Predictability of duration and severity of congenital hydronephrosis as a cause of smooth muscle deterioration in pyelo-ureteral junction obstruction.

Between 1989 and 1990, 31 new unilateral PUJO, prenatally diagnosed (16th-37th week of gestational age), underwent pyeloplasty between 19 and 105 days of age. The correlation between severity (V) (volume of hydronephrotic kidney) and duration (dT) of congenital hydronephrosis from its first detection in utero to surgery and histological findings were prospectively evaluated in this series. A dT longer than 70 days and a V larger than 50 ml., were considered as predictable for hypotrophy with fibrosis of the upper urinary tract smooth musculature. In conclusion, time seems to play an important role in the increase of the volume of the obstructed urinary tract to the extent of a large-scale hydronephrosis.