Efficacy Comparison of Ultrasound-Guided and Dual-Guided (Ultrasound Plus Nerve Stimulation) Subcostal Quadratus Lumborum Block in Retroperitoneal Laparoscopic Nephrectomy: A Randomized Controlled Trial.

Objective: To compare the effectiveness of ultrasound (US) guidance alone versus combined nerve stimulation (NS) and US in subcostal quadratus lumborum block (SQLB) for patients undergoing laparoscopic nephrectomy. Methods: Eighty-four patients scheduled for laparoscopic nephrectomy were randomized to receive a SQLB with either US alone (US group) or combined US and NS guidance (US-NS group). Each patient received 25 mL of 0.5% ropivacaine for the block. The primary endpoint was the block success rate within 5 minutes after block. Secondary endpoints included the extent of sensory block, intravenous morphine equivalent consumption, NRS scores, frequency of rescue analgesia administration, puncture time, number of needle insertion attempts, ultrasonic images quality, and incidence of adverse reactions and complications. Results: The US-NS group demonstrated significantly higher block success rate compared to the US group (92.5% vs 62.5%, P < 0.05). Additionally, the US-NS group exhibited lower opioid requirements and fewer rescue analgesia interventions within the initial 24-hour postoperative period, broader sensory block coverage at 5, 10, and 15 minutes following injection, and lower NRS scores both at rest and during coughing at 6, 12, 24, and 48 hours post-surgery. However, the US-NS group required a longer puncture duration and more attempts to complete the SQLB. No significant differences were found between the two groups regarding the quality of ultrasound images and the incidence of adverse effects. Conclusion: Dual guidance with NS and US was superior to US alone for performing SQLB, resulting in higher block success rates and improved analgesic efficacy for laparoscopic nephrectomy.