Intraluminal pressure profiles during flexible ureterorenoscopy

Area of Science:

• Urology
• Endourology
• Nephrology

Background:

• Ureterorenoscopy (URS) and retrograde intrarenal surgery (RIRS) involve irrigation, potentially increasing renal pelvic pressure (PP).
• Elevated PP during URS may lead to adverse effects, necessitating investigation into pressure dynamics.

Purpose of the Study:

• To measure intraluminal renal pelvic pressure (PP) during flexible ureterorenoscopy (fURS) and retrograde intrarenal stone surgery (RIRS).
• To assess the magnitude and variability of PP during different phases of RIRS.

Main Methods:

• Twelve patients undergoing RIRS were enrolled.
• Renal pelvic pressure (PP) was continuously monitored using a ureteral catheter during ureteroscope insertion and stone treatment.
• A standardized irrigation rate of 8 ml/min was used.

Main Results:

• Baseline PP averaged 10 mmHg.
• PP increased to a mean of 35 mmHg during simple ureterorenoscopy and 54 mmHg during stone management.
• Pelvic pressure peaks reached up to 328 mmHg, with frequent peaks exceeding 50 mmHg.

Conclusions:

• Flexible ureterorenoscopy generates very high renal pelvic pressures, often exceeding 300 mmHg.
• Observed pressures surpass the threshold for pyelovenous backflow (around 30 mmHg), indicating a significant risk.
• Developing methods to monitor and reduce PP during fURS is crucial for patient safety.