Study Design. Retrospective review of prospectively collected data.
Objective. To assess the prevalence, risk factors, and clinical outcomes for pseudarthrosis after a lumbar pedicle subtraction osteotomy (PSO).
Summary of Background Data. There exists no large series that examines pseudarthrosis rates of PSOs.
Methods. Data of 171 consecutive patients with adult deformity who underwent a lumbar PSO by 2 surgeons at a single institution with a minimum 2-year follow-up were analyzed. Pseudarthrosis diagnosed through sagittal malalignment and instrumentation failure noted on radiograph was confirmed intraoperatively.
Results. Eighteen (10.5%) of 171 patients developed pseudarthrosis after a PSO. Eleven of the 18 patients (6.4% of all patients, 61.1% of the 18 patients with pseudarthrosis) had pseudarthrosis at the PSO site, L3 being the most common; other locations included the lumbosacral junction (4/18), thoracolumbar junction (2/18), and upper thoracic spine (1/18). Preoperative pseudarthrosis level was a predictor of the postoperative level of pseudarthrosis (93%). Fifteen of the 18 patients (83%) had no interbody fusion directly above or below the PSO site, 16 (88%) had a history of pseudarthrosis at the time of PSO surgery and 2 of 3 patients who had prior radiation to the lumbar region developed pseudarthrosis. Most pseudarthroses occurred within the first 2 years (n = 13/18), between 2 and 5 years (n = 3/18), and more than 5 years (n = 2/18) postoperatively. Prior pseudarthrosis (P < 0.0001), pseudarthrosis at the PSO site (P < 0.0001), prior decompression in the lumbar region (P = 0.0037), prior radiation to the lumbar region (P < 0.0001), and presence of inflammatory/neurological disorders (P < 0.0036) were identified as risk factors. All 18 patients with pseudarthroses required revision surgery (posterior-only surgery, n = 12; anteroposterior surgery, n = 6) due to loss of sagittal alignment and pain. The mean pre-revision Scoliosis Research Society score was 85, post-revision score was 95 (P = 0.0166), and the mean pre-revision Oswestry Disability Index score was 42.5, post-revision score was 34.5 (P = 0.0203).
Conclusion. The overall prevalence of pseudarthrosis was 10.5% of which 61% occurred at the actual PSO site and Scoliosis Research Society and Oswestry Disability Index scores improved significantly after pseudarthrosis repair.
Level of Evidence: 4
There exists no large series that examines pseudarthrosis rates after lumbar PSO (pedicle subtraction osteotomy). Eighteen of 171 patients developed pseudarthrosis after a PSO, of which 11 occurred at the PSO site. All 18 patients required revision surgery due to loss of sagittal alignment and pain. Scoliosis Research Society (SRS) and Oswestry Disability Index (ODI) scores improved after pseudarthrosis repair.
*University of North Texas Health Science Center Fort Worth, TX and
†Department of Orthopaedic Surgery, Washington University School of Medicine, St Louis, MO.
Address correspondence and reprint requests to Lawrence G. Lenke, MD, Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8233, St Louis, MO 63110; E-mail: firstname.lastname@example.org
Acknowledgment date: September 27, 2012. First revision date: December 11, 2013. Second revision date: March 25, 2014. Acceptance date: March 26, 2014.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work.
Relevant financial activities outside the submitted work: board membership, consultancy, payment for lectures, patents, grants/grants pending, royalties, travel/accommodations/meeting expenses, fellowship grant, and philanthropic research funding from the Fox Family Foundation.