Impact of cervical sagittal parameters on axial neck pain in patients with cervical kyphosis

BACKGROUND: Cervical sagittal alignment (CSA) is closely related with cervical disk degeneration and impacts the spinal function, especially in the setting of cervical kyphosis (CK). In this study, we evaluated the influence of cervical sagittal parameters on the development of axial neck pain (ANP) in patients with CK. METHODS: Data pertaining to 263 patients with CK who visited the outpatient department of our hospital between January 2012 and December 2018 were retrospective analyzed. The most common symptoms of ANP were neck pain, stiffness, or dullness. Visual analog scale (VAS) was used to evaluate ANP. The following radiographic parameters were evaluated: CK types, C2-7 sagittal vertical axis (SVA), thoracic inlet angle (TIA), T1 slope, neck tilt (NT), cranial tilt, and cervical tilt. Sagittal alignment of CK was classified into 2 types: global and regional type. Multivariate logistic regression analysis was performed to identify risk factors for ANP. RESULTS: Patients who complained of ANP were categorized as ANP group (VAS score ≥ 3; n = 92), while those without ANP were categorized as non-ANP group (VAS score < 3; n = 171). There was no significant between-group difference with respect to age (P = 0.196), gender (P = 0.516), TIA (P = 0.139), NT (P = 0.676), CK type (P = 0.533), cranial tilt (P = 0.332), cervical tilt (P = 0.585), or cervical disk degeneration (P = 0.695). The T1 slope and C2-7 SVA in the ANP group were significantly greater than that in the non-ANP group (P < 0.05). On multivariate logistic regression, C2-7 SVA [ odds ratio (OR) 2.318, 95% confidence interval 1.373–4.651, P = 0.003) and T1 slope (OR 2.563, 95% CI 1.186–4.669, P = 0.028) were identified as risk factors for ANP. CONCLUSIONS: Our findings suggest a significant effect of cervical sagittal parameters on the occurrence of ANP in patients with CK. Greater T1 slope and larger C2-7 SVA may lead to the development of neck pain.