The additional value of ambulatory urodynamic measurements compared with conventional urodynamic measurements

To study the additional diagnostic value of ambulatory urodynamic measurements/monitoring (AUM) in patients with lower urinary tract symptoms (LUTS).

We reviewed the urodynamic data, collected at the urology department of our University Hospital between 2002 and 2007. During this period, 2393 urodynamic investigations were conducted. In 108 patients both conventional urodynamic measurements (CUM) and AUM were conducted.

In 25 patients an AUM was conducted for bladder evacuation problems due to absent bladder contractility, seen on CUM. In 21 cases, AUM showed the presence of contractility of the bladder under normal conditions at home. Their symptoms were due to other factors such as a concomitant non-relaxation of the urinary sphincter or pelvic floor, psychological reasons or obstruction, for all of which treatment could be initiated. In 32 cases, the indication for AUM was an inconclusive CUM. Of these patients 16 had clear overactive contractions on AUM.

AUM has a more important place in the second-line diagnostic evaluation of patients with LUTS than generally considered. In half of the cases (16 of 32) in which CUM could not provide a diagnosis, AUM helped us to diagnose overactive bladder. Moreover, in the absence of AUM, many patients would have been misdiagnosed with an acontractile bladder based on their CUM results, which would most probably have resulted in life-time clean intermittent self-catheterization.