Correlation between kinematic sagittal parameters of the cervical lordosis or head posture and disc degeneration in patients with posterior neck pain: retrospective cross-sectional study

Abstract Background The aim of this study was to examine degrees of the cervical disc degeneration and the parameters of cervical sagittal balance in plain radiographs, representing cervical lordosis or head posture in subjects with posterior neck pain. Methods This study was a retrospective cross-sectional study that analyzed 113 patients with posterior neck pain with or without radiating pain. The kinematic sagittal parameters of cervical radiographs were obtained at the occipito-cervical (O-C2) angle, sagittal Cobb’s angles of C1-C2, C2-C7, and sagittal vertical axis (SVA) of C1-C7 and C2-C7. Cervical disc degeneration was evaluated using the sum of Pfirrmann grades and total modified Matsumoto scores calculated from magnetic resonance images (MRI) of the cervical spine. Pearson’s correlation analysis was conducted to evaluate the relationship of these parameters and a linear regression method was used to determine associations between sagittal cervical alignment and disc degeneration. Results A significant positive correlation was found for the C2-C7 angle using the sum of the Pfirrmann grades and total modified Matsumoto scores. The O-C2 angle was negatively correlated with the sum of the Pfirrmann grades and total modified Matsumoto scores. The C1-C2 angle was also negatively correlated with the sum of the Pfirrmann grades. No significant relationship was found between the cervical SVA and cervical disc degeneration. Conclusions The sagittal cervical parameters representing cervical kyphosis and jaw lifting posture, were found to be significantly correlated with the degree of cervical disc degeneration. These findings suggest that the loss of the natural sagittal lordosis of the cervical spine may contribute to the progression of disc degeneration, rather than the forward head posture.