The long-term clinical syndrome that results from PUVs is known as the “valve-bladder syndrome.” Affected patients have large bladder volumes and subsequent overflow incontinence, which occur because bladder compliance and sensation decrease in response to longstanding obstruction. The large bladder volumes perpetuate obstructive injury to the kidneys. The injured kidneys, in turn, worsen the overfilling problem because their damaged collecting ducts become unable to appropriately concentrate urine. Some of these changes may be reversible if bladder pressure is regularly reduced, as with clean intermittent catheterization.