Compressive Follower Load Influences Cervical Spine Kinematics and Kinetics During Simulated Head-First Impact in an in Vitro Model

Saari, Amy; Dennison, Christopher R.; Zhu, Qingan; Nelson, Timothy S.; Morley, Philip L.; Oxland, Thomas R.; Cripton, Peter A.; Itshayek, Eyal

doi:10.1115/1.4024822

Cited by 21 publications

(27 citation statements)

References 39 publications

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“…This resulted in a follower load of 51 N on each side of the specimen, with a further 50 N applied to the cranial end of the specimen due to the weight of the impact plate. This preload magnitude is comparable to previous in vitro cervical spine studies that have replicated the weight of the head and the stiffening effect due to passive muscle activity [8,13,14].…”

Section: Methodssupporting

confidence: 85%

“…The impact time was identified as the point at which the load in the cranial load cell exceeded 200 N [8]. The data period analyzed included the time of impact to 0.03 seconds after impact; this encompassed the entire primary impact for all specimens.…”

Section: Discussionmentioning

confidence: 99%

“…The magnitudes of the maximum cranial (F cra ) and caudal (F cau ) loads were identified, as was the time from impact until the maximum cranial (T cra ) and caudal (T cau ) loads. The time to injury (T 2/3 ) was also identified, which was defined as the time at which the caudal load dropped to two-thirds of the peak level [8]. The image data were used to identify the time at which observable injury occurred (T inj ), defined as the frame at which fracture or major disc pathology such as a prolapse was induced.…”

Section: Discussionmentioning

confidence: 99%

“…Previous research investigating axial impacts and injury mechanisms in the cervical spine has focused on head constraint [3], the effect of the impact surface angle and padding [4,5], vertebral compression [6], horizontally positioned impacts [7], the effect of axial preload [8], and burst fracture injuries [9]. These studies have demonstrated the complex nature of spinal injuries and the variation of injury mechanism(s) under seemingly similar conditions.…”

Section: Introductionmentioning

confidence: 97%

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An investigation into axial impacts of the cervical spine using digital image correlation

et al. 2015

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Section: Methodssupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

An investigation into axial impacts of the cervical spine using digital image correlation

et al. 2015

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“…More recent studies (cadaveric) on the neck evaluated the effects of lateral eccentricity (the perpendicular distance from the axial force to the centre of the spine) on peak loads, kinematics and spinal canal occlusions of sub-axial cervical spine specimens tested in dynamic axial compression 70 , and noted differences in the kinematics, kinetics, and injuries of ex vivo osteoligamentous human cervical spine and surrogate head complexes that were instrumented with simulated musculature relative to specimens that were not instrumented with musculature 71 . Unfortunately, these studies provide no useful leads for investigating the cervical spine in vivo.…”

Section: Introductionmentioning

confidence: 99%

Normal neck motion

Charlton¹

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Musculoskeletal disorders affect humankind perhaps more than any other category of malady, and at all ages. Prominent amongst such disorders are those apparently afflicting the vertebral column presenting with symptoms of headache and neck pain. Diagnosis of the cause of symptoms implicating structures or dysfunction of the neck as source is fraught with difficulty. Local neck joint kinetic behaviour and motion amplitude commands attention from those with an interest in manipulation, like chiropractors and physiotherapists, as well as surgeons, who all commonly examine patients for an association between perceived anomalies of local joint motion and such symptoms.Anecdotal impressions about the significance of findings made in this fashion form the rationale for therapy, including manual therapy.Although there are data on global neck kinematics, studies of local neck joint kinematic behaviour in appropriate age and gender cohorts of sufficient size to be clinically useful are scarce and contradictory. Remarkably, as investigators seek, but have yet to find, reliable and accurate diagnostic tests to quantify local neck joint motion, surgeons also seek surgically without any such data to relieve spondylotic myelopathy and/or radiculopathy caused by mechanical pathology in an intervertebral disc in the cervical spine with insertion of artificial disc prostheses. Thus, for those addressing the causes of otherwise unexplained neck related symptoms, especially surgeons and chiropractors, accurate data and a thorough understanding of neck kinematics (understanding of joint behaviour without consideration of forces) are essential, but absent. This leads to six sets of values of sufficient size for each gender and three age ranges, accounting for inter-observer variation, which no previous study has undertaken in this way. Earlier reports of notional "normal" values for both motion amplitudes and ICR locations appear not to be based on equivalent data.This thesis reveals sufficient differences in values in enough joints for the three different age cohorts representing the commonest age groups presenting with neck pain and related disorders, and in both genders, to render current catalogues of normal motion somewhat unsatisfactory. For normal sagittal plane local joint motion from C2-3 to C6-7 in the human neck, for rotation amplitude values, the Null Hypotheses that no such data in neck kinematics can show differences in values from age cohort to age cohort and/or from gender cohort to gender cohort are rejected. The Null Hypotheses for Instantaneous Axes of Rotation are confirmed.Further, the thesis produces sufficient new evidence to propose more accurate ranges that can be considered as clinically relevant normals as the basis for investigations into clinical causes and assessment of treatment results for mechanically implicated neck pain and related disorders.4

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Spine biomechanical testing methodologies: The controversy of consensus vs scientific evidence

2021

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Biomechanical testing methodologies for the spine have developed over the past 50 years. During that time, there have been several paradigm shifts with respect to techniques. These techniques evolved by incorporating state-of-the-art engineering principles, in vivo measurements, anatomical structure-function relationships, and the scientific method. Multiple parametric studies have focused on the effects that the experimental technique has on outcomes. As a result, testing methodologies have evolved, but there are no standard testing protocols, which makes the comparison of findings between experiments difficult and conclusions about in vivo performance challenging. In 2019, the international spine research community was surveyed to determine the consensus on spine biomechanical testing and if the consensus opinion was consistent with the scientific evidence. More than 80 responses to the survey were received. The findings of this survey confirmed that while some methods have been commonly adopted, not all are consistent with the scientific evidence. This review summarizes the scientific literature, the current consensus, and the authors' recommendations on best practices based on the compendium of available evidence.

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Compressive Follower Load Influences Cervical Spine Kinematics and Kinetics During Simulated Head-First Impact in an in Vitro Model

Cited by 21 publications

References 39 publications

An investigation into axial impacts of the cervical spine using digital image correlation

An investigation into axial impacts of the cervical spine using digital image correlation

Normal neck motion

Spine biomechanical testing methodologies: The controversy of consensus vs scientific evidence

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