Measurement of spinopelvic parameters in healthy adults of Indian origin - A cross sectional study

Restoration of spinopelvic balance during spinal surgery is very important to ensure a good outcome. Many studies have been conducted to define the normal ranges, examining the correlation between these individual parameters and their relation with spinal parameters of thoracic kyphosis and lumbar lordosis. The ranges, specific to individual ethnicities, is very essential to restore the sagittal balance in patients suffering from spinal degenerative conditions. Hence this study aims to define the average ranges of relevant spinopelvic parameters in the adult population of Indian origin.

A observational cross sectional study was conducted in 130 healthy volunteers in Mumbai without having any spine, hip or pelvis pathology. Spinopelvic parameters like Pelvic Incidence(PI), Sacral Slope(SS) and Pelvic Tilt(PT) were studied and compared between various other similar studies with patients of different ethnicities. The correlation of those parameters with each other was also evaluated.

The mean value of PI was 51.50(±6.85°), that of SS was 39.17° (±6.26°) and for PT it was 12.32°(±5.41°). These values were statistically significant between both sexes for PI and PT. The strongest positive correlation among the parameters was between pelvic incidence and sacral slope, with a r-value of 0.668. Comparison of our study with similar studies within the country (Chennai, Delhi and Surat) showed statistically significant differences in PT and SS of all three studies while PI was not significant when compared with the Surat study.

There appears to be considerable variation of the values of the spinopelvic parameters as determined by various studies due to ethnic variations. Further studies should be done with larger samples and directed towards early detection of individuals at risk of developing degenerative spinal disorders with sagittal imbalance, so that interventions can be made at an earlier stage.