Anterior urethral valves: A rare cause of infravesical obstruction in children

Anterior urethral valves: A rare cause of infravesical obstruction in children

Anterior Urethral Valves: A Rare Cause of Infravesical Obstruction in Children By M. Zia-ul-Miraj Lahore, Pakistan Purpose: The aim of this study was...

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Anterior Urethral Valves: A Rare Cause of Infravesical Obstruction in Children By M. Zia-ul-Miraj Lahore, Pakistan

Purpose: The aim of this study was to report the clinical presentation, mode of diagnosis, and treatment of patients with anterior urethral valves (AUV), a rare congenital anomaly causing infravesical obstruction in children. Methods: Three patients with anterior urethral valves were admitted in the Pediatric Urology Unit at The Children’s Hospital, Lahore, Pakistan, during the period 1997 through 1998. Main clinical features included difficulty in voiding, dribbling of urine, incontinence, poor urinary stream, hematuria, and urinary tract infections. The diagnosis was confirmed by voiding cysto-urethrogram (VCUG) in 2 patients and retrograde urethrogram in 1 patient. A total of 4 valves were found; 1 patient had 2 valves. Two patients had associated vesico-ureteric reflux. Endoscopic resection was performed in all patients.


NTERIOR URETHRAL VALVES (AUV) are rare congenital anomalies causing lower urinary tract obstruction in children. They can occur as an isolated entity or in association with a proximal diverticulum, both of which probably represent a spectrum of disease.1,2 It is suggested that the valves cause proximal urethral dilatation that eventually results in a saccular diverticulum.3 An adverse mechanism also has been proposed, suggesting that undermining of the distal urethra by progressive enlargement of a congenital diverticulum results in a distal valvelike flap of tissue.4 The embryology of AUV remains uncertain. Various proposed etiological mechanisms include an abortive attempt at urethral duplication,5,6 failure of alignment between the proximal and distal urethra,7,8 imbalanced tissue growth in the developing urethra resulting in excessive tissue remnant acting as a valve,7 and congenital cystic dilatation of periurethral glands, resulting in a flaplike valve.5 The clinical presentation of AUV is highly variable, depending on the age of patient and the degree of obstruction. Unless suspected, the diagnosis at times may

From the Department of Paediatric Urology, The Children’s Hospital and The Institute of Child Health, Lahore, Pakistan. Address reprint requests to M. Zia-ul-Miraj, 86-S, Model Town Extension, Lahore, Pakistan. Copyright 娀 2000 by W.B. Saunders Company 0022-3468/00/3504-0004$03.00/0 556

Results: Postoperatively, all patients were able to pass urine with good stream. At 9 to 24 months’ follow-up, all patients remain well and asymptomatic. Conclusions: Although rare, AUV must be considered in the differential diagnosis of lower urinary tract obstruction. They present with all degrees of severity depending on the age of patient and the degree of obstruction. A properly performed and carefully interpreted VCUG is essential for diagnosis. Transurethral resection is the treatment of choice. J Pediatr Surg 35:556-558. Copyright 娀 2000 by W.B. Saunders Company. INDEX WORDS: Anterior urethra, valves, congenital, obstructive uropathy.

be difficult. The author presents his experience with patients having AUV along with a literature review. MATERIALS AND METHODS Medical records of 3 patients with AUV admitted in the Pediatric Urology Unit at The Children’s Hospital, Lahore, Pakistan, from 1997 through 1998 were reviewed retrospectively. Their age ranged from 20 months to 7 years. Main clinical features included difficulty in voiding, dribbling of urine, poor urinary stream, recurrent urinary tract infections, hematuria, and incontinence (Table 1). Renal functions were normal in 2 patients, whereas 1 patient (case 2) had raised serum creatinine levels of 2.8 mg/dL (normal range, 0.5 to 1.5 mg/dL). Voiding cysto-urethrogram (VCUG) confirmed the diagnosis in 2 patients, whereas in the remaining patient a retrograde urethrogram proved diagnostic (case 1, Fig 1). Two patients had associated vesico-ureteric reflux (VUR): 1 had grade IV bilateral VUR (case 2), whereas the other had grade III VUR on the left side (case 3). Ultrasound scan (USS) showed bilateral hydroureteronephrosis and left-sided hydroureteronephrosis in these patients, respectively. A total of 4 valves were observed, 1 in the bulbar urethra, and 3 in the pendulous urethra. At urethroscopy, 3 valves appeared as a ventrally based ‘‘cusp-shaped’’ flap, and one appeared as a circumferential ‘‘iris-shaped’’ diaphragm. Transurethral endoscopic resection of the valves was carried out in all patients using a pediatric resectoscope.


