FSU_F and mean load of L1 to L3 (r = 0.814, p = 0.004) and the mean vBMD of L1 to L3 (r = 0.745, p = 0.013), whereas there was no statistically significant association between the FSU_F and FSU_L1–L3 or between FSU_F and the mean displacement of L1 to L3 (p > 0.05). In conclusion, FEM measurements of single vertebrae at the lumbar spine may be able to predict the biomechanical strength of incidentally fractured vertebral segments along the thoracolumbar spine, while FSUs seem to predict only segment-specific fracture risk.

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.

Stress Analysis of the Lower Lumbar Spine Three-joint Complex According to Different Pelvic Incidences

2021 ◽  
Author(s):  
Qi Lai ◽  
Jun Yin ◽  
Zi Zhen Zhang ◽  
Jie Yang ◽  
Zongmiao Wan
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Pelvic Incidence ◽  
Facet Joint ◽  
The Other ◽  
Von Mises Stress ◽  
Facet Joints ◽  
Lower Lumbar Spine ◽  
Flexion Extension ◽  
Lower Lumbar

Abstract Background: Pelvic incidence is closely related to degeneration of the facet joint and intervertebral disc and is related to the orientation of the facet joints. Currently, very few studies have been conducted on the force analysis of the three-joint complex in patients with different pelvic incidence measurements under different sports postures. We designed this study to better assess the influence of pelvic incidence on the stress of the lumbar three-joint complex. Finite element analysis can provide a biomechanical basis for the relationship between different pelvic incidences and degenerative diseases of the lower lumbar spine.Methods: We developed three nonlinear finite element models of the lumbar spine (L1-S1) with different pelvic incidences (27.44°, 47.05°, and 62.28°) and validated them to study the biomechanical response of facet joints and intervertebral discs with a follower preload of 400 N, under different torques (5 Nm, 10 Nm, and 15 Nm), and compared the stress of the three-joint complex of the lower lumbar spine (L3-S1) in different positions (flexion-extension, left-right bending, and left-right torsion).Results: In the flexion position, the stress of the disc in the low pelvic incidence model was the largest among the three models; the stress of the facet joint in the high pelvic incidence model was the largest among the three groups during the extension position. During torsion, the intradiscal pressure of the high pelvic incidence model was higher than that of the other two models in the L3/4 segment, and the maximum von Mises stress of the annulus fibrosus in the L5/S1 segment with a large pelvic incidence was greater than that of the other two models.Conclusions: Pelvic incidence is related to the occurrence and development of degenerative lumbar diseases. The stress of the lower lumbar facet joints and fibrous annulus of individuals with a high pelvic incidence is greater than that of individuals with a low pelvic incidence or a normal pelvic incidence. Although this condition only occurs in individual segments, to a certain extent, it can also reflect the influence of pelvic incidence on the force of the three-joint complex of the lower lumbar spine.

Statistical Shape and Alignment Modeling of the Lumbar Spine

2013 ◽  
Author(s):  
Justin F. M. Hollenbeck ◽  
Paul J. Rullkoetter ◽  
Christopher Cain ◽  
Clare K. Fitzpatrick ◽  
Peter J. Laz
Keyword(s):  
Lumbar Spine ◽  
Sagittal Plane ◽  
Shape Modeling ◽  
Component Placement ◽  
Informed Decisions ◽  
Modeling Techniques ◽  
Statistical Shape ◽  
Vertebral Bodies ◽  
Statistical Shape Modeling

The mechanics of the lumbar spine are dependent on the morphology of the vertebral bodies and their alignment. As intersubject anatomic variability is significant, this paper developed a method to characterize shape and alignment variability in the lumbar spine using statistical shape modeling techniques. The primary modes of variation between subjects were sagittal plane curvature of the spine and height of the discs. Quantifying the biomechanical variation of the lumbar spine across the population facilitates designers and clinicians in making informed decisions regarding implant sizing and component placement.

scholarly journals Comparison of the Sagittal Spine Lordosis by Supine Computed Tomography and Upright Conventional Radiographs in Patients with Spinal Trauma

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Samy Bouaicha ◽  
Claudia Lamanna ◽  
Thorsten Jentzsch ◽  
Hans-Peter Simmen ◽  
Clément M. L. Werner
Keyword(s):  
Computed Tomography ◽  
Lumbar Spine ◽  
Cobb Angle ◽  
Sagittal Plane ◽  
Spinal Injury ◽  
Thoracolumbar Spine ◽  
Retrospective Data Analysis ◽  
Radiographic Measurements ◽  
Group A ◽  
Group B

