text: A total of 57 consecutive patients with primary ureteropelvic junction obstruction were randomized to undergo 7/14Fr internal endopyelotomy stent placement for 2 ( group 1 ) and 4 ( group 2 ) weeks .
entities.text: 7/14Fr internal endopyelotomy stent placement
entities.type: intervention
entities.text: A total of 57 consecutive patients with primary ureteropelvic junction obstruction
entities.type: participant