Two-year radiological outcome of adult spinal deformity treated with lumbar pedicle subtraction osteotomy or posterior lumbar interbody fusion. A propensity score-matched analysis.

Study Design: Retrospective cohort study OBJECTIVES: The purpose of this study was to compare the 2-year radiological outcome and revision rates in patients with ASD treated with either PSO or PLIF, when PLIF was used to improve sagittal balance.

Methods: In 2016, PLIF was introduced at our institution as an alternative method when restoring lumbar lordosis. We analyzed two cohorts of patients with ASD undergoing either: PSO in 2010-2015 or PLIF in 2016-2020, retrospectively. The rate of mechanical failure was analyzed using competing risk analysis.

Results: We included 141 patients (111 PSO and 30 PLIF). After propensity score matching, 60 patients undergoing PSO and 30 patients undergoing PLIF were included. Baseline demographics were comparable between groups but radiographic parameters differed significantly on Sacral Slope; 23±13 vs 28±10, and segmental lordosis; 7±14° vs 14±13° (p-value<0.05) for PSO and PLIF, respectively. Post-operatively, PSO patients had a larger global lordosis; 54±12 vs 48±14 and segmental lordosis of 33±10 vs 26±10 (p-value <0.05), than PLIF patients. Competing risk analysis showed a cumulative incidence of revision surgery of 38.3% (95% CI 28-43) vs 16.7 (95% CI 3-30) (p-value <0.05) for PSO and PLIF at 2-year follow-up.

Conclusion: A significantly lower revision rate was seen for patients undergoing PLIF compared with PSO at a 2-year follow-up. A satisfactory sagittal correction was obtained for both groups regardless of the procedure. Thus, PLIF could be a viable option in selected cases.