Intrarenal Pressure During Steerable Ureteroscopy Renal Evacuation by CVAC System Using Intrarenal Pressure Measurement: A Pilot Study

Abstract

Introduction:

Steerable Ureteroscopic Renal Evacuation (SURE), a novel technology utilizing the CVAC system, demonstrated promising outcomes for larger renal stones by enhancing stone clearance. This study aims to continuously monitor intrarenal pressure (IRP) during ureteroscopy with laser lithotripsy with CVAC system.

Materials and Methods:

Patients undergoing ureteroscopic laser lithotripsy using the SURE technique at our institution were prospectively enrolled. IRP was measured using a 5F Pollack catheter in conjunction with a 12/14F ureteral access sheath. IRP values were recorded live and documented every minute. We defined 40 mm Hg as the IRP threshold.

Result:

Simultaneous placement of a 12/14-Fr access sheath and a Pollack catheter was feasible in 13/25 (52%) patients. Seven (53.8%) patients were nonstented. The mean preoperative stone size was 1.25 cm (interquartile range [IQR] 0.65–1.61). The mean IRP during the procedure was 17 mm Hg (IQR 12–23), with a maximum recorded IRP of 37 mm Hg (IQR 29–37). IRP briefly exceeded 40 mm Hg when fragments occluded the suction channel; the 1-minute recording interval did not capture this transient excursion, which resolved after the push–pull syringe maneuver. The stone clearance rate was 100% (IQR 93–100) based on computed tomography.

Conclusion:

The SURE technique facilitates complete stone clearance while maintaining IRP within a safe range. IRP >40 mm Hg signaled clogs that resolved with push–pull syringe maneuver. We recommend activating push–pull syringe every minute to maintain patency. These findings support SURE as a safe and effective alternative to percutaneous nephrolithotomy in patients with moderate stone burden.