Ultrasound-guided quadratus lumborum block for postoperative analgesia

BACKGROUND Ultrasound-guided quadratus lumborum block (QLB) is a truncal block with several technique variations. It has been reported as providing effective analgesia for postoperative pain. OBJECTIVES The aim of this review was to evaluate the efficacy and safety of QLB for postoperative analgesia. The primary outcome was cumulative opioid consumption at 24 h postoperatively. The main secondary outcomes were the time to the first rescue opioid analgesic, pain scores at 24 h postoperatively and the incidence of postoperative nausea and vomiting (PONV). DESIGN This was a systematic review and meta-analyses of observational studies and randomised controlled trials (RCTs). PRISMA-P guidelines were followed, and the review was registered in PROSPERO. GRADE was used to assess the quality of evidence. DATA SOURCES The search was performed from several databases (Ovid MEDLINE, PubMed, Scopus, Web of Science, CINAHL and the Cochrane CENTRAL) from inception up to June 2019. ELIGIBILITY CRITERIA RCTs and prospective observational studies that investigated the postoperative analgesic properties of US-guided single shot QLB in adult patients undergoing abdominal or hip surgery were included. QLB was compared with other analgesics. RESULTS Twenty-seven studies constituting 1557 patients were reviewed. Twelve studies with 803 patients were included in the meta-analysis on the primary outcome. Overall opioid consumption at 24 h postoperatively was reduced [mean difference, −11.15 (95% CI, −15.33 to −6.97) mg, I 2 = 99%, moderate certainty in GRADE] and the time to the first opioid analgesic was longer in patients with QLB: 7 studies with 499 patients, mean difference, 189.32 (95% CI, 114.4 to 264.23) min, I 2 = 98%. There were no differences in pain grades. The incidence of PONV was lower in patients with QLB [11 studies with 744 patients, OR 0.40 (95% CI, 0.27 to 0.58), I 2 = 7%]. Reported complications and adverse effects of QLB were minimal. CONCLUSION QLB reduced postoperative opioid consumption, prolonged the time to the first rescue opioid analgesic and diminished the incidence of PONV. QLB appears to be an applicable option for postoperative analgesia after abdominal and hip surgery. REGISTRATION NUMBER PROSPERO, https://www.crd.york.ac.uk/prospero/, CRD42016039921.