Dynamic responses of the head and cervical spine to axial impact loading

Nightingale, Roger W.; McElhaney, James H.; Richardson, William J.; Myers, Barry S.

doi:10.1016/0021-9290(95)00056-9

Cited by 165 publications

(135 citation statements)

References 13 publications

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“…In these configurations, and to a lesser extent in the lateral configuration, the dummy also exhibited an initial s-shape phase where the torso was significantly stopped. A similar behaviour had been described in tests using full cadavers and cervical spine segments in axial loading 24,25,37 , or in FE simulations of head and neck in combined axial and lateral loading 7 . When induced by constraining the head in rotation in cervical spine segments, it was associated with Bilateral Facet Dislocation at the lower cervical spine level 23 .…”

Section: Comparison With the Literaturesupporting

confidence: 64%

“…When induced by constraining the head in rotation in cervical spine segments, it was associated with Bilateral Facet Dislocation at the lower cervical spine level 23 . However, the ATD did not exhibit the bi-modal behaviour sometimes observed in cadaveric segments 24 , as upper and lower neck force maxima occurred simultaneously, and did not present dynamic buckling or any higher order buckling shapes as reported by these authors. Figure 8 presents the peak impact forces compared to results from similar configuration cadaveric drop-tests in the sagittal plane 26,37 .…”

Section: Comparison With the Literaturesupporting

confidence: 44%

“…These moments occurred roughly at the same time as the peak axial force at both levels. Although they may not be representative of the lower levels at injury reached in a human neck in flexion 31 , lower neck moments in combination with axial force (or the use of the N ij(C7-T1) ) appear relevant to injury mechanisms located at the lower levels of the cervical spine, especially since these injuries have also been described to be associated with the main force pulse at T1 level in cadaveric experiments 24 . As for the lateral components measured in this study: the highest lateral shear force (984 N) was reached in the lateral (0,30) configuration at 3.1 m.s -1 .…”

Section: Considerations For Neck Injury Risk Assessmentmentioning

confidence: 99%

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Hybrid III ATD in Inverted Impacts: Influence of Impact Angle on Neck Injury Risk Assessment

et al. 2009

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-The purpose of this paper is to present a protocol of inverted drop-tests using a 50 th percentile Hybrid III Anthropomorphic Test Device (ATD) and investigate the influence of angle and velocity at impact on neck injury risk assessment. The tests were based on existing cadaveric experimental protocols for inverted seated positions. In this study selected ATD impact orientations were also assessed in both the sagittal and coronal planes. Twenty-six tests were performed at impact velocities from 1.4 m.s -1 to 3.1 m.s -1 . The drop tests confirmed previously described behaviour of the ATD in axial loading of its head/neck/thorax complex. They also showed a significant influence of the initial impact angle on neck injury criteria currently used by researchers in rollover crashworthiness tests. At 1.4 m.s -1 , the peak upper neck axial force of 4350 N was reduced by an average 1760 N ± 80 N for configurations with 30 degrees initial impact angle in any plane, compared to a reference inverted vertical configuration. The N ij was also significantly influenced. For a given impact velocity, an out-of-both-planes initial configuration resulted in the highest combined outputs. Based on these results, similar dynamic conditions (intrusion velocity, impact duration) may result in significantly different loadings of the Hybrid III neck.

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Section: Comparison With the Literaturesupporting

confidence: 64%

Section: Comparison With the Literaturesupporting

confidence: 44%

Section: Considerations For Neck Injury Risk Assessmentmentioning

confidence: 99%

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Hybrid III ATD in Inverted Impacts: Influence of Impact Angle on Neck Injury Risk Assessment

et al. 2009

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“…This also has theoretical basis regarding the vulnerability of the spine when loaded along its stiffest axis (Liu and Dai 1989). Under similar loading conditions, fractures of the cervical spine have been observed to occur well before significant motion of the skull (Myers and Nightingale 1999;Nightingale et al 1996), which supports the concept that the transmission of force through the spine is more important than the resulting angular kinematics. On the other hand, the angular motion of the head, an important factor in most brain injuries, was highly correlated with impact orientation.…”

Section: Introductionsupporting

confidence: 54%

“…A 28 kg steel plate, padded and unpadded, impacted the temporoparietal junction above the external auditory meatus with a velocity of approximately 6 m/s. Nightingale et al (1996) and Toomey et al (2009) conducted inverted axial impacts at approximately 3.2 m/s with ligamentous cadaver head-neck complexes against surfaces of varying orientation to determine the effects of head inertia and impact surface on injury risk to the cervical spine. Select time-dependent responses of the THUMS-for example, resultant head CG acceleration-resulting from the simulated experimental conditions were quantitatively compared to the physical test results, where available, via cross-correlation analysis.…”

