A Cervico-Thoraco-Lumbar Multibody Dynamic Model for the Estimation of Joint Loads and Muscle Forces

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Tsolmonbaatar Khurelbaatar ◽  
Kyungsoo Kim ◽  
Yoon Hyuk Kim
Keyword(s):  
Facet Joint ◽  
Experimental Studies ◽  
Contact Forces ◽  
Cervical Region ◽  
Computational Studies ◽  
Muscle Forces ◽  
Facet Joints ◽  
Whole Spine ◽  
Joint Loads

Computational musculoskeletal models have been developed to predict mechanical joint loads on the human spine, such as the forces and moments applied to vertebral and facet joints and the forces that act on ligaments and muscles because of difficulties in the direct measurement of joint loads. However, many whole-spine models lack certain elements. For example, the detailed facet joints in the cervical region or the whole spine region may not be implemented. In this study, a detailed cervico-thoraco-lumbar multibody musculoskeletal model with all major ligaments, separated structures of facet contact and intervertebral disk joints, and the rib cage was developed. The model was validated by comparing the intersegmental rotations, ligament tensile forces, facet joint contact forces, compressive and shear forces on disks, and muscle forces were to those reported in previous experimental and computational studies both by region (cervical, thoracic, or lumbar regions) and for the whole model. The comparisons demonstrated that our whole spine model is consistent with in vitro and in vivo experimental studies and with computational studies. The model developed in this study can be used in further studies to better understand spine structures and injury mechanisms of spinal disorders.

scholarly journals Calibration and validation of a novel hybrid model of the lumbosacral spine in ArtiSynth–The passive structures

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250456
Author(s):  
Robin Remus ◽  
Andreas Lipphaus ◽  
Marc Neumann ◽  
Beate Bender
Keyword(s):  
Simulation Model ◽  
Facet Joint ◽  
Contact Forces ◽  
Combined Loading ◽  
Sensitivity Analyses ◽  
Lumbosacral Spine ◽  
Mechanical Responses ◽  
Functional Spinal Unit ◽  
Starting Point

In computational biomechanics, two separate types of models have been used predominantly to enhance the understanding of the mechanisms of action of the lumbosacral spine (LSS): Finite element (FE) and musculoskeletal multibody (MB) models. To combine advantages of both models, hybrid FE-MB models are an increasingly used alternative. The aim of this paper is to develop, calibrate, and validate a novel passive hybrid FE-MB open-access simulation model of a ligamentous LSS using ArtiSynth. Based on anatomical data from the Male Visible Human Project, the LSS model is constructed from the L1-S1 rigid vertebrae interconnected with hyperelastic fiber-reinforced FE intervertebral discs, ligaments, and facet joints. A mesh convergence study, sensitivity analyses, and systematic calibration were conducted with the hybrid functional spinal unit (FSU) L4/5. The predicted mechanical responses of the FSU L4/5, the lumbar spine (L1-L5), and the LSS were validated against literature data from in vivo and in vitro measurements and in silico models. Spinal mechanical responses considered when loaded with pure moments and combined loading modes were total and intervertebral range of motions, instantaneous axes and centers of rotation, facet joint contact forces, intradiscal pressures, disc bulges, and stiffnesses. Undesirable correlations with the FE mesh were minimized, the number of crisscrossed collagen fiber rings was reduced to five, and the individual influences of specific anatomical structures were adjusted to in vitro range of motions. Including intervertebral motion couplings for axial rotation and nonlinear stiffening under increasing axial compression, the predicted kinematic and structural mechanics responses were consistent with the comparative data. The results demonstrate that the hybrid simulation model is robust and efficient in reproducing valid mechanical responses to provide a starting point for upcoming optimizations and extensions, such as with active skeletal muscles.

The Effects of Orientation of Lumbar Facet Joints on the Facet Joint Contact Forces

Spine ◽  
2018 ◽  
Vol 43 (4) ◽  
pp. E216-E220 ◽  
Author(s):  
Xiang Liu ◽  
Zhiping Huang ◽  
Ruozhou Zhou ◽  
Qingan Zhu ◽  
Wei Ji ◽  
...  
Keyword(s):  
Facet Joint ◽  
Contact Forces ◽  
Facet Joints ◽  
Joint Contact ◽  
Lumbar Facet ◽  
Lumbar Facet Joints

Evaluation of Predicted Knee Joint Muscle Forces During Gait Using an Instrumented Knee Implant

