Hydronephrosis means dilatation of the hollow system of the affected kidney with different degree of parenchymal atrophy. The aim of the study was to evaluate the therapeutic results in patients with congenital hydronephrosis. During 1996 - 2001, 62 children were operated on at our institution. There were 44 boys and 18 girls. 48 patients had obstruction of the pyeloureteric junction (PUJ) due to congenital dysplasia, 14 patients had extrinsic obstruction of the PUJ from crossing renal vessels. In all patients a dysmembering pyeloplasty (Anderson-Hynes procedure) was done, in case of extrinsic obstruction, enhanced by transposition of the vascular bundle. 4 patients developed signs of simultaneous obstruction of the PUJ and ureterovesical junction (UVJ). 3 of them required additional resection of the iuxtavesical ureter and its reimplantation after 3 - 4 weeks on nephrostomy. Such patients do not develop typical dilated obstructive megaureters. In all patients the obstruction has been relieved. No substantial difference between therapeutic results of each particular group of patients was found.

        Key words: hydronephrosis, aberrant vessels, pyeloplasty, reimplantation of the ureter