Comparison of intrapelvic pressures during flexible ureteroscopy, mini-percutaneous nephrolithotomy, standard percutaneous nephrolithotomy, and endoscopic combined intrarenal surgery in a kidney model

Purpose To compare intrapelvic pressure (IPP) levels achieved during f-URS, mini-PCNL, standard PCNL, and endoscopic combined intrarenal surgery in a kidney model. Methods A silicone model simulating the complete urinary tract was used for all the experiments. We compared: a 9.5Fr f-URS, a 12Fr mini-nephroscope and a 26Fr nephroscope. The irrigation pressure was set at 40 and 193 cmH 2 O. We compared: f-URS-S ± ureteral access sheath (UAS, 10/12Fr, 11/13Fr, 12/14Fr) ± 273 μm laser fiber, Mini-PCNL with different sizes of operating sheath (15/16Fr, 16.5/17.5Fr, 21/22Fr) ± 365 μm laser fiber, Standard PCNL with an operating sheath of 30Fr ± Lithotripter LithoClast Master 11.4Fr. Results f-URS: IPP values ranged between 1.4 and 46.2 cmH 2 O. Factors reducing IPP were an irrigation pressure at 40 cmH 2 O, an occupied working channel, and the use of a UAS except with the 10/12Fr at 193 cmH 2 O. Mini-PCNL: IPP values ranged between 2.4 and 39.7 cmH 2 O. Factors reducing IPP were irrigation pressure at 40 cmH 2 O, a large operating sheath (> 15/16Fr). The occupation of the working channel did not affect the IPP at 40 cmH 2 O, while it decreased at 193 cmH 2 O. Standard PCNL: IPP values ranged between 1.4 and 7.3 cmH 2 O. Occupancy of the working channel did not affect IPP at 40 cmH 2 O, while it increased at 193 cmH 2 O. Conclusion We recorded for the first time IPP values according to different endourological techniques and configurations. IPP never exceed 50 cmH 2 O irrespectively of the assessed technique/setup. The factors reducing IPP were a low irrigation pressure (40 cmH 2 O), the use of a UAS or a working sheath appropriate to the diameter of the endoscope, as well as the occupation of the working channel in the case of f-URS.