Classification of Normal Sagittal Spine Alignment using Roussouly Classification in Indian Population: A Cross-Sectional Study

Background: The quantification of spinal deformity enables a surgeon to interpret and plan a treatment strategy with better accuracy. It is important to examine the correlation between individual parameters and their relation with spinopelvic parameters. Roussouly et al . described different patterns of spinal curves which guide the surgical treatment. This study aims to investigate the accuracy of the Roussouly classification to describe all types of spinal shapes in the Indian population. Materials and Methods: A standing left lateral radiograph, including spine and pelvis, was taken from the base of the skull to the proximal femur. Subjects stood comfortably with shoulders and elbows flexed, hands placed on supports, with hips and knees extended fully. A single observer measured the spinopelvic parameters (pelvic incidence [PI], pelvic tilt [PT], sacral slope [SS], and sagittal vertical axis). Results: The average PI was found to be 49.69 ± 11.44, the mean PT was 12.65 ± 6.37, and the mean SS was 35.23 ± 8.75. We did not find any significant difference between females and males for any of the parameters in consideration. It was found that type 3 was most common followed by type 1, type 4, and type 2, respectively, as per Roussouly classification. Conclusion: Our results showed considerable variation in the values of spinopelvic parameters as compared to previously published literature.