Two mid-urethral slings show similar efficacy in stress urinary incontinence

"The transobturator sling was developed with the intent to reduce the complications associated with the retropubic sling, but there is really little robust data comparing the two procedures in efficacy or safety," explained co-author Michael Albo, MD, clinical professor of surgery/urology and co-director of the Women's Pelvic Medicine Center at the University of California, San Diego.

To this end, Dr. Albo and his co-investigators from the Urinary Incontinence Treatment Network initiated TOMUS (Trial of Mid-urethral Slings). The researchers randomized 597 women with urinary incontinence to undergo either transobturator or retropubic sling procedures (299 and 298 patients, respectively). Primary outcome was objective and subjective treatment cure at 12 months. Objective measurement criteria included negative stress test, negative 24-hour pad test, and no retreatment for stress incontinence, while subjective cure measures included no self-reported symptoms of stress incontinence, no leakage on 3-day voiding diary, and no retreatment. Patient satisfaction, change in quality of life, and adverse events were also assessed.

Subjective cure rates were 55.8% for the transobturator group and 62.2% for the retropubic group, which did not meet the study's equivalence criteria.

Procedures differ in adverse events

The sling procedures differed, however, in adverse events. In the retropubic group, nine patients had voiding dysfunction requiring surgery, and 15 patients had intraoperative bladder perforations; neither event occurred in the transobturator arm. The transobturator group had a higher incidence of intraoperative vaginal perforations and neurologic symptoms.

No difference in pain or de novo urgency was observed between the two groups, Dr. Albo reported, nor were there differences in patient satisfaction or quality of life.

The group's findings should help guide clinicians in choosing which procedure to use in a given patient.

"Clinicians can now rely on the strongest level of evidence when advising similar patients about the surgical options for stress incontinence," Dr. Albo told Urology Times.

The researchers intentionally chose a short, 12-month time point to measure the primary outcome in TOMUS due to the uncertainty about whether the two procedures were equivalent in terms of safety, Dr. Albo noted. The study was initially designed to follow the patients for 24 months, and data from that point is forthcoming. An extended version of TOMUS will follow patients for 5 years beyond the 24-month follow-up, he said.

Following the AUA meeting, results from the study were published in the New England Journal of Medicine (2010; 362:2066-76).

First author Holly Richter, MD, PhD, disclosed financial or other relationship with Pfizer, Inc. and Xanodyne Pharmaceuticals, Inc.