Quadratus Lumborum Block versus Thoracic Paravertebral Block for Postoperative Recovery Quality after Percutaneous Nephrolithotomy: A Randomized Noninferiority Trial

We aimed to determine whether anterior quadratus lumborum block (QLB) at the lateral supra-arcuate ligament is noninferior to thoracic paravertebral block (TPVB) for postoperative recovery quality after percutaneous nephrolithotomy (PCNL). A total of 72 adults (American Society of Anesthesiologists physical status I–II) undergoing elective unilateral PCNL were randomized to QLB ( n = 36) or TPVB ( n = 36). Before general anesthesia, patients received ultrasound-guided anterior QLB (0.5% ropivacaine, 30 mL) or TPVB (0.5% ropivacaine, 20 mL), with standardized multimodal analgesia including patient-controlled intravenous morphine. The primary outcome was the Quality of Recovery-15 (QoR-15) score at 24 h; noninferiority required the lower bound of the 95% confidence interval (CI) for the difference (QLB minus TPVB) to exceed the prespecified margin of −6 points in both the modified intention-to-treat and per-protocol populations. Secondary outcomes were pain intensity, morphine consumption, patient satisfaction, and adverse events. Median QoR-15 scores at 24 h were 124 (interquartile range [IQR], 118–128) for QLB and 122 (IQR, 117–125) for TPVB (median difference, 2; 95% CI, −1 to 5; p < 0.001 for noninferiority), robust at stricter margins and confirmed per protocol. In secondary and exploratory analyses, QLB prolonged time to first analgesia (from postanesthesia care unit [PACU] admission; restricted mean survival time difference, 7.9 h; 95% CI, 5.9 to 9.8; time-averaged hazard ratio, 0.18; 95% CI, 0.10 to 0.31; p < 0.001), reduced 24-h morphine consumption (−4 mg; 95% CI, −6 to 0; p = 0.035), and lowered pain area under the curve at rest (−10 cm·h; 95% CI, −15 to −4) and on movement (−15 cm·h; 95% CI, −22 to −8; both p < 0.001). Hypotension occurred in 4 of 35 patients (11%) with QLB versus 13 of 36 (36%) with TPVB (relative risk, 0.32; 95% CI, 0.11 to 0.88; p = 0.015). Anterior QLB was noninferior to TPVB for postoperative recovery quality after PCNL. Associated reductions in pain and opioid use, and a lower observed incidence of hypotension, seen in secondary and exploratory analyses, are hypothesis-generating and warrant confirmation. Graphical abstract available for this article. Chinese Clinical Trial Registry, ChiCTR2100044431.