Correlation analysis of cervical anteversion and curvature changes with sagittal parameters in patients with cervical spondylosis

English Keywords:Cervical spondylosis  Sagittal parameters  Correlation analysis  Imaging parameters

English Abstract:

  【Abstract】 Objectives: To apply the anterior tilt slope(ATS) for the first time to assess the degree of cervical anteversion, and to explore and analyze the correlations between the cervical anteversion and cervical curvature changes and sagittal spinal alignment parameters in patients with cervical spondylosis. Methods: A total of 201 patients with cervical spondylosis who were treated in the Department of Orthopedics(Cervical Spine) outpatient clinic from May 2020 to July 2023 were included in the study, consisting of 79(39%) males and 122(61%) females, aged 25.6±6.5(18-40) years. Imaging parameters were measured on the total spinal lateral X-ray films, including the cervical parameters, such as cervical lordosis(CL), upper cervical Cobb angle, C1-7 Cobb angle, and T1 slope(T1S), cervical sagittal vertical axis(cSVA), Borden value of cervical curvature, anterior tilt slope(ATS); thoracolumbar parameters, such as thoracic kyphosis(TK) and lumbar lordosis(LL); as well as pelvic parameters, such as sacral slope(SS), pelvic tilt(PT), pelvic incidence(PI), sagittal vertical axis(SVA). The curvature changes and cervical anteversion were staged according to the Borden value and ATS in the cervical spine parameters, and their relationships with each spinal sagittal parameter in different classification were compared. Results: According to ATS, the cercical anteversion of patients was classified into type Ⅰof 67 cases, type Ⅱ of 70 cases, type Ⅲ of 40 cases, and type Ⅳ of 24 cases. According to the Borden value, the cervical curvature was classified into type kyphotic of 65 cases, type straight of 92 cases, type lordotic of 29 cases, and type sigmoid of 15 cases. There were significant positive correlations between Borden values and CL, C1-7 Cobb angle, and T1S(P<0.001). ATS had significant positive correlations with T1S and cSVA(P<0.001), and positive correlations with CL, C1-7 Cobb angle, and Borden value(P<0.05). SVA was significantly positively correlated with C1-7 Cobb angle, T1S, cSVA, Borden value, ATS, and SS(P<0.001), whereas there was no significant correlation between each of the cervical spine parameters and pelvic parameters. In different cervical anteversion classifications, significant differences were observed between cSVA, T1S, TK, and SVA(P<0.001), and severe degree of cervical anteversion further aggravated the sagittal imbalance. In different types of cervical curvature, there were significant differences between CL, C1-7 Cobb angle, T1S, Borden value, TK, SS, SVA, and ATS(P<0.05), and when the curvature straightened or became kyphotic, it would cause compensatory reduction of the cervicothoracic junction. Conclusions: In patients with cervical spondylosis, cervical anteversion and curvature changes exhibit significant correlations with thoracic parameters among the sagittal parameters. When cervical anteversion is aggravated and changes in cervical curvature mainly cause compensatory changes in the T1S and TK angles, the SVA is significantly larger in those with significant cervical anteversion.