title: Unilateral ureteropelvic junction obstruction in children: long-term followup after unilateral pyeloplasty.
abstract: OBJECTIVE
  The benefit of surgery on renal function in unilateral ureteropelvic junction stenosis (UPJS) is still debated. We evaluated renal function outcome after unilateral pyeloplasty in 53 children.
  
  
  METHODS
  We retrospectively reviewed 123I-hippuran renography performed at diagnosis and 5 to 15 years (mean +/- SD 7 +/- 3 years) after successful pyeloplasty. UPJS was prenatally detected in 26 children because of urinary tract infection in 17 and miscellaneous reasons in 10. Relative function (RF) and absolute function were measured on background corrected renograms. Absolute function of the affected and contralateral kidneys was determined by an accumulation index (AI), representing the percent injected dose extracted by each kidney 30 to 90 seconds after the heart peak.
  
  
  RESULTS
  Preoperatively 33 of the 53 UPJS kidneys had a decreased AI but only 8 had a RF of less than 40%, which was improved in 7 at followup. In addition, the AI improved in 29 kidneys, of which 19 (36%) normalized. Of the UPJS kidneys 14 had an initially decreased AI that remained abnormal at followup. In these kidneys preoperative RF was less than 40% in all. At followup RF was greater than 40% in 4 children, in whom the AI of the UPJS kidney did not improve but the AI of the contralateral one decreased from supranormal to normal. Seven contralateral kidneys had a supranormal AI, whereas the AI remained normal in 3, of which the RF in the UPJS kidney remained at less than 40%. The AI and RF were normal in 20 UPJS kidneys and remained normal.
  
  
  CONCLUSIONS
  When normal, the AI and RF reflected renal function outcome similarly. The AI added relevant information in UPJS kidneys with impaired function, showing compensation of the contralateral kidney.
authors.affiliation: Nuclear Medicine Department, University Hospital, Lausanne, Switzerland.
authors.forename: Ariane
authors.initials: A
authors.lastname: Boubaker
authors.forename: John O
authors.initials: JO
authors.lastname: Prior
authors.forename: Blaise
authors.initials: B
authors.lastname: Meyrat
authors.forename: Angelika
authors.initials: A
authors.lastname: Bischof Delaloye
authors.forename: Irene M
authors.initials: IM
authors.lastname: McAleer
authors.forename: P
authors.initials: P
authors.lastname: Frey
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D007682:Kidney Pelvis / Q000601:surgery*; D008297:Male; D011866:Radioisotope Renography; D012189:Retrospective Studies; D014517:Ureteral Obstruction / Q000000981:diagnostic imaging / Q000601:surgery*
chemical_list: D003287:Contrast Media; D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid