CORRELATION OF CYSTOGRAPHIC BLADDER MORPHOLOGY AND NEUROANATOMY IN BOYS WITH POSTERIOR URETHRAL VALVES

Purpose. We have observed a difference in the radiographic appearance of the body of the bladder (trabeculated) and its base (smooth) in boy s with severely obstructing posterior urethral valves. We wanted to de termine if (1) this was a reproducible finding and (2) there was an an atomic and/or physiologic explanation for it. Materials and methods. W e reviewed the initial voiding cystourethrogram in 47 boys with severe posterior urethral valves. The interureteric ridge was used as the di vision between the body and base of the bladder, The presence of trabe culation for each region was recorded. Results. Ages ranged from 1 day to 6 years at the time of initial cystographic evaluation (median 14 days). The body of the bladder was trabeculated and the base smooth in 72 % (34 patients). In the remaining patients, both the body and base were smooth. In no patient was the base trabeculated. Conclusions. Th e cystographic morphology of the urinary bladder in boys with posterio r urethral valves can be explained by its neuroanatomy. The body of th e bladder, which contracts during voiding because of parasympathetic ( cholinergic) stimulation, becomes trabeculated, The bladder base relax es during voiding due to sympathetic (alpha adrenergic) stimulation an d remains smooth. Thus, this difference in the cystographic appearance of the two parts of the urinary bladder reflects the normal innervati on and the mechanics of micturition in boys with urethral obstruction.