Analgesic effectiveness of quadratus lumborum block for patients after abdominal surgery: a systematic review and meta-analysis

Abstract

Background: A series of studies have reported that quadratus lumborum block (QLB) can have a great postoperative analgesia for lower abdominal surgery. However, a meta-analysis of the analgesic effect of QLB in patients undergoing lower abdominal surgery has not been published.Methods： We searched the databases of Pubmed, Embase, Cochrane Library, and Web of Science (updated to October 15, 2019). We cumulative opioid consumption at 6, 12, 24 and 48h after surgery; pain score (rest and dynamic) at 6, 12, 24 and 48h after surgery; occurrence of common opioid-related complications at 24h after surgery . Opioid consumption as the main outcome.Results：Thirteen randomized controlled trials (RCTs) including 751 patients were analysed. Compared with control group, QLB group can effectively reduce 24 and 48h cumulative opioid consumption 10.1mg (95%CI: -13,-7.2; p<0.00001) and 16.22mg (95%CI: -19.39,13.03; p<0.00001) in patients with cesarean section, but can reduce effectively cumulative opioid consumption in patients undergoing laparoscopic surgery at 6, 12 and 24h. Posterior QLB group and transmuscular QLB group reduced 24h cumulative opioid consumption 4.03mg ( 95%CI: -7.89, -0.19; p=0.04) and 12.44mg ( 95%CI: -20.2, -4.68; p=0.002), respectively. QLB group reduced rest visual analogue scale (VAS) score at 12 , 24 and 48 h ,however, the effective reduction of rest VAS score in patients undergoing cesarean section only occurs at 24h after surgery.Conclusion：QLB seems to provide better analgesia for patients undergoing laparoscopic surgery than patients undergoing cesarean section. Transmuscular QLB appears to have reduced postoperative opioid consumption compared to posterior QLB. More future RCTs are needed to support our conclusions.