scholarly journals Effect of the Intra-Abdominal Pressure and the Center of Segmental Body Mass on the Lumbar Spine Mechanics – A Computational Parametric Study

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
W. M. Park ◽  
S. Wang ◽  
Y. H. Kim ◽  
K. B. Wood ◽  
J. A. Sim ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Computational Models ◽  
Muscle Force ◽  
Weight Bearing ◽  
Upper Body ◽  
Abdominal Pressure ◽  
Lumbosacral Spine ◽  
Simulation Accuracy ◽  
Joint Force ◽  
Geometric Center

Determination of physiological loads in human lumbar spine is critical for understanding the mechanisms of lumbar diseases and for designing surgical treatments. Computational models have been used widely to estimate the physiological loads of the spine during simulated functional activities. However, various assumptions on physiological factors such as the intra-abdominal pressure (IAP), centers of mass (COMs) of the upper body and lumbar segments, and vertebral centers of rotation (CORs) have been made in modeling techniques. Systematic knowledge of how these assumptions will affect the predicted spinal biomechanics is important for improving the simulation accuracy. In this paper, we developed a 3D subject-specific numerical model of the lumbosacral spine including T12 and 90 muscles. The effects of the IAP magnitude and COMs locations on the COR of each motion segment and on the joint/muscle forces were investigated using a global convergence optimization procedure when the subject was in a weight bearing standing position. The data indicated that the line connecting the CORs showed a smaller curvature than the lordosis of the lumbar spine in standing posture when the IAP was 0 kPa and the COMs were 10 mm anterior to the geometric center of the T12 vertebra. Increasing the IAP from 0 kPa to 10 kPa shifted the location of CORs toward the posterior direction (from 1.4 ± 8.9 mm anterior to intervertebral disc (IVD) centers to 40.5 ± 3.1 mm posterior to the IVD centers) and reduced the average joint force (from 0.78 ± 0.11 Body weight (BW) to 0.31 ± 0.07 BW) and overall muscle force (from 349.3 ± 57.7 N to 221.5 ± 84.2 N). Anterior movement of the COMs from −30 mm to 70 mm relative to the geometric center of T12 vertebra caused an anterior shift of the CORs (from 25.1 ± 8.3 mm posterior to IVD centers to 7.8 ± 6.2 mm anterior to IVD centers) and increases of average joint forces (from 0.78 ± 0.1 BW to 0.93 ± 0.1 BW) and muscle force (from 348.9 ± 47.7 N to 452.9 ± 58.6 N). Therefore, it is important to consider the IAP and correct COMs in order to accurately simulate human spine biomechanics. The method and results of this study could be useful for designing prevention strategies of spinal injuries and recurrences, and for enhancing rehabilitation efficiency.

Effect of position and height of a mobile core type artificial disc on the biomechanical behaviour of the lumbar spine

2008 ◽  
Vol 222 (2) ◽  
pp. 229-239 ◽  
Author(s):  
A Rohlmann ◽  
T Zander ◽  
B Bock ◽  
G Bergmann
Keyword(s):  
Lumbar Spine ◽  
Facet Joint ◽  
Axial Rotation ◽  
Intradiscal Pressure ◽  
Upper Body ◽  
Artificial Disc ◽  
Lateral Bending ◽  
Implant Position ◽  
Joint Force ◽  
Flexion Extension

The extent of natural disc removal and the implant position and height of an artificial disc with a mobile core were studied for their effects on intersegmental rotation, intradiscal pressure, and facet joint force. A validated finite element model of the lumbar spine was used. The model was loaded with the upper body weight, a follower load, and muscle forces to simulate standing, flexion, extension, lateral bending, and axial rotation. The implant position was varied up to 2 mm in an anterior and posterior direction and up to 3 mm in a lateral direction. Three different implant heights were simulated. The effect of removing the lateral parts of the annulus was also studied. The implant position and height markedly affect intersegmental rotation and facet joint forces but have hardly any influence on intradiscal pressure in the adjacent discs. Removing the lateral parts of the annulus increases intersegmental rotation and facet joint force mainly for lateral bending and axial rotation. The calculated translation of the mobile implant core is about 1 mm at most, and thus its effect is often overestimated. Great care should be taken to choose the optimal implant height and to insert the implant in the best position for each individual patient.

