Preoperative screening for detrusor activity found inefficient practice

Screening for detrusor activity in women who are undergoing surgery for pure or predominant stress incontinence is not an efficient practice, according to findings from a large study presented here on Thursday.

"If your patient has pure or predominant stress incontinence, there's probably only a 10% chance that you will find detrusor activity on urodynamic testing," said Charles Nager, MD, professor of obstetrics and gynecology at the University of California, San Diego. "Urodynamics are used preoperatively to screen for destrusor activity. This study would suggest that there is a relatively low yield."

The study initially looked at 655 women (mean age, 51 years) with pure or predominant stress incontinence who were enrolled in a multicenter surgical trial and who were randomized to undergo Burch or autologous fascial sling procedures. The study aimed to describe noninvasive uroflowmetry and filling cystometry values in order to develop reference values for investigators conducting urodynamic studies.

A total of 582 women met nonivasive uroflowmetry criteria, and 585 met filling cystometry baseline inclusion criteria, with 567 of the 585 meeting plausibility screening. The vast majority of women (95%) undergoing surgery for pure or predominant stress incontinence had uroflowmetry maximum urinary flow rates of greater than 11 mL per second. They also had baseline vesical and abdominal pressures measuring between 12 and 60 cm of water.

"If someone were doing a urodynamic study, and the baseline pressures were outside of the range of 12 through 60, that would indicate that the system is not set up properly," explained Dr. Nager. "These are normative values for this group of women."Researchers also observed that 10% of patients who had demonstrable stress incontinence and qualified for stress incontinence surgery with a positive cough test did not show urodynamic stress incontinence when the catheter was in the bladder."The fact that they are not showing urodynamic stress incontinence is most likely related to the effect of the catheter inside the urethra causing some partial restriction," Dr. Nager said.