Analysis of global spine sagittal parameters in cervical spondylotic patients and asymptomatic subjects

Abstract

Background: Degenerative changes associated with cervical spondylotic can result in a change of normal sagittal alignment, and this may be the initial change of kyphosis and sagittal imbalance. Few studies have analyzed the correlations between the cervical spine lordosis and global spine balance in patients with cervical spondylotic. This study is applied to investigate the characteristics and relationships of cervical and global sagittal parameters in normal adults and cervical spondylotic patients. Methods: We reviewed 46 asymptomatic control subjects (normal group, NG) and 48 cervical spondylotic patients (cervical spondylotic group, CSG), who had both cervical MRI and global radiographs obtained together, between January 2016 and September 2018. Data includes C1-2 angle, C2–7 lordosis (CL), T1 slope (T1S), thoracic inlet angle (TIA), C2–7 sagittal vertical axis (CSVA), sagittal vertical axis(SVA), thoracic-kyphosis(TK), thoracic-lumbar lordosis(TL), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). The values were presented as the mean ± standard deviation. Student t-test and Pearson’s correlation coefficient were used for statistical analysis. Probability values less than 0.05 were considered statistically significant. Results: 1.Comparison of global sagittal parameters between the normal group and cervical spondylosis group. A total of 48 cervical spondylotic patients with an average age of 57.91±9.58 and 46 healthy people with an average age of 28.00±8.09 were recruited in our study. CL in the NG was significantly lower than CSG (P<0.05), while TK and TL were significantly lower than in the CSG(P< 0.01). However, a comparison of the NG and CSG yielded no significant differences in C1-2, TIA, TIS, LL, PT, PI, SS, CSVA, and SVA. 2.The relationship between cervical and global sagittal alignment. CL positively correlated with T1S (r=0.433) and TK (r=0.335) while negatively correlated with CSVA (r=-0.309) in cervical spondylosis group. TIA has positively correlated with T1S (r=0.376 in NG and r=0.416 in CSG) and no correlated with other parameters in both groups. Conclusions Cervical spondylosis causes changes in sagittal parameters of the cervical and thoracic spine but does not affect on lumbar and pelvic parameters. TIA is a relative constant parameter, not affected by cervical spondylotic.