Ureteropelvic junction obstruction in the neonate.

The widespread use of maternal ultrasonography has resulted in an increasing number of asymptomatic newborns being diagnosed with hydronephrosis. A total of 89 neonates with hydronephrosis secondary to ureteropelvic junction obstruction have been referred for evaluation and treatment during the last 6 years. In the majority the condition was diagnosed readily with ultrasonography, voiding cystography and excretory urography. Twenty-five per cent underwent more quantitative assessment using nuclear renal imaging. Only 2 patients (8 per cent) had a percutaneous study. Early reconstruction was performed in 75 per cent of the patients and it proved to be safe and effective. Twenty-three neonates were followed nonoperatively. One patient (4 per cent) demonstrated clinical deterioration necessitating later surgical intervention. Careful surveillance is mandatory in all infants followed nonoperatively.