Renal function in patients with hydronephrosis.

The glomerular filtration rate and pelvic drainage function were reinvestigated after 3-5 years in 50 patients with hydronephrosis secondary to functional obstruction in the pelvic-ureteric junction. Pyeloplasty by the Anderson-Hynes' technique had been performed in 28 kidneys, while 12 patients were not operated upon and 10 had had a nephrectomy. The glomerular filtration rate was determined with the clearance technique and isotope renography. 16 out of 28 kidneys subjected to pyeloplasty and 11/12 non-operated kidneys had a normal renal parenchymal function at the first investigation in spite of severely disturbed drainage function. In the non-operated series the renal parenchymal function was unchanged in 11 patients. Deterioration was observed in 1 kidney, probably because of chronic pyelonephritis. Uncomplicated cases of pelvic-ureteric junction obstruction should not be operated upon unless necessitated by symptoms. A yearly control programme including a renal function test and plain films of the upper urinary tract is recommended for these patients.