Clinical efficacy of the Galdakao-modified supine Valdivia position vs. the lithotomy position in FANS-UAS-assisted IPC-RIRS for renal calculi

Objective To evaluate the clinical efficacy and safety of a modified Galdakao-modified supine Valdivia (GMSV) position combined with a flexible and navigable suction ureteral access sheath (FANS-UAS) in intelligent pressure-controlled retrograde intrarenal surgery (IPC-RIRS) for the treatment of renal calculi. Methods This single-center retrospective cohort study included 158 patients with renal calculi who underwent FANS-UAS-assisted IPC-RIRS between June 2023 and June 2025. Patients were categorized into the GMSV position group ( n  = 78) and conventional lithotomy position group ( n  = 80) according to the intraoperative position used. Operative time, positioning time, stone retrieval basket use, postoperative hospital stay, stone-free rate (SFR) on postoperative day 1 and day 30, reoperation rate, and perioperative complications were compared between groups. Results Operative time was significantly shorter in the GMSV group than in the lithotomy group (41.35 ± 7.32 min vs. 55.21 ± 8.25 min, P  P  = 0.048). The SFRs on postoperative day 1 were 87.18% and 73.75% in the GMSV and lithotomy groups, respectively, while the corresponding SFRs on postoperative day 30 were 92.31% and 81.25%, respectively. The GMSV group achieved significantly higher SFRs at both time points (both P  P  > 0.05). Conclusion The GMSV position, combined with FANS-UAS-assisted IPC-RIRS, significantly improved the SFR and reduced operative time, while providing similar safety and positioning efficiency compared with the lithotomy position.