Impact responses of the cervical spine: A computational study of the effects of muscle activity, torso constraint, and pre-flexion

Nightingale, Roger W.; Sganga, Jake; Cutcliffe, Hattie C.; Bass, Cameron R.

doi:10.1016/j.jbiomech.2016.01.006

Cited by 32 publications

(40 citation statements)

References 28 publications

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“…In computer simulated head-impact tests, neck muscle activation prior to a potentially injurious event (i.e. bracing for impact) increased peak compressive and shear forces in the lower cervical spine, when compared to no muscle activation (Nightingale et al, 2016). The current study demonstrates that simulating neck muscle bracing by superimposing an axial compression force =onto the intervertebral motions associated with bilateral and unilateral CFD (particularly anterior shear and axial rotation) generally increased loading of the facets.…”

Section: Discussionmentioning

confidence: 62%

“…The current study data may help explain why facet fracture has not occurred during the experimental production of CFD in cadavers. Lower cervical bilateral CFDs are associated with intervertebral flexion and anterior shear motions (Hodgson and Thomas, 1980;Ivancic, 2012;Nightingale et al, 2016), whilst loading and anatomical asymmetry likely superimposes intervertebral axial rotation and lateral bending onto the external injury vector, causing unilateral CFD (Allen et al, 1982;Hodgson and Thomas, 1980;Maiman et al, 1983;Roaf, 1960). Facet fractures are associated with up to 70% of CFDs (Anissipour et al, 2017;Dvorak et al, 2007); however, in 170 cervical spine head-first impact tests, only 19 CFDs have been produced and none had associated facet fracture (Foster et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…However, motion segments do not exhibit physiological kinematics during cervical trauma (Ivancic et al, 2008;Nightingale et al, 1996;Nightingale et al, 2016;Panjabi et al, 2007), and it is important to obtain quantitative information about the mechanical response of cervical FSUs and the facets during constrained intervertebral motions to develop improved injury tolerance levels. When extrapolating these results beyond physiological limits it is important to recognize that the quasi-static rates applied in this study were substantially slower than the ~3 m/s associated with head-impact loading causing cervical injury (McElhaney et al, 1979;Nightingale et al, 1996;Van Toen et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

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The effect of axial compression and distraction on cervical facet mechanics during anterior shear, flexion, axial rotation, and lateral bending motions

Quarrington

Costi

Freeman

et al. 2019

Journal of Biomechanics

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The subaxial cervical facets are important load-bearing structures, yet little is known about their mechanical response during physiological or traumatic intervertebral motion. Facet loading likely increases when intervertebral motions are superimposed with axial compression forces, increasing the risk of facet fracture. The aim of this study was to measure the mechanical response of the facets when intervertebral axial compression or distraction is superimposed on constrained, non-destructive shear, bending and rotation motions. Twelve C6/C7 motion segments (70±13 yr, nine male) were subjected to constrained quasi-static anterior shear (1 mm), axial rotation (4°), flexion (10°), and lateral bending (5°) motions. Each motion was superimposed with three axial conditions: 1) 50 N compression; 2) 300 N compression (simulating neck muscle contraction); and, 3) 2.5 mm distraction. Angular deflections, and principal and shear surface strains, of the bilateral C6 inferior facets were calculated from motion-capture data and rosette strain gauges, respectively. Linear mixed-effects models (α=0.05) assessed the effect of axial condition. Minimum principal and maximum shear strains were largest in the compressed condition for all motions except for maximum principal strains during axial rotation. For right axial rotation, maximum principal strains were larger for the contralateral facets, and minimum principal strains were larger for the left facets, regardless of axial condition. Sagittal deflections were largest in the compressed conditions during anterior shear and lateral bending motions, when adjusted for facet side.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of axial compression and distraction on cervical facet mechanics during anterior shear, flexion, axial rotation, and lateral bending motions

Quarrington

Costi

Freeman

et al. 2019

Journal of Biomechanics

View full text Add to dashboard Cite

show abstract

“…Stemper et al investigated the cervical spine issue by a rear-impact lordotic, straight or kyphotic neutral curvature 7 . The model is one of the 50th percentile male's different cervical spine models 39,40,41,42,43,44,45 . Currently, the same attempt has not been created for the 50th percentile female 46 that limit the development of vehicle protection systems focuses on neck injuries for the incidence is affected by the gender of the accident sufferer 47 .…”

