Suspected pyelo-ureteral junction obstruction in the fetus: when to do what? I. A clinical update.

In fetal hydronephrosis, pyeloplasty is still recommended shortly after birth. Otherwise, according to older studies, the kidneys are said to deteriorate, and the chances for recovery diminish. Modern diagnostic tools, estimating renal function and the degree of obstruction, have shown that this is not always true; to what extent, however, is uncertain. The present survey of pelvic dilatation discloses that a surprisingly large number of patients are free of other symptoms and signs, independent of their age. Significative obstruction was found in only half of the hydronephroses. Renal-function reduction, usually moderate and probably compensated for, was observed in only one third. Progressive deterioration was either absent or slow and mild. Improvement on release occurred in half of the function-reduced kidneys. Antenatally detected cases exhibited the same pattern; furthermore, urinary tract infections occurred only exceptionally and usually mildly, even in those patients who were not operated. Infants showed a tendency to spontaneous resolution of the hydronephroses. Therefore, the correction in the neonate has no scientific support. A renal-function defect or significant obstruction must first be verified before an operation should be performed (within 3-6 months). Otherwise, the intervention may be postponed for years or, perhaps, needs never to be performed.