Anterior quadratus lumborum blocks for postoperative pain treatment following intra‐abdominal surgery: A systematic review with meta‐analyses and trial sequential analyses

Background The anterior quadratus lumborum (QL) block may be used for postoperative pain management for intra‐abdominal surgeries, but the evidence is uncertain. We aimed to investigate the benefit and harm of the anterior QL block compared to placebo/no block for intra‐abdominal surgery. Methods We searched Medline, Embase, and CENTRAL for randomized controlled trials investigating anterior QL block for postoperative pain management for adult patients undergoing any intra‐abdominal surgery. The two co‐primary outcomes were cumulative 24‐h opioid consumption and serious adverse events. We performed meta‐analysis, trial sequential analysis (TSA), assessed the risk of bias, and present the certainty of evidence with the Grading of Recommendations, Assessment, Development and Evaluation approach. Results Thirty‐five trials randomizing 2418 patients were included in the meta‐analyses. Anterior QL block may reduce cumulative 24‐h intravenous opioid consumption compared to placebo/no block (MD −10.42 mg, 96.7% CI −14.83 to −6.01, TSA‐adjusted CI −17.03 to −3.82, p