Cervical spine joint loading with neck flexion

Barrett, Jeff M.; McKinnon, Colin D.; Callaghan, Jack P.

doi:10.1080/00140139.2019.1677944

Cited by 41 publications

(26 citation statements)

References 37 publications

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“…De Sio et al [ 35 ] conclude in their review that the asymmetric working posture (extreme head and neck flexion, trunk inclination and rotation towards one side, lifting one or both shoulders, increased curvature of the thoracic vertebral column, and incorrect positioning of the lower limbs) during treatment, combined with, on the other hand, the assumption of static body postures over a longer period of time, are responsible for the etiology of MSDs in Ds and DAs. This working posture, especially the neck flexion, causes a 1.6-fold increase in cervical disc compression and a four-fold increase in anteroposterior shear at a posture of 45° compared to the neutral position [ 36 ]. Thus, these increases in cervical disc compression and shear forces during flexion, lateral flexion, and rotational movements must also be taken into account [ 37 , 38 ].…”

Section: Discussionmentioning

confidence: 99%

Ergonomic Comparison of Four Dental Workplace Concepts Using Inertial Motion Capture for Dentists and Dental Assistants

Ohlendorf

Fraeulin

Haenel

et al. 2021

IJERPH

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When the inventory is arranged in a dental practice, a distinction can be made between four different dental workplace concepts (DWCs). Since the prevalence of musculoskeletal diseases in dental professionals is very high, preventive solution need to be investigated. As the conventionally used DWCs have, to date, never been studied in terms of their ergonomics, this study aims to investigate the ergonomic risk when working at the four different DWCs. In total, 75 dentists (37 m/38 f) and 75 dental assistants (16 m/59 f) volunteered to take part in this study. Standardized cooperative working procedures were carried out in a laboratory setting and kinematic data were recorded using an inertial motion capture system. The data were applied to an automated version of the Rapid Upper Limb Assessment (RULA). Comparisons between the DWCs and between the dentists and dental assistants were calculated. In all four DWCs, both dentists and dental assistants spent 95–97% of their working time in the worst possible RULA score. In the trunk, DWCs 1 and 2 were slightly favorable for both dentists and dental assistants, while for the neck, DWC 4 showed a lower risk score for dentists. The ergonomic risk was extremely high in all four DWCs, while only slight advantages for distinct body parts were found. The working posture seemed to be determined by the task itself rather than by the different inventory arrangements.

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Section: Discussionmentioning

confidence: 99%

Ergonomic Comparison of Four Dental Workplace Concepts Using Inertial Motion Capture for Dentists and Dental Assistants

Ohlendorf

Fraeulin

Haenel

et al. 2021

IJERPH

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“…During the movement of the neck in the different directions, the loads on the cervical intervertebral discs increases resulting in an increase in cervical intervertebral disc pressure ( Bayoglu et al, 2019 ). Another study reported a twofold increase in pressure in the cervical discs with flexion and a fourfold increase of the shear forces ( Barrett et al, 2020 ). This additional load, generated by flexion, leads to capsular ligament laxity of the facet joints ( Steilen et al, 2014 ), the so-called buckling effect ( Nightingale et al, 1996 ).…”

Section: Discussionmentioning

confidence: 99%

Influence of Axial Load and a 45-Degree Flexion Head Position on Cervical Spinal Stiffness in Healthy Young Adults

Hofstetter¹,

Häusler²,

Schweinhardt³

et al. 2021

Front. Physiol.

