title: Differences between intrinsic and extrinsic ureteropelvic junction obstruction related to crossing vessels: histology and functional analyses.
abstract: OBJECTIVE
  In children, ureteropelvic junction obstruction (UPJO) is mostly caused by intrinsic factors (IUPJO); extrinsic UPJO are rare and often due to crossing vessels (CVs).
  
  
  METHODS
  We retrospectively reviewed all data of children with UPJO that underwent surgery in our institution from 2004 to 2011. Analyses included age at surgery, gender, preoperative and postoperative results of ultrasound and renal scans [differential renal function (DRF); signs of obstruction], and pathology reports. Available histological specimens of cases with CV were compared to a random selection of intrinsic cases in a blinded fashion. After additional Masson's trichrome staining, the specimens were scored for fibrosis, muscular hypertrophy, and chronic inflammation.
  
  
  RESULTS
  Out of 139 patients with UPJO, 39 cases were associated with CV. Median age at surgery was 68 months (range 2-194) in the CV group and 11.5 months (range 0-188) in IUPJO group. Laparoscopic dismembered pyeloplasty (LDMP) was carried out in 134 and open DMP in five patients. Preoperative ultrasound identified 28/39 cases with CV. DRF below 40 % was more frequently seen in CV patients (p = 0.020). Histological analyses revealed no differences between the CV and IUPJO specimens in total. CV patients with higher grades of muscular hypertrophy had lower preoperative DRF, compared to those with higher preoperative DRF (p = 0.026). Functional recovery after (L)DMP was excellent in both groups.
  
  
  CONCLUSIONS
  We could not find any significant histological differences between CV and IUPJO in children. To obtain excellent functional recovery, surgical procedures with a definite correction of the UPJ should be preferred in paediatric patients with CV.
authors.affiliation: Department for Pediatric Surgery and Pediatric Urology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen, 72076, Germany. mail@verenaellerkamp.de.
authors.forename: V
authors.initials: V
authors.lastname: Ellerkamp
authors.affiliation: Institutes for Pathology and Neuropathology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen, 72076, Germany.
authors.forename: R R
authors.initials: RR
authors.lastname: Kurth
authors.affiliation: Department for Pediatric Surgery and Pediatric Urology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen, 72076, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Schmid
authors.affiliation: Department for Pediatric Surgery and Pediatric Urology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen, 72076, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Zundel
authors.affiliation: Department for Pediatric Surgery and Pediatric Urology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen, 72076, Germany.
authors.forename: S W
authors.initials: SW
authors.lastname: Warmann
authors.affiliation: Department for Pediatric Surgery and Pediatric Urology, University Hospital Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen, 72076, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Fuchs
mesh_terms: D002648:Child; D002675:Child, Preschool; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007682:Kidney Pelvis / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D011379:Prognosis; D020127:Recovery of Function; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D014513:Ureter / Q000098:blood supply* / Q000000981:diagnostic imaging; D014517:Ureteral Obstruction / Q000175:diagnosis* / Q000503:physiopathology; D014563:Urodynamics / Q000502:physiology*
keywords: Child; Crossing vessels; Hydronephrosis; Ureteral obstruction