Hybrid Rigid-Deformable Model for Prediction of Neighboring Intervertebral Disk Loads During Flexion Movement After Lumbar Interbody Fusion at L3–4 Level

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Tien Tuan Dao
Keyword(s):  
Lumbar Spine ◽  
Computational Models ◽  
Interbody Fusion ◽  
Clinical Decision ◽  
Intervertebral Disk ◽  
Design Guideline ◽  
Spinal Loads ◽  
Stress Changes ◽  
Stress Behaviors

Knowledge of spinal loads in neighboring disks after interbody fusion plays an important role in the clinical decision of this treatment as well as in the elucidation of its effect. However, controversial findings are still noted in the literature. Moreover, there are no existing models for efficient prediction of intervertebral disk stresses within annulus fibrosus (AF) and nucleus pulposus (NP) regions. In this present study, a new hybrid rigid-deformable modeling workflow was established to quantify the mechanical stress behaviors within AF and NP regions of the L1–2, L2–3, and L4–5 disks after interbody fusion at L3–4 level. The changes in spinal loads were compared with results of the intact model without interbody fusion. The fusion outcomes revealed maximal stress changes (10%) in AF region of L1–2 disk and in NP region of L2–3 disk. The minimal stress change (1%) is noted at the NP region of the L1–2 disk. The validation of simulation outcomes of fused and intact lumbar spine models against those of other computational models and in vivo measurements showed good agreements. Thus, this present study may be used as a novel design guideline for a specific implant and surgical scenario of the lumbar spine disorders.

Reliability of standing weight-bearing (0.25T) MR imaging findings and positional changes in the lumbar spine

2017 ◽  
Vol 47 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Bjarke B. Hansen ◽  
Philip Hansen ◽  
Anders F. Christensen ◽  
Charlotte Trampedach ◽  
Zoreh Rasti ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Mr Imaging ◽  
Weight Bearing ◽  
Imaging Findings

Use of Kinetic and Kinematic Data to Evaluate Load Transfer as a Mechanism for Flexion Relaxation in the Lumbar Spine

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Samuel J. Howarth ◽  
Paul Mastragostino
Keyword(s):  
Lumbar Spine ◽  
Body Mass ◽  
Full Range ◽  
Added Mass ◽  
Erector Spinae ◽  
Lower Limbs ◽  
Upper Body ◽  
Low Back ◽  
Kinematic Data ◽  
Flexion Relaxation

Flexion relaxation (FR) in the low back occurs when load is transferred from the spine's extensor musculature to its passive structures. This study investigated the influence of added upper body mass on low back kinetics and kinematics at the FR onset. Sixteen participants (eight male, eight female) performed standing full forward spine flexion with 0%, 15%, and 30% of their estimated upper body mass added to their shoulders. Electromyographic data were obtained from the lumbar erector spinae. Ground reaction forces and kinematic data from the lower limbs, pelvis, and spine were recorded. Extensor reaction moments (determined using a bottom-up linked segment model) and flexion angles at the FR onset were documented along with the maximum spine flexion. The angle at the FR onset increased significantly with added mass (p < 0.05). Expressing the FR onset angle as a percent of the full range of trunk flexion motion for that condition negated any differences between the added mass conditions. These findings demonstrate that low back kinetics play a role in mediating FR in the lumbar spine.

AN ALGORITHM TO CALCULATE THE COMPONENTS OF ALL MUSCLE FORCES DURING EACH PHASES OF THE GAIT CYCLE, FOR THE PELVIC-FEMUR COMPLEX

2005 ◽  
Vol 05 (04) ◽  
pp. 539-548 ◽  
Author(s):  
SANTANU MAJUMDER ◽  
AMIT ROYCHOWDHURY ◽  
SUBRATA PAL
Keyword(s):  
Finite Element ◽  
Hip Joint ◽  
Computational Models ◽  
Gait Cycle ◽  
Muscle Force ◽  
Fe Analysis ◽  
Muscle Forces ◽  
Force Magnitude ◽  
Flexion Extension ◽  
Force Components

With the help of finite element (FE) computational models of femur, pelvis or hip joint to perform quasi-static stress analysis during the entire gait cycle, muscle force components (X, Y, Z) acting on the hip joint and pelvis are to be known. Most of the investigators have presented only the net muscle force magnitude during gait. However, for the FE software, either muscle force components (X, Y, Z) or three angles for the muscle line of action are required as input. No published algorithm (with flowchart) is readily available to calculate the required muscle force components for FE analysis. As the femur rotates about the hip center during gait, the lines of action for 27 muscle forces are also variable. To find out the variable lines of action and muscle force components (X, Y, Z) with directions, an algorithm was developed and presented here with detailed flowchart. We considered the varying angles of adduction/abduction, flexion/extension during gait. This computer program, obtainable from the first author, is able to calculate the muscle force components (X, Y, Z) as output, if the net magnitude of muscle force, hip joint orientations during gait and muscle origin and insertion coordinates are provided as input.

