Paradigm shifts in fluid management using suction irrigation pressure autoregulating systems in modern flexible ureteroscopy with flexible and navigable suction access sheath: an evidence-based narrative from EAU Endourology.

PURPOSE OF REVIEW: This review is timely due to the rapid integration of suction systems, automated irrigation, and intrarenal pressure (IRP) monitoring in flexible ureteroscopy (FURS). These technological advances are redefining fluid management from a passive supporting role to an active determinant of surgical safety and efficacy, necessitating a consolidated evidence-based overview for clinical practice.

RECENT FINDINGS: Contemporary literature highlights a paradigm shift driven by flexible and navigable suction ureteral access sheath (FANS), suction irrigation pressure autoregulating systems (SIPS) and real-time IRP monitoring. Key themes include the critical role of steady-state flow rates (>40-60 ml/min) in mitigating laser-induced thermal injury, the importance of the ratio of endoscope-to-sheath diameter (RESD) for optimizing fragment clearance and intrarenal pressure control, and the superiority of SIPS in maintaining "pressure-neutral" environments. In-vitro and initial in-vivo studies demonstrate that these technologies enable continuous laser lithotripsy, enhance stone-free rates, and reduce procedural complications.

SUMMARY: The integration of AI-driven SIPS with FANS marks a fundamental shift in endourologic fluid management. SIPS optimizes the suction irrigation ratio (SIR), enables steady-state flows >60 ml/min for continuous lasering, and reduces operator duty cycles. Increasing flow to 100 ml/min improves stone fragment extraction and ergonomics. With appropriate ratio of endoscope to sheath diameter and built-in safety alarms in SIPS, SIPS can mitigate high-IRP risks. Further research is needed to optimize settings for higher energy use.