Predicting adequate segmental lordosis correction in lumbar spinal stenosis patients undergoing oblique lumbar interbody fusion: a focus on the discontinuous segment

Purpose: To identify the factors associated with a correction of the segmental angle (SA) with a total change greater than 10° in each level following minimally invasive oblique lumbar interbody fusion (MIS-OLIF). Methods: Patients with lumbar spinal stenosis who underwent single- or two-level MIS-OLIF were reviewed. Segments with adequate correction of the SA >10° after MIS-OLIF in immediate postoperative radiograph were categorized as discontinuous segments (D segments), whereas those without such improvement were assigned as continuous segments (C segments). Clinical and radiological parameters were compared, and multivariate logistic regression analysis was performed to identify factors associated with SA correction >10° after MIS-OLIF. Results: Of 211 segments included, 38 segments (18.0%) were classified as D segments. Compared with C segments, D segments demonstrated a significantly smaller preoperative SA (mean ± standard deviation [SD], − 1.1° ± 6.7° vs. 6.6° ± 6.3°, p < 0.001), larger change of SA (mean ± SD, 13.5° ± 3.4° vs. 3.1° ± 3.9°, p < 0.001), and a higher rate of presence of facet effusion (76.3% vs. 48.6%, p = 0.002). Logistic regression revealed preoperative SA (odds ratio (OR) [95% confidence interval (CI)]:0.733 [0.639–0.840], p < 0.001) and facet effusion (OR [95% CI]:14.054 [1.758–112.377], p = 0.027) as significant predictors for >10° SA correction after MIS-OLIF. Conclusion: Preoperative kyphotic SA and facet effusion can predict SA correction >10° following MIS-OLIF. For patients with lordotic SA and no preoperative facet effusion, supplemental procedures, such as anterior column release or posterior osteotomy, should be prepared for additional lumbar lordosis correction required for remnant global sagittal imbalance after MIS-OLIF.