uretero pelvic junction obstruction in the newborn

uretero pelvic junction (upj) obstruction is a common cause of hydronephrosis in infants. the frequent use of fetal ultrasound is allowing early (prenatal) diagnosis of numerous uropathies previously delayed until the child either became symptomatic or had a palpable mass. newborn with severe obstruction often has marked improvement following correction, therefore, early diagnosis and operation are important. from 1993 to 2002, 21 patients were operated on for severe upj obstruction who were diagnosed before 6 weeks of age. only 10 patients (63%) had antenatal ultrasonographic diagnosis, the remaining were diagnosed by postnatal ultrasound and ivp or radionuclide scan for palpable renal enlargement or for associated anomalies. eighteen of them had unilateral and three had bilateral obstruction. twenty-four pyeloplasties were done; all pyeloplasties were dismembered with tailoring of the dilatated renal pelvis. postoperative renal function was followed with laboratory blood test, urine test or radionuclide scan or ivp. postoperative complications included urinary tract infection in three patients and postoperative stenosis in one patient were seen. no mortality occurred on infants in unilateral but one occurred in bilateral obstruction. also, there was one unrelated late death. we report documented functional improvement with minimal complications in unilateral or bilateral pyeloplasty in newborns with upj obstruction. we recommend that if the initial scan shows substantially reduced function in the obstructed kidney, a pyeloplasty (rather than nephrectomy) generally should be performed, because the newborn kidney has tremendous capacity for improvement in renal function following decompression.