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Background: Neck pain is a major cause of disability worldwide. Poor neck posture such as using a smartphone or work-related additional cervical axial load, such headgear of aviators, can cause neck pain. This study aimed at investigating the role of head posture or additional axial load on spinal stiffness, a proxy measure to assess cervical motor control.Methods: The posterior-to-anterior cervical spinal stiffness of 49 young healthy male military employees [mean (SD) age 20 ± 1 years] was measured in two head positions: neutral and 45-degree flexed head position and two loading conditions: with and without additional 3 kg axial load. Each test condition comprised three trials. Measurements were taken at three cervical locations, i.e., spinous processes C2 and C7 and mid-cervical (MC).Results: Cervical spinal stiffness measurements showed good reliability in all test conditions. There was a significant three-way interaction between location × head position × load [F(2, 576) = 9.305, p < 0.001]. Significant two-way interactions were found between measurement locations × loading [F(2, 576) = 15.688, p < 0.001] and measurement locations × head position [F(2, 576) = 9.263, p < 0.001]. There was no significant interaction between loading × head position [F(1, 576) = 0.692, p = 0.406]. Post hoc analysis showed reduction of stiffness in all three measurement locations in flexion position. There was a decrease in stiffness in C2 with loading, increase in stiffness in C7 and no change in MC.Discussion: A flexed head posture leading to decreased stiffness of the cervical spine might contribute to neck pain, especially if the posture is prolonged and static, such as is the case with smartphone users. Regarding the additional load, stiffness decreased high cervical and increased low cervical. There was no change mid cervical. The lower spinal stiffness at the high cervical spine might be caused by capsular ligament laxity due to the buckling effect. At the lower cervical spine, the buckling effect seems to be less dominant, because the proximity to the ribs and sternum provide additional stiffness.

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“…The authors of the study pointed out that the predominant use of the internet and handheld devices may be associated with this increase in cervical malalignment in younger patients. Many handheld device users flex their neck while viewing the device [ 17 , 18 , 19 , 20 ], which can cause harm to the cervical spine [ 21 , 22 ]. As this concerning prevalence of abnormal curvature is expected to continue, the clinical importance of the assessment of cervical alignment is growing.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Accuracy of Magnetic Resonance Imaging for Sagittal Cervical Spine Alignment: A Retrospective Cohort Study

Noh

Lee

et al. 2021

IJERPH

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(1) Background: Although radiography performed on the subject in an upright position is considered the standard method for assessing sagittal cervical alignment, it is frequently determined, or reported, based on MRI performed on the subject in a supine position. (2) Methods: Cervical alignment observed in both imaging modalities was assessed using four methods: the C2-7 Cobb angle, the absolute rotation angle (ARA), Borden’s method, and the sagittal vertical axis (SVA). Cervical alignment was determined (lordosis, kyphosis, and straight) based on radiography. Then, the diagnostic cut-off values for the MRI images and their corresponding diagnostic accuracies were assessed. (3) Results: The analysis included 142 outpatients. The determined diagnostic cut-off values for lordosis, using three measurements (Cobb angle, ARA, and Borden’s method), were −8.5°, −12.5°, and 3.5 mm, respectively, and the cut-off values for kyphosis were −4.5°, 0.5°, and −1.5 mm, respectively. The cut-off value for SVA > 40 mm was 19.5 mm. The Cobb angle, ARA, and Borden’s method, on MRI, showed high negative predictive values for determining kyphosis. The SVA on MRI measurements also showed high negative predictive values for determining >40 mm. (4) Conclusions: MRI measurements may be predictive of cervical alignment, especially for the exclusion of kyphosis and SVA > 40 mm. However, caution is needed in the other determinations using MRI, as their accuracies are limited.

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Cervical spine joint loading with neck flexion

Cited by 41 publications

References 37 publications

Ergonomic Comparison of Four Dental Workplace Concepts Using Inertial Motion Capture for Dentists and Dental Assistants

Ergonomic Comparison of Four Dental Workplace Concepts Using Inertial Motion Capture for Dentists and Dental Assistants

Influence of Axial Load and a 45-Degree Flexion Head Position on Cervical Spinal Stiffness in Healthy Young Adults

Diagnostic Accuracy of Magnetic Resonance Imaging for Sagittal Cervical Spine Alignment: A Retrospective Cohort Study

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