Quadratus lumborum block for postoperative analgesia: a systematic review and meta-analysis

Purpose The goal of the present systematic review is to determine the efficacy of the quadratus lumborum block (QLB) in providing postoperative analgesia for abdominal wall and hip surgeries when compared with placebo or other analgesic techniques. Methods Electronic databases (Medline, Embase, Cochrane Central, and Scopus) were searched for keywords and controlled vocabulary terms related to QLB from their inception to November 2019. The included studies compared ultrasound-guided single-injection QLB to placebo and other analgesic techniques in adult patients. Results Forty-two randomized-controlled trials provided the data for this systematic review. Eight studies were assessed as high risk of bias in at least one domain. The included studies had significant heterogeneity with regard to the type of surgery, comparator groups, and outcomes measured; therefore, a limited quantitative analysis was undertaken for the comparison of QLB vs no block or placebo in patients undergoing Cesarean delivery only. For Cesarean delivery, the QLB reduced the opioid use by 24.1 (95% confidence interval, 17.3 to 30.9) mg oral morphine equivalents in the first postoperative 24 hr compared with no block or placebo with no difference in pain scores at rest. For other surgical procedures, the pain scores and opioid use were lower in the QLB group when compared with placebo or no regional anesthesia technique. When compared with other regional anesthetic techniques, the analgesic benefit of QLB was marginal. Conclusion Quadratus lumborum block provided analgesic benefits compared with placebo for use in the abdominal wall and hip surgery, with only marginal benefits compared with other regional analgesic techniques. The identified studies used different variants of QLB in many different surgery types. These findings and conclusions, therefore, should be considered preliminary. Trial registration PROSPERO (CRD42018095965); registered 6 June 2018.