2008 ◽  
Author(s):  
Justin W. Fernandez ◽  
Hyung J. Kim ◽  
Massoud Akbarshahi ◽  
Jonathan P. Walter ◽  
Benjamin J. Fregly ◽  
...  
Keyword(s):  
Contact Forces ◽  
In Vivo Studies ◽  
Muscle Forces ◽  
Model Calculations ◽  
Musculoskeletal Models ◽  
Model Predictions ◽  
Joint Contact ◽  
Knee Muscle

Many studies have used musculoskeletal models to predict in vivo muscle forces at the knee during gait [1, 2]. Unfortunately, quantitative assessment of the model calculations is often impracticable. Various indirect methods have been used to evaluate the accuracy of model predictions, including comparisons against measurements of muscle activity, joint kinematics, ground reaction forces, and joint moments. In a recent study, an instrumented hip implant was used to validate calculations of hip contact forces directly [3]. The same model was subsequently used to validate model calculations of tibiofemoral loading during gait [4]. Instrumented knee implants have also been used in in vitro and in vivo studies to quantify differences in biomechanical performance between various TKR designs [5, 6]. The main aim of the present study was to evaluate model predictions of knee muscle forces by direct comparison with measurements obtained from an instrumented knee implant. Calculations of muscle and joint-contact loading were performed for level walking at slow, normal, and fast speeds.

Development of a Computational Elbow Model with Experimental Validation of Kinematics and Muscle Forces

2016 ◽  
Vol 32 (4) ◽  
pp. 407-414 ◽  
Author(s):  
Jonathan R. Kusins ◽  
Ryan Willing ◽  
Graham J.W. King ◽  
Louis M. Ferreira
Keyword(s):  
Computational Model ◽  
Experimental Model ◽  
Radial Head ◽  
Elbow Joint ◽  
Total Joint Replacement ◽  
Experimental Studies ◽  
Muscle Forces ◽  
Motion Simulator ◽  
Valgus Angle

A computational elbow joint model was developed with a main goal of providing complimentary data to experimental results. The computational model was developed and validated using an experimental elbow joint phantom consisting of a linked total joint replacement. An established in-vitro motion simulator was used to actively flex/extend the experimental elbow in multiple orientations. Muscle forces predicted by the computational model were similar to the experimental model in 4 out of the 5 orientations with errors less than 7.5 N. Valgus angle kinematics were in agreement with differences less than 2.3°. In addition, changes in radial head length, a clinically relevant condition following elbow reconstruction, were simulated in both models and compared. Both lengthening and shortening of the radial head prosthesis altered muscle forces by less than 3.5 N in both models, and valgus angles agreed within 1°. The computational model proved valuable in cross validation with the experimental model, elucidating important limitations in the in-vitro motion simulator’s controller. With continued development, the computational model can be a complimentary tool to experimental studies by providing additional noninvasive outcome measurements.

Non-Contact Experimental Assessment of Spinal Facet Joint Cartilage Dehydration

2012 ◽  
Author(s):  
Loren Kim ◽  
Peter Simon ◽  
Gunnar Andersson ◽  
Howard S. An ◽  
Nozomu Inoue ◽  
...  
Keyword(s):  
Facet Joint ◽  
Morphological Changes ◽  
High Surface ◽  
Experimental Studies ◽  
Volume Ratio ◽  
Ambient Air ◽  
Thickness Measurement ◽  
Joint Cartilage ◽  
Exponential Trend

Dehydration may cause undesirable morphological changes in small hydrated tissue with high surface-to-volume ratio during in vitro experimentation that can result in erroneous data. The lumbar facet joint cartilage, an example of such tissue, is highly susceptible to dehydration due its high content of water (60% to 80% by volume) when exposed to ambient air [1]. Recent studies involving thickness measurement of articular human and bovine cartilage from the tibial plateau reported distinct decreases in thickness due to dehydration and the importance of maintaining its hydration during biomechanical experimental studies [1–3]. Knee joint and facet joint cartilage are characterized as hyaline cartilage surrounded by synovial fluid and encased in a joint capsule. The fact that both are synovial joints suggests that facet joint cartilage may show similar dehydration rates; however, due to its smaller size and different surface-to-volume, the dehydration rate is expected to be higher for facet joint cartilage. To the best of the authors’ knowledge, the rate of facet joint cartilage dehydration has not been quantified before. It is hypothesized that the facet joint cartilage thickness will decrease in an inverse exponential trend and significant changes will be seen as dehydration time intervals time increases. The objectives of this study were: 1) quantify the dimensional stability of the cartilage samples under a sequential dehydration protocol, and 2) to evaluate the cartilage shrinkage rate.

