BACKGROUND: To compare the two suction technologies, namely suction mini-percutaneous nephrolithotomy (SM-PCNL) and flexible ureteroscopy using flexible and navigable suction ureteral access sheaths (FANS) for renal stone management.

METHODS: Propensity-matched pair analysis was conducted on prospectively collected data from two global registries. The Suction mini-PCNL registry (STUMPS) included 30 centers across 21 countries, and the Flexible and Navigable Suction Access Sheath in Ureteroscopy registry (FANS) involved 25 centers across 20 countries. Each group included 686 patients after matching for age, sex, Guy's stone score, and stone volume. The primary outcome was the stone-free rate (SFR), assessed by 30-day non-contrast CT scan, categorized as Grade A (100% clearance or zero residual fragment, ZRF), Grade B (single ≤ 4 mm residual fragment), or Grade C (any fragment > 4 mm or multiple fragments).

RESULTS: In the matched cohort, immediate ZRF was significantly higher in SM-PCNL (85.7% vs. 60.1%, p < 0.001), and reinterventions were fewer (0.9% vs. 4.4%, p < 0.001). FANS demonstrated significantly superior recovery profiles with lower postoperative pain scores (VAS 1.0 vs. 2.0, p < 0.001), shorter hospital stays (1.0 vs. 2.0 days, p < 0.001), and reduced need for basket extraction (9.5% vs. 24.5%, p < 0.001). Operative time difference of 6 min, favoring SM-PCNL was noted (46 vs. 40 min, p < 0.001). Complication rates were low and comparable: fever managed by observation (2.1% FANS vs. 3.2% SM-PCNL, p = 0.29) or antibiotics (3.1% FANS vs. 6.0% SM-PCNL, p = 0.08), blood transfusion (0.1% FANS vs. 0.3% SM-PCNL, p > 0.99). No sepsis case was reported for both modalities. Multivariable analysis identified SM-PCNL as a significant independent predictor of Grade A stone-free status (OR 4.06, 95% CI 3.06-5.43, p < 0.001). Notably higher stone complexity GSS 2 and 3 had significantly better predictive odds of lower SFR than stone volume. Stone volume was a predictor of any complications (OR 1.16, 95% CI 1.03-1.30, p = 0.01).

CONCLUSIONS: Both techniques are safe and effective; SM-PCNL is better for achieving 100% stone clearance, especially in GSS 2 and 3 cases. FANS offers faster recovery and lower postoperative pain scores. The Guy's stone score is useful to predict 100% SFR for both modalities. Even though the proposed re-intervention rate was higher in FANS, as ours is only a 30-day follow-up study, the true reintervention rate and outcomes are lacking.