Abstract
Introduction
The anatomical relationship between elements of the spinopelvic linear chain does not appear to be uniform across different ethnic and population groups, based on measurements of radiographic parameters presented in the literature in populations with different origins. These studies have demonstrated variability in spinal and pelvic parameters among the groups studied, which makes it important to know their normative values, specific for a population. Such knowledge enables surgeons to individualize treatment goals for deformities in a specific adult population. The aim of this study was to present normal values of sagittal spinal and spinopelvic parameters in a Brazilian population sample and analyze the effect of age on these parameters.
Materials and Methods
This is a prospective observational study involving asymptomatic volunteers in a Brazilian population sample. The volunteers that accepted to participate had obtained total spine radiography in addition to collecting demographic data, including age and sex. The radiographic parameters evaluated were: Sagittal vertical axis (EVS), T1-spinopelvic inclination (T1-SPI), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), and thoracic kyphosis (TK). We also consider the mismatch between the PI and the LL (PI-LL). These radiographic parameters were compared between the age groups of volunteers, divided into three groups: 18 to 39, 40 to 59, and older than 60 years.
Results
In total, 167 asymptomatic volunteers were enrolled, 105 women and 62 men with a mean age of 45.8 years (range, 18–74). In regards to the age group, 54 volunteers had 18 to 39, 79 had 40 to 59, and 34 had older than 60 years of age. The mean values of radiographic parameters in the total sample were: SVA −11.77 mm, T1-SPI- 5.47 degrees, IP: 46.93 degrees, PT: 13.77 degrees, SS: 33.05 degrees, LL: 54.53 degrees, PI-LL: −6.98 degrees, and TK: 40.54 degrees. Comparing the values regarding age, it was observed that higher the age of individuals is, occurs a statistically significant increase in the values of SVA, PT, T1-SPI, and PI-LL (p < 0.001, < 0.001, 0.001, and 0.004, respectively).
Conclusion
The study presented normal values of sagittal spine and spinopelvic parameters in a sample of a Brazilian population, and also showed that there is an increase in anterior tilt of the trunk and a larger pelvic retroversion directly proportional to the increase in age of the individuals.