Compressive Follower Load Influences Cervical Spine Kinematics and Kinetics During Simulated Head-First Impact in an in Vitro Model

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Amy Saari ◽  
Christopher R. Dennison ◽  
Qingan Zhu ◽  
Timothy S. Nelson ◽  
Philip Morley ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Injury Risk ◽  
Muscle Activation ◽  
Ex Vivo ◽  
Reaction Force ◽  
Experimental Studies ◽  
Follower Load ◽  
Muscle Forces

Current understanding of the biomechanics of cervical spine injuries in head-first impact is based on decades of epidemiology, mathematical models, and in vitro experimental studies. Recent mathematical modeling suggests that muscle activation and muscle forces influence injury risk and mechanics in head-first impact. It is also known that muscle forces are central to the overall physiologic stability of the cervical spine. Despite this knowledge, the vast majority of in vitro head-first impact models do not incorporate musculature. We hypothesize that the simulation of the stabilizing mechanisms of musculature during head-first osteoligamentous cervical spine experiments will influence the resulting kinematics and injury mechanisms. Therefore, the objective of this study was to document differences in the kinematics, kinetics, and injuries of ex vivo osteoligamentous human cervical spine and surrogate head complexes that were instrumented with simulated musculature relative to specimens that were not instrumented with musculature. We simulated a head-first impact (3 m/s impact speed) using cervical spines and surrogate head specimens (n = 12). Six spines were instrumented with a follower load to simulate in vivo compressive muscle forces, while six were not. The principal finding was that the axial coupling of the cervical column between the head and the base of the cervical spine (T1) was increased in specimens with follower load. Increased axial coupling was indicated by a significantly reduced time between head impact and peak neck reaction force (p = 0.004) (and time to injury (p = 0.009)) in complexes with follower load relative to complexes without follower load. Kinematic reconstruction of vertebral motions indicated that all specimens experienced hyperextension and the spectrum of injuries in all specimens were consistent with a primary hyperextension injury mechanism. These preliminary results suggest that simulating follower load that may be similar to in vivo muscle forces results in significantly different impact kinetics than in similar biomechanical tests where musculature is not simulated.

scholarly journals Facet joint ankylosis in r-axSpA: detection and 2-year progression on whole spine low-dose CT and comparison with syndesmophyte progression

Rheumatology ◽  
2020 ◽  
Vol 59 (12) ◽  
pp. 3776-3783
Author(s):  
Rosalinde Stal ◽  
Floris van Gaalen ◽  
Alexandre Sepriano ◽  
Juergen Braun ◽  
Monique Reijnierse ◽  
...  
Keyword(s):  
Low Dose ◽  
Facet Joint ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Facet Joints ◽  
Low Dose Ct ◽  
Patient Level ◽  
Smallest Detectable Change ◽  
Whole Spine ◽  
Joint Ankylosis

Abstract Objectives To evaluate the occurrence and progression of facet joint ankylosis in the whole spine using low-dose CT (ldCT) in radiographic axial spondyloarthritis (r-axSpA) and compare progression of facet joint ankylosis and syndesmophytes. Methods Patients with r-axSpA from the Sensitive Imaging in Ankylosing Spondylitis (SIAS) cohort underwent ldCT at baseline (n = 60) and 2 years (n = 53). Facet joints (right and left, levels C2-S1) were scored as ankylosed, not ankylosed or unable to assess. Joints that were frequently poorly visible (>15% missing), were excluded. Inter-reader reliability on the patient level was assessed with intraclass correlation coefficients (ICCs) and smallest detectable change (SDC). Ankylosis was assessed at joint level and patient level for both timepoints. Syndesmophytes were assessed with CT syndesmophyte score. Results Levels C5-T2 were difficult to assess and excluded from all further analyses. Facet joint ICCs were good to excellent for status scores (0.72–0.93) and poor to excellent for progression scores (0.10–0.91). Facet joint ankylosis was detected at every level but most frequently in the thoracic joints. In total, 48% of patients showed 2-year progression. Most progression occurred in the thoracic segment. Using SDCs as cutoff, 18% of patients had progression of facet joint ankylosis only, whereas 20% of patients had progression of syndesmophytes only. Conclusion This is the first study evaluating facet joints in the whole spine by ldCT in r-axSpA. Facet joint ankylosis was detected most often in the thoracic spine. Assessing facet joints in addition to syndesmophytes detected substantially more patients with damage progression over two years.

