Summary: Thoracic pedicle subtraction osteotomy (TPSO) improves focal thoracic deformity, however little data exists on the impact of TPSO upon global spinopelvic balance. Analysis of 41 TPSO procedures demonstrated that focal correction at the TPSO site favorably impacted regions of the spine remote from the osteotomy site, including improvement in global spinopelvic balance and normalization of pelvic parameters. Normalization of pelvic parameters, especially pelvic tilt, has previously been shown to strongly correlate with improved clinical outcome.
Introduction: Thoracic pedicle subtraction osteotomy (TPSO) can correct rigid thoracic deformity with significant focal correction. However, little data exists on the impact of TPSO upon global spinopelvic parameters. Purpose: evaluate the radiographic outcome of TPSO on regional and global spinopelvic alignment.
Methods: Multicenter, retrospective radiographic analysis of adult spinal deformity (ASD) patients receiving TPSO. Analysis included focal and regional measures (kyphosis and scoliosis at TPSO site) thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), global measures: sagittal vertical axis (SVA), T1 and T9 spinopelvic inclination (SPI), and pelvic measures: pelvic tilt (PT), pelvic incidence (PI) and sacral slope (SS).
Results: Between 2003‐2009, 41 patients received TPSO for ASD. Deformities included; primarily sagittal (n=21), coronal (n=13), and multiplanar (n=7) deformities. Resection levels ranged from T2 to T12;T8 was most common level (n=9). Mean sagittal correction for primary sagittal deformities was 34 degrees. Mean coronal correction for primary coronal deformity was 43 degrees. Mean total angular correction (sagittal + coronal correction) for multiplanar deformities was 76 degrees. Postoperative TK, TLK and SVA were significantly less than preoperative values (Table). Mean SVA correction was 26 mm. Postoperative TK improvement generated favorable PT correction (Table).
Conclusion: TPSO corrects regional and global spinal deformities. Total angular correction for all patients was 54 degrees, SVA correction was 26mm. Focal thoracic correction generated improved pelvic parameters including improved PT. Regional improvements in spinal balance following TPSO favorably impact the pelvis allowing postoperative normalization of pelvic parameters. Normalization of pelvic parameters, especially PT, has been shown to correlate with improved clinical outcome.