Special investigations for female incontinence

Abstract

Urodynamics is the measurement of the ability of the bladders and urethra to store and expel urine. This article describes some of the investigations that are used in the diagnosis and management of incontinence in women and that come under the umbrella of ‘urodynamics’.

Pad tests quantify the amount of urine loss and are also helpful in patient counselling and measuring the results of intervention. Urinary flow rates are assessed by uroflowmetry and help identify poor bladder emptying (the cause of which can then be determined by pressure-flow studies). Filling cystometry is the main test of the lower urinary tract’s ability to store urine and measures the capacity, stability and compliance of the bladder, as well as assessing the competence of the urethra. Pressure-flow studies are used to identify the cause of poor bladder emptying. In selected cases, it is necessary to image the lower urinary tract whilst simultaneously measuring pressure and flow; this is achieved by videourodynamics. When abnormalities cannot be demonstrated by any of these clinic-based investigations, ambulatory urodynamics provide a means of measuring the physiological function of the lower urinary tract over a long period of time, away from the hospital environment. The ability of the urethra to contain urine within the bladder can be quantified by a variety of techniques including urethral pressure profilometry, urethro retro-resistance pressure and leak point pressure, but currently, these tests have limited clinical value. Urodynamics is not necessary for every woman with urinary incontinence but is highly desirable before considering irreversible surgical intervention.