Posteromedial Quadratus Lumborum Block Versus Wound Infiltration After Caesarean Section A Randomised, Double-Blind, Controlled Study

BACKGROUND Reducing pain and minimising the use of opioids after caesarean section are crucial to enhancing maternal recovery and promoting mother-newborn interaction. Various techniques have been implemented to improve analgesia. We compared the analgesic efficacy of posteromedial quadratus lumborum block with that of wound infiltration following elective caesarean section. OBJECTIVE We hypothesised that within a multimodal analgesia approach, posteromedial quadratus lumborum block would, due to its potential to relieve visceral pain, result in a 15% reduction in 24-h postoperative opioid consumption compared with wound infiltration. DESIGN A double-blind, randomised, placebo-controlled clinical study. SETTING A single-centre study between August 2019 and May 2020. PATIENTS One hundred and sixteen women were randomly allocated into two groups. In the quadratus lumborum group, 20 ml 0.9% saline was injected into the surgical wound followed by bilateral posteromedial quadratus lumborum block using 20 ml 0.25% levobupivacaine per side. In the wound infiltration group, 20 ml of 0.25% levobupivacaine was injected into the surgical wound followed by a bilateral posteromedial quadratus lumborum injection with 20 ml 0.9% saline per side. MAIN OUTCOME MEASURES The primary outcome was opioid (piritramide) consumption at 24 h. Secondary outcomes were piritramide consumption at 48 h, time-to-first analgesic request, pain scores at rest and with movement, surgery-to-first-ambulation time, surgery-to-breastfeeding time, sedation, pruritus and complications. RESULTS Piritramide consumption in 24 h was significantly lower with posteromedial quadratus lumborum block (1.5 +/- 1.8 mg) than with wound infiltration (2.2 +/- 1.7 mg) (P = 0.04), mean difference of -0.7 mg, (95% CI -1.3 to -0.03). In those who required piritramide, time-to-first analgesic request was significantly longer with posteromedial quadratus lumborum block 11 [7 to 14] h, than with wound infiltration 7 [5 to 11] h (P = 0.02). Pain scores were low, with no differences recorded at rest and with movement. There were no differences in time-to-ambulation and time-to-breastfeed between the groups. CONCLUSION As a component of multimodal post-caesarean section analgesia, posteromedial quadratus lumborum block was associated with lower 24-h opioid consumption compared with wound infiltration.