A recent multicenter study provides some justification for the increasing popularity of transobturator slings in the treatment of stress urinary incontinence in patients with and without concurrent pelvic organ prolapse.
Researchers found that the use of transobturator tape (TOT) (Monarc Subfascial Hammock, American Medical Systems, Minnetonka, MN) in these patients worked at least as well as, and may potentially work better than, the widely used tension-free vaginal tape (TVT) approach (Ethicon Gynecare, Somerville, NJ). