title: Pyeloplasty in children: is there a difference in patients with or without crossing lower pole vessel?
abstract: BACKGROUND
  Most of the children with hydronephrosis do not require any surgical intervention. However, in individual cases, irreversible loss of renal function can develop. Predictive criteria have been proven ineffective so far in determining in which children obstruction will lead to renal damage. The aim of our retrospective study was to determine the role of a crossing lower pole vessel (CV) in children undergoing pyeloplasty.
  
  
  METHODS
  Between 1996 and 2003, 137 patients (age between 6 weeks and 16 years) with unilateral ureteropelvic junction obstruction and no associated urological pathologies underwent Anderson-Hynes dismembered pyeloplasty. A total of 112 patients were evaluated with complete data. One of the following criteria was considered to be indication for surgery in children with grade 4 hydronephrosis: differential renal function (DRF) <40%; clinical symptoms such as pyolenephritis and flank pain; during follow-up renographies, a reduction of DRF >10% and washout patterns II or III b according to O'Reilly. We looked at the age during surgery and the kind of presentation. DRF was measured using diuretic renography preoperatively and 1 year postoperatively. A postoperative change in DRF of group A (children without CV, n = 84) was compared to that in group B (children with CV, n = 28).
  
  
  RESULTS
  Median age at the time of surgery was 5 months in group A compared to 23 months in group B. Only in 21.4% of the children with CV compared to 60.7% without CV hydronephrosis was diagnosed by ultrasound examination antenatally. We found a preoperative DRF of 42.4% +/- 11.2 SD in group A, and of 38.9% +/- 11.7 SD in group B. The percentage of postoperative improvement was 3.3% in group A and 15.4% in group B.
  
  
  CONCLUSIONS
  Children with ureteropelvic junction obstruction and CV received a delayed surgical treatment and showed a greater reduction in differential renal function preoperatively, in contrast to patients without CV. Our data show that CV is a risk factor for deterioration of renal function in children with hydronephrosis and we advocate for an early pyeloplasty in these children, especially if they have a high-grade dilatation and equivocal washout patterns in diuretic renographies. Further prospective studies are necessary in order to understand the natural history of CV and to reveal the importance of the crossing lower pole vessel as a structural anomaly lacking maturation.
authors.affiliation: Abteilung für Kinderchirurgie, Universitaetsklinik für Kinder- und Jugendmedizin, Tübingen 72076, Germany. hanswalter.hacker@ksl.ch
authors.forename: Hans-Walter
authors.initials: HW
authors.lastname: Hacker
authors.forename: Philipp
authors.initials: P
authors.lastname: Szavay
authors.forename: Helmut
authors.initials: H
authors.lastname: Dittmann
authors.forename: Hans-P
authors.initials: HP
authors.lastname: Haber
authors.forename: Joerg
authors.initials: J
authors.lastname: Fuchs
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging / Q000209:etiology; D007223:Infant; D007668:Kidney / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000503:physiopathology; D007677:Kidney Function Tests; D007682:Kidney Pelvis / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color; D014513:Ureter / Q000000981:diagnostic imaging / Q000601:surgery*; D014517:Ureteral Obstruction / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*