Study Design.Retrospective data analysis.Objective.To compare the sagittal lordosis of the lumbar spine by supine computed tomography (CT) and upright conventional radiographs.Summary of Background Data.There is sparse data about position and modality dependent changes of radiographic measurements in the sagittal lumbar spine.Methods.The anatomical and functional Cobb angles of the thoracolumbar spine in 153 patients with spinal injury were measured by conventional upright sagittal radiographs and supine CT scans. Patients were assigned either to group A (n=101), with radiologically confirmed vertebral fractures, or to group B (n=52), without any osseous lesions. The interchangeability of the two imaging modalities was calculated using a ±3° and 5° range of acceptance.Results.Group A showed a mean intraindividual difference of −3.8° for both the anatomical and the functional Cobb angle. Only 25.7% and 27.7% of the 101 patients showed a difference within the tolerated ±3° margin. Using the ±5° limits, only 46 and 47 individuals fell within the acceptable range, respectively. In the patients in group B, the mean intraindividual difference was −2.1° for the anatomical and −1.5° for the functional Cobb angle. Of the 52 patients, only 14 and 13 patients, respectively demonstrated an intraindividual difference within ±3°. With regard to a threshold of ±5°, both the functional and anatomical values were within the defined margins in only 25 (48%) patients.Conclusion.The use of supine CT measurements as a baseline assessment of the sagittal lordosis of the injured thoracolumbar spine does not appear to be appropriate when upright conventional sagittal plane radiographs are used for follow-up measurements.

scholarly journals A modification of the standard midline posterior approach to the intertransverse area of the lumbar spine

2010 ◽  
Vol 92 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Christopher Roy Weatherley ◽  
Ihab Mohammad Emran ◽  
Richard Leonard Martyn Newell
Keyword(s):  
Lumbar Spine ◽  
Blood Loss ◽  
Tissue Damage ◽  
Lumbar Spine Surgery ◽  
Lumbar Region ◽  
Facet Joints ◽  
Surgical Experience ◽  
Midline Approach ◽  
Arterial Anatomy ◽  
Improve Standard

A midline approach to the lumbar region is most frequently used for posterior lumbar spine surgery. The exposure of the deeper layer of muscles, however, is imprecise and can entail substantial tissue damage and blood loss. During 10 years of operative surgical experience, we have developed an improved and less traumatic technique for exposure of the lumbar transverse processes and intertransverse region in which the tendons of multifidus and longissimus muscles are isolated at every level and divided laterally to the facet joints. This method eases identification and accurate cauterisation of the subjacent arteries, thereby reducing tissue damage and blood loss. It takes no more time and clarifies the exposure of the lumbar transverse processes and intertransverse region. Cadaveric dissection confirms the muscular and arterial anatomy of the region. We recommend use of this modified approach to improve standard practice.

scholarly journals Internal Mechanics of a Subject-Specific Wrist in the Sagittal Versus Dart-Throwing Motion Plane in Adult and Elder Models: Finite Element Analyses

2021 ◽  
Vol 11 (11) ◽  
pp. 5275
Author(s):  
Vered Mahpari ◽  
Yafa Levanon ◽  
Yael Kaufman-Cohen ◽  
Meital Zilberman ◽  
Sigal Portnoy
Keyword(s):  
Finite Element ◽  
Contact Area ◽  
Sagittal Plane ◽  
Carpal Bones ◽  
Shear Stresses ◽  
Extension Model ◽  
Radiocarpal Joint ◽  
Dart Throwing ◽  
Adult Model ◽  
Throwing Motion

Introduction: Most of the wrist motions occur in a diagonal plane of motion, termed the dart-throwing motion (DTM) plane; it is thought to be more stable compared with movement in the sagittal plane. However, the effect of the altered carpus motion during DTM on the stress distribution at the radiocarpal joint has yet to be explored. Aim: To calculate and compare the stresses between the radius and two carpal bones (the scaphoid and the lunate) in two wrist positions, extension and radial extension (position in DTM), and between an adult and an elder model. Methods: A healthy wrist of a 40-year-old female was scanned using Magnetic Resonance Imaging in two wrist positions (extension, radial extension). The scans were transformed into three-dimensional models and meshed. Finite element (FE) analyses in each position of the wrist were conducted for both adult and elder models, which were differentiated by the mechanical properties of the ligaments. The distal surfaces of the carpal bones articulating with the metacarpals were loaded by physically accurate tendon forces for each wrist position. Results: The von Mises, shear stresses and contact stresses were higher in the extension model compared with the radial-extension model and were higher for the radius-scaphoid interface in the adult model compared with the elder model. In the radius-scaphoid interface, the stress differences between the two wrist positions were smaller in the elder model (11.5% to 22.5%) compared with the adult model (33.6–41.5%). During radial extension, the contact area at the radius-lunate interface was increased, more so in the adult model (222.2%) compared with the elder model (127.9%), while the contact area at the radius-scaphoid was not affected by the position of the wrist in the adult model (100.9%) but decreased in the elder model (50.2%) during radial extension. Conclusion: The reduced stresses during radial extension might provide an explanation to our frequent use of this movement pattern, as the reduced stresses decrease the risk of overuse injury. Our results suggest that this conclusion is relevant to both adults and elder individuals.

