Micro-ureteroscopy vs. ureteroscopy: effects of miniaturization on renal vascularization and intrapelvic pressure

Area of Science:

• Urology
• Minimally Invasive Surgery
• Renal Physiology

Background:

• Conventional ureteroscopy (URS) can lead to complications like fever and sepsis due to elevated intra-pelvic pressure (IPP).
• Micro-ureteroscopy (m-URS) is a miniaturized technique designed to mitigate these risks.
• Understanding the comparative impact of m-URS and URS on IPP and renal hemodynamics is crucial for patient safety.

Purpose of the Study:

• To compare intra-pelvic pressure (IPP) during micro-ureteroscopy (m-URS) versus conventional ureteroscopy (URS).
• To evaluate the effects of m-URS and URS on renal hemodynamic parameters.
• To assess the volume of irrigation fluid required for each procedure.

Main Methods:

• An experimental study utilizing a porcine model (14 female pigs).
• Procedures included 7 conventional URS (8/9.8 Fr) for 45 minutes and 7 m-URS (4.85 Fr) for 60 minutes.
• IPP was measured using a catheter pressure transducer, and renal hemodynamics were assessed via Doppler ultrasound.

Main Results:

• Micro-ureteroscopy (m-URS) resulted in significantly lower mean peak diastolic velocity decrease (p < 0.01) and a lesser increase in resistive index compared to conventional URS.
• IPP did not reach 30 mmHg in 90% of renal units with m-URS, versus 65% with URS (not significant).
• m-URS required substantially less irrigation fluid (485 mL) compared to URS (1475 mL) (p < 0.001).

Conclusions:

• Micro-ureteroscopy (m-URS) requires less irrigation fluid volume than conventional ureteroscopy.
• m-URS leads to a lesser extent of increase in renal intra-pelvic pressure (IPP) compared to conventional URS.
• These findings suggest m-URS may offer a safer alternative by reducing potential complications related to elevated IPP.