Normative values of cervical sagittal alignment according to global spine balance: based on 126 asymptomatic Chinese young adults

摘要

Purpose To explore the normal distribution of cervical sagittal alignment and the relationship between cervical alignment and global spine balance in asymptomatic young adults. Methods A total of 67 males and 59 females aged from 18 to 30 years old were recruited from 11/2011 to 12/2014. The C-0-C-2 angle, disk angles from C-2-C-3 to C-6-C-7, vertebral angles from C-3 to C-7, T-1 slope, thoracic kyphosis (TK), lumbar lordosis, pelvic incidence, sacral slope, C-2-C-7 sagittal vertical axis (SVA), center of gravity of head to C-7 SVA (CGH-C(7)SVA), C-7-S(1)SVA were measured and statistically analyzed. The Roussouly classification was utilized. Results Mean value of C-0-C-7 was 26.0 degrees +/- 12.8 degrees, composed of 15.2 degrees +/- 6.7 degrees for C-0-C-2, 9.1 degrees +/- 12.1 degrees for sum of disk angles from C-2-C-3 to C-6-C-7, and 1.4 degrees +/- 10.2 degrees for sum of vertebral angles from C-3 to C-7. C-2-C(7)SVA (18.6 mm +/- 7.9 mm) and CGH-C(7)SVA (22.9 mm +/- 12.3 mm) were offset ideally by C-7-S(1)SVA (-21.6 mm +/- 31.0 mm). Significant difference was found between cervical alignment of different Roussouly types (p < 0.01). There was significant correlation between cervical alignment and T-1 slope (p < 0.01), TK (p < 0.01). There was significant correlation between adjacent segmental angles from T-1 slope up to C-0-C-2 angle (p < 0.05). Conclusion Normative values of each vertebral angle and disk angle were established. The cervical lordosis occurred mainly at C-0-C-2 and disk levels, which was influenced by parameters of other parts of the spine, such as T-1 slope, TK and the Roussouly classification. There was significant correlation between adjacent disk angles.