Pedicle Subtraction Osteotomies for Correcting Sagittal Imbalance

Background Data: Restoration of sagittal balance typically involves Smith Peterson osteotomy (SPO) or pedicle subtraction osteotomy (PSO). Since 2008, PSO was used for patients with kyphosis at our centers. Purpose: The aim of this study is to report the results of PSO for correcting fixed sagittal imbalance at a minimum follow up of 24 months. Study Design: Prospective descriptive study. Methods: Twenty four consecutive patients with sagittal imbalance (9 females/15 males), with a mean age at surgery of 33.4 years, were treated with 25 PSOs and prospectively followed for a mean of 36 months. The etiology for imbalance was posttraumatic (n=9), Scheuermann disease (n=6), congenital (n=5), Post-tuberculous (n=3), and post-laminectomy (n=1). PSO was performed at T7 (n=1), T8 (n=1), T9 (n=2), T10 (n=1), T11 (n=3), T12 (n=4), and at L1 (n=6), L2 (n=5), and at L3 (n=2). Radiographic and clinical outcomes analysis was performed. Results: The mean operative time was 5.6±3.2 hours and the mean blood loss was 1,319±1,416 ml. Patients reported very good satisfaction (86%) and good function (79%) at final follow-up. The mean correction of the kyphotic angle at the osteotomy site was 32.3°±5.0°. No permanent neurological deficits were encountered. Postoperative complications included pulling out of screws (n=1) and recurrence of deformity within 48 hours after surgery requiring revision and longer fixation, transient lower limb paraesthesia (n=2), superficial infection (n=1), and significant wound hematoma requiring drainage (n=2). Progressive distal junctional kyphosis occurring in a patient with Scheuermann’s disease was managed 6 months later with vertebral column resection and distal fixation. One patient developed pseudarthrosis and implant failure 9 months postoperatively. He was revised by graft augmentation and rods exchange. Conclusion: PSO can provide satisfactory clinical and radiographic outcomes with acceptable risk and morbidity. (2012ESJ016)