Multiscale modelling of the human lumbar facet capsular ligament: analysing spinal motion from the joint to the neurons

Due to its high level of innervation, the lumbar facet capsular ligament (FCL) is suspected to play a role in low back pain (LBP). The nociceptors in the lumbar FCL may experience excessive deformation and generate pain signals. As such, understanding the mechanical behaviour of the FCL, as well as that of its underlying nerves, is critical if one hopes to understand its role in LBP. In this work, we constructed a multiscale structure-based finite-element (FE) model of a lumbar FCL on a spinal motion segment undergoing physiological motions of flexion, extension, ipsilateral and contralateral bending, and ipsilateral axial rotation. Our FE model was created for a generic FCL geometry by morphing a previously imaged FCL anatomy onto an existing generic motion segment model. The fibre organization of the FCL in our models was subject-specific based on previous analysis of six dissected specimens. The fibre structures from those specimens were mapped onto the FCL geometry on the motion segment. A motion segment model was used to determine vertebral kinematics under specified spinal loading conditions, providing boundary conditions for the FCL-only multiscale FE model. The solution of the FE model then provided detailed stress and strain fields within the tissue. Lastly, we used this computed strain field and our previous studies of deformation of nerves embedded in fibrous networks during simple deformations (e.g. uniaxial stretch, shear) to estimate the nerve deformation based on the local tissue strain and fibre alignment. Our results show that extension and ipsilateral bending result in largest strains of the lumbar FCL, while contralateral bending and flexion experience lowest strain values. Similar to strain trends, we calculated that the stretch of the microtubules of the nerves, as well as the forces exerted on the nerves' membrane are maximal for extension and ipsilateral bending, but the location within the FCL of peak microtubule stretch differed from that of peak membrane force.

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Is intervertebral disc degeneration related to segmental instability? An evaluation with two different grading systems based on clinical imaging

Acta Radiologica ◽

10.1177/0284185117715284 ◽

2017 ◽

Vol 59 (3) ◽

pp. 327-335 ◽

Cited By ~ 3

Author(s):

David Volkheimer ◽

Fabio Galbusera ◽

Christian Liebsch ◽

Sabine Schlegel ◽

Friederike Rohlmann ◽

...

Keyword(s):

Intervertebral Disc Degeneration ◽

Statistical Significance ◽

Axial Rotation ◽

Spinal Motion ◽

X Ray ◽

Grading Systems ◽

Flexion Extension ◽

The Difference ◽

Magnetic Resonance Imaging Mri

Background Several in vitro studies investigated how degeneration affects spinal motion. However, no consensus has emerged from these studies. Purpose To investigate how degeneration grading systems influence the kinematic output of spinal specimens. Material and Methods Flexibility testing was performed with ten human T12-S1 specimens. Degeneration was graded using two different classifications, one based on X-ray and the other one on magnetic resonance imaging (MRI). Intersegmental rotation (expressed by range of motion [ROM] and neutral zone [NZ]) was determined in all principal motion directions. Further, shear translation was measured during flexion/extension motion. Results The X-ray grading system yielded systematically lesser degeneration. In flexion/extension, only small differences in ROM and NZ were found between moderately degenerated motion segments, with only NZ for the MRI grading reaching statistical significance. In axial rotation, a significant increase in NZ for moderately degenerated segments was found for both grading systems, whereas the difference in ROM was significant only for the MRI scheme. Generally, the relative increases were more pronounced for the MRI classification compared to the X-ray grading scheme. In lateral bending, only relatively small differences between the degeneration groups were found. When evaluating shear translations, a non-significant increase was found for moderately degenerated segments. Motion segment segments tended to regain stability as degeneration progressed without reaching the level of statistical significance. Conclusion We found a fair agreement between the grading schemes which, nonetheless, yielded similar degeneration-related effects on intersegmental kinematics. However, as the trends were more pronounced using the Pfirrmann classification, this grading scheme appears superior for degeneration assessment.

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The 6-Plus–Person Lift Transfer Technique Compared With Other Methods of Spine Boarding

Journal of Athletic Training ◽

10.4085/1062-6050-43.1.6 ◽

2008 ◽

Vol 43 (1) ◽

pp. 6-13 ◽

Cited By ~ 47

Author(s):

Gianluca Del Rossi ◽

Mary Beth H. Horodyski ◽

Bryan P. Conrad ◽

Christian P. Di Paola ◽

Matthew J. Di Paola ◽

...

