Pressure-flow relationship in partial obstruction of ureter in pigs

In 10 female pigs, the proximal part of the left ureter was obstructed for 10 weeks by implantation of the ureter into the psoas muscle. After 9 weeks of obstruction, 6 systems showed delayed or impaired drainage at renographic examination. Renal function was slightly impaired in 1 case. At operation, 4 systems were macroscopically normal while the rest showed slight to moderate dilatation. The intrapelvic resting pressure was normal in 8 of 9 cases. At perfusion, all systems responded within the normal limits at 8 cm3/min while high-pressure responses were found in 4 units above 8 cm3/min. No correlation was found between the resting pressure and the pressure response and the degree of dilatation or impairment of renal function.