Differences between intrinsic and extrinsic ureteropelvic junction obstruction related to crossing vessels: histology and functional analyses.
PURPOSE
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.


CONCLUSION
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.
['Ellerkamp|V|V|', 'Kurth|R R|RR|', 'Schmid|E|E|', 'Zundel|S|S|', 'Warmann|S W|SW|', 'Fuchs|J|J|']
D002648:Child D002675:Child, Preschool D003952:Diagnostic Imaging D005260:Female D005500:Follow-Up Studies D006801:Humans D007223:Infant D007231:Infant, Newborn D007682:Kidney Pelvis D008297:Male D011379:Prognosis D020127:Recovery of Function D012189:Retrospective Studies D012720:Severity of Illness Index D013997:Time Factors D014513:Ureter D014517:Ureteral Obstruction D014563:Urodynamics
Crossing vessels Child Hydronephrosis Ureteral obstruction