Management of posterior urethral valves on the basis of urodynamic findings

Abnormal urodynamic findings are common in boys with a history of posterior urethral valves. However, to our knowledge there are few reports on the results of treating these abnormal findings. We analyzed the treatment of abnormal urodynamic parameters and its outcome in 21 boys who underwent valve ablation.

After valve ablation multichannel urodynamic studies were performed in 31 boys, including 21 in whom studies were done before and after therapy was started for abnormal parameters. Detrusor instability and impaired bladder compliance were treated with anticholinergics or augmentation cystoplasty, and impaired detrusor contractility was managed with clean intermittent catheterization.

Before therapy 17 of 21 boys had impaired compliance and detrusor instability, 2 had impaired compliance without instability and 2 had instability alone. After treatment 8 boys had impaired compliance and 4 had detrusor instability. After anticholinergics were initiated new onset myogenic failure in 2 boys necessitated clean intermittent catheterization. Of the 13 patients who presented with urinary incontinence 10 became dry and 3 had improvement with therapy. Vesicoureteral reflux in 10 boys at the time of the initial urodynamic study resolved in 7 with anticholinergic medication and in 1 after clean intermittent catheterization was begun for severely impaired compliance. All 21 boys were treated with anticholinergics and 2 were ultimately treated with augmentation cystoplasty. Clean intermittent catheterization was also instituted in 5 patients, including the 2 who required clean intermittent catheterization after myogenic failure developed. Five boys with high voiding pressures were found to have outlet obstruction due to residual valve tissue in 2, bladder neck obstruction in 2 and urethral stricture in 1 despite normal flow rates in 2.

Urodynamic studies are helpful in guiding therapy in boys after valve ablation. Anticholinergic therapy can improve compliance, decrease detrusor instability, improve continence and eliminate vesicoureteral reflux in the majority of boys, although there is an associated risk of myogenic failure. Flow rates and fluoroscopic voiding studies are often unable to detect outlet obstruction and must be obtained in conjunction with voiding pressure measurements to make this diagnosis.