Findings from a large cohort of men with post-radical prostatectomy incontinence provide some insight on the diagnostic benefit of videourodynamic studies for guiding management decisions.
Overall, they found that, compared with the clinical history, VUDS provides little additional benefit in guiding treatment, especially in men with complaints of stress urinary incontinence.
The study, a retrospective analysis based on a single-center experience, included data from 670 men who were divided into three groups: 330 men with stress urinary incontinence, 54 with urgency urinary incontinence, and 286 with mixed urinary incontinence (stress and urgency), based on their symptomatic complaints. For each group, men were categorized as to whether their VUDS findings indicated stress incontinence alone, stress incontinence and detrusor overactivity (DO), or DO alone, and then the data were analyzed for correlations between the clinical and VUDS diagnoses.
The sensitivity, specificity, and positive and negative predictive values of the clinical complaints of stress and urgency incontinence for establishing a diagnosis were analyzed using the VUDS findings as the gold standard. The results showed a diagnosis of stress incontinence based on clinical symptoms alone had a high sensitivity (95.5%) and reasonably high positive predictive value (76%). However, the diagnostic accuracy of urgency incontinence based on clinical history was lower, with a sensitivity of only 65% and positive predictive value of 42%.
"Urodynamic studies are recommended to establish a precise diagnosis prior to undertaking invasive treatment for bothersome incontinence after radical prostatectomy," said first author Sender Herschorn, MD, professor and chair of urology at the University of Toronto. "However, the results of our study suggest that history is indicative of the VUDS findings for the majority of men.
"According to our study, if a man has complaints of stress incontinence, which accounted for over 90% of the patients in our study, VUDS in general would not seem to add much clinically relevant information for guiding treatment planning.
Post-radiation patients fare worse
Data were also analyzed to investigate a possible impact of postsurgical adjuvant or salvage radiation therapy on urinary tract function, and statistically significant differences were found between men with and without a history of radiation therapy. Average pad use per day was significantly higher among men who had received radiation therapy compared with their counterparts who had not (3.69 vs. 2.96; p=.010). In analyses of VUDS data, a history of radiation was associated with a significantly higher voiding pressure (36.46 cm H2O vs. 30.47 cm H2O; p=.125), a significantly lower maximum flow rate (14.36 mL/sec vs. 16.83 mL/sec; p=.0104), and a significantly lower bladder capacity (340.82 mL vs. 393.29 mL; p=.0003).
"These post-radiation findings are consistent with a previous study in which we found urodynamics were changed in men who were followed for up to 2 years after radiation therapy. The data can likely be explained by an effect of radiation on the bladder and urethra," Dr. Herschorn said.
"However, in some cases there may be artifact relating to the testing itself since having a catheter in place when there is urethral rigidity or fibrosis might incorrectly manifest itself as outlet obstruction. These findings may explain some of the difficulties in managing these patients after radiation."