Postoperatively, urethral obstruction was relieved immediately in all patients as indicated by a good urinary stream. All patients remain symptom free and have normal renal functions at follow-up ranging from 9 to 24 months. Serum creatinine levels in patient 2 have returned to normal levels of 0.9 mg/dL. USS has shown complete disappearance of hydroureteronephrosis in case Journal of Pediatric Surgery, Vol 35, No 4 (April), 2000: pp 556-558



Table 1. Clinical Details of Patients With Anterior Urethral Valves Case No. (Age)

1 (2 yr) 2 (20 mo)

3 (7 yr)

Clinical Features

Straining at micturition, dribbling since birth, episodes of acute retention Straining at micturition, dribbling since birth, recurrent UTIs, hematuria Poor urinary stream, recurrent UTIs, incontinence

Endoscopic Appearance of AUV

Associated Anomaly Treatment Outcome

Ventral cusplike flap




Two valves found: proximal: ventral cusplike flap distal: ‘‘irislike‘‘diaphragm Ventral cusplike flap

Bilateral VUR



Left VUR



Abbreviations: AUV, anterior urethral valves; UTIs, urinary tract infections; TUR, transurethral resection; VUR, vesicoureteric reflux.

3, and marked improvement of the upper tracts in case 2. A regular long-term follow-up has been arranged for all patients. DISCUSSION

AUV may be found anywhere in the anterior urethra. Forty percent of the valves are located in the bulbar urethra, 30% at the penoscrotal junction, and 30% in the pendulous urethra.7,8 AUV in the fossa navicularis also have been reported.8 Rarely, 2 concurrent AUV may be observed in the same patient, as was the case in 1 of our patients (case 2). Only one such case has been reported previously.9 AUV present with a spectrum of variable severity. Obstructive changes accompanying AUV have been classified by Firlit3 as a continuity of pathology, dividing them into 4 basic types depending on the degree of urethral dilatation, presence of a diverticulum, and the grade of upper tract dilatation. The common presenting complaints include difficulty in voiding, dribbling on micturition, incontinence, poor urinary stream, and recurrent urinary tract infections. However, presentation is highly variable depending on the age of patient and the degree of obstruction. In the neonatal period and infancy, AUV may cause severe obstruction resulting in megacys-

Fig 1. Retrograde urethrogram shows anterior urethral valve (arrow) with proximal urethral dilatation. At urethroscopy, a ventrally based ‘‘cusplike’’ valve was found (case 1).

tis, bladder rupture, bilateral severe hydroureteronephrosis, azotaemia and urinary ascites.10-12 Older children with minimal obstruction may present with enuresis, postvoiding dribbling, or failure to thrive.11 At times, AUV may escape diagnosis until adulthood.3 VCUG is the diagnostic investigation of choice for AUV.7,12 Typically, the urethra appears dilated proximal to the valve and narrow distal to it. A valve may appear as a linear filling defect along the ventral wall, or it may be indicated by a dilated urethra ending in a smooth bulge (Fig 2) or an abrupt change in the caliber of the dilated urethra.12 A urethrogram suggestive of meatal stricture in the presence of a normal meatus is typical of a valve in the fossa navicularis.8 In addition to defining a lesion in the urethra, VCUG also may show an associated diverticulum, megacystis, VUR, or any other associated anomaly. VUR has been reported in one third and upper tract deterioration in half of cases.12 Two of our cases showed

Fig 2. VCUG shows dilated urethra ending in a smooth bulge, which marks the site of an anterior urethral valve. Note abrupt change of the urethral caliber at this site. There was an associated grade-III VUR on the left side (case 3).



