Pressure matters: intrarenal pressures during normal and pathological conditions, and impact of increased values to renal physiology.

PURPOSE: To perform a review on the latest evidence related to normal and pathological intrarenal pressures (IRPs), complications of incremented values, and IRP ranges during endourology. METHODS: A literature search was performed using PubMed, restricted to original English-written articles, including animal, artificial model, and human studies. Different keywords were: percutaneous nephrolithotomy, PCNL, ureteroscopy, URS, RIRS, irrigation flow, irrigation pressure, intrarenal pressure, intrapelvic pressure and renal pelvic pressure. RESULTS: Normal IRPs range from zero to a few cm H2O. Pyelovenous backflow may occur at pressure range of 13.6-27.2 cm H2O. During upper tract endourology, complications such as pyelorenal backflow, sepsis, and renal damage are directly related to increased IRPs. Duration of increased IRPs and concomitant obstruction are independent predictors of complication development. CONCLUSIONS: IRP increase remains a neglected predictor of upper tract endourology complications and its intraoperative monitoring should be taken into consideration. Further research is necessary, to quantify pressures generated during upper tract endourology, and introduce means of controlling them.