Pressure volume relationships in human hydronephrosis.

Pressure volume curves were obtained in 8 children with ureteropelvic junction obstruction prior to pyeloplasty after totally obstructing the ureteropelvic junction. All human renal pelves displayed a similar shape pressure volume curve. The human renal pelvis is able to accommodate to increasing volumes by maintaining a relatively low intrapelvic pressure Once its capacity is reached, pressures rise to pathologically high levels at a much faster rate. These findings suggest that hydronephrosis can be viewed as a compensatory mechanism which protects some kidneys from further overdistention, high intrapelvic pressures, and progressive renal deterioration by virtue of acquired changes in compliance, pelvic size, and renal function which limit the rate of pressure rise within the hydronephrotic kidney.