Quadratus lumborum block for postoperative analgesia after cesarean delivery: a systematic review and meta-analysis

Background: Quadratus lumborum block (QLB) can reduce pain and opioid consumption after cesarean delivery. This systematic review investigated the effectiveness of QLB in reducing postoperative opioid use and its effect on pain scores compared with other analgesic methods after cesarean delivery.

Methods: Six medical databases were searched from their inception to August 2019. Trials were eligible if parturients underwent cesarean delivery under spinal anesthesia (not epidural or general anesthesia). The primary outcome was postoperative opioid consumption during the first 24 and 48 h. Secondary outcomes included pain scores, patient satisfaction, and side effects. The risk of bias was assessed using the Cochrane tool. Where possible, meta-analytic techniques were used to synthesize data, presented as mean difference with 95% confidence interval (CI).

Results: Twelve studies involving 904 patients were identified and analyzed. Opioid (intravenous morphine) consumption was significantly reduced with QLB when compared with placebo or no block during the first 24 h by 14.1 mg, (95% CI -20.8 to -7.5 mg) and 48 h by 20.8 mg, (95% CI -33.1 to -8.5 mg). Additionally, QLB significantly reduced 12-h pain scores at rest and during movement. However, this difference disappeared at 24 and 48 h. There was insufficient evidence regarding postoperative opioid use or pain scores with the use of QLB compared to intrathecal morphine.

Conclusions: The review findings show the superior analgesic effect of QLB when compared with systemic opioids in reducing postoperative opioid consumption, when intrathecal morphine is not administered.