Posterior lumbar interbody fusion versus interspinous stabilization in lumbar spinal stenosis: a meta-analysis.

backgroundPosterior lumbar interbody fusion (PLIF) and interspinous stabilization (ISS) are both used to treat lumbar spinal stenosis (LSS), but their comparative effectiveness and safety remain debated. Evidence comparing these approaches has evolved with the introduction of newer ISS devices and advances in contemporary surgical practice.

methodsA systematic search of PubMed, Google Scholar, Embase, and Scopus was conducted up to December 2, 2025, to identify comparative studies evaluating PLIF versus ISS for LSS. Nineteen studies met the inclusion criteria, comprising 214,155 patients (203,414 PLIF; 10,741 ISS). Outcomes included pain and functional measures, reoperation and revision rates, perioperative parameters, and complications. Three additional analyses were performed: subgroup analysis by publication period (before 2017 vs. 2017 onward), sensitivity analysis after excluding studies with very large sample sizes, and a study-design sensitivity analysis after excluding randomized controlled trials (RCTs).

resultsPLIF and ISS showed no significant differences in short- and mid-term pain or disability outcomes, including VAS leg and back pain at 3 months and 1 year, ΔVAS, ODI at 3 months and 1 year, and ΔODI. PLIF was associated with a greater change in segmental range of motion (ΔROM) (MD 6.96, 95% CI 4.94-8.97; p < 0.001). Compared with PLIF, ISS was associated with shorter operative time (MD 80.26 min, 95% CI 55.97-104.55; p < 0.001), lower blood loss (MD 260.54 mL, 95% CI 173.89-347.18; p < 0.001), and shorter hospital stay (MD 3.50 days, 95% CI 2.07-4.94; p < 0.001). Reoperation rates did not differ significantly between groups (RR 1.09, 95% CI 0.47-2.51). Similarly, revision rates were not significantly different between PLIF and ISS (RR 1.14, 95% CI 0.56-2.31). PLIF was associated with higher rates of mechanical complications (RR 1.60, 95% CI 1.09-2.33; p = 0.015), infectious complications (RR 3.50, 95% CI 2.67-4.58; p < 0.001), cardiopulmonary complications (RR 5.29, 95% CI 1.07-26.19; p = 0.041), and overall complications (RR 2.44, 95% CI 1.82-3.26; p < 0.001). In studies published before 2017, PLIF was associated with greater ΔROM and lower reoperation rates, but these differences were no longer observed in studies published from 2017 onward. Excluding studies with very large sample sizes did not materially change the main findings. Similarly, exclusion of the two RCTs did not materially alter the direction or statistical significance of the pooled estimates.

conclusionsPLIF and ISS provide broadly comparable short- and mid-term pain and functional outcomes for LSS. ISS is associated with consistent perioperative advantages and lower overall complication rates, while differences in reoperation and revision rates were not significant. Subgroup and sensitivity analyses, including the analysis excluding RCTs, suggest that earlier PLIF advantages in ΔROM and reoperation were not maintained in more recent studies, whereas the perioperative benefits of ISS remained robust. Larger randomized studies with longer follow-up and device-specific analyses are needed.