The Usage of Ureteral Catheter Outside of the Ureteral Access Sheath to Facilitate Stone Passage Through the UAS During RIRS: A Case Report

Retrograde intrarenal surgery (RIRS) is a key technique for managing renal calculi. Despite advancements like the flexible and navigable suction ureteral access sheath (FANS-UAS), efficient stone fragment evacuation remains challenging due to limited irrigation flow and backflow-induced displacement. We report a novel technique using a ureteral catheter (UC) placed external to the FANS-UAS to generate directional, low-pressure saline irrigation during RIRS, aimed at enhancing stone evacuation and maintaining optimal intrarenal pressure (IRP). The integration of an external UC during RIRS is a simple, cost-effective modification that significantly enhances stone fragment evacuation and maintains safe IRP levels.