The role of the facet capsular ligament in providing spinal stability

Bermel, Emily; Barocas, Victor H.; Ellingson, Arin M.

doi:10.1080/10255842.2018.1514392

Cited by 25 publications

(13 citation statements)

References 55 publications

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“…As soon as the column moves towards extension, the ALL is stretched and limits this movement immediately but with a gradual slope (in fact the slope of the curve is smaller in extension respect to flexion). This may be due to the mechanical role of the facet joints and the capsular ligaments, which contribute with the ALL to stabilize extension [35]. Conversely, during flexion the lumbar spine allowed more degrees of movement in flexion before stiffening.…”

Section: Discussionmentioning

confidence: 99%

Digital Image Correlation (DIC) Assessment of the Non-Linear Response of the Anterior Longitudinal Ligament of the Spine during Flexion and Extension

et al. 2020

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While the non-linear behavior of spine segments has been extensively investigated in the past, the behavior of the Anterior Longitudinal Ligament (ALL) and its contribution during flexion and extension has never been studied considering the spine as a whole. The aims of the present study were to exploit Digital Image Correlation (DIC) to: (I) characterize the strain distribution on the ALL during flexion-extension, (II) compare the strain on specific regions of interest (ROI) of the ALL in front of the vertebra and of the intervertebral disc, (III) analyze the non-linear relationship between the surface strain and the imposed rotation and the resultant moment. Three specimens consisting of 6 functional spinal units (FSUs) were tested in flexion-extension. The full-field strain maps were measured on the surface of the ALL, and the most strained areas were investigated in detail. The DIC-measured strains showed different values of peak strain in correspondence with the vertebra and the disc but the average over the ROIs was of the same order of magnitude. The strain-moment curves showed a non-linear response like the moment-angle curves: in flexion the slope of the strain-moment curve was greater than in extension and with a more abrupt change of slope. To the authors’ knowledge, this is the first study addressing, by means of a full-field strain measurement, the non-linear contribution of the ALL to spine biomechanics. This study was limited to only three specimens; hence the results must be taken with caution. This information could be used in the future to build more realistic numerical models of the spine.

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Section: Discussionmentioning

confidence: 99%

Digital Image Correlation (DIC) Assessment of the Non-Linear Response of the Anterior Longitudinal Ligament of the Spine during Flexion and Extension

et al. 2020

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“…For example, obvious changes in the disc volume can be observed in the models with the same cross-sectional area ratio and different lordotic angles. Furthermore, the de nition of the ligaments was accomplished based on our observer measurements and did not conform to a uniform standard, even though ligaments play a signi cant role in the maintenance of lumbar stability [6,11,29] and are a key index in ROMs. Therefore, the de nition of ligaments should be investigated and calibrated in future studies to further develop more accurate FEA models.…”

Section: Discussionmentioning

confidence: 99%

Measurement and calibration of the nucleus position and its cross-sectional area ratio to increase the accuracy of finite element analysis

Zhang

et al. 2019

Preprint

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Background: As a widely used biomechanical research method, finite element analysis (FEA) is a significant tool for investigating the pathogenesis of disc degenerative diseases and optimizing of spine surgical methods. However, the definitions of the relative nucleus position and its cross-sectional area ratio do not conform to a uniform standard, thus affecting the accuracy (ACC) of the FEA. Hence, this study aimed to determine a precise definition of the relative nucleus position and its cross-sectional area ratio to increase ACC of following FEA studies. Methods: The lumbar relative nucleus position and its cross-sectional area ratio were measured from magnetic resonance imaging data, and then calibrated and validated via FEA. Imaging data from patients without disc degeneration were recruited. The L4-L5 nucleus and disc cross-sectional areas and the distances between the edges of the annulus and nucleus were measured; the ratios between these values were calculated as P1 and P2, respectively. The FEA model was constructed using these measured values, and the relative nucleus position was calibrated by estimating the differences in the range of motions (ROMs) between the model, wherein the ligaments, facet joints and nucleus were supressed, and an in vitro study. Then, ACC were re-estimated in the model with all non-bony structures to validate the measured and calibrated indicators. Results: The interobserver homogeneity is acceptable, and the measured P1 and P2 values are 1.22 and 38%, respectively. Furthermore, an ACC of up to 99% was attained for the model under flexion–extension conditions when the calibrated P1 value (1.62) was used, with a model validation of greater than 90% attained under all loading conditions. Conclusion: The measured and calibrated relative nucleus position and its cross-sectional area ratio increase the ACC of the FEA model, and can therefore be used in subsequent studies.

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“…Friction model Cartilage material model 2012Mooney-Rivlin 2nd order, incompressible Noailly et al (2007) Asymmetric tension/compression, with hypoeleastic cartilage in compression Hussain et al (2010) Poroelastic using: E = 10.4 MPa , = 0.4 present) or maximum overclosure values (max gap) but usually did not provide much information about the pressureoverclosure relationship. Fourteen studies (out of 49) did not provide any other information than using a "soft contact" or "non-linear contact" formulation (Aroeira et al 2018;Bermel et al 2018;Charles et al 2013;Cheung et al 2003;Deng et al 2017;Goto et al 2002;Kim et al 1991;Lo et al 2019;Pitzen et al 2002;Song et al 2014Song et al , 2018Teo and Ng 2001;Zeng et al 2017). Only six of the 50 models with cartilage behaviour modelled as soft contact reported all required information on the pressureoverclosure law, of which only four also reported friction behaviour.…”

Section: Referencesmentioning

confidence: 99%

Biomechanical modelling of the facet joints: a review of methods and validation processes in finite element analysis

Mengoni

2020

Biomech Model Mechanobiol

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There is an increased interest in studying the biomechanics of the facet joints. For in silico studies, it is therefore important to understand the level of reliability of models for outputs of interest related to the facet joints. In this work, a systematic review of finite element models of multi-level spinal section with facet joints output of interest was performed. The review focused on the methodology used to model the facet joints and its associated validation. From the 110 papers analysed, 18 presented some validation of the facet joints outputs. Validation was done by comparing outputs to literature data, either computational or experimental values; with the major drawback that, when comparing to computational values, the baseline data was rarely validated. Analysis of the modelling methodology showed that there seems to be a compromise made between accuracy of the geometry and nonlinearity of the cartilage behaviour in compression. Most models either used a soft contact representation of the cartilage layer at the joint or included a cartilage layer which was linear elastic. Most concerning, soft contact models usually did not contain much information on the pressure-overclosure law. This review shows that to increase the reliability of in silico model of the spine for facet joints outputs, more needs to be done regarding the description of the methods used to model the facet joints, and the validation for specific outputs of interest needs to be more thorough, with recommendation to systematically share input and output data of validation studies.

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The role of the facet capsular ligament in providing spinal stability

Cited by 25 publications

References 55 publications

Digital Image Correlation (DIC) Assessment of the Non-Linear Response of the Anterior Longitudinal Ligament of the Spine during Flexion and Extension

Digital Image Correlation (DIC) Assessment of the Non-Linear Response of the Anterior Longitudinal Ligament of the Spine during Flexion and Extension

Measurement and calibration of the nucleus position and its cross-sectional area ratio to increase the accuracy of finite element analysis

Biomechanical modelling of the facet joints: a review of methods and validation processes in finite element analysis

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