Influence of sagittal and axial types of ossification of posterior longitudinal ligament on mechanical stress in cervical spinal cord: A finite element analysis

Khuyagbaatar, Batbayar; Kim, Kyung-Soo; Park, Won Man; Kim, Yoon Hyuk

doi:10.1016/j.clinbiomech.2015.08.013

Cited by 13 publications

(36 citation statements)

References 26 publications

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“…46 The maximum stresses were 63–97 kPa at the 60% occupying ratio in the pre-operative model under flexion, neutral, and extension positions. These results were comparable to those in our previous studies, as the maximum stresses were 20–140 kPa in the multi-level segmental OPLL 24 and 210 kPa in the continuous OPLL 29 with 60% of the occupying ratio. Kato et al 21 showed that the maximum stress was 60 kPa in the 40% of OPLL compression.…”

Section: Discussionsupporting

confidence: 91%

“…OPLL models with occupying ratio between 0% and 60% were then reproduced by moving the OPLL in a perpendicular direction to the surface of the spinal cord in order to compress the spinal cord by applying imposed displacement of the OPLL model based on previous study. 24 The occupying ratio of 0% refers to the healthy model or no sign of ossified ligaments in the cervical spine. The OPLL occupying ratio was defined as a reduction in anterior–posterior diameter of the spinal canal by thickened ossified ligaments.…”

Section: Methodsmentioning

confidence: 99%

“…Influence of flexion motion on the spinal cord was investigated, 16 and the hyperextension injury of the cervical spinal cord was analyzed in simple cases. 17 Moreover, the stress and strain distributions in the spinal cord were simulated during various column injury patterns, [18][19][20] ossified ligaments, [21][22][23][24] and contusion injuries. 14,[25][26][27][28] In our previous study, an FE model of the cervical spine with the spinal cord, including white matter, gray matter, dura mater with nerve roots, denticulate ligaments, and cerebrospinal fluid (CSF), was developed and investigated the effect of surgical extents in three different decompression methods on changes in stress, strain, and posterior shift of the spinal cord for cervical OPLL.…”

Section: Introductionmentioning

confidence: 99%

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Increased stress and strain on the spinal cord due to ossification of the posterior longitudinal ligament in the cervical spine under flexion after laminectomy

Khuyagbaatar

Kim

Park

et al. 2017

Proc Inst Mech Eng H

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Myelopathy in the cervical spine due to cervical ossification of the posterior longitudinal ligament could be induced by static compression and/or dynamic factors. It has been suggested that dynamic factors need to be considered when planning and performing the decompression surgery on patients with the ossification of the posterior longitudinal ligament. A finite element model of the C2-C7 cervical spine in the neutral position was developed and used to generate flexion and extension of the cervical spine. The segmental ossification of the posterior longitudinal ligament on the C5 was assumed, and laminectomy was performed on C4-C6 according to a conventional surgical technique. For various occupying ratios of the ossified ligament between 20% and 60%, von-Mises stresses, maximum principal strains in the spinal cord, and cross-sectional area of the cord were investigated in the pre-operative and laminectomy models under flexion, neutral position, and extension. The results were consistent with previous experimental and computational studies in terms of stress, strain, and cross-sectional area. Flexion leads to higher stresses and strains in the cord than the neutral position and extension, even after decompression surgery. These higher stresses and strains might be generated by residual compression occurring at the segment with the ossification of the posterior longitudinal ligament. This study provides fundamental information under different neck positions regarding biomechanical characteristics of the spinal cord in cervical ossification of the posterior longitudinal ligament.

