Meta-analysis finds minimal benefit of liposomal bupivacaine in TAP blocks for postoperative pain

This meta-analysis evaluates the efficacy of liposomal bupivacaine (LB) versus standard bupivacaine (SB), with or without adjuvants, in transversus abdominis plane (TAP) blocks for postoperative analgesia. Registered in PROSPERO (CRD420251084761), this meta-analysis screened randomized controlled trials (RCTs) published from 2000 to 2025 in PubMed, the Cochrane Library, Embase, and Wanfang databases. The primary outcome was the cumulative morphine milligram equivalent (MME) within 1 day after surgery. Secondary outcomes included the MME within 2–3 days after surgery, pain scores on postoperative days 1–3, time to first rescue analgesia, time to first flatus passage, time to first ambulation, postoperative nausea and vomiting (PONV), local anesthetic-related adverse events and toxicity, and length of hospital stay. A total of 13 randomized controlled trials (RCTs) (n = 1,528) were included in this meta-analysis. Compared to standard bupivacaine, liposomal bupivacaine reduced the MME within 1 day after surgery (mean difference (MD): −0.62 mg, 95%CI: −1.13 to −0.11). Liposomal bupivacaine also reduced pain scores on postoperative days 1–3, measured by the numeric rating scale (NRS; day 1: MD −0.65, 95% CI −1.03 to −0.28; day 2: MD −0.40, 95% CI −0.77 to −0.04; day 3: MD −0.30, 95% CI -0.48 to −0.13), prolonged the duration of analgesia (MD 5.39 h, 95% CI 0.06–10.72), and accelerated flatus passage (MD −0.23 day, 95% CI −0.35 to −0.11). No superiority of LB over SB plus adjuvants was observed in postoperative opioid consumption or pain relief. The quality of evidence was rated as low to very low for these outcomes. Liposomal bupivacaine used in TAP blocks can provide only minimal reductions in opioid consumption and pain relief after surgery compared to standard bupivacaine. Given that the quality of evidence was low to very low, large-scale RCTs are required to validate our findings.