Complications and outcomes of pedicle subtraction osteotomies for fixed sagittal imbalance

Study Design. Radiographic analysis, outcomes analysis (pain scale, Oswestry, SRS-24), and accumulation of complications. Outcomes and complications collected prospectively. Radiographic analysis performed retrospectively. Objectives. To assess the benefits and stress complications of pedicle subtractions osteotomies for patients with fixed sagittal imbalance. Summary of Background Data. Few reports on pedicle subtraction osteotomies exist in the peer-review literature for conditions other than trauma and ankylosing spondylitis. Materials and Methods. Thirty-three consecutive patients with sagittal imbalance treated with lumbar pedicle subtraction osteotomy at one institution (minimum 2-year follow-up) were analyzed. Complications were also analyzed for the entire group of consecutive pedicle subtraction osteotomies done at our institution to date (n = 66). Results. For the 33 patients with minimum 2-year follow-up, there were significant improvements in the overall Oswestry score (P 0.0001) and pain score (P = 0.0001). Most patients reported improvement in pain and self-image and reported overall satisfaction based on ultimate SRS-24 questionnaire. There was one pseudarthrosis in the lumbar spine through an area of pedicle subtraction osteotomy (area of previous laminectomy and nonunion), and six patients had thoracic pseudarthroses (levels other than the osteotomy level) and one patient had a pseudarthrosis at L5-51. Two patients had acute angular kyphosis at the thoracolumbar junction at the proximal end of the construct. Five patients who experienced transient neurologic deficits resolved their deficits after central canal enlargement. Conclusions. The clinical result with pedicle subtraction osteotomy is reduced with pseudarthrosis in the thoracic or lumbar spine and subsequent breakdown adjacent to the fusion. For patients with a degenerative sagittal imbalance etiology the results were worse and the complications were higher. Central canal enlargement is critical.