Background Neck pain afflicts 30-50% of the U.S. population annually; however we currently have poor diagnostic differentiation techniques to inform individualized treatment. Planar neck kinematics has been shown to be correlated with neck pain, but neck motion is much more complex than pure planar activities. Our objective was to define a methodology for determining aberrant neck kinematics and assess it. Methods We examined a complex neck kinematic activity of neck circumduction and computed the pathway of motion using the instantaneous helical axis approach in 81 patients with non-specific neck pain and in 20 non-matched symptom free subjects. Neck circumduction, or rolling of the head, represents a complex neck kinematic activity, investigating the innate coupled motion of the cervical spine at the end ranges of motion in all directions. Instance of discontinuities in the helical axis patterns, or folds, were identified and labeled as occurrences of aberrant motion. Findings The instances of aberrant motion, or folds, which are nearly non-existent in the healthy sample group, are present in both the pre- and post-treatment neck pain patients. Following a treatment intervention of the symptomatic patients, pain and neck disability index decreased significantly (P < 0.001) concomitant with a decrease in the number of folds (P = 0.021). Interpretation The present study highlights a new technique using an instantaneous helical axis approach to detect subtle abnormalities in the pathway of motion of the head about the trunk, during a neck circumduction exercise.
Bibliographical noteFunding Information:
The author's would like to thank Heesung Sohn and Lauren Thorson from the Interactive Visualization Lab at the University of Minnesota for their help in developing the visualization tool used to view the helical axes overtop the skeletal model. Student funding was provided through an NIH/NIAMS Musculoskeletal Training Grant ( T32 AR050938 ). This work was supported in part by the NSF ( IIS-1054783 ).
- Aberrant motion
- Cervical spine
- Helical axis
- Neck pain