Evaluations of the spinal curvatures in the sagittal plane: Reference measurements, categorization, discriminatory and diagnostic accuracy

Introduction. This study aimed to propose a categorization of body postures and to provide indexes/scores for the postural patterns. Methods. The body posture of the 3 spinal regions in 180 asymptomatic young people, mean age: 16.1 (0.77) years, was evaluated quantitatively in the sagittal plane (cinemetry and the curvature index). The same images were presented to experts who, by way of qualitative analyses, provided the postural diagnosis of each curvature for all of the young people. individuals with the same postural patterns were grouped together and the qualitative data were crossed with the quantitative values. Thus, scores were attributed to normal curvature, tendencies, and deviations. The one-way ANoVA test for independent samples was used to compare the patterns and the Bonferroni post-hoc test served to analyse effects between neighbouring changes. The mean difference and the 95% confidence interval were also calculated to compare the patterns. An alpha level of 5% was adopted for all analyses. The sensitivity, specificity, positive and negative likelihood ratios, and the predictive value for the suggested reference intervals were calculated to determine the diagnostic accuracy. Results. Significantly different scores were attributed to the postural pattern curves: 0: curve inversion; 0.1-10: rectification; 10.1-11: tendency for rectification; 11.1-14: normal; 14.1-15: tendency for hyperlordosis/hyperkyphosis; > 15: hyperlordosis/hyperkyphosis. The scores presented great discriminatory capacity and diagnostic accuracy among the postural patterns. Conclusions. This categorization could aid researchers and health professionals in evaluating postural deviations.