Ultrasound-guided quadratus lumborum block for postoperative analgesia in renal surgery: a systematic review and meta-analysis of randomized controlled trials

Background Quadratus lumborum block (QLB) guided by ultrasound is a novel local block anesthesia technique, which can be used in various surgeries for multimodal analgesia. Its analgesic effectiveness for renal surgery is still uncertain. The aim of this meta-analysis was to assess the postoperative analgesic efficacy of QLB in adult patients undergoing renal surgery. Methods We systematically searched randomized controlled trials (RCTs) through the databases of Cochrane Library, Embase, and PubMed until June 21, 2021. Postoperative consumption of opioid in the first 24-h was set as the primary outcome. The risk of bias was evaluated by Cochrane methodology. Results Ten RCTs involving 577 patients were eligible for our inclusion criteria. Ultrasound-guided QLB significantly reduced postoperative consumption of opioid in the first 24 h after surgery (mean differences [MD] - 17.58, 95% confidence interval [CI] - 23.14 to - 12.02, P < 0.00001, I-2 = 98%). Similarly, the results were consistent in subgroups analysis of both different types of renal surgeries and different QLB approaches. The QLB also significantly decreased postoperative static pain scores at different time points, and reduced the incidence of postoperative nausea and vomiting (PONV) (risk ratio [RR] = 0.48, 95% CI 0.33 to 0.70, P = 0.0002, I-2 = 0%) and the number of rescue analgesia patients (RR = 0.34, 95% CI 0.20 to 0.58, P < 0.0001, I-2 = 0%). No major complications related to QLB were reported in the included studies. Conclusions Ultrasound-guided QLB improves postoperative analgesic efficacy and reduces PONV in adult patients undergoing renal surgery. There is currently limited evidence concerning the analgesic effects of different QLB approaches after renal surgery, and further research is required in this area. PROSPERO registration PROSPERO Registration CRD42021260821.