Keyword(s):

Spinal Injury ◽

Three Dimensional ◽

Axial Rotation ◽

Linear Displacement ◽

Angular Motion ◽

Spinal Segment ◽

Spinal Motion ◽

Spinal Immobilization ◽

Flexion Extension ◽

Spine Board

Abstract Context: To achieve full spinal immobilization during on-the-field management of an actual or potential spinal injury, rescuers transfer and secure patients to a long spine board. Several techniques can be used to facilitate this patient transfer. Objective: To compare spinal segment motion of cadavers during the execution of the 6-plus–person (6+) lift, lift-and-slide (LS), and logroll (LR) spine-board transfer techniques. Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Eight medical professionals (1 woman, 7 men) with 5 to 32 years of experience were enlisted to help carry out the transfer techniques. In addition, test conditions were performed on 5 fresh cadavers (3 males, 2 females) with a mean age of 86.2 ± 11.4 years. Main Outcomes Measure(s): Three-dimensional angular and linear motions initially were recorded during execution of transfer techniques, initially using cadavers with intact spines and then after C5-C6 spinal segment destabilization. The mean maximal linear displacement and angular motion obtained and calculated from the 3 trials for each test condition were included in the statistical analysis. Results: Flexion-extension angular motion, as well as anteroposterior and distraction-compression linear motion, did not vary between the LR and either the 6+ lift or LS. Compared with the execution of the 6+ lift and LS, the execution of the LR generated significantly more axial rotation (P = .008 and .001, respectively), more lateral flexion (P = .005 and .003, respectively), and more medial-lateral translation (P = .003 and .004, respectively). Conclusions: A small amount of spinal motion is inevitable when executing spine-board transfer techniques; however, the execution of the 6+ lift or LS appears to minimize the extent of motion generated across a globally unstable spinal segment.

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FINITE ELEMENT MODELING OF HUMAN THORACIC SPINE

Journal of Musculoskeletal Research ◽

10.1142/s0218957704001302 ◽

2004 ◽

Vol 08 (04) ◽

pp. 133-144 ◽

Cited By ~ 3

Author(s):

Tian-Xia Qiu ◽

Ee-Chon Teo

Keyword(s):

Finite Element ◽

Thoracic Spine ◽

Three Dimensional ◽

Axial Rotation ◽

Torsional Stiffness ◽

Fe Model ◽

Thoracic Vertebrae ◽

Fundamental Information ◽

Flexion Extension ◽

Scoliosis Correction

Mathematical models, which can accurately represent the geometric, material and physical characteristics of the human spine structure, are useful in predicting biomechanical behaviors of the spine. In this study, a three-dimensional finite element (FE) model of thoracic spine (T1–T12) was developed, based on geometrical data of embalmed thoracic vertebrae (T1–T12) obtained from a precise flexible digitizer, and validated against published thoracolumbar experimental results in terms of the torsional stiffness of the whole thoracic spine (T1–T12) under axial torque alone and combined with distraction and compression loads. The torsional stiffness was increased by over 60% with application of a 425 N distraction force. A trend in increasing torsional stiffness with increasing distraction forces was detected. The validated model was then loaded under moment rotation in three anatomical planes to determine the ranges of motion (ROMs). The ROMs were approximately 37°, 31°, 32°, 51° for flexion, extension, lateral bending and axial rotation, respectively. These results may offer an insight to better understanding the kinematics of the human thoracic spine and provide clinically relevant fundamental information for the evaluation of spinal stability and instrumented devices functionality for optimal scoliosis correction.

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Cervical motion segment contributions to head motion during flexion\extension, lateral bending, and axial rotation

The Spine Journal ◽

10.1016/j.spinee.2015.08.042 ◽

2015 ◽

Vol 15 (12) ◽

pp. 2538-2543 ◽

Cited By ~ 22

Author(s):

William J. Anderst ◽

William F. Donaldson ◽

Joon Y. Lee ◽

James D. Kang

Keyword(s):

Axial Rotation ◽

Head Motion ◽

Lateral Bending ◽

Motion Segment ◽

Flexion Extension ◽

Cervical Motion

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Numerical investigation on the stability of human upper cervical spine (C1–C3)

