Description of age-related changes in cervical sagittal alignment based on pelvic incidence classification in asymptomatic Chinese population

PurposeTo investigate the pelvic incidence (PI)- and age-related cervical alignment changes of Chinese healthy population.MethodsSix hundred and twenty-five asymptomatic adult subjects, who underwent the standing whole spinal radiograph, were recruited in this work. The sagittal parameters were measured, including Occipito-C2 angle (O-C2), C2-7 angle (C2-7), cranial arch, caudal arch, T1-slope (T1S), C2-7 sagittal vertical axis (C2-7 SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), PI, and sagittal vertical axis (SVA). All subjects were stratified into 5 age groups, namely 40-59 years, 60-64 years, 65-69 years, 70-74 years, and 75 years and above, with each age group further divided into 2 subgroups based on PI (deeming PI < 50 degrees as low PI, and PI >= 50 degrees as high PI). The correlations between PI or age, and other sagittal parameters were assessed. The age-related changes of sagittal parameters in each PI subgroup were also assessed, followed by one-way analysis of variance analysis for change comparison between age groups.ResultsThe average cervical sagittal parameters were as below: 18.2 +/- 6.8 degrees for O-C2, 10.4 +/- 10.2 degrees for C2-7, 3.9 +/- 7.5 degrees for cranial arch, 6.5 +/- 7.1 degrees for caudal arch, 23.6 +/- 7.3 degrees for T1S, and 21.0 +/- 9.7 mm for C2-7 SVA. There was no obvious difference observed between PI and cervical sagittal parameters, excepting for caudal arch. While, C2-7, cranial arch, caudal arch, T1S, and C2-7 SVA increased remarkably with the age. Thereof, C2-7 exhibited great increases at the age of 60-64 years and 70-74 years, respectively, cranial arch increased notably at 60-64 years of age, and caudal arch developed obviously at 70-74 years of age, regardless of PI.ConclusionThis study showed the PI- and age-related cervical alignment changes of Chinese healthy population. Based on the classification in our study, high or low PI apparently did not correlate with the occurrence of cervical degenerative disease.

Automated summary

The purpose of this study was to investigate the PI- and age-related cervical alignment changes of Chinese healthy population. The results showed that there was no obvious difference observed between PI and cervical sagittal parameters, except for caudal arch. However, C2-7, cranial arch, caudal arch, T1S, and C2-7 SVA increased remarkably with age. Based on the classification in the study, high or low PI apparently did not correlate with the occurrence of cervical degenerative disease.