Urodynamic studies in pediatric urology.

In any type of lower urinary tract dysfunction it is mandatory to obtain as much information as possible on the function of the urinary tract. By definition of the International Continence Society, any investigation that produces such information is part of urodynamics. Thus, voiding and defecation history, physical examination, voiding frequency charts and defecation diaries are all essential parts of urodynamics. Repeated free uroflowmetry is considered an essential routine investigation by the International Children's Continence Society. Static and dynamic ultrasonography of the lower urinary tract and the pelvic floor can give important information on lower urinary tract anatomy and function, in a noninvasive manner. Invasive urodynamic studies such as voiding cystourethrography and cystometry are reserved for patients for whom the outcome of such studies is expected to change the therapeutic regime. Invasive urodynamic tests are performed primarily for one of two reasons. First, to confirm an expected diagnosis in new patients. Second, to ensure that the storage pressures in the bladder remain safe for normal functioning of the kidneys in children with chronic disease.