An in vitro study of intracavitary pressures during percutaneous nephrolithotomy.

Pyelorenal reflux and irrigant extravasation secondary to raised intrapelvic pressure during percutaneous nephrolithotomy account for a significant percentage of the operative morbidity. The effect of irrigant flow rate, height of irrigant reservoir, diameter of Amplatz sheath and lithotripsy on intracavitary pressures has been studied in an in vitro model. The elevation of pressures produced by these variables suggests that percutaneous techniques should be modified.