vesico-ureteric reflux. VCUG must be performed properly, including the entire urethra on the film.6 A careful interpretation is absolutely essential to establish the diagnosis because a valve can be overlooked easily. If no abnormality is detected on VCUG but symptoms persist, the examination should be repeated, or a retrograde urethrogram performed, which may reveal the anomaly.6 In one of our patients (case 1), VCUG failed to detect the lesion that was afterwards outlined by a retrograde urethrogram (Fig 1). Endoscopic examination of the urethra usually confirms the diagnosis. Typically, the valve appears as a filmy, ventrally located ‘‘cusplike’’ or ‘‘semilunar’’ flap of tissue, or a circumferential ‘‘irislike’’ membrane.6,7,10 All the AUV in the current series were cusplike, except for 1 that appeared as an irislike diaphragm. Recognition of the valve may be difficult because retrograde flow during urethroscopy flattens the valve against the urethral wall. Unless the lesion is considered in boys with outflow obstruction, it can be missed easily.1 Bladder expression while

searching the anterior urethra, and elevation of the cusp with the help of the loop of a pediatric resectoscope are invaluable in identification of the lesion. On occasion, after ‘‘normal’’ radiological studies, AUV may be unexpectedly found at endoscopic examination. Various reported methods of treatment include open urethrotomy and excision of the valve,9,13 segmental urethrectomy of the valve-bearing area along with a primary end-to-end anastomosis,13 and transurethral resection of the valve.6 Open excision may result in complications like extravasation of urine, stricture formation, and urethro-cutaneous fistula.14 However, open surgical correction is indicated in certain instances such as severe urethral deformity. Transurethral valve ablation with the help of a pediatric resectoscope is the treatment of choice for AUV.6 Various complications of endoscopic resection include stricture, urethro-cutaneous fistula, and persistent urethral dilatation. In all of our cases, endoscopic resection proved successful.

REFERENCES 1. Burstein JD, Firlit CF: Anterior urethra, in Kelalis PP, King LR, Belman AB (eds): Clinical Pediatric Urology (ed 2). Philadelphia, PA, WB Saunders, 1985, pp 558-561 2. Graham SD, Krueger RP, Glenn JF: Anterior urethral diverticulum associated with posterior urethral valves. J Urol 128:376-377, 1982 3. Firlit CF: Urethral abnormalities. Urol Clin North Am 5:31-35, 1978 4. Tank ES: Anterior urethral valves resulting from congenital urethral diverticula. Urology 30:467-469, 1987 5. Williams DI, Retik AB: Congenital valves and diverticula of the anterior urethra. Br J Urol 41:228-230, 1969 6. Kaplan GW, Scherz HC: Anterior urethral valves, in Kelalis PP, King LR, Belman AB (eds): Clinical Pediatric Urology (ed 3). Philadelphia, PA, WB Saunders, 1992, pp 851-853 7. Karnak I, Senocak ME, Buyukpamukcu N, et al: Rare congenital abnormalities of the anterior urethra. Pediatr Surg Int 12:407-409, 1997

8. Scherz HC, Kaplan GW, Packer MG: Anterior urethral valves in the fossa navicularis in children. J Urol 138:1211-1213, 1987 9. Yaxley RP: Congenital valves of the anterior urethra. Med J Aust 2:295-296, 1969 10. Firlit RS, King LR, Firlit CF: Obstructive anterior urethral valves in boys. J Urol 119:879-881, 1978 11. Waterhouse K, Scordamaglia LJ: Anterior urethral valves: A rare cause of bilateral hydronephrosis. J Urol 87:556-559, 1962 12. Glazier DB, Underberg SJ, Cummings KB: Neonatal bladder rupture due to anterior urethral valves. Br J Urol 80:819-820, 1997 13. Golimbu M, Orc AM, Al-Askari S, et al: Anterior urethral valves. Urology 12:343-345, 1978 14. Rushton HG, Parrott TS, Woodard JR: The role of vesicostomy in the management of anterior urethral valves in neonates and infants. J Urol 138:107-109, 1987