Measurement of renal pelvis pressures during endourologic procedures.

Twenty-five kidneys underwent nephrostomy puncture with placement of a pigtail catheter into an upper pole calyx for manometric recording during nephroscopy without a working sheath and with an Amplatz sheath with and without a Rutner adapter. Intrarenal pressures remained below 16 cm of water (H2O) at all times with the Amplatz sheath with or without a Rutner adapter, whereas without a sheath the pressures ranged from 15 to 31 cm H2O (i.e., pressures associated with significant pyelovenous and pyelosinus backflow). Similar results were obtained in monitoring intrarenal pressures during clinical procedures. A working sheath should be utilized for all percutaneous nephroscopic procedures to minimize the incidence of pyelovenous and pyelosinus backflow as well as of perirenal extravasation of the irrigation solution. Even with a wide-lumen ureteral catheter in place, drainage via the ureter is not sufficient to maintain the intrapelvic pressure in the physiologic range.