Surgical and Radiographic Outcomes After Pedicle Subtraction Osteotomy According to Surgeon's Experience

STUDY DESIGN: Retrospective case series. OBJECTIVE: The aim of this study was to evaluate and compare the surgical, radiographic, and clinical outcomes of pedicle subtraction osteotomy (PSO) according to surgeon's experience. SUMMARY OF BACKGROUND DATA: Although PSO has been widely used to correct spinal deformities, it still remains technically demanding procedure with high complications. METHODS: Comparative analysis of 40 consecutive patients treated with lumbar PSOs was performed. According to time period, the former and latter 20 patients were divided into group 1 and group 2, respectively. Patients' demographic data, operative, radiographic/clinical outcomes, and complications were compared between the groups. RESULTS: Baseline characteristics and preoperative radiographic parameters were not different between the groups. Significant reductions of operative time (569.6 vs. 392.0 minutes, P = 0.000), surgical bleeding (1777.5 vs. 949.5 mL, P = 0.002), and transfused volume of red blood cell (1232.6 vs. 864.1 mL, P = 0.041) in group 2 were observed. Postoperative sagittal vertical axis was significantly different between the groups (40.1 and -3.6 mm, groups 1 and 2, respectively, P = 0.008), and the difference was sustained to the ultimate follow-up (59.4 vs. 13.2 mm, P = 0.003). There was a difference regarding the amount of curve correction by PSO, which was significantly greater in group 2 (25.7° vs. 35.8°, P = 0.023). Intraoperative complications (7 vs. 1, P = 0.019) were significantly lower in group 2. Total complications (20 vs. 10, P = 0.070), postoperative transient neurologic deficit (2 vs. 1), and revision surgery (4 vs. 3) were also lower in group 2, without statistical significance. The amount of the improvement of SRS-22 score was not different between the groups (P = 0.395). CONCLUSION: PSO may be performed in patients with fixed sagittal imbalance with an acceptable rate of complications after about 20 cases. With acquisition of surgical experiences, surgeons could perform PSO more effectively and safely.