First described by Blanco (2007), ultrasound-guided quadratus lumborum block (QLB) belongs to the fascial plane block where local anesthetic is injected next to the quadratus lumborum muscle (Elsharkawy et al., 2019). According to the needle tip position in relation to the quadratus lumborum muscle, there are mainly 4 approaches for QLB: I) lateral QLB (QLB1); II) posterior QLB (QLB2); III) anterior (QLB3, also known as transmuscular QLB, and IV) intramuscular QLB (El-Boghdadly et al., 2016; Nassar et al., 2021). In this OE Original, we conduct a systematic review and meta-analysis to examine randomized controlled trials (RCTs) and determine the efficacy and safety of QLB for the postoperative pain management in patients undergoing....