Ultrasound-guided erector spinae plane block versus anterior quadratus lumborum block for postoperative analgesia after percutaneous nephrolithotomy: A randomized controlled study

ABSTRACT Background: Percutaneous nephrolithotomy (PCNL) is associated with significant postoperative pain. Ultrasound-guided erector spinae plane block (ESPB) and anterior quadratus lumborum block (QLB) are increasingly used for analgesia; however, direct comparative evidence in PCNL remains limited. This randomized controlled study compared their analgesic efficacy following unilateral PCNL. Methods: Eighty-four adult patients (American Society of Anaesthesiologists I–III) were randomized to receive ESPB or anterior QLB. Three patients in each group had block failure . The primary outcome was time to first rescue analgesia. Secondary outcomes included Numeric Rating Scale (NRS) pain scores at rest and during movement at 1, 2, 6, 12, and 24 h, total tramadol consumption, complications, time to ambulation, and length of hospital stay. Results: Time to first rescue analgesia was significantly longer in Group E compared to Group Q (406.15 ± 161.97 min vs. 326.15 ± 155.61 min; mean difference 80 min; 95% CI 9–151; P = 0.022; Cohen’s d = 0.50). At 2 h, fewer patients in Group E required rescue analgesia (7.7% vs. 25.6%; P = 0.033). NRS scores at rest and during movement were comparable at all time points. Total tramadol consumption over 24 h was similar; however, fewer patients in Group E required tramadol at 12 h (23.1 vs. 43.6%; P = 0.049). Complication rates, ambulation time, and length of hospital stay were comparable. Conclusion: Both ESPB and anterior QLB provide effective postoperative analgesia after PCNL. ESPB offers moderate effect size prolongation in time to first rescue analgesia, suggesting a modest early postoperative analgesic advantage without increased complications.