UPJ Obstruction

Stephen Confer, MDBen O. Donovan, MD

Brad Kropp, MDDominic Frimberger, MDUniversity of Oklahoma Department of Urology

Section of Pediatric Urology

UPJ Obstruction• Most common site of urinary tract

obstruction in children

• Majority are discovered antenatally– 1:800-1500 pregnancies– 80% antenatal hydronephrosis– 2:1 boys:girls– 2/3 on the left– 10-40% bilateral

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

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

Associated Anomalies

• Another urologic abnormality-50%– Contralateral UPJ 10-40%– Renal dysplasia, aplasia, MCKD– VUR up to 40%

• Found in 21% of VATER patients

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

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

Diagnosis

• Renal 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

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

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

Diagnosis

• IVP– 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

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 > 15-22 cm

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

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

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

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 (48 - 72 if VUR present)

• Penrose for 3 - 5 days– Prevents urinoma formation

• 94 - 98% success rate

Dismembered Pyeloplasty

Surgical Options• Foley V-Y-Plasty

– Good for 1-2 cm obstruction– Best for high inserting ureter– Best with relatively small pelvis

Foley Y-V-Plasty

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

Spiral Flap

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 - 62-94% secondary success 66-100%

• less successful if associated with a crossing vessel

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

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