Bio-Medical Materials and Engineering ◽

10.3233/bme-211247 ◽

2021 ◽

pp. 1-13

Author(s):

Waseem Ur Rahman ◽

Wei Jiang ◽

Guohua Wang ◽

Zhijun Li

Keyword(s):

Finite Element ◽

Cervical Spine ◽

Axial Rotation ◽

Upper Cervical Spine ◽

Fe Model ◽

Facet Joints ◽

Flexion Extension ◽

Upper Cervical ◽

The Stability

BACKGROUND: The finite element method (FEM) is an efficient and powerful tool for studying human spine biomechanics. OBJECTIVE: In this study, a detailed asymmetric three-dimensional (3D) finite element (FE) model of the upper cervical spine was developed from the computed tomography (CT) scan data to analyze the effect of ligaments and facet joints on the stability of the upper cervical spine. METHODS: A 3D FE model was validated against data obtained from previously published works, which were performed in vitro and FE analysis of vertebrae under three types of loads, i.e. flexion/extension, axial rotation, and lateral bending. RESULTS: The results show that the range of motion of segment C1–C2 is more flexible than that of segment C2–C3. Moreover, the results from the FE model were used to compute stresses on the ligaments and facet joints of the upper cervical spine during physiological moments. CONCLUSION: The anterior longitudinal ligaments (ALL) and interspinous ligaments (ISL) are found to be the most active ligaments, and the maximum stress distribution is appear on the vertebra C3 superior facet surface under both extension and flexion moments.

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Biomechanics of transvertebral screw fixation in the thoracic spine: an in vitro study

Journal of Neurosurgery Spine ◽

10.3171/2015.11.spine15562 ◽

2016 ◽

Vol 25 (2) ◽

pp. 187-192 ◽

Cited By ~ 3

Author(s):

Nestor G. Rodriguez-Martinez ◽

Amey Savardekar ◽

Eric W. Nottmeier ◽

Stephen Pirris ◽

Phillip M. Reyes ◽

...

Keyword(s):

Pedicle Screw ◽

Thoracic Spine ◽

Axial Rotation ◽

Lateral Bending ◽

Motion Segment ◽

Thoracic Spinal ◽

Flexion Extension ◽

Intact Condition ◽

The Mean ◽

The Stability

OBJECTIVE Transvertebral screws provide stability in thoracic spinal fixation surgeries, with their use mainly limited to patients who require a pedicle screw salvage technique. However, the biomechanical impact of transvertebral screws alone, when they are inserted across 2 vertebral bodies, has not been studied. In this study, the authors assessed the stability offered by a transvertebral screw construct for posterior instrumentation and compared its biomechanical performance to that of standard bilateral pedicle screw and rod (PSR) fixation. METHODS Fourteen fresh human cadaveric thoracic spine segments from T-6 to T-11 were divided into 2 groups with similar ages and bone quality. Group 1 received transvertebral screws across 2 levels without rods and subsequently with interconnecting bilateral rods at 3 levels (T8–10). Group 2 received bilateral PSR fixation and were sequentially tested with interconnecting rods at T7–8 and T9–10, at T8–9, and at T8–10. Flexibility tests were performed on intact and instrumented specimens in both groups. Presurgical and postsurgical O-arm 3D images were obtained to verify screw placement. RESULTS The mean range of motion (ROM) per motion segment with transvertebral screws spanning 2 levels compared with the intact condition was 66% of the mean intact ROM during flexion-extension (p = 0.013), 69% during lateral bending (p = 0.015), and 47% during axial rotation (p < 0.001). The mean ROM per motion segment with PSR spanning 2 levels compared with the intact condition was 38% of the mean intact ROM during flexion-extension (p < 0.001), 57% during lateral bending (p = 0.007), and 27% during axial rotation (p < 0.001). Adding bilateral rods to the 3 levels with transvertebral screws decreased the mean ROM per motion segment to 28% of intact ROM during flexion-extension (p < 0.001), 37% during lateral bending (p < 0.001), and 30% during axial rotation (p < 0.001). The mean ROM per motion segment for PSR spanning 3 levels was 21% of intact ROM during flexion-extension (p < 0.001), 33% during lateral bending (p < 0.001), and 22% during axial rotation (p < 0.001). CONCLUSIONS Biomechanically, fixation with a novel technique in the thoracic spine involving transvertebral screws showed restoration of stability to well within the stability provided by PSR fixation.

