Comparison of vacuum-assisted flexible ureteroscopy and percutaneous nephrolithotomy for 2–3 cm upper tract stones: a real-world cohort study

Objectives This real-world study aimed to compare the perioperative and recovery outcomes of single-use digital flexible ureterorenoscopy with a flexible-tip vacuum-assisted ureteral access sheath (FV-UAS) against standard percutaneous nephrolithotomy (PCNL) for managing upper urinary tract stones measuring 2–3 cm. Patients and methods This single-center, retrospective cohort study enrolled 116 patients (69 FV-UAS, 47 PCNL) between January 2023 and December 2024. The co-primary outcomes were the stone-free rate (SFR) on postoperative day 1 and at 1 month. The SFR on postoperative day 1 was assessed by kidney-ureter-bladder (KUB) radiography or ultrasound, while the SFR at 1 month was assessed by non-contrast computed tomography (NCCT). Secondary outcomes included operative time, length of hospital stay (LOS), hydronephrosis resolution at 90 days, complication rates, and trends in serum creatinine and neutrophil-to-lymphocyte ratio (NLR). Results Baseline characteristics were comparable. While the FV-UAS group demonstrated a numerically higher immediate SFR (92.75% vs. 76.59%, P = 0.0132), this finding should be interpreted as exploratory due to the limited sensitivity of KUB/ultrasound for early residual fragment detection. The stone-free rate at 1 month, assessed by NCCT, was excellent and comparable between groups (98.55% vs. 91.49%, P = 0.1564). Operative time (64.0 ± 9.3 vs. 72.3 ± 8.8 min, P = 0.0048) and LOS (3.5 vs. 6.2 days, P < 0.0001) were shorter in the FV-UAS group, which also had lower peak postoperative pain scores and body temperature. The rise in serum creatinine was slightly lower in the FV-UAS group, though the clinical significance of this small absolute difference is uncertain. The overall complication rate (Clavien-Dindo Grade I-V) was markedly lower for FV-UAS (10.1% vs. 40.4%, P < 0.001). Rates of complete hydronephrosis resolution at 90 days were comparable (94.20% vs. 87.23%, P = 0.3863). Conclusion In this real-world study, the FV-UAS technique for 2–3 cm upper tract stones was associated with comparable outcomes and stone clearance compared to PCNL. It offered excellent stone clearance, faster recovery, reduced postoperative pain and inflammation, and a more favorable safety profile, particularly regarding bleeding. FV-UAS represents a compelling minimally invasive alternative for selected patients in this stone size category.