title: Lower pole pelvi-ureteric junction obstruction in duplicated collecting systems.
abstract: 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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Francisco
authors.initials: F
authors.lastname: Gonzalez
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Canning
authors.forename: Grace
authors.initials: G
authors.lastname: Hyun
authors.forename: Pasquale
authors.initials: P
authors.lastname: Casale
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000209:etiology*; D007223:Infant; D007668:Kidney / Q000002:abnormalities* / Q000601:surgery; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome; D014513:Ureter / Q000002:abnormalities* / Q000601:surgery; D014517:Ureteral Obstruction / Q000150:complications* / Q000601:surgery