Comparative urodynamic findings after primary valve ablation, vesicostomy or proximal diversion

There is little known about the effect of urinary diversion on the bladder of children with posterior urethral valves. There is a fear that diversion may result in contracted noncompliant bladders. We wished to compare urodynamic parameters in patients who underwent primary ablation of posterior urethral valves and in those who underwent diversion in the form of vesicostomy or pyelostomy.

Urodynamics were done in 32 boys with a history of posterior urethral valves divided into 3 groups based on initial treatment: 1) transurethral valve ablation; 2) cutaneous vesicostomy, subsequent closure and valve ablation, and 3) proximal cutaneous pyelostomy, subsequent reconstitution and valve ablation.

Patients who underwent initial diversion with vesicostomy or pyelostomy had bladders with larger functional capacity, better compliance and less instability. Chronic renal failure developed in 25% of the patients who underwent primary valve ablation and 33% of those who underwent diversion. Average period of diversion in vesicostomy and pyelostomy patients was 25 months.

Based on our findings temporary diversion does not seem to damage bladders. On the contrary, placing a damaged bladder at rest may help to improve bladder function. Bladder function following reconstitution correlated poorly with ultimate outcome and progression to renal failure. While we do not recommend temporary diversion as the treatment of choice for patients with posterior urethral valves, we believe that when chosen as treatment, it can be safely performed with little risk of further damage to the bladder.