| Abstrakt: |
Study design: Retrospective analysis of prospectively collected data. Objective: To determine the influence of postoperative ideal lordosis distribution and ideal sagittal harmony on mechanical complications in patients undergoing one-level lumbar pedicle subtraction osteotomy (L-PSO). Summary of background data: Many variables have been associated with mechanical complications after L-PSO. However, the impact of restoring the ideal inflexion point, lumbar apex, and sagittal shape is still underexplored. Methods: Analyzed risk factors were: age and patient-related variables, PSO level, interbody cages, rod material/diameter, number of rods, upper instrumented vertebra, lower instrumented vertebra, PI-LL mismatch, global tilt (GT), postoperative level of lumbar apex (LApex), postoperative level of inflexion point (InfxP), and postoperative type of Roussouly sagittal profile (R-type). These last variables were compared to ideal (based on pelvic incidence). Univariate and multivariate analyses were performed to identify risks for mechanical complications with a minimum 2-year follow-up. Results: A total of 87 patients were included. Mean follow-up was 4.5?±?1.7 years. 40.2% of the patients suffered postoperative mechanical complications (7 PJK, 4 PJF, 18 pseudoarthrosis/rod breakage, 6 screw pullout). Mean time for complications was 584?±?416 days from surgery. Univariate analysis showed that age (63 vs 57 years; P?=?0.04), BMI (28.1 vs 25.9; P?=?0.024), preoperative-GT (50.7° vs 38.7°; P?<?0.001), postoperative-GT (28.9° vs 23.4°; P?=?0.018), postoperative LApex location mismatched from ideal (77.8% vs 22.2%; P?=?0.036), and postoperative R-type mismatched from ideal (67.6% vs 22.6%; P?<?0.001) were significantly related to mechanical complications. The independent factors selected by multivariate analysis were: postoperative R-type mismatched from ideal OR 11.3 (95% CI? ?3.9–32.6; P?<?0.001), age OR 1.05 (95% CI 1–1.1; P?=?0.03), and LApex matching OR 0.5 (95% CI 0.27–0.97; P?=?0.04). The further the LApex was from its ideal position, the higher the risk of mechanical complications (P?=?0.036). Conclusions: Over other multiple suspected risk factors, proper lumbar apex position and ideal sagittal shape restoration played an important role in postoperative mechanical complications after L-PSO. Level of evidence: III. |
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