Abstract
Introduction: This study aimed to compare radiographic alignment, functional outcomes, and complication profiles between anterior and posterior interbody cage positions in posterior lumbar interbody fusion (PLIF) for lumbar spondylolisthesis.
Methods: A total of 129consecutive patients underwent single-level PLIF using a banana-shaped polyetheretherketone (PEEK) cage via a standard posterior midline approach (January 2022-January 2024; minimum 24-month follow-up). Based on postoperative cage center position relative to the midpoint of the superior endplate of the caudal vertebral body, patients were classified as anterior (n = 61) or posterior (n = 68). Primary outcomes included lumbar lordosis correction (ΔLL), pelvic incidence–lumbar lordosis (PI–LL) mismatch, Oswestry Disability Index (ODI), and visual analog scale pain scores. Multivariable logistic regression incorporating propensity score covariate adjustment was performed to identify independent predictors of radiographic, fusion, and clinical success.
Results: Anterior cage placement was associated with significantly greater postoperative LL (56.1° vs. 50.5°; p < 0.001), lower PI–LL mismatch (5.4° vs. 11.3°; p < 0.001), and improved adjusted odds of radiographic success (odds ratio [OR] 4.8, 95% confidence interval [CI] 2.1-11.2; p < 0.001) and clinical success (OR 3.9, 95% CI 1.4-10.7; p = 0.008). Greater segmental lordosis correction (Δ5.0° vs. 3.4°; p < 0.001), slip reduction (8.3% vs. 5.3%; p < 0.001), and sagittal vertical axis improvement (15.2 vs. 9.0 mm; p < 0.001) were also observed in the anterior group.Both groups exceeded minimal clinically important difference thresholds at all time points, but functional improvement was greater in the anterior group (24-month ODI: 33.8 vs. 42.1; p < 0.001). Estimated blood loss was significantly higher in the anterior group (522.1 vs. 411.0 mL; p = 0.001). Late implant-related complications were substantially more frequent in the posterior group (anterior 6.6% vs. posterior 26.5%; p = 0.004), while adjacent segment disease rates were comparable at 24 months (9.8% vs. 11.8%; p = 0.81).
Conclusions: Anterior cage positioning during PLIF was associated with superior sagittal alignment correction, greater functional improvement, and fewer late implant-related complications at 24-month follow-up.
