Posterior Urethral Valve

1. Posterior Urethral Valves
Dr Hammad ur Rehman
PGR Paeds Surgery

2. Posterior Urethral Valves
• Posterior urethral valves are obstructing membranes within
the lumen of the urethra, extending from the
verumontanum .
• Occur only in boys.
• Commonest cause of bladder outlet obstruction

3. Embryology

4. Anatomy

5. Types
• Type I:
Obstructing membrane that extends distally from each side of
the verumontanum towards the membranous urethra where they
fuse anteriorly

8. Type II
Described as folds extending cephalad from the verumontanum to
the bladder neck

9. Type III
Represent a diaphragm or ring-like membrane with a central
aperture just distal to the verumontanum

11. Epidemiology
• INCIDENCE: 1/ 5000 – 8,000 male infants.
• GENETICS: debatable, but have been seen in siblings. Males only
• Type I > 95%
• Type III - 5%
• Children with Type III PUVs have a worse prognosis as a group
• 50% of patients with PUV will have vesicoureteral reflux
• 50% unilateral, 50% bilateral

12. Antenatal Diagnosis & Management
2/3 of the patient diagnosed antenatally
Distended, thick walled bladder.
Hydronephrosis.
Dilated prostatic urethra (Keyhole sign)
Oligohydramnios : Most of the amniotic fluid after the 16th
gestation depend on the fetal urine
Oligohydramnios would suggest primary renal impairment or
obstruction.
Oligohydramnios - accounts for co-presentation of pulmonary
hypoplasia

13. In fetus with suspected PUV and normal
amniotic fluid , serial sonograms are necessary
Oligohydramnios
VAS
Gestational Age
> 32 Weeks < 32 Weeks
Early Delivery Endoscopic Ablation

14. Before Intervention
• Karyotyping
• To confirm male gender
• Chromosomal Abnormalities
• Fetal Renal function Assessment
• Urinary Electrolytes
• B2 microglobulin level

15. Clinical Presentation
 POST- NATAL DIAGNOSIS:
Time and mode of presentation would depend on the severity of the condition
 Newborn
 Palpable abdominal mass
Distended bladder, hydronephrotic kidney
Bladder may feel like a small walnut in the suprapubic area
 Ascites
40% of time due to obstructive uropathy
 History of Oligohydramnios
 Respiratory distress from pulmonary hypoplasia
Severity often does not correlate with degree obstruction
Primary cause of death in newborns

16. Clinical Presentation
Early Infancy
 Dribbling / poor urinary stream
 Urosepsis
 Dehydration
 Electrolyte abnormalities
 Uremia
 Failure to thrive; due to renal insufficiency
Toddlers
 Better renal function (less obstruction)
 Febrile UTI
 Voiding dysfunction – incontinence
 Daytime incontinence may be the only symptom in boys with less severe
obstruction

17. INVESTIGATIONS
• Treat acute, associated problems.
• VCUG- ‘Gold standard’

18. Features on VCUG
1. Dilated, thick walled, trabeculated bladder
2. Elongated and dilated prostatic urethra with narrow bladder neck.
3. Folds of valves could be seen as filling defects from the area of the
verumontanum.
4. VUR, diverticula.

21. USG
• Prostatic urethra for characteristic dilation
• Thickening of the bladder wall

22. DMSA Scan
• Thin or abnormal parenchyma on USG
• High grade VUR
• Study should delay until 6-8 weeks to allow maturation of
renal function

23. Initial managment
A - Bladder Drainage
• A 5 or 8 Fr pediatric feeding tube is ideal
• A Foley catheter should not be used, due to the tendency of the balloon to occlude the ureteral orifice
and cause a bladder spasm.
• Secondary obstruction
B - Broad spectrum antibiotic coverage
C - Metabolic panel
• Assess renal function and metabolic abnormalities
• Acidosis, hyperkalemia common problems
D - Pulmonary resuscitation
E - If urinary ascities - paracentesis

24. Treatment
Endoscopic Valve Ablation
• Should be done after stabilization of neonate
• An 8 French or 9.5 French cystoscope is used with bugbee
electrode
• Leaflets should be incised at 5 and 7 o’clock position (12 o'clock)
• Following valve ablation feeding tube is left for one to two days
• Follow up after two to four weeks with USG and VCUG
• Renal function should be monitor carefully
• Complication : incomplete valve ablation , stricture formation,
iatrogenic hypospadias

25. Vesicostomy and delayed valves ablation
• Alternative to Valve Ablation
• Indications
• Pediatric cystoscope is too large
• Severe hydroureteronephrosis
• Urinary ascities
• High grade VUR
• Poor renal function
• Most popular technique is Blocksom
• Valve ablation should not be performed at the time to vesicostomy

27. Temporary upper tract diversion
• Reserve for rare cases in which
valve ablation or vesicostomy
fail to improve upper tract drainage
• Sober –en-T ureterostomy is preferred method

28. Management of Urinary Ascities
• Rupture of renal fornix with urinary extravasation and transduction in
to peritoneum can occur.
• Infant can develop perirenal urinoma or urinary ascities.
• Electrolytes abnormalities can result from urinary absorption.
• Evaluation begin with USG, VCUG, renal Scintigraphy
• Inserting a 5 French or 8 French feeding tube into the bladder may
decompress the bladder and upper urinary tract sufficiently that the
forniceal extravasation stops.
• Percutaneous drainage is needed if the extravasation and the serum
creatinine continue to increase, or respiratory compromise.

29. • Occasionally, exploration through a small flank incision may be
necessary.

30. Follow-up After Initial Therapy
• Antibiotic prophylaxis should be continued until the upper tract
dilation improves.
• Periodic follow-up with ultrasound, electrolyte measurements
• Early treatment with anticholinergic therapy (oxybutynin) may also be
beneficial.

31. Prognosis
Favourable
• Serum creatinine concentration
less than 0.8 mg/dL one month
after initial treatment, or at age 1
year.
• Visualization of the
corticomedullary junction
differentiation
• Achieving diurnal continence by
the age of 5 years
• Presence of a pressure pop-off
mechanism
• Normal appearance of the
contralateral kidney at diagnosis.
• Absence of reflux on the initial
VCUG
Unfavorrable

32. Long-term renal insufficiency
1. Polyuria
2. Salt-losing nephropathy
3. Metabolic acidosis
4. Renal osteodystrophy
5. Growth retardation