Lower pole pelvi-ureteric junction obstruction in duplicated collecting systems

OBJECTIVE: To determine the incidence and efficacy of treatment for pelvi-ureteric junction obstruction (PUJO, the most common cause of hydronephrosis in the fetal kidney) in duplicated systems. PATIENTS AND METHODS: We retrospectively assessed patients with PUJO in a duplex collecting system, reviewing each case for age, sex, anatomy, presenting symptoms and type of management. RESULTS: From 1994 to 2004, 1413 patients were identified to have hydronephrosis; 243 of them had pyeloplasty for PUJO, and five (2%) involved the lower pole of a duplicated collecting system. In two of the patients the presentation was prenatal hydronephrosis (mean age at diagnosis 6 weeks) and the remainder presented with flank pain and pyelonephritis (mean age 5 years); all were boys. There was only one incomplete duplication (Y type). Four patients had a dismembered pyeloplasty and one a ureteric calycostomy. Vesico-ureteric reflux was present in three patients and two required common sheath reimplantation. On a radioisotope scan during the follow-up (mean 12 months) the five patients showed an improvement and no evidence of functional obstruction. CONCLUSION: The incidence of PUJO in duplicated systems was 2%; treatment should be individualized and requires a careful preoperative evaluation. This anomaly appears to be more common in boys and in completely duplicated systems.