Urodynamic Testing and Interpretation

The lower urinary tract (LUT) consists of the bladder and urethra and allows for the low-pressure storage of urine with conscious control of micturition. Urodynamics is the measurement of the relevant physiological parameters of the LUT to assess its function and dysfunction. Clinicians can perform urodynamics noninvasively and invasively. The standard urodynamic test includes both forms of assessment. The test involves noninvasive evaluation of bladder emptying, and invasive assessments of bladder storage function and bladder emptying function. Invasive monitoring utilizes the insertion of catheters into the bladder and other body cavities. A clear question should, therefore, be posed and answered when performing standard urodynamic testing, and its results should guide therapeutic intervention. Urodynamic testing is a collaborative and dynamic investigation involving both the patient and clinician and should incorporate clear communication and open cooperation. Standard urodynamic testing is performed in patients with LUT symptoms (LUTS). It involves noninvasive uroflowmetry, followed by invasive cystometry and a pressure-flow study. The addition of tests such as concurrent electromyography (EMG) of pelvic floor muscles and urethral pressure profiles can supplement the investigation for further clinical detail. Video urodynamics is when standard urodynamics is combined with fluoroscopic imaging with radiographic contrast used in bladder filling. This form of assessment is particularly more informative in neurological patients who have neurogenic bladders and in patients who have had previous surgery or trauma-related anatomical defects.Ambulatory urodynamics has a portable device continuously monitoring bladder and abdominal pressures via invasive catheters. Natural filling of the bladder occurs through diuresis, rather than infusion via a catheter. It is a second line investigation aiming to reproduce symptoms through normal ambulatory activity in patients for whom standard urodynamic testing has not yielded definitive answers.