Modified Single-Side-Lying Quadratus Lumborum Block Combined with Liposomal Bupivacaine versus Transversus Abdominis Plane Block for Post-Cesarean Analgesia: A Randomized Controlled Trial

Background: Inadequate post-cesarean analgesia remains a common clinical issue, associated with increased opioid use and risks of chronic pain and postpartum depression. Although the anterior quadratus lumborum block (QLB III) is more effective than transversus abdominis plane (TAP) block, it requires repeated positioning and may cause quadriceps numbness. To address these limitations, we designed a modified QLB to overcome these drawbacks. This study evaluated its analgesic efficacy and safety when combined with liposomal bupivacaine in cesarean delivery. Methods: This single-center, randomized, single-blind trial enrolled 70 patients undergoing elective cesarean delivery. Patients were randomized to modified QLB (Group Q) or TAP block (Group T). The primary outcome was postoperative Day 1 VAS pain score. Secondary outcomes included VAS scores on Days 2, 3, during uterine compression and oxytocin infusion, opioid consumption, recovery metrics, and adverse events. Results: Baseline characteristics were well balanced between the two groups (all p > 0.05). The modified QLB group achieved significantly lower VAS pain scores at rest, during uterine palpation and oxytocin infusion throughout the first three postoperative days (all p < 0.001), alongside fewer PCIA demands and reduced morphine-equivalent consumption. Recovery indicators and overall adverse event rates were comparable between groups, with no severe neurological or local complications observed in either cohort. Conclusion: Modified single lateral decubitus QLB combined with liposomal bupivacaine yields superior analgesia and reduces opioid consumption compared with the TAP block, demonstrating favorable safety and clinical value for enhancing postoperative recovery following cesarean delivery. Nevertheless, these findings are limited by the single-center design and relatively small sample size, and long-term follow-up of chronic pain and postpartum mental outcomes was not performed. Trial Registration Number: ChiCTR2400094584. The trial is publicly available and is registered at https://www.chictr.org.cn on December 25, 2024.