The analgesic efficacy of quadratus lumborum block in caesarean delivery: a meta-analysis and trial sequential analysis.

Abstract

Quadratus lumborum block (QLB) has recently gained popularity for postoperative analgesia after cesarean delivery (CD) as it provides both visceral and somato-sensory blockade of the abdomen. Aim of this meta-analysis was to evaluate the analgesic potential of QLB after CD. Electronic database from inception to December 2019 was searched systematically for randomized-controlled trials comparing QLB with injection of inactive solution in women undergoing CD. Primary outcome was consumption of morphine at 24h. Morphine consumption at 48h, dynamic and static pain scores at various time intervals were the secondary outcomes studied. Seven trials met the inclusion criteria. Morphine consumption was reduced significantly with QLB in comparison to sham or no block at 24h (mean difference [MD] -9.84mg; 95% confidence interval [CI] -18.16, -0.50; p = 0.04; I2 = zero). Adequate "information size" for above outcome was confirmed with trial sequential analysis, ruling out any possibility of a false-positive result. QLB significantly reduced pain scores at rest (MD -1.13; 95% CI -1.75, -0.56; p = 0.00) and on movement (MD -1.48; 95% CI -2.5, -0.46; p = 0.01) at 6h. However, statistically significant difference in pain scores persisted only for dynamic pain at 24h (MD -0.55; 95% CI -1.04, -0.06; p = 0.03). QLB does not provide any additional analgesic benefit to the parturient receiving intrathecal morphine. QLB significantly reduces opioid requirements in CD and may have analgesic effects lasting 24h.