Operative outcomes 24 hours after retrograde intrarenal surgery for solitary renal calculi using a flexible and navigable suction ureteral access sheath. A prospective global multicenter study by the European Association of Urology Section on Urolithiasis.

Background: Suction techniques showed potential to improve outcomes of retrograde intra-renal surgery (RIRS). We assessed the 24-hour stone-free rate (SFR) and complications after RIRS using flexible and navigable suction ureteral access sheaths (FANS-UAS).

Methods: Sixteen centers prospectively contributed to data (August 2023-October 2023). Inclusion criteria: age ≥18 years, single renal stone, pre and 24-hour post-RIRS CT scan. Exclusion criteria were: ureteral stone, anomalous kidney, multiple stones. SFR was divided into: 1) grade A - no fragments; 2) grade B - fragments ≤2 mm; 3) grade C - fragments 2.1-4 mm; and 4) grade D - fragments >4 mm. A multivariable logistic regression analysis model was performed to assess factors associated with the odds of having grade A stone-free status. Data are expressed as median (interquartile range), absolute numbers and frequencies, odds ratio (OR), and 95% confidence interval (CI).

Results: One hundred forty-two patients with a median age of 52 years (40-61) were enrolled. 61.3% were males. Median stone volume was 1165 mm (656-1936). Median operative time was 48.5 (36.25-71.75) min. Transient fever (37°C-37.5°C) occurred in 10 (7%) patients. No sepsis case occurred. 96.5% of patients were stone-free (Grade A+B). Grade A SFR was 52.8%. All patients were discharged within 48 hours. Bone window (OR 3.156 95% CI 1.177-9.130, P=0.027) was the only factor significantly associated with higher odds of 100% SFR, while stone volume (OR 0.999, 95% CI 0.999-1.000, P=0.007) was significantly associated with lower odds.

Conclusions: Imaging and clinical evidence demonstrate excellent perioperative outcomes just 24 hours post RIRS with FANS-UAS. The technique demonstrates a good safety profile, ability for immediate high SFR, and a low rate of infective complications.