Meta-analysis: The utility of the anterior quadratus lumborum block in abdominal surgery

Background: Regional anesthesia is routinely used in Enhanced Recovery After Surgery pathways to improve postoperative recovery times. No consensus has been reached on optimal block type. This study reviews the current literature as it pertains to the anterior quadratus lumborum (aQL) block in all abdominal surgeries, as well as its efficacy compared to the transversus abdominis plane (TAP) block. Methods: PubMed was searched for original, peer-reviewed articles that include "(anterior) quadratus lumborum block." 89 articles were included. Data was extracted according to PRISMA guidelines, with articles manually reviewed by two independent reviewers. A meta-analysis was then conducted on a subset of 14 randomized control trials (RCT) evaluating total oral morphine equivalent consumed at 12 and 24 h post-operatively in patients who received an aQL block compared to control. Results: 28 articles were included with 14 RCT used in a random-effects meta-analysis. There was a significant reduction in post-operative pain scores and opioid use in patients who receive an aQL block for abdominal surgeries. Meta-analysis determined a decrease in total oral morphine equivalent consumed at both 12 and 24 h postoperatively compared to controls. Compared to no region block, both the aQL and TAP block show a significant reduction in pain and post-operative opioid consumption. Conclusion: The literature demonstrates non-inferiority of the aQL block compared to the TAP block in abdominal surgery, with some studies suggesting its superiority. Limitations include heterogeneity in study type and design, as well as the presence of confounding variables when comparing across surgery types.