1. UPJ Obstruction Stephen Confer, MD Ben O. Donovan, MD Brad Kropp, MD
Dominic Frimberger, MD
University of Oklahoma
Department of Urology
Section of Pediatric Urology

2. UPJ Obstruction
Most common site of urinary tract obstruction in children
Majority are discovered antenatally
1: pregnancies
80% antenatal hydronephrosis
2:1 boys:girls
2/3 on the left
10-40% bilateral

3. Etiology Unknown Intrinsic lesion with the ureteropelvic wall
Inefficient drainage through an aperistaltic segment
Overdistention of the pelvis leads to hypertrophy and decreased GFR
If high grade obstruction, penal parenchymal changes and impaired function result
Histology shows loss of normal smooth muscle, hypertrophy, and fibrosis
Less commonly: valvular mucosal folds, persistant fetal convolutions, upper ureteral polyps

4. Etiology
Extrinsic compression by an aberrant accessory or early branching vessel to the lower pole
15-52% of the cases in children
Most common cause in adults
Secondary UPJ obstruction
Severe VUR or lower urinary tract obstruction
permanent kink at the UPJ due to tortuosity
high inserting ureter

5. Associated Anomalies Another urologic abnormality-50%
Contralateral UPJ 10-40%
Renal dysplasia, aplasia, MCKD
VUR up to 40%
Found in 21% of VATER patients

6. Presentation Historically presented as a palpable mass Newborn
Antenatal hydronephrosis 80%
UTI, hematuria, failure to thrive, feeding difficulties, sepsis, azotemia
Later in life
30% diagnosed after UTI
25% diagnosed after hematuria
Episodic abdominal pain and vomiting due to intermittent obstruction

7. Diagnosis Most are diagnosed antenatally
Hydronephrosis on prenatal ultrasound
Most are asymptomatic at birth
The major question:
Is the obstruction clinically significant?
Radiologic evaluation helps to determine this, however there is no perfect way to diagnose obstruction

8. Diagnosis Renal U/S Doppler U/S 1st study performed in the neonate
Lacks specificity to determine significance
Doppler U/S
Tests Resistive Index
Increases sensitivity and specificity of U/S
RI > 0.7 may be significant
Wide range of variability limits this test

9. Diagnosis Diuretic Renal Scan Standardized protocol in children
IVF - 15cc/kg NS 30 minutes prior to study
Catheterization
Measure urine output every 10 minutes
Renogram acquisition for 20 minutes or until pelvis full
Lasix 1 mg/kg
Diuresis renogram acquisition for 20 minutes
Gives good differential function and drainage pattern

10. Diagnosis Disadvantages Variable response to Lasix
Variable timing of Lasix administration
Variable renal pelvic compliance
Do not correlate well with pressure-flow studies
Not as helpful with equivocal results

11. Diagnosis IVP Retrograde pyelograms functional study
usually wait until 4 wks. Old
pelviectasis after drainage
Retrograde pyelograms
mainly in cases of non-functioning kidneys
can r/o distal obstruction

12. Diagnosis Pressure-flow (Whitaker)
fill pelvis at 10ml/min normal saline
difference between pelvis and bladder
invasive
questionable accuracy if compliant pelvis
injection at non-physiologic rates
obstruction if pressure difference > cm

13. Follow-up U/S on day 2 - 3 of life Persistent hydronephrosis
VCUG to evaluate PUV or VUR
Prophylactic antibiotics if VUR present
No PUV or VUR - repeat U/S and diuretic renal scan at 1 month
Continued hydro - surgery vs. observation
observation - U/S and/or renal scan every 3-4 months for 1 year and then every 4-6 months
surgery - open/endopyelotomy/laparoscopy

14. Conservative Management
Principles:
50% of antenatal hydro resolved postpartum
unable to accurately diagnose true obstruction
observations that asymptomatic hydronephrosis can resolve spontaneously
Studies with infants with renal function >35-40% in the affected kidney and variable washout patterns
“Rule of 1/3” - 1/3 stay the same, 1/3 improve, 1/3 worsen

15. Indications for Surgical Intervention
Presence of symptoms associated with the obstruction
Impairment of overall renal function
Progressive impairment of ipsilateral function
Development of stones or infection
Hypertension

16. Surgical Management Open Pyeloplasty Gold Standard
Dismembered pyeloplasty is the most common
removal of stenotic or adynamic segment
proximal ureter is mobilized, spatulated posteriorlaterally
reanastomosed to the pelvis
pelvic reduction may be necessary is large and redundant
stent or nephrostomy tube if desired
Foley for 24 hours ( if VUR present)
Penrose for days
Prevents urinoma formation
% success rate

17. Dismembered Pyeloplasty

18. Surgical Options Foley V-Y-Plasty Good for 1-2 cm obstruction
Best for high inserting ureter
Best with relatively small pelvis

19. Foley Y-V-Plasty

20. Surgical Options Spiral flap
Good for long obstructions (better in adults)
Length of flap limited only by size of pelvis
(keep length: width at 3:1)
good when UPJ angle > 90

21. Spiral Flap

22. Surgical Management Endopyelotomy Antegrade or retrograde
Cold knife or electric current
Acucise is very popular
dilation balloon with hot wire
86% success in adults
Slightly less effective in children
Direct vision antegrade approach is most common
retrograde less useful due to small ureteral caliber
primary success % secondary success %
less successful if associated with a crossing vessel

23. Surgical Management Laparoscopic pyeloplasty
Same indications as open or endourologic procedures
Dismembered pyeloplasty is most common procedure performed
Without crossing vessels, may do any number of flap procedures
Up to 94% success rate, similar to open pyeloplasty

24. Conclusions More children are diagnosed with antenatal U/S
Current diagnostic tests do not differentiate between kidneys that will need surgery and those that will improve spontaneously
Solitary kidney, bilateral UPJ, or poorly functioning kidneys should be considered for earlier surgery