Evolution of Management of Posterior Urethral Valve : Journal of Indian Association of Pediatric Surgeons (2024)

Young in 1919 described three types of valves, clinical presentation, and treatment. Dewans described single diaphragm with central defect as in Young's type 3 – congenital obstructing posterior urethral membrane.

Anatomical and pathological changes are dilated posterior urethra, abnormal dilated bladder, muscular hypertrophy with abnormal collagen, and autonomic nerve distribution. Bladder dynamics are abnormal. Kidney is dysplastic, may be focal or segmental, or there may be hydronephrosis. Postnatally kidney may acquire infection leading to pyelonephritic changes. Raised bladder pressure, impaired urinary drainage leads to dilated tortuous ureter with or without vesicoureteric reflux.

Antenatal maternal ultrasonography (USG) shows distended hypertrophic urinary bladder, hydronephrosis or dysplastic kidney, failure of bladder to empty, oligohydramnios, and ecogenic line in dilated posterior urethra-keyhole sign. For confirmation of posterior urethral valve (PUV), repeated persistent above sonographic finding is useful in the diagnosis. Antenatal management includes open surgery of vesicostomy or cystoscopic ablation of valve. This procedure is associated with fetal loss and maternal morbidity, and hence, open fetal decompression of bladder has been abandoned.[¹] Percutaneous Vesicoamniotic shunt is still in use as antenatal decompression. There is a little evidence of the efficacy of the prenatal intervention in comparison to the postnatal management of PUV. Despite 30 years of research, fetal lower urinary tract obstruction remains a difficult entity to treat. Intervention may lead to survival, and physicians must remain alert for the distinct possibility of long-term morbidity in survivors. Fetal surgery for obstructive uropathy should be performed only for carefully selected patient who has severe oligohydramnios and normal-appearing kidney.[²]

Due to antenatal USG, more babies present with bladder outlet obstruction in neonatal period. The detection of PUV has increased up to 30% during the neonatal period. Infant and older babies present with abdominal masses, abnormal urinary stream, urinary tract infection, and failure to thrive. Apart from blood electrolytes, renal function test, USG is the most noninterventional investigation for the diagnosis of PUV.[³] The availability of real-time ultrasound unit with small transducer has made perineal USG, a practical proposition in infants. The finding of dilated posterior urethra, dilated bladder, hydroureters, and renal dysplasia in a male infant indicate high probability of posterior urethral valve.[⁴] USG also helps in comparing the changes of bladder and hydroureteronephrosis following ablation. However, micturating cystourethrogram under strict aseptic precaution is followed in most institution for the diagnosis of PUV. Sharma, et al.[⁵] described the voiding cystourethrogram in different age groups.

After initial management with catheter drainage of the bladder, appropriate intravenous fluid therapy, antibiotics, and treatment of any other complications, baby is stabilized for primary ablation of valve. With recent development, most centers have appropriate size modern endoscope for primary ablation of valve. Indigenous valvulotome is being used by Abraham and others as blind procedure. Urinary diversion is indicated in babies with fulminating infection, uncontrolled azotemia, massive vesicoureteric reflux with infection and pyonephrosis, and preterm newborn. Vesicostomy is most often performed due to simple procedure. However, in cases of massive hydroureteronephrosis, urosepsis, diversion in the higher ureter is better to control sepsis and renal drainage. Ureterostomy may be done one side or both side depending on the condition of the kidneys. After stabilization of the baby, the valve is ablated. Urinary diversion helps in resolving the vesicoureteric reflux in majority of cases. Following improvement of renal function and control of infection, secondary surgery is required for undiversion of urinary tract. Closer of ureterostomy, re-implantation of refluxing ureter, and nephroureterectomy are required depending on the condition of the kidney and ureter.[³]

Hendren in 1970[⁶] described a new approach of early complete reconstruction in infant with severe obstructive uropathy. Surgery included Fulguration of Valve, y-v plasty of bladder neck. Dilated ureter was straightened, shortened and re-implanted in the bladder. The result was good. However, the technique has not been followed later. Most of the surgeons at that time advocated urinary diversion to control the hydroureteronephrosis and infection. Ablation of valve and undiversion of urinary tract were completed later.

