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Utility and Challenges of Flexible and Navigable Suction Ureteral Access Sheath (FANS) vs. Suction Mini-PCNL in Children: A Comparative Analysis - Beyond the Abstract

The question is no longer whether to use suction in pediatric stone surgery — it is which suction platform to use, and when. This prospective multicenter study across eight international centers is the first head-to-head comparison of Flexible and Navigable Suction Ureteral Access Sheaths (FANS-UAS) and Suction-assisted Mini-Percutaneous Nephrolithotomy (SM-PCNL) in 96 children with renal stones ≤2 cm, and the findings offer practical guidance for case selection.

Stone-free outcomes were comparable at 30 days — 66.0% Grade A clearance with FANS-UAS versus 58.7% with SM-PCNL (p=0.296), with no Grade C outcomes in the FANS-UAS arm. The more striking differences were perioperative: FANS-UAS delivered nearly half the operative time (42.5 vs. 82.5 minutes, p=0.025) and a shorter hospital stay (2 vs. 3 days, p<0.001), with equivalent complication profiles (12.0% vs. 8.7%, p=0.845), no transfusions, and no ureteric injuries in either group. FANS-UAS was exclusively used for multiple calyceal stones (28% vs. 0%), yet clearance and safety were maintained — reflecting the retrograde platform's whole-system access without additional percutaneous tracts.

Two findings deserve particular attention in clinical practice. First, all FANS-UAS patients required pre-stenting, introducing a second general anesthetic that does not appear in the operative time figures. Urologists comparing these techniques head-to-head must factor in total anesthetic burden, not operative time alone — especially in a population where cumulative exposure matters. Second, BMI meaningfully influenced technique selection (14.0 vs. 19.0 kg/m², p<0.001), and showed a near-significant trend toward lower stone-free rates at higher values (OR 0.88, p=0.084). In leaner, younger children, ureteral access is more challenging, basket use was higher (64.0% vs. 30.4%, p=0.002), and sheath navigation within a small collecting system demands advanced ureteroscopic skill.

On multivariable analysis, modality was not an independent predictor of complete clearance (OR 0.47, p=0.244). Stone location was — lower and middle pole stones outperformed the upper pole, regardless of technique. Stone volume above 1500 mm³ was the sole significant predictor of complications (OR 45.39, p=0.022), underscoring that burden stratification should anchor the preoperative conversation.

The practical takeaway: FANS-UAS and SM-PCNL are complementary rather than competing. FANS-UAS suits leaner children, multifocal stones, and settings prioritizing reduced invasiveness and shorter operative time. SM-PCNL remains the anchor for higher stone burden, challenging lower-pole anatomy, and institutions where percutaneous expertise is the stronger skillset. With miniaturized scopes (6–6.3 Fr), sheaths (8–9.5 Fr), and shorter sheath lengths (25–30 cm) now available, single-stage FANS-UAS without pre-stenting is set to become a reality — and is the focus of our planned Part 2 study.

Written by: Ee Jean Lim,1 Steffi Kar Kei Yuen,2 Bhaskar Kumar Somani,3 Thomas R W Herrmann,4 Kemal Sarica,5 Anna Bujons Tur,6 Yesica Quiroz Madarriaga,7 Jaisukh Kalathia,8 Deepak Reddy Ragoori,9 Gopal Ramdas Tak,9 Khi Yung Fong,1 Roy Zen Sing Teng,1 Azimdjon N Tursunkulov,10 Yiloren Tanidir,11 Rohit Joshi,12 Chandra Mohan Vaddi,13 Olivier Traxer,14 Daniele Castellani,15 Vineet Gauhar16

  1. Department of Urology, Singapore General Hospital, Singapore.
  2. S.H. Ho Urology Centre, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China.
  3. University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK.
  4. Department of Urology, Kantonspital Frauenfeld, Spital Thurgau AG, Frauenfeld, Switzerland.
  5. Department of Urology, Biruni University Hospital, Turkey.
  6. Autonomous University of Barcelona, Urology Department, Fundació Puigvert, Spain, Barcelona.
  7. Department of Urology, Fundació Puigvert, Carrer de Cartagena, 340-350, Barcelona, 08025, Spain.
  8. Fortune Urology Clinic, Botad, Gujarat, India.
  9. Department of Urology, Asian Institute of Nephrology and Urology, Hyderabad, India.
  10. Urology Division, AkfaMedline Hospital, Tashkent, Uzbekistan.
  11. Department of Urology, Medicana Atasehir Hospital, Istanbul, Turkey.
  12. Department of Urology, Aarna Superspeciality Hospital, Gujarat, India.
  13. Department of Urology, Preeti Urology & Kidney Hospital, Hyderabad, India.
  14. Department of Urology, Sorbonne University, AP-HP, Hôpital Tenon, F-75020, Paris, France.
  15. Faculty of Medicine and Surgery, Libera Università Mediterranea (LUM) Giuseppe Degennaro, Casamassima, Italy.
  16. Department of Urology, Asian Institute of Nephrology and Urology, Hyderabad, India; Department of Urology, Ng Teng Fong General Hospital, Singapore.
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