Section: Experiments Reconstruction With Thumsmentioning

confidence: 99%

Sensitivity of Head and Cervical Spine Injury Measures to Impact Factors Relevant to Rollover Crashes

Mattos

McIntosh

Grzebieta

et al. 2015

Traffic Injury Prevention

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Objective: Serious head and cervical spine injuries have been shown to occur mostly independent of one another in pure rollover crashes. In an attempt to define a dynamic rollover crash test protocol that can replicate serious injuries to the head and cervical spine, it is important to understand the conditions that are likely to produce serious injuries to these 2 body regions. The objective of this research is to analyze the effect that impact factors relevant to a rollover crash have on the injury metrics of the head and cervical spine, with a specific interest in the differentiation between independent injuries and those that are predicted to occur concomitantly.Methods: A series of head impacts was simulated using a detailed finite element model of the human body, the Total HUman Model for Safety (THUMS), in which the impactor velocity, displacement, and direction were varied. The performance of the model was assessed against available experimental tests performed under comparable conditions. Indirect, kinematic-based, and direct, tissue-level, injury metrics were used to assess the likelihood of serious injuries to the head and cervical spine.Results: The performance of the THUMS head and spine in reconstructed experimental impacts compared well to reported values. All impact factors were significantly associated with injury measures for both the head and cervical spine. Increases in impact velocity and displacement resulted in increases in nearly all injury measures, whereas impactor orientation had opposite effects on brain and cervical spine injury metrics. The greatest cervical spine injury measures were recorded in an impact with a 15• anterior orientation. The greatest brain injury measures occurred when the impactor was at its maximum (45 • ) angle. Conclusions:The overall kinetic and kinematic response of the THUMS head and cervical spine in reconstructed experiment conditions compare well with reported values, although the occurrence of fractures was overpredicted. The trends in predicted head and cervical spine injury measures were analyzed for 90 simulated impact conditions. Impactor orientation was the only factor that could potentially explain the isolated nature of serious head and spine injuries under rollover crash conditions. The opposing trends of injury measures for the brain and cervical spine indicate that it is unlikely to reproduce the injuries simultaneously in a dynamic rollover test.

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Biomechanical tolerance of whole lumbar spines in straightened posture subjected to axial acceleration

Stemper

Chirvi

Doan

et al. 2017

Journal Orthopaedic Research

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Quantification of biomechanical tolerance is necessary for injury prediction and protection of vehicular occupants. This study experimentally quantified lumbar spine axial tolerance during accelerative environments simulating a variety of military and civilian scenarios. Intact human lumbar spines (T12-L5) were dynamically loaded using a custom-built drop tower. Twenty-three specimens were tested at sub-failure and failure levels consisting of peak axial forces between 2.6 and 7.9 kN and corresponding peak accelerations between 7 and 57 g. Military aircraft ejection and helicopter crashes fall within these high axial acceleration ranges. Testing was stopped following injury detection. Both peak force and acceleration were significant (p < 0.0001) injury predictors. Injury probability curves using parametric survival analysis were created for peak acceleration and peak force. Fifty-percent probability of injury (95%CI) for force and acceleration were 4.5 (3.9-5.2 kN), and 16 (13-19 g). A majority of injuries affected the L1 spinal level. Peak axial forces and accelerations were greater for specimens that sustained multiple injuries or injuries at L2-L5 spinal levels. In general, force-based tolerance was consistent with previous shorter-segment lumbar spine testing (3-5 vertebrae), although studies incorporating isolated vertebral bodies reported higher tolerance attributable to a different injury mechanism involving structural failure of the cortical shell. This study identified novel outcomes with regard to injury patterns, wherein more violent exposures produced more injuries in the caudal lumbar spine. This caudal migration was likely attributable to increased injury tolerance at lower lumbar spinal levels and a faster inertial mass recruitment process for high rate load application. Published 2017. This article is a U.S. Government work and is in the public domain in the USA. J Orthop Res 36:1747-1756, 2018.

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Dynamic responses of the head and cervical spine to axial impact loading

Cited by 165 publications

References 13 publications

Hybrid III ATD in Inverted Impacts: Influence of Impact Angle on Neck Injury Risk Assessment

Hybrid III ATD in Inverted Impacts: Influence of Impact Angle on Neck Injury Risk Assessment

Sensitivity of Head and Cervical Spine Injury Measures to Impact Factors Relevant to Rollover Crashes

Biomechanical tolerance of whole lumbar spines in straightened posture subjected to axial acceleration

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