Effectiveness of quadratus lumborum block for postoperative pain: a systematic review and meta-analysis

Introduction: This study aimed to evaluate the effect of quadratus lumborum (QL) block on pain after surgeries under general or spinal anesthesia. Evidence acquisition: A systematic review and meta-analysis of randomized controlled trials (RCTs) were performed to compare pain scores at rest and with movement 48 h postoperatively in a QL block group and a control group both with placebo block and without block and the time to first additional analgesics. The analgesic effect of the QL block according to the type of surgery and block approach was also examined. A literature search was performed using well-known databases for articles published up to March 2019. Evidence synthesis: Nine RCTs were included. Compared to the control group, pain scores at rest were significantly lower for 48 h postoperatively in the QL block group. QL block reduced pain scores with movement at six, 12, and 24 h postoperatively. The QL block group exhibited the most improved numerical pain scores at 12 h postoperatively both at rest and with movement, with a mean difference (MD) of -2.16 (95% confidence interval [CI] -3.12 to -1.20) and -2.26 [95% CI -3.54 to -0.98]), respectively. The subgroup analysis of pain scores at rest showed a statistically significant subgroup difference (P=0.02, I2=75.7%), suggesting a different analgesic effect of QL block based on the approach. Time to first additional analgesics postoperatively was longer in the QL block group than in the control group (MD 333.51 minutes [95% CI 69.37 to 597.64]). Conclusions: QL block may be a good multimodal analgesic approach for pain after abdominal surgeries.restrictio