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 mu m laser fiber, Mini-PCNL with different sizes of operating sheath (15/16Fr, 16.5/17.5Fr, 21/22Fr) +/- 365 mu m 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.