Kinematics of the head and associated vertebral artery length changes during high-velocity, low-amplitude cervical spine manipulation
Bibliographic record
Abstract
Abstract Background Cervical spine manipulation (CSM) is a frequently used treatment for neck pain. Despite its demonstrated efficacy, concerns regarding CSM safety remain. The purpose of this study was to quantify the angular displacements of the head relative to the sternum and the associated vertebral artery (VA) length changes during the thrust phase of CSM. Methods Bilateral rotation and lateral flexion CSM procedures were delivered from C1 to C7 to three male cadaveric donors. For each CSM the force-time profile was recorded using a thin, flexible pressure pad (100-200Hz), to determine the timing of the thrust. Three dimensional displacements of the head relative to the sternum were recorded using an eight-camera motion analysis system (120-240Hz) and angular displacements of the head relative to the sternum were computed in Matlab. Positive kinematic values indicate flexion, left lateral flexion, and left rotation. Ipsilateral refers to the same side as the clinician's contact and contralateral, the opposite. Length changes of the VA were recorded using eight piezoelectric ultrasound crystals, inserted along the entire vessel. VA length changes were calculated as D=(L1-L0)/L0, where L0= length of the whole VA (sum of segmental lengths) or the V3 segment at CSM thrust onset; L1= whole VA or V3 length at peak force during the CSM thrust. Results VA length changes during the thrust phase were greatest with ipsilateral rotation CSM (producing contralateral head rotation): [mean ± SD (range)] whole artery [1.3 ± 1.0 (-0.4 to 3.3%)]; and V3 segment [2.6 ± 3.6 (-0.4 to 11.6%)]. For ipsilateral rotation CSM, head angular displacements relative to the sternum during the thrust were: flexion/extension [1.2 ± 3.4 (-6.6 to 7.6º)]; rotation [-10.2 ± 3.5 (-16.1 to -3.7º)]; and lateral flexion [8.8 ± 3.0 (2.5 to 14.1º)]. Conclusion Mean head angular displacements and VA length changes were small during CSM thrusts. Of the four different CSM measured, mean VA length changes were largest during rotation procedures. This suggests that if clinicians wish to limit VA length changes, consideration should be given to the type of CSM used.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".