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Analysis of the impact responses in a degenerated spinal motion segment FE model

Journal of Mechanical Science and Technology ◽

10.1007/s12206-008-0923-6 ◽

2009 ◽

Vol 23 (1) ◽

pp. 19-25 ◽

Cited By ~ 2

Author(s):

YoungEun Kim ◽

Haewon Choi

Keyword(s):

Fe Model ◽

Spinal Motion ◽

Motion Segment ◽

Impact Responses ◽

The Impact ◽

Spinal Motion Segment

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Establishment of FE model of lumbar spinal motion segment in postmenopausal women with vQCT technique

Bone ◽

10.1016/j.bone.2008.07.167 ◽

2008 ◽

Vol 43 ◽

pp. S121-S122

Author(s):

Shengyong Wu ◽

Yuezeng Cai ◽

Penglin Wang ◽

Jing Lan ◽

Liying Wang ◽

...

Keyword(s):

Postmenopausal Women ◽

Fe Model ◽

Spinal Motion ◽

Motion Segment ◽

Lumbar Spinal ◽

Spinal Motion Segment

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The atlantoaxial capsular ligaments and transverse ligament are the primary stabilizers of the atlantoaxial joint in the craniocervical junction: a finite element analysis

Journal of Neurosurgery Spine ◽

10.3171/2019.4.spine181488 ◽

2019 ◽

Vol 31 (4) ◽

pp. 501-507 ◽

Cited By ~ 1

Author(s):

Rinchen Phuntsok ◽

Chase W. Provost ◽

Andrew T. Dailey ◽

Douglas L. Brockmeyer ◽

Benjamin J. Ellis

Keyword(s):

Finite Element ◽

Axial Rotation ◽

Craniocervical Junction ◽

Tectorial Membrane ◽

Atlantoaxial Joint ◽

Transverse Ligament ◽

Lateral Bending ◽

Ligamentous Injury ◽

Capsular Ligament ◽

Flexion Extension

OBJECTIVEPrior studies have provided conflicting evidence regarding the contribution of key ligamentous structures to atlantoaxial (AA) joint stability. Many of these studies employed cadaveric techniques that are hampered by the inherent difficulties of testing isolated-injury scenarios. Analysis with validated finite element (FE) models can overcome some of these limitations. In a previous study, the authors completed an FE analysis of 5 subject-specific craniocervical junction (CCJ) models to investigate the biomechanics of the occipitoatlantal joint and identify the ligamentous structures essential for its stability. Here, the authors use these same CCJ FE models to investigate the biomechanics of the AA joint and to identify the ligamentous structures essential for its stability.METHODSFive validated CCJ FE models were used to simulate isolated- and combined ligamentous–injury scenarios of the transverse ligament (TL), tectorial membrane (TM), alar ligament (AL), occipitoatlantal capsular ligament, and AA capsular ligament (AACL). All models were tested with rotational moments (flexion-extension, axial rotation, and lateral bending) and anterior translational loads (C2 constrained with anterior load applied to the occiput) to simulate physiological loading and to assess changes in the atlantodental interval (ADI), a key radiographic indicator of instability.RESULTSIsolated AACL injury significantly increased range of motion (ROM) under rotational moment at the AA joint for flexion, lateral bending, and axial rotation, which increased by means of 28.0% ± 10.2%, 43.2% ± 15.4%, and 159.1% ± 35.1%, respectively (p ≤ 0.05 for all). TL removal simulated under translational loads resulted in a significant increase in displacement at the AA joint by 89.3% ± 36.6% (p < 0.001), increasing the ADI from 2.7 mm to 4.5 mm. An AACL injury combined with an injury to any other ligament resulted in significant increases in ROM at the AA joint, except when combined with injuries to both the TM and the ALs. Similarly, injury to the TL combined with injury to any other CCJ ligament resulted in a significant increase in displacement at the AA joint (significantly increasing ADI) under translational loads.CONCLUSIONSUsing FE modeling techniques, the authors showed a significant reliance of isolated- and combined ligamentous–injury scenarios on the AACLs and TL to restrain motion at the AA joint. Isolated injuries to other structures alone, including the AL and TM, did not result in significant increases in either AA joint ROM or anterior displacement.

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