Factors Associated with Cervical Spine Alignment in an Asymptomatic Population: A Preliminary Analysis

Cervical sagittal imbalance compromises health-related quality of life and can lead to myriad incapacitating symptoms through compression of the spinal cord. Questions regarding which parameters play primary roles in the progression of cervical sagittal imbalance and which might be compensatory factors remain unanswered.

This study enrolled 246 asymptomatic volunteers from July 2016 to June 2018. After demographic and radiologic parameters were measured, the data were analyzed using correlation coefficient test and multiple regression analysis. A predictive equation was assessed with variance analysis, residual analysis, collinearity analysis, and a paired t test.

Average values are as follows: orbital tilt, 64 ± 6°; orbital slope (OS), 15 ± 6°; C0-C2 lordosis (C0C2), 28 ± 8°; cervical lordosis (CL), 5 ± 11°; C2-C7 sagittal vertical axis (C2C7SVA), 15 ± 8 mm; T1 slope (TS), 17 ± 6°; thoracic inlet angle, 69 ± 8°; thoracic kyphosis, 34 ± 9°; lumbar lordosis, 50 ± 10°; sacral slope, 38 ± 7°; pelvic index, 48 ± 9°; sagittal vertical axis, 10 ± 19 mm. Correlations of C2C7SVA were observed with body mass index (BMI), OS, C0C2, CL, and TS. The validated predictive equation was: C2C7SVA = 0.38 × BMI - 0.73 × OS + 0.73 × C0C2 + 0.15 × CL + 0.18 × TS - 6.53.

BMI, OS, C0C2, CL, and TS were primary influencers in the progression of cervical sagittal imbalance and established a predictive equation of asymptomatic population, which can provide clinical advice and remind surgeons of the primary influencers of reconstructive surgery for better prognoses.