Cement leakage and post-operative outcomes after lower-versus higher-volume bone cement injection in percutaneous vertebroplasty: a systematic review and meta-analysis of randomized controlled trials.

purposeCement leakage is a common and occasionally serious complication of percutaneous vertebroplasty (PVP). We compared cement leakage (primary outcome) and post-operative pain (VAS) and disability (ODI) (secondary outcomes) between trial-defined lower-volume and higher-volume cement injection in osteoporotic vertebral compression fractures.

methodsWe searched PubMed, Embase, Scopus, the Cochrane Library, CNKI and Wanfang from January 2018 to 31 December 2025 (last search date), and included randomized controlled trials (RCTs). Risk of bias was assessed with RoB 2. "Lower-volume" denotes each trial's smaller-volume arm. Reported lower-volume arms ranged from 1.5 to 2.5 mL to < 6 mL, whereas higher-volume arms ranged from 2.6 to 3.5 mL to 7.0 mL or ≥ 6 mL, depending on the trial definition. Risk ratios (RR) for leakage and mean differences (MD) for VAS/ODI were pooled with random-effects models; an exploratory subgroup (lower-arm ≤ vs. > ~ 3.5 mL) was examined, and sensitivity analyses included leave-one-out analysis, exclusion of the single cervical trial, and exclusion of trials with ambiguous volume labels. Differences in VAS/ODI were interpreted against established minimal clinically important difference (MCID) thresholds.

resultsSixteen RCTs were included. Lower-volume injection was associated with a markedly lower risk of cement leakage (RR 0.30, 95% CI 0.22-0.40; I² = 0%), consistent across subgroups (test for interaction P > 0.30) and stable in leave-one-out analysis (RR 0.27-0.31) and on exclusion of the single cervical trial. Post-operative VAS differed negligibly between arms (MD 0.01 points, 95% CI -0.11 to 0.12), as did ODI among the 12 trials that actually measured it (MD -0.04 points, 95% CI -0.52 to 0.44); both were well below accepted MCID thresholds. Four trials did not measure ODI and were excluded from the ODI analysis.

conclusionTrial-defined lower-volume cement injection was associated with a substantially reduced risk of cement leakage, while differences in post-operative pain and disability were negligible and below accepted MCID thresholds. Because no non-inferiority margin was pre-specified, these findings should not be read as statistical non-inferiority. Given the wide variation in volume definitions and procedural detail across trials, the evidence supports an individualized lower-volume strategy rather than a single universally optimal volume.