Three-dimensional spinal and pelvic alignment in an asymptomatic population

Study Design. A 3-dimensional (3-D) analysis of asymptomatic spinal and pelvic alignment. Objective. To obtain 3-D reference values of spinal and pelvic parameters, vertebral and intervertebral orientations. Summary of Background Data. Referential values of spine and pelvis alignment are essential for the assessment of posture and balance. However, only 2-D referential values have been reported using standing sagittal radiographs, and, to our knowledge, no 3-D referential values have been reported to date. Methods. A biplanar radiographic technique was used to obtain the 3-D reconstruction of the spine and pelvis of 34 asymptomatic standing subjects. The 3-D values were calculated for most of the spinal and pelvic parameters. In addition, 3-D vertebral and intervertebral orientations were computed, and the apical and junctional zones were investigated. Results. As reported in 2-D, a large variability and particular correlations were observed for the 3-D spinal and pelvic parameters. However, significant differences were found between 3-D and 2-D values. The 3- D vertebral and intervertebral sagittal rotations showed specific features in the apical and junctional zones of the asymptomatic spine. Conclusion. These data may be used as 3- D referential values of spinal and pelvic alignment.