Current issues regarding posterior urethral valves.

There are a number of factors that affect ureteral dilatation in patients with posterior urethral valves. These include large urinary outputs, a noncompliant bladder, and distal ureteric fibrosis. Dilatation alone does not imply obstruction, and careful studies should be obtained to document obstruction prior to considering any surgery. Our prejudice leads us to avoid ureteric reconstruction in the period immediately after valve ablation. Our findings suggest that these patients have hypertonic bladders immediately after valve ablation period, so it could be hazardous to reimplant the ureter in such a bladder and thereby expose these kidneys to unnecessary high pressures. Each patient with persistent dilatation should be treated on an individual basis. Some will require no treatment, some reimplantation with or without tailoring, and some an augmentation cystoplasty. More conservative approaches include double and triple voiding regimens, intermittent catheterization, anticholinergics, alpha sympathomimetic blockers, and regimens to decrease urinary output. These same regimens also seem to have a role in improving the level of continence, as does the onset of adolescence. Fortunately, the majority of patients with posterior urethral valves can be treated with valve ablation alone. Unfortunately, a number of patients who have creatinines of less than 1.0 mg per dl following treatment in the first year of life will go onto renal failure years later. Rapid progression to renal failure usually does not ensue until the teenage period, when proteinuria and hypertension seem to be the hallmarks. The progressive renal failure that develops in these patients may be related to the hyperfiltration syndrome that Brenner and Levine reported in patients with a decreased number of nephrons. A role for decreased intake of protein may have some influence in preserving the function of patients with a reduced number of nephrons and hopefully will affect the ultimate prognosis. The author anxiously awaits the formation and results of studies that will employ such a dietary regimen for patients with a history of severe valves in the hope of preserving renal function. However, such reports are not likely to be forthcoming during this decade.