Prediction of the Modal Characteristics of the Human Spine at Resonant Frequency Using Finite Element Models

2005 ◽  
Vol 219 (4) ◽  
pp. 277-284 ◽  
Author(s):  
Li-Xin Guo ◽  
Ee-Chon Teo
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Sagittal Plane ◽  
Whole Body Vibration ◽  
Vertical Motion ◽  
Element Model ◽  
Upper Body ◽  
Whole Body ◽  
Body Vibration ◽  
Human Spine

To understand the dynamic characteristics of the human spine, a detailed three-dimensional finite element model of the lower thorax to pelvis segment, T12-pelvis, was developed based on actual vertebral geometry. After modal analysis, the resonant frequencies of different spinal segments were obtained. The vibration mode of T12-pelvis shows that the human upper body mainly performs the vertical motion during whole-body vibration and the lumbar spine segment conducts translation and rotation in the sagittal plane. The lower segments of the lumbar spine move in flexion and the upper lumbar segments move in extension. This investigation may be helpful in understanding further the biomechanical behaviour of the human spine under the condition of whole-body vibration and to offer potential references for spinal disease treatments and product design in industry.

Cancellous Bone Young’s Modulus Variation Within the Vertebral Body of a Ligamentous Lumbar Spine—Application of Bone Adaptive Remodeling Concepts

1995 ◽  
Vol 117 (3) ◽  
pp. 266-271 ◽  
Author(s):  
Vijay K. Goel ◽  
Steven A. Ramirez ◽  
Weizeng Kong ◽  
Lars G. Gilbertson
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Young’S Modulus ◽  
Bone Remodeling ◽  
Vertebral Body ◽  
Cancellous Bone ◽  
Young's Modulus ◽  
Control Variable ◽  
Compressive Load ◽  
Vertebral Bodies

Bone remodeling theory based on strain energy density (SED) as the feedback control variable was used in conjunction with the finite element method to analyze the shape of the vertebral bodies within the ligamentous motion segment. The remodeling theory was once again applied to the altered two motion segments model to predict the Young’s modulus distribution of the cancellous bone within the vertebral bodies. A three-dimensional finite element model of the two motion segments ligamentous lumbar spine (L3-5) was developed. Bone remodeling response (external as well as internal) of the motion segments to a uniaxial compressive load of 424.7 N was studied. The external shape of the converged model matched the normal shape of a vertebral body. The internal remodeling resulted in regional cancellous bone Young’s moduli (or bone density) distributions similar to those reported in the literature; posterocentral regions of the vertebrae were predicted to have greater values of the elastic modulus than that of the outer regions. The results of the present study suggest that vertebral body assumes an adequate/optimum structure in terms of both its shape and its elastic moduli distribution within the cancellous region in response to the applied load. Extensions of the present model and its clinically relevant applications are discussed.

Research on Solid Modeling and a Different Mode of Loading with Finite Element Analysis for Flat End Mill

2012 ◽  
Vol 500 ◽  
pp. 550-555
Author(s):  
Qing Shan Liu ◽  
Guang Yu Tan ◽  
Guang Jun Liu ◽  
Yan Li Su ◽  
Guang Hui Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cutting Force ◽  
High Speed ◽  
Force Model ◽  
Shear Stresses ◽  
End Mill ◽  
Element Analysis ◽  
High Speed Cutting ◽  
Loading Mode

This work aims to investigate parameterized modeling and a different mode of loading with finite element analysis for flat end mill. A loading mode is chosen according to the cutting force model of overall end mills. Normal and shear stresses which calculate from the cutting force experiments are loaded on the rack face of flat end mill. The stress distribution of end mill in high-speed cutting is obtained by finite element analysis. It is shown that the maximum stress is located at major flank face near the tool tip, rather than the nose of tool and the chisel edge. It shows the tool breakage mechanism in the local region. In the end, we compared the finite element analysis results with the experiment ones. It indicates that the analysis results agree well with the experimental data. Therefore, the proposed loading mode is available.

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