Intrarenal pressure monitoring via flexible and navigable suction ureteral access sheath in retrograde intrarenal surgery: A preclinical animal study and a pilot clinical study

Abstract Background Elevated intrarenal pressure (IRP) during retrograde intrarenal surgery (RIRS) can lead to deleterious complications. Emerging non‐invasive, real‐time IRP monitoring tools are proving crucial for enhancing procedural safety. This study evaluates a newly developed flexible and navigable suction ureteral access sheath (FANS) with IRP monitoring capabilities through animal study and a clinical trial, assessing its accuracy and operational benefits. Methods A preclinical animal study and a prospective clinical trial involving 100 patients were conducted. The animal study confirmed the accuracy of IRP‐monitoring FANS, whilst the clinical trial compared its performance to conventional FANS in RIRS. The evaluated outcomes included the accuracy of IRP measurements, the irrigation flow rate, the duration of the operation, and the stone‐free rate (SFR). Statistical comparisons were performed using appropriate tests with a significant threshold of p < .05. Registration for this study is recorded under the identifier NCT06729801 at ClinicalTrials.gov. Results In the animal study, IRP‐monitoring FANS demonstrated high accuracy in real‐time IRP measurement, comparable to percutaneous nephrostomy‐based monitoring. In the clinical study, IRP‐monitoring FANS enabled increased irrigation flow whilst maintaining safe IRP levels within 30 mmHg. Operative time was significantly shortened in IRP‐monitoring FANS group (50.9 vs. 67.6 min, p < .01), with similar SFRs between groups. No notable discrepancies in the rates of complications were observed. Conclusions The IRP‐monitoring FANS improves stone retrieval efficiency and shortens operative time whilst ensuring safety through real‐time IRP monitoring. This novel device marks a major improvement in both the safety and effectiveness of RIRS for managing large renal stones.