Pedicle Subtraction Osteotomy for the Treatment of Fixed Sagittal Imbalance *

This chapter includes patients severely disabled from a fixed deformity in their lumbar spines. The majority of the patients had noncompensated deformities with high sagittal vertical axis secondary to hypolordotic lumbar spines. With the patients limited to requiring pedicle subtraction osteotomy (PSO) to correct their deformities, there was no control group to compare less-invasive procedures such as Smith-Petersen osteotomy, or combined anterior and posterior corrections. The chapter aims to analyze the clinical and radiographic outcomes for patients undergoing lumbar PSO. There was a mean correction of 33.52° of lordosis at the osteotomy level. One (3.7%) patient developed a pseudoarthrosis at the site of the osteotomy. The choice of osteotomy should be based on the morphology and rigidity of the deformity. An alternative technique involves preserving the inferior facet of the cranial vertebra and the superior facet of the caudal vertebra. Reducing the structures to each other with osteotomy closure achieves direct bone apposition, restoring the integrity of the posterior column.