Spinopelvic Parameters: Lumbar Lordosis, Pelvic Incidence, Pelvic Tilt, and Sacral Slope

The pelvic incidence defines the amount of lordosis required in the lumbar spine, and a lumbar lordosis within 11° of the pelvic incidence defines alignment of the lumbo-pelvic region. Pelvic tilt is a compensatory mechanism that allows patients to achieve sagittal balance in the setting of decreased lumbar lordosis with the primary compensatory mechanisms being hip extension and knee flexion. Planning an adult lumbar deformity operation requires a comprehensive history and physical examination and thorough radiographic evaluation with the goal of restoring alignment between the pelvic incidence and lumbar lordosis and restoring a normal pelvic tilt.