The Evaluation of Intrarenal Pressure Using a Novel Single-Use Flexible Ureteroscope with Live Intrarenal Pressure Monitoring-An Experimental Study in Porcine Models

(1) Background: This study aims to evaluate how different irrigation settings and the use of ureteral access sheaths (UASs) of varying sizes impact intrarenal pressure (IRP) during flexible ureteroscopy (fURS) procedures in pigs. (2) Methods: This study utilized three anesthetized female pigs. A novel flexible ureteroscope with the ability to continuously record live intrarenal pressure was used to perform ureteroscopy in different settings. Ureteroscopy was performed without UAS and with the use of 11/13 and 12/14 UAS at the ureteropelvic junction. Two different irrigation methods were employed for each parameter: one using gravity flow and the other using manual pumping with a commercial pump. IRP was also recorded with the presence of a laser fiber or lithotripsy basket. (3) Results: The recorded mean IRP during flexible URS without UAS was 28.25 (+/- 11.2) under gravity irrigation; 35.46 (+/- 10.08) under manual pumping; 22.5 (+/- 3.05) and 30.75 (+/- 5.79) with a laser fiber under gravity irrigation and manual pumping, respectively; and 16.45 (+/- 1.27) and 17.27 (+/- 3.69) with a lithotripsy basket under gravity irrigation and manual pumping, respectively. With an 11/13 UAS, the mean IRP was 15.41 (+/- 8.57) and 19.33 (+/- 4.26) under gravity and manual pumping irrigation, respectively; 14.56 (+/- 2.50) and 18.64 (+/- 5.13) with a laser in each irrigation setting, respectively; and 13.10 (+/- 3.39) and 13.86 (+/- 4.63) with a lithotripsy basket, respectively. With a 12/14 UAS, the mean IRP was 7.64 (+/- 3.08) and 9.25 (+/- 1.42) under gravity and manual pumping irrigation, respectively; 9.50 (+/- 6.04) and 10.28 (3.46), respectively, in each setting when the laser fiber was used; and 5.32 (+/- 1.57) and 6.26 (+/- 1.79), respectively, when the lithotripsy basket was inserted. (4) Conclusion: Novel flexible ureteroscopes with integrated pressure sensors are both a feasible and reliable tool during fURS, giving the surgeon the ability to live-track the IRP. The results of the IRP measurements with and without UAS are in accordance with the current literature and exhibit a consistent pattern with previous studies.