Effects of intramuscular quadratus lumborum block on post-cesarean pain: a randomized controlled trial

The goal of post-cesarean analgesia includes minimizing pain and enabling early ambulation. Quadratus lumborum block has emerged as a part of multimodal analgesia for this procedure. This randomized controlled trial compared the analgesic effects of anterior quadratus lumborum block (QLB3) and intramuscular quadratus lumborum block (QLB4). A total of 128 parturients undergoing cesarean delivery (64 per group) were enrolled in this study. Parameters including butorphanol consumption, PCA utilization, pain scores, block duration, adverse events and maternal satisfaction were assessed. QLB4 was associated with significantly lower 24/48-hour butorphanol use, less PCA pressing at 6-24 h, lower 6/12-hour NRS pain scores and a much lower block resolution rate at 12-24 h than QLB3 (all p < 0.05). QLB4 had a lower incidence of lower extremity hypoesthesia (0% vs. 46.88%), shorter procedural time, and higher maternal satisfaction scores (all p < 0.05). No significant between-group differences in late-stage opioid use, pain scores or other adverse events were found. QLB4 provides more effective, longer-lasting post-cesarean analgesia with superior safety and patient satisfaction, and greater procedural efficiency, making it a valuable multimodal analgesia option for cesarean delivery.Clinical trial registration: This trial was registered on the Chinses Clinical Trial Registry on 27/08/2025 (ChiCTR2500108272).