Can extra-articular strains be used to measure facet contact forces in the lumbar spine? An in-vitro biomechanical study

2008 ◽  
Vol 222 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Q A Zhu ◽  
Y B Park ◽  
S G Sjovold ◽  
C A Niosi ◽  
D C Wilson ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Facet Joint ◽  
Axial Rotation ◽  
Contact Forces ◽  
Facet Joints ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Joint Contact ◽  
Strain Coupling ◽  
Accuracy And Repeatability

Experimental measurement of the load-bearing patterns of the facet joints in the lumbar spine remains a challenge, thereby limiting the assessment of facet joint function under various surgical conditions and the validation of computational models. The extra-articular strain (EAS) technique, a non-invasive measurement of the contact load, has been used for unilateral facet joints but does not incorporate strain coupling, i.e. ipsilateral EASs due to forces on the contralateral facet joint. The objectives of the present study were to establish a bilateral model for facet contact force measurement using the EAS technique and to determine its effectiveness in measuring these facet joint contact forces during three-dimensional flexibility tests in the lumbar spine. Specific goals were to assess the accuracy and repeatability of the technique and to assess the effect of soft-tissue artefacts. In the accuracy and repeatability tests, ten uniaxial strain gauges were bonded to the external surface of the inferior facets of L3 of ten fresh lumbar spine specimens. Two pressure-sensitive sensors (Tekscan) were inserted into the joints after the capsules were cut. Facet contact forces were measured with the EAS and Tekscan techniques for each specimen in flexion, extension, axial rotation, and lateral bending under a ±7.5 N m pure moment. Four of the ten specimens were tested five times in axial rotation and extension for repeatability. These same specimens were disarticulated and known forces were applied across the facet joint using a manual probe (direct accuracy) and a materials-testing system (disarticulated accuracy). In soft-tissue artefact tests, a separate set of six lumbar spine specimens was used to document the virtual facet joint contact forces during a flexibility test following removal of the superior facet processes. Linear strain coupling was observed in all specimens. The average peak facet joint contact forces during flexibility testing was greatest in axial rotation (71±25 N), followed by extension (27±35 N) and lateral bending (25±28 N), and they were most repeatable in axial rotation (coefficient of variation, 5 per cent). The EAS accuracy was about 20 per cent in the direct accuracy assessment and about 30 per cent in the disarticulated accuracy test. The latter was very similar to the Tekscan accuracy in the same test. Virtual facet loads (r.m.s.) were small in axial rotation (12 N) and lateral bending (20 N), but relatively large in flexion (34 N) and extension (35 N). The results suggested that the bilateral EAS model could be used to determine the facet joint contact forces in axial rotation but may result in considerable error in flexion, extension, and lateral bending.

Effect of CT-based attenuation correction on uptake ratios in skeletal SPECT

2007 ◽  
Vol 46 (01) ◽  
pp. 38-42 ◽  
Author(s):  
V. Schulz ◽  
I. Nickel ◽  
A. Nömayr ◽  
A. H. Vija ◽  
C. Hocke ◽  
...  
Keyword(s):  
Vertebral Body ◽  
Facet Joint ◽  
One Dimension ◽  
Patient Specific ◽  
Data Sets ◽  
Facet Joints ◽  
Lumbar Vertebral Body ◽  
Ct System ◽  
Ct Data ◽  
Attenuation Corrected

SummaryThe aim of this study was to determine the clinical relevance of compensating SPECT data for patient specific attenuation by the use of CT data simultaneously acquired with SPECT/CT when analyzing the skeletal uptake of polyphosphonates (DPD). Furthermore, the influence of misregistration between SPECT and CT data on uptake ratios was investigated. Methods: Thirty-six data sets from bone SPECTs performed on a hybrid SPECT/CT system were retrospectively analyzed. Using regions of interest (ROIs), raw counts were determined in the fifth lumbar vertebral body, its facet joints, both anterior iliacal spinae, and of the whole transversal slice. ROI measurements were performed in uncorrected (NAC) and attenuation-corrected (AC) images. Furthermore, the ROI measurements were also performed in AC scans in which SPECT and CT images had been misaligned by 1 cm in one dimension beforehand (ACX, ACY, ACZ). Results: After AC, DPD uptake ratios differed significantly from the NAC values in all regions studied ranging from 32% for the left facet joint to 39% for the vertebral body. AC using misaligned pairs of patient data sets led to a significant change of whole-slice uptake ratios whose differences ranged from 3,5 to 25%. For ACX, the average left-to-right ratio of the facet joints was by 8% and for the superior iliacal spines by 31% lower than the values determined for the matched images (p <0.05). Conclusions: AC significantly affects DPD uptake ratios. Furthermore, misalignment between SPECT and CT may introduce significant errors in quantification, potentially also affecting leftto- right ratios. Therefore, at clinical evaluation of attenuation- corrected scans special attention should be given to possible misalignments between SPECT and CT.

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