Ureteropelvic junction obstruction in infants and children: functional evaluation of the obstructed kidney preoperatively and postoperatively.

We evaluated 14 children with primary ureteropelvic junction obstruction, using preoperative excretory urography and renal imaging with the renal cortical labeling agent 99mtechnetium dimercaptosuccinic acid. All children with a reduction in function of 10 per cent or more in the obstructed kidney had severe calicectasis; others with severe calicectasis had minimal functional loss. Renal scanning with dimercaptosuccinic acid discourages surgery in the questionably obstructed kidney and encourages repair in the severely obstructed kidney. In 10 children who had followup renal imaging after repair relative function was not significantly different.