Analgesic Effectiveness of Liposomal Bupivacaine versus Plain Local Anesthetics for Abdominal Fascial Plane Blocks: A Systematic Review and Meta-analysis of Randomized Trials

Background: Liposomal bupivacaine is reported to prolong the duration of analgesia when used for abdominal fascial plane blocks compared to plain local anesthetics; however, evidence from randomized trials is mixed. This meta-analysis aims to compare the analgesic effectiveness of liposomal bupivacaine to plain local anesthetics in adults receiving abdominal fascial plane blocks. Methods: Randomized trials comparing liposomal bupivacaine and plain (nonliposomal) local anesthetics in abdominal fascial plane blocks were sought. The primary outcome was area under the curve rest pain between 24 to 72 h postoperatively. Secondary outcomes included rest pain at individual timepoints (1, 6, 12, 24, 48, and 72 h); analgesic consumption at 0 to 24, 25 to 48, and 49 to 72 h; time to analgesic request; hospital stay duration; and opioid-related side effects. Data were pooled using the Hartung-Knapp-Sidik-Jonkman random effects method. Results: Sixteen trials encompassing 1,287 patients (liposomal bupivacaine, 667; plain local anesthetics, 620) were included. The liposomal bupivacaine group received liposomal bupivacaine mixed with plain bupivacaine in 10 studies, liposomal bupivacaine alone in 5 studies, and both preparations in 1 three-armed study. No difference was observed between the two groups for area under the curve pain scores, with a standardized mean difference (95% CI) of -0.21 cm.h (-0.43 to 0.01; P = 0.058; I = 48%). Results were robust to subgroup analysis based on (1) potential conflict of interest and (2) mixing of plain local anesthetics with liposomal bupivacaine. The two groups were not different for any of the day 2 or day 3 secondary outcomes. Conclusions: This systematic review and meta-analysis suggests similar analgesic effectiveness between liposomal bupivacaine and plain local anesthetics when used for fascial plane block of the abdominal wall. The authors' analysis does not support an evidence-based preference for liposomal bupivacaine compared to plain local anesthetics for abdominal fascial plane blocks.