Comparison of intrathecal morphine, lateral quadratus lumborum block, and their combination for analgesia and quality of recovery after Caesarean delivery: a randomised, double-blind, two-centre clinical trial

BACKGROUND: Lateral quadratus lumborum block (QLB) is a potential alternative to intrathecal morphine (ITM) for analgesia after Caesarean delivery. We compared quality of recovery (QoR) and analgesia with lateral QLB, ITM, or ITM+QLB. METHODS: In this randomised, double-blind, placebo-controlled trial, women undergoing Caesarean delivery under spinal anaesthesia were allocated to (1) bilateral lateral QLB with 20 ml 0.5% ropivacaine; (2) 100 μg preservative-free ITM with sham QLB; or (3) ITM+QLB. The primary outcome was the QoR-40 score at 24 h. Secondary outcomes included pain scores, opioid consumption, and adverse effects. Given three-group comparisons, statistical significance was set at P<0.017. RESULTS: Fifty-eight women were analysed. Noninferiority testing for QoR-40 at 24 h between ITM and QLB was inconclusive (mean difference -0.9; 90% confidence interval [CI] -0.9 to 13.5). QLB reduced the resting pain score at 6 h compared with ITM (mean difference 2.9 [95% CI 1.3, 4.5]; P<0.001). Compared with ITM alone, ITM+QLB reduced the resting pain at 6 h (mean difference 3.3 [1.9, 4.8]; P<0.001), coughing pain at 6 h (3.0 [1.4, 4.7]; P<0.001), and worst pain at 24 h (1.8 [0.6, 3.1]; P=0.006). Oxycodone consumption and nausea or vomiting did not differ between groups. Pruritus was more frequent with QLB and ITM+QLB compared with ITM alone but was predominantly mild. CONCLUSIONS: Noninferiority of QLB vs ITM for QoR-40 at 24 h was inconclusive. However, QLB reduced early resting pain vs ITM, whereas ITM+QLB further reduced early resting and coughing pain and worst pain at 24 h vs ITM alone. Larger trials are needed to confirm these findings. CLINICAL TRIAL REGISTRATION: NCT02871713 (https://clinicaltrials.gov/study/NCT02871713).