Section: Computer Modellingmentioning

confidence: 99%

Whiplash Injury Mechanisms of Car Rear Occupants: A Review

Haniffah

Dawal

Julaihi

2020

MJPHM

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Whiplash injury due to low severity vehicles crash is a global problem. The injury has long-term clinical and biomechanical implications. Since the mid-1960s, injury statistics have continuously revealed that females face a higher risk of suffering the injury category compare to males. Besides, in a frontal crash, the injury measures from the adult rear dummies were mainly higher than the same size dummies located in driver and front occupant seat. However, most regulations and user crash tests have focused on vehicle drivers and front-seat passenger due to high occupancy and mortality rates in the front seat. In this paper, mechanisms of whiplash injury were reviewed to contribute a further inclusive understanding of human impact reaction, variability quantification, validation, and prevention. The objective of this study is to develop a new design of head restraint (HR) for car rear occupants. In order to raise consideration whiplash injury and prevention mechanisms, impacts are simulated with computer modelling (Ls-Dyna simulation) and validated using Matlab. Therefore, a review of these injury mechanisms indicates the development of new anti-whiplash technology in the automotive safety area is necessary.

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“…This well-known fact is seldom accounted for when developing dynamic FE models. The majority of the dynamic FE studies either set the vertebral bodies (VBs) as rigid bodies [ 23 , 24 , 25 ], or use quasi-static bone properties [ 26 , 27 , 28 , 29 ], or use non-calibrated elastic-plastic material laws with a non-calibrated hardening parameter [ 26 , 30 , 31 ], or arbitrarily increase Young’s modulus from quasi-static regime to match the rise in stiffness [ 28 , 32 , 33 ]. Appropriate material properties, however, are essential for the accuracy of finite element models.…”

Section: Introductionmentioning

confidence: 99%

A Novel Modelling Methodology Which Predicts the Structural Behaviour of Vertebral Bodies under Axial Impact Loading: A Finite Element and DIC Study

2020

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Cervical spine injuries (CSIs) arising from collisions are uncommon in contact sports, such as rugby union, but their consequences can be devastating. Several FE modelling approaches are available in the literature, but a fully calibrated and validated FE modelling framework for cervical spines under compressive dynamic-impact loading is still lacking and material properties are not adequately calibrated for such events. This study aimed to develop and validate a methodology for specimen-specific FE modelling of vertebral bodies under impact loading. Thirty-five (n = 35) individual vertebral bodies (VBs) were dissected from porcine spine segments, potted in bone cement and μCT scanned. A speckle pattern was applied to the anterior faces of the bones to allow digital image correlation (DIC), which monitored the surface displacements. Twenty-seven (n = 27) VBs were quasi-statically compressively tested to a load up to 10 kN from the cranial side. Specimen-specific FE models were developed for fourteen (n = 14) of the samples in this group. The material properties were optimised based on the experimental load-displacement data using a specimen-specific factor (kGSstatic) to calibrate a density to Young’s modulus relationship. The average calibration factor arising from this group was calculated (K¯GSstatic) and applied to a control group of thirteen (n = 13) samples. The resulting VB stiffnesses was compared to experimental findings. The final eight (n = 8) VBs were subjected to an impact load applied via a falling mass of 7.4kg at a velocity of 3.1ms−1. Surface displacements and strains were acquired from the anterior VB surface via DIC, and the impact load was monitored with two load cells. Specimen-specific FE models were created for this dynamic group and material properties were assigned again based on the density–Young’s modulus relationship previously validated for static experiments, supplemented with an additional factor (KGSdynamic). The optimised conversion factor for quasi-static loading, K¯GSstatic, had an average of 0.033. Using this factor, the validation models presented an average numerical stiffness value 3.72% greater than the experimental one. From the dynamic loading experiments, the value for KGSdynamic was found to be 0.14, 4.2 times greater than K¯GSstatic. The average numerical stiffness was 2.3% greater than in the experiments. Almost all models presented similar stiffness variations and regions of maximum displacement to those observed via DIC. The developed FE modelling methodology allowed the creation of models which predicted both static and dynamic behaviour of VBs. Deformation patterns on the VB surfaces were acquired from the FE models and compared to DIC data, achieving high agreement. This methodology is now validated to be fully applied to create whole cervical spine models to simulate axial impact scenarios replicating rugby collision events.

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Impact responses of the cervical spine: A computational study of the effects of muscle activity, torso constraint, and pre-flexion

Cited by 32 publications

References 28 publications

The effect of axial compression and distraction on cervical facet mechanics during anterior shear, flexion, axial rotation, and lateral bending motions

The effect of axial compression and distraction on cervical facet mechanics during anterior shear, flexion, axial rotation, and lateral bending motions

Whiplash Injury Mechanisms of Car Rear Occupants: A Review

A Novel Modelling Methodology Which Predicts the Structural Behaviour of Vertebral Bodies under Axial Impact Loading: A Finite Element and DIC Study

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