Fig. 1.

The important radiological determinants of adult spinal deformity. The important radiological determinants include regional variables (CL, TK, and LL), global variables (SVA and TPA), and sagittal spinopelvic variables (PI, PT, and SS). The degree of disruption of the normal spinopelvic morphology is determined via the calculation of spinopelvic mismatch, which is the difference between PI and LL. CL, cervical lordosis; TK, thoracic kyphosis; LL, lumbar lordosis; SVA, sagittal vertical axis; TPA, T1 pelvic angle; PI, pelvic incidence; PT, pelvic tilt; SS, sacral slope.