The Intrapelvic Pressure during Retrograde Intrarenal Surgery in the Setting of Ureteral Access Sheath Size: Experimental Study on 3D Printed Model

Introduction: There is no standardised, universal method to assess physical conditions such as pressure in the pelvicalyceal system in real time during RIRS (retrograde intrarenal surgery). Therefore, the problem of increased pressure in the upper urinary tract during the procedure is underestimated. Moreover, it can potentially cause micro-damage and longer postoperative recovery. The aim of this study was to evaluate intrapelvic pressure (IPP) during RIRS procedures. Materials and Methods: The 3D printed models of the pelvicalyceal system were printed based on a CT scan of the real patient. They were used to perform 50 RIRS procedures with laser lithotripsy of artificially synthesised kidney stones with two different sizes of ureteral access sheath-UAS (10/12Fr vs. 12/14Fr) together with different energy settings generated by the holmium:YAG laser. IPP monitoring during RIRS was performed with the use of the PressureWire X Guidewire compatible with the CoroFlow system. Results and Conclusions: The results showed that a high IPP of up to 400 cmH2O would be achieved using a 10/12Fr UAS, while the use of a 12/14Fr UAS would significantly reduce the peak pressure to approximately 100 cmH2O; hence, the size of the UAS is a pivotal factor of the IPP generated during the procedure.