General anaesthesia with gated or controlled mechanical ventilation and its influence on peri and post operative outcomes of retrograde intra renal surgery when using flexible and navigable suction access sheath, an EAU-endourology and Global FANS collaborative study group: a prospective study.

Abstract

Background: Retrograde intrarenal surgery (RIRS) is a preferred treatment for renal stones, yet challenges such as kidney movement due to respiration hinder surgical precision and outcomes. The introduction of flexible and navigable suction ureteral access sheaths (FANS) and novel techniques like gated respiration aim to improve stone-free rates (SFR) and reduce complications. This study evaluates the impact of gated respiration on perioperative outcomes in RIRS with FANS.

Methods: A prospective multicenter study enrolled 562 adult patients undergoing RIRS with FANS under general anesthesia. Patients were divided into two groups: non-gated respiration (Group 1) and gated respiration (Group 2). Stone-free status (SFS) was assessed at 30 days using NCCT scans. SFS was defined as follows: grade A, zero fragments; grade B, a single fragment ≤ 2 mm; grade C, a single fragment 2.1-4 mm; and grade D, single/multiple fragments > 4 mm. Procedural efficiency, perioperative complications, and surgeon-reported outcomes were compared.

Results: Patients in Group 2 had significantly higher zero residual fragment (Grade A) rates (64.2% vs. 59%) and overall SFR (Grade A + B: 98.3% vs. 91.3%, p = 0.001). Gated respiration improved sheath navigation (91.2% vs. 85.1%, p = 0.038) and visibility during lithotripsy (p = 0.004), while reducing complications like mild bleeding due to sheath movement (3.1% vs. 11.2%, p < 0.001). Logistic regression identified gated respiration as a significant predictor of SFS (OR 6.26, 95% CI 2.28-22.6, p < 0.001).

Conclusion: Gated respiration synergistically enhances the efficacy of FANS in RIRS, improving SFR, procedural safety, and surgeon experience. This study highlights the importance of respiratory control as an adjunct to RIRS, emphasizing the need for interdisciplinary collaboration between surgical and anesthesiology teams.