Does the preoperative lumbar sagittal profile affect the selection of osteotomy level in pedicle subtraction osteotomy for thoracolumbar kyphosis secondary to ankylosing spondylitis?

Patients in group B had significantly worse preoperative sagittal alignments compared to group A. The distribution of osteotomy levels varied between the 2 groups due to the different lumbar profiles; however, satisfactory correction was achieved in both groups. The preoperative lumbar profiles need to be considered in selecting the optimal osteotomy level. Patients with kyphotic lumbar profiles are suitable candidates for PSO at L2/L3, while L1/L2 PSO is appropriate for patients with lordotic lumbar profiles.