In Vivo Tibiofemoral Contact Kinematics and Contact Forces During Dynamic Weight-Bearing Activities Following Total Knee Arthroplasty

2008 ◽  
Author(s):  
Kartik M. Varadarajan ◽  
Angela Moynihan ◽  
Darryl D’Lima ◽  
Clifford W. Colwell ◽  
Harry E. Rubash ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Computational Models ◽  
Imaging System ◽  
Weight Bearing ◽  
Contact Forces ◽  
Inverse Dynamic ◽  
Contact Kinematics ◽  
Total Knee

Accurate knowledge of in vivo articular contact kinematics and contact forces is required to quantitatively understand factors limiting life of total knee arthroplasty (TKA) implants, such as polyethylene component wear and implant loosening [1]. Determination of in vivo tibiofemoral contact forces has been a challenging issue in biomechanics. Historically, instrumented tibial implants have been used to measure tibiofemoral forces in vitro [2] and computational models involving inverse dynamic optimization have been used to estimate joint forces in vivo [3]. Recently, D’Lima et al. reported the first in vivo measurement of 6DOF tibiofemoral forces via an instrumented implant in a TKA patient [4]. However this technique does not provide a direct estimation of tibiofemoral contact forces in the medial and lateral compartments. Recently, a dual fluoroscopic imaging system has been used to accurately determine tibiofemoral contact locations on the medial and lateral tibial polyethylene surfaces [5]. The objective of this study was to combine the dual fluoroscope technique and the instrumented TKAs to determine the dynamic 3D articular contact kinematics and contact forces on the medial and lateral tibial polyethylene surfaces during functional activities.

scholarly journals Assessment of the functional state of the spine in athletes and ballet dancers with lumbosacral pain syndrome

2019 ◽  
Vol 26 (3) ◽  
pp. 21-30
Author(s):  
S. P Mironov ◽  
M. B Tsykunov ◽  
G. M Burmakova
Keyword(s):  
Lumbar Spine ◽  
Functional State ◽  
Lumbar Vertebrae ◽  
Pain Syndrome ◽  
Lumbosacral Spine ◽  
Bioelectric Activity ◽  
Ballet Dancers ◽  
Facet Syndrome ◽  
Lower Lumbar

The paper presents the data of evaluation of dysfunction in lumbosacral pain in 898 athletes, ballet and circus artists aged 15 to 45 years. The median age was 25.8 year. 537 men and 361 women. In 409 people, pain syndrome is caused by osteochondrosis of the lumbar spine. 238 patients were diagnosed with spondylolysis of the lower lumbar vertebrae, 172 with facet syndrome, spondylarthrosis and 79 with pathology of the ligaments of the lumbosacral spine. Asymmetry in strength, tone of muscles-stabilizers of the spine and their bioelectric activity, which are eliminated in the course of treatment, was noted.

Investigation of Lumbosacral Spine Anatomical Variation Effect on Load-Partitioning Under Follower Load Using Geometrically Personalized Finite Element Model

2014 ◽  
Author(s):  
Sadegh Naserkhaki ◽  
Jacob L. Jaremko ◽  
Greg Kawchuk ◽  
Samer Adeeb ◽  
Marwan El-Rich
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Anatomical Variation ◽  
Load Sharing ◽  
Element Model ◽  
Collagen Fibers ◽  
Spinal Curvature ◽  
Lumbosacral Spine ◽  
Follower Load ◽  
Spinal Load

The spinal load sharing and mechanical stresses developed in the spine segments due to mechanical loads are dependent on the unique spinal anatomy (geometry and posture). Variation in spinal curvature alters the load sharing of the lumbar spine as well as the stiffness and stability of the passive tissues. In this paper, effects of lumbar spine curvature variation on spinal load sharing under compressive Follower Load (FL) are investigated numerically. 3D nonlinear Finite Element (FE) models of three ligamentous lumbosacral spines are developed based on personalized geometries; hypo-lordotic (Hypo-L), normal (Normal-L) and hyper-lordotic (Hyper-L) cases. Analysis of each model is performed under Follower Load and developed stress in the discs and forces in the collagen fibers are investigated. Stresses on the discs vary in magnitude and distribution depending on the degree of lordosis. A straight hypo-lordotic spine shows stresses more equally distributed among discs while a highly curved hyper-lordotic spine has stresses concentrated at lower discs. Stresses are uniformly distributed in each disc for Hypo-L case while they are concentrated posteriorly for Hyper-L case. Also, the maximum force in collagen fibers is developed in the Hyper-L case. These differences might be clinically significant related to back pain.

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