Three-dimensional Cervical Movement Characteristics in Healthy Subjects and Subgroups of Chronic Neck Pain Patients Based on Their Pain Location.

STUDY DESIGN A cross-sectional observational study of three-dimensional (3D) cervical kinematics in 41 chronic neck pain (CNPs) patients and 156 asymptomatic controls. OBJECTIVE The objective was to investigate 3D cervical kinematics by analyzing and comparing quantitative and qualitative parameters in healthy subjects and CNPs. Furthermore, subgroups were formed to explore the influence of pain-location on cervical kinematics. The possible correlation of kinematic parameters with the degree of functional disability was examined as well. SUMMARY OF BACKGROUND DATA In patients with chronic neck pain, a clear pathological cause is frequently not identifiable. Therefore, the need to assess neck pain with a broader view than structure or anatomical-based divergences is desirable. METHODS Movements of the cervical spine were registered using an electromagnetic tracking system. Quantitative and qualitative kinematics were analyzed for active axial rotation, lateral bending, and flexion-extension motion components. RESULTS During lateral bending, the range of the main motion demonstrated significant higher values (P = 0.001) in the controls (mean: 68.67° ± 15.17°) than patients (mean: 59.28° ± 15.41°). Significant differences were demonstrated between subgroups for several kinematic parameters (P < 0.05). Although differences were predominantly recorded between the "symmetrical" and "asymmetrical" pain group, some parameters also distinguished subgroups from controls. On average, the symmetrical group showed significant less harmonic movement patterns, expressed by qualitative parameters, in comparison with the "asymmetrical" group and controls. Furthermore, the "asymmetrical" group showed significant lower scores on quantitative parameters than the "symmetrical" group and controls. The degree of functional disability correlated moderately with changes in qualitative parameters. CONCLUSION In this study, chronic neck pain patients with a symmetrical pain pattern showed significant poorer quality of movement, while those with asymmetrical pain showed a significant reduction in quantitative measures. Subgrouping of neck patients based on pain location may be of help for further research and clinics. LEVEL OF EVIDENCE 4.