DISUSED URINARY BLADDER

I. Hypertonicity of Disused Canine Urinary Bladder

Abstract

The bladders of 21 female dogs were maintained in a chronic empty state for 5 to 147 days by either ileal conduit, ureterocutaneostomy or ureterovaginostomy.
Serial cystometrograms revealed that disused bladders rapidly developed hypertonicity. By the 5th to 6th week after the diversion, the maximum bladder capacity and the compliance had decreaced to 25.2% and 13.1%, respectively. The hysteresis effect (i. e. an increase in bladder capacity which occurs on the second filling when two cystometrograms are obtained in immediate succession) was observed only during the first 8 weeks after diversion. This effect was negligible before and 10-21 weeks after diversion. Cultures of bladder rinsings revealed that 55% of the disused bladders contained substantial quantities of bacteria. No statistically significant differences, however, were shown in the parameters of the cystometrograms between the infected group and the uninfected group. The denervation super-sensitivity tests were performed by subcutaneous injection of bethanechol chloride (0.03mg/kg body weight). The tests were negative for both the pre- and postoperative groups.
We speculate that depriving the bladder of its distension-evacuation cycle alters the viscoelasticity of the smooth muscle, in turn inducing hypertonicity.