Anatomic effect of distention therapy in unstable bladder: new approach.

The recent clinical success of distention therapy in the treatment of the unstable bladder is reviewed. Bladder stability and increased capacity as measured by cystometry following distention therapy as well as relief of symptoms have prompted this anatomic study. The neuromuscular pathways of conduction in rat and rabbit bladder wall were examined following short-term (two-hour) and prolonged (six-hour) distention. Treated and control animals were studied at fixed intervals for four months. Prolonged distention did not alter either smooth muscle cell architecture or intercellular junctions. It did produce a transient phase of degeneration among the unmyelinated nerve fibers in the bladder wall consisting of axonal swelling and lysis of organelles. A quantitative estimate of nerve injury was compiled using pooled histograms. These results suggest that bladder stability following distention therapy may be related to nerve degeneration in the bladder wall.