Pediatric Head and Neck Dynamics in Frontal Impact: Analysis of Important Mechanical Factors and Proposed Neck Performance Corridors for 6- and 10-Year-Old ATDs

Dibb, Alan T.; Cutcliffe, Hattie C.; Luck, Jason F.; Cox, Courtney A.; Myers, Barry S.; Bass, Cameron R.; Arbogast, Kristy B.; Seacrist, Thomas; Nightingale, Roger W.

doi:10.1080/15389588.2013.824568

Cited by 12 publications

(4 citation statements)

References 24 publications

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“…Because pediatric volunteers cannot be tested at crash-relevant rates, future work should explore novel computational methods to determine whether the observed ATD-volunteer differences in kinematics and reaction loads remain at increased loading rates. Such efforts have been conducted for frontal impacts (Dibb et al 2014). Lastly, a 6-year-old ATD would ideally have been used to evaluate the influence of the shirt donned by the 6-to 8-year-olds but was unavailable at the time of volunteer testing.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Pediatric ATD Biofidelity as Compared to Child Volunteers in Low-Speed Far-Side Oblique and Lateral Impacts

Seacrist

Locey

Mathews

et al. 2014

Traffic Injury Prevention

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In general, the ATDs overestimated lateral excursion in both impact directions, while underestimating forward excursion of the head and neck in oblique impacts compared to the pediatric volunteers. This was primarily due to pendulum-like lateral bending of the entire ATD torso compared to translation of the thorax relative to the abdomen prior to the lateral bending of the upper torso in the volunteers, likely due to the multisegmented spinal column in the volunteers. Additionally, the effect of belt pretightening on occupant kinematics was greater for the ATDs than the volunteers.

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Section: Discussionmentioning

confidence: 99%

Evaluation of Pediatric ATD Biofidelity as Compared to Child Volunteers in Low-Speed Far-Side Oblique and Lateral Impacts

Seacrist

Locey

Mathews

et al. 2014

Traffic Injury Prevention

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“…The first was the neck from the Duke University Head Neck Model (DUHNM) developed by the Duke Injury Biomechanics Laboratory consisting of an osteoligamentous cervical spine, and 23 active muscle pairs. [20][21][22] The second model represents the HIII neck and was developed by the National Crash Analysis Center (NCAC) at The George Washington University and is distributed by LSTC. 23 Both necks were positioned between finite element models of the HIII head and torso developed by NCAC and distributed by LSTC.…”

Section: Methodsmentioning

confidence: 99%

“…The model output provides detailed kinematic analysis of simulated on-field impacts; controlling for impact position, timing, and cervical muscle response. 20,21 Six neck conditions were tested and four metrics were used to assess the resulting kinematics of these impacts under varying neck conditions. There were two hypotheses evaluated in this study.…”

Section: Introductionmentioning

confidence: 99%

The role of cervical muscles in mitigating concussion

Eckersley

Nightingale

Luck

et al. 2019

Journal of Science and Medicine in Sport

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“…Other limitations, such as the application of volunteer initial neck angle to the model, may affect activation optimization. However, activation states were generally found to be robust to small disturbances (Dibb 2011;Dibb et al 2013). Notwithstanding this limitation, the reported activation states represent physiologically appropriate sets of initial conditions, as evidenced by the model's corridor fits.…”

Section: Discussionmentioning

confidence: 99%

Importance of Muscle Activations for Biofidelic Pediatric Neck Response in Computational Models

Dibb¹,

Cox²,

Nightingale³

et al. 2013

Traffic Injury Prevention

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Objective: During dynamic injury scenarios, such as motor vehicle crashes, neck biomechanics contribute to head excursion and acceleration, influencing head injuries. One important tool in understanding head and neck dynamics is computational modeling. However, realistic and stable muscle activations for major muscles are required to realize meaningful kinematic responses. The objective was to determine cervical muscle activation states for 6-year-old, 10-year-old, and adult 50th percentile male computational head and neck models. Currently, pediatric models including muscle activations are unable to maintain the head in an equilibrium position, forcing models to begin from nonphysiologic conditions. Recent work has realized a stationary initial geometry and cervical muscle activations by first optimizing responses against gravity. Accordingly, our goal was to apply these methods to Duke University's head-neck model validated using living muscle response and pediatric cadaveric data.Methods: Activation schemes maintaining an upright, stable head for 22 muscle pairs were found using LS-OPT. Two optimization problems were investigated: a relaxed state, which minimized muscle fatigue, and a tensed activation state, which maximized total muscle force. The model's biofidelity was evaluated by the kinematic response to gravitational and frontal impact loading conditions. Model sensitivity and uncertainty analyses were performed to assess important parameters for pediatric muscle response. Sensitivity analysis was conducted using multiple activation time histories. These included constant activations and an optimal muscle activation time history, which varied the activation level of flexor and extensor groups, and activation initiation and termination times.Results: Relaxed muscle activations decreased with increasing age, maintaining upright posture primarily through extensor activation. Tensed musculature maintained upright posture through coactivation of flexors and extensors, producing up to 32 times the force of the relaxed state. Without muscle activation, the models fell into flexion due to gravitational loading. Relaxed musculature produced 28.6-35.8 N of force to the head, whereas tensed musculature produced 450-1023 N. Pediatric model stiffnesses were most sensitive to muscle physiological cross-sectional area.Conclusions: Though muscular loads were not large enough to cause vertebral compressive failure, they would provide a prestressed state that could protect the vertebrae during tensile loading but might exacerbate risk during compressive loading. For example, in the 10-year-old, a load of 602 N was produced, though estimated compressive failure tolerance is only 2.8 kN. Including muscles and time-variant activation schemes is vital for producing biofidelic models because both vary by age. The pediatric activations developed represent physiologically appropriate sets of initial conditions and are based on validated adult cadaveric data.

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Pediatric Head and Neck Dynamics in Frontal Impact: Analysis of Important Mechanical Factors and Proposed Neck Performance Corridors for 6- and 10-Year-Old ATDs

Cited by 12 publications

References 24 publications

Evaluation of Pediatric ATD Biofidelity as Compared to Child Volunteers in Low-Speed Far-Side Oblique and Lateral Impacts

Evaluation of Pediatric ATD Biofidelity as Compared to Child Volunteers in Low-Speed Far-Side Oblique and Lateral Impacts

The role of cervical muscles in mitigating concussion

Importance of Muscle Activations for Biofidelic Pediatric Neck Response in Computational Models

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