Inspite of above-mentioned treatments, good number of patients have a persistent bladder outlet obstruction with progressive severe hydroureteronephrosis. The valve bladder has a sustained bladder distention with polyuria. The valve bladder is proved to be due to bladder over distention, incomplete evacuation of urine, and bladder dysfunction. Treatment consists of drainage of the upper tract and bladder. Intermittent catheterization and upper tract drainage are essential for the control of the valve bladder. Anticholinergic is used to control the bladder dysfunction. Deterioration of the function of the urinary tract leads to end-stage renal disease.[⁵]

By avoiding diversion in most cases, bladder function is preserved and the need for bladder augmentation is decreased.[⁷] Bladder healing with early ablation depends on bladder filling and emptying (cycling) with low outflow resistance. Early ablation achieves both goals of maximum bladder and renal function recovery.[⁸] Renal insufficiency associated with valve is often secondary to renal dysplasia. Even upper tract diversion fails to recover in the presence of renal dysplasia.

Noncompliant and small bladder may require augmentation by intestine or by dilated ureter. Baby with end-stage renal disease requires renal transplantation. Bladder capacity should be improved before renal transplantation so that transplanted kidney drain freely in the bladder. Urodynamic studies are recently used to determine the bladder function and urinary tract following ablation of PUV. It shows radiological evidence of bladder dysfunction, postvoid residual urine, persistent vesicoureteral reflux, detrusor sphincter dyssynergia.

Anticholinergic drug, oxybutynin is used to control the bladder dysfunction and its effect is very limited. Tolterodine tablet also helps to control the medical therapy in addition to oxybutynin. This drug should be used in the absence of bladder outlet obstruction. In the presence of bladder outlet obstruction, alpha-adrenergic blockers (terazosin) are being used to control the postvoid urine.[⁹] Precaution is to be taken to avoid side effects of hypotension.

Persistent bladder dysfunction has been implicated as a cause of deterioration of upper tract and renal function. Urodynamic study is routinely used for follow-up study. Bladder neck hypertrophy is indicated as a cause of bladder outlet obstruction in patient with postoperative PUV. However, this concept has been disputed by Glassberg[¹⁰] and Waterhouse.[¹¹] On the contrary, various scientists revisited the bladder neck and acknowledged that bladder neck obstruction persisted in postablation PUV. Bladder neck is incised by endoscope secondarily with better bladder evacuation and significant low residual volume of urine[^12,13,14] I have incised bladder neck secondarily in twelve cases during the last 20years with better evacuation of the bladder. Singh et al.[¹⁵] opined that valve ablation with bladder neck incision gives statistically significant better urodynamics in voiding phase and lesser PVR in comparison in valve ablation only. BNI is an effective treatment for functional bladder neck obstruction refractory to alphablocker and provide durable result.[¹⁶] Chatterjee et al.[¹⁷] also reported uniform data system to monitor the detrusor pressure during follow-up and practicing BNI with ablation of valve and secondary BNI with encouraging result. He is also contemplating rhabdoid sphincter spasm in the PUV obstruction. However, it required further long-term study for confirmation. BNI is not associated with additional risk of incontinence and dry ejacul*tion in early adulthood.[¹⁸] Sarin and Sinha did not find any benefit of BNI in children with PUV.[¹⁹]

During the past 15 years, primary ablation of the valve has been done in most of the cases in my series and only sixteen babies required diversion by vesicostomy or ureterostomy before or after ablation of valve. The incidence of secondary surgery has lessened to a large extent to control v-u reflux. The incidence of end-stage renal failure is also lessened to a large extent due to adequate management of bladder dysfunction by bladder neck incision, anticholinergic drugs, and alpha-adrenergic blocker.

The long-term follow-up study emphasizes the importance of checking renal and bladder function throughout life in men born with PUV. In our follow-up, renal function is assessed by estimation of creatinine, creatinine clearance, albumin creatinine ratio, and DTPA scan. Bajpai and Singh[²⁰] suggested plasma renin activity as an early marker of progressive renal disease. Increasing attention of bladder dysfunction and treatment would improve the long-term prognosis.

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