Parameters of sagittal and spinopelvic alignment in young adult, adult and elderly asymptomatic: a radiographic analysis

Background: Adult spinal deformity (ASD) has been reported to be as high as 60% in the elderly population, however, few studies have evaluated these normality parameters and pathologic alignment and the findings have not yet been established, especially among Brazilians. Objective: Verify the sagittal and spinopelvic balance parameters between young adults, adults and the elderly of the Brazilian and their influence on gender. Methods: This study investigated 167 asymptomatic individuals from Brazilians sample. Eight radiographic parameters were measured: sagittal vertical axis (SVA), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), spinopelvic inclination - T1 (SPI-T1), thoracic kyphosis (TK), lumbar lordosis (LL), and the PI minus the LL (PI - LL). Results: The mean of the radiographic parameters were: SVA (11.77mm); SS (33.05°); PT (13.77°); PI (46.93°); LL (54.53°); TK (40.54°) and T1 (SPi-T1) was -5.74°. We observed that women presented a lower SVA, higher SS and LL and larger negative SPi-T1. We also observed that individuals older than 60 years had higher mean SVA, PT and SPiT1. Conclusion: Full length, free-standing spine radiographs were obtained in 167 asymptomatic individuals in a sample of Brazilians. Standard values and deviations of spino-pelvic sagittal alignment were established according to gender and age from 18 'to 60'. The remarkable change of spino-pelvic sagittal alignment was verified, such as the decrease of SVA, higher SS and LL and larger negative T1-SPiSPi-T1 in young adult and adult women, while that the elderly than 60 years have had higher values of the SVA, PT, and T1-SPiSPi-T1.