Normative data for parameters of sagittal spinal alignment in healthy subjects: an analysis of gender specific differences and changes with aging in 626 asymptomatic individuals.

ABSTRACT

PURPOSE: This study aims to establish normative data for parameters of spino-pelvic and spinal sagittal alignment, gender related differences and age-related changes in asymptomatic subjects. METHODS: A total of 626 asymptomatic volunteers from Japanese population were enrolled in this study, including 50 subjects at least for each gender and each decade from 3rd to 8th. Full length, free-standing spine radiographs were obtained. Cervical lordosis (CL; C3-7), thoracic kyphosis (TK; T1-12), lumbar lordosis (LL; T12-S1), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and sagittal vertical axis (SVA) were measured. RESULTS: The average values (degrees) are 4.1 ± 11.7 for CL, 36.0 ± 10.1 for TK, 49.7 ± 11.2 for LL, 53.7 ± 10.9 for PI, 14.5 ± 8.4 for PT, and 39.4 ± 8.0 for SS. Mean SVA is 3.1 ± 12.6 mm. Advancing age caused an increase in CL, PT and SVA, and a decrease in LL and SS. There was a significant gender difference in CL, TK, LL, PI, PT and SVA. From 7th decade to 8th decade, remarkable decrease of LL & TK and increase of PT were seen. A large increase of SVA was also seen between 60' and 70'. CONCLUSION: Standard values of spino-pelvic sagittal alignment were established in each gender and each decade from 20' to 70'. A remarkable change of spino-pelvic sagittal alignment was seen from 7th decade to 8th decade in asymptomatic subjects.