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Section: Discussionsupporting

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Increased stress and strain on the spinal cord due to ossification of the posterior longitudinal ligament in the cervical spine under flexion after laminectomy

Khuyagbaatar

Kim

Park

et al. 2017

Proc Inst Mech Eng H

Self Cite

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“…We compare the maximum stresses in the cervical vertebrae for all load cases in the two conditions with and without neck brace, an approach that has been used in previous studies, e.g. [48][49][50][51][52].…”

Section: Discussionmentioning

confidence: 99%

Assessment of the protective performance of neck braces for motorcycle riders: a finite-element study

Khosroshahi

Ghajari

Galvanetto

2018

International Journal of Crashworthiness

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Neck protective devices for motorcyclists have been introduced fairly recently but there is no standard method to evaluate their performance. The goal of this study is to compare the response of riders' necks to direct impacts on the helmet with and without such a device. We investigate three common types of cervical injury mechanisms i.e. hyperflexion, hyperextension and lateral bending using FEM. The rotational movement of the head with respect to the torso, the neck shearing and axial loads and the stress distribution throughout the cervical vertebrae show that using the investigated type of neck protective device, which is designed to restrain the head-neck motion, can in some cases increase the risk of neck injury. Hence, the design of such devices needs further study and their assessment requires the introduction of relevant standards of evaluation.

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“…Nishida et al then explored the static and dynamic effects of the ossification of the PLL (8). Finally, Khuyagbaatar et al (9) modelled both single-level and multi-level compressions caused by ossification of the PLL.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical comparison of spinal cord compression types occurring in Degenerative Cervical Myelopathy

Levy

Baucher

Roche

et al. 2021

Clinical Biomechanics

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Objective: To study spinal cord compressions occurring in Degenerative Cervical Myelopathy (DCM) using a comprehensive biomechanical model defined by actual features observed in patients, in a view to better understand the pathogenesis and further predict patients evolution. Methods: Anatomical MRIs from 20 DCM patients were collected. Compression indices derived from spinal canal and spinal cord were measured at the compression site. Mean values were compared to values reported in literature and to the Spine Model for Safety and Surgery (comprehensive 3D finite element model of the spine), further used for simulations. Based on those results, a 30% reduction in cord cross-sectional area at C5-C6 intervertebral disk was defined as the compression threshold inducing myelopathy. Four main compression patterns were simulated. Median diffuse, median focal and lateral compression types were modelled as a migration of the disk into the spinal canal evenly, at the central line only and laterally, respectively. Circumferential type involved a posterior compression by the ligamentum flavum. All constraints in spinal cord were quantified along inferior-superior axis, along compression development and within atlasdefined spinal cord regions.Results: Regardless of compression types, predominant stress was found along anteroposterior axis but also along inferior-superior axis, attributable to a slight sliding of the disk in that direction because of natural spine anatomical restrictions. Anterior GM and WM regions globally received the highest stress while lateral pathways were the least affected. Compression applied along the complete anterior side of the cord (median diffuse) globally induced the highest constraints. Additional posterior compression by ligamentum flavum (circumferential) might focus constraints in the anterior gray matter region. Along inferior-superior axis, median diffuse and circumferential types showed a peak of constraints at compression site while median focal and lateral types showed lower constraints values but extending further. Conclusion:Median diffuse type would be the most detrimental based on stress amplitude. Anterior regions would be the most at risk, except for circumferential type where posterior regions would be equally affected. Ischemia would be a significant component in addition to applying constraints to explain the pathogenesis of DCM, in particular for lateral pathways. Future work will look at patient-specific simulations and 3/31 relation with clinical symptoms. Biomechanical models could become strong predictors of degenerative changes.

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Influence of sagittal and axial types of ossification of posterior longitudinal ligament on mechanical stress in cervical spinal cord: A finite element analysis

Cited by 13 publications

References 26 publications

Increased stress and strain on the spinal cord due to ossification of the posterior longitudinal ligament in the cervical spine under flexion after laminectomy

Increased stress and strain on the spinal cord due to ossification of the posterior longitudinal ligament in the cervical spine under flexion after laminectomy

Assessment of the protective performance of neck braces for motorcycle riders: a finite-element study

Biomechanical comparison of spinal cord compression types occurring in Degenerative Cervical Myelopathy

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