Smith-Petersen osteotomy of the spine.

The Smith-Petersen osteotomy has been a mainstay in the treatment of sagittal deformity since it was first described in 1945. The primary indication for an osteotomy is fixed sagittal deformity. When an osteotomy is performed in a patient with ankylosing spondylitis, it can be combined with an anterior column osteoclasis to achieve a correction of up to 40 degrees to 50 degrees. When performed for other indications, the osteotomy can result in approximately 10 degrees of correction per level treated.