Login to Access Video or Poster Abstract: MP50-19
Sources of Funding: None

Introduction

To evaluate effects of varying UAS sizes (10/12F - 12/14F) and changing irrigation flow rates modulated by custom designed pump system, on RA-RIRS intra-renal pressure levels.

Methods

To evaluate changing irrigation flow rate effects on intra-renal pressure values during RA-RIRS, a customized pump system adjusted for stepwise flow rate increases between 5-60 ml/min, was connected to two different flexible uretero-renoscopes (FlexX2 and FlexXC, Karl Storz GmbH, Germany) coupled to the Avicenna Roboflex. Free channel flow rates through each instrument working channel were measured several times for a set irrigant height. After assessing baseline flow rates with constant flow, the study was repeated using a custom designed pump system (ELMED, Turkey). RA-RIRS intrarenal pressures were measured percutaneously using 4 different manufacturer’s access sheaths positioned in the proximal ureter (9.5/11.5F Cook, 10/12F Rocamed, 10.7/12.7F Cook and 12/14F Boston Scientific). Studies were repeated subsequently in the Minnesota University kidney model with calyceal puncture, as with patients.

Results

Smaller sized UAS ( 9.5/11.5F) limited irrigant efflux along the outer side and resulted in increased intrarenal pressures in a short time even without a pump system. For larger UAS sizes, intrarenal pressures continued to remain <30cmH2O even with irrigation rates of up to 20ml/min. Lastly, when 12/14F UAS was used, intrarenal pressures were < 30cmH2O despite irrigation flow rates up to 60ml/min.

Conclusions

Using an appropriate sized UAS during RA-RIRS is of paramount importance. Careful irrigant flow rate adjustment with precisely controlled intrarenal pressure values, preferably using a specially designed pump system, can enable surgeons to perform RA-RIRS safely with clear vision with larger UAS sizes. This approach may increase stone free rates, and reduce pressure build-up plus infection-related complication risk, particularly in cases with large and complex stones needing longer operating times.

Funding

None