The analgesic effect of transmuscular quadratus lumborum block versus erector spinae plane block for women undergoing elective Caesarean section: A randomized controlled trial.

Background: We aimed to compare the analgesic effect and quality of recovery of transmuscular quadratus lumborum block (QLB) and erector spinae plane block (ESPB) in the presence of multimodal analgesia following Caesarean section.

Methods: This randomised controlled trial included full-term pregnant women who underwent elective Caesarean section under spinal anaesthesia without intrathecal morphine. The included women were randomised to receive either bilateral QLB (n = 51) or bilateral thoracic ESPB (n = 51), in addition to the control group (n = 51) who did not receive any block. All participants received regular paracetamol (1 g/6h) and diclofenac (50 mg/8 h). Intravenous morphine was used as a rescue analgesic. The primary outcome was time to first morphine requirement. Secondary outcomes included total postoperative morphine consumption and total Obstetric Quality of Recovery-11 (ObsQoR-11) score.

Results: We analysed 51, 50 and 48 patients in the QLB, ESPB and control groups, respectively. The time to first morphine requirement in both QLB and ESPB groups was longer than that in the control group (median [quartiles] time: 6 [6,12] h, 6 [6,6] h and 4 [3,4] h, respectively; p-value <0.001), without significant differences between the two former groups. The total morphine consumption in both QLB and ESPB groups was lower than that in the control group (median [quartiles]:0 [0,5] mg, 0 [0,5] mg and 25 [25,30] mg, respectively; p-value <0.001), without significant differences between the two former groups. The QLB and ESPB groups had comparable ObsQoR-11 score, and both groups' scores were higher than the control group.

Conclusion: In patients undergoing elective Caesarean section under spinal anaesthesia without intrathecal morphine, both QLB and ESPB provided superior analgesia and quality of recovery compared to the standard care, without significant difference between the two blocks.