Real-time Monitoring with DISS and FANS Systems to Assure Safe and Effective Stone Treatment: Insights from Ex-Vivo Experimental Study from EAU Endourology

To evaluate the real-time safety profile and intrarenal pressure (IRP) dynamics of two suction-assisted ureteroscopic systems, the Direct In-Scope Suction (DISS) and Flexible and Navigable Suction (FANS) ureteral access sheath, in an ex-vivo model. Four porcine kidney-ureter units were used, harvested from two female pigs (32–34 kg). A 20G intravenous catheter was inserted into the middle calyx for continuous IRP monitoring via a pressure transducer and monitor. Each kidney underwent four experimental configurations combining 7.5 Fr PU3033AH or 9.2 Fr PU400A DISS scopes with 9.5/11.5 Fr or 12/14 Fr FANS sheaths. Irrigation was performed using a manual hand pump, and suction was applied at 100 mmHg either through the ureteroscope or sheath. Measurements included baseline and maximal IRPs, suction-induced changes, mucosal injury, and time to endoscopic stone-free status (ESFS). Sixteen experiments were completed. Activation of suction consistently reduced IRP across all settings. The The 7.5 Fr DISS + 9.5/11.5 Fr FANS configuration achieved the lowest pressures (4–12 mmHg) but caused pelvicalyceal collapse and six mucosal injuries. In contrast, the 9.2 Fr DISS + 12/14 Fr FANS combination-maintained IRP between 12 and 28 mmHg with efficient fragment evacuation and minimal collapse. Both DISS and FANS effectively maintained IRP within a safe range. Controlled, balanced suction was crucial for safety, while excessive negative pressure or prolonged manual irrigation risked collapse and mucosal injury. The 9.2 Fr DISS + 12/14 Fr FANS configuration demonstrated stable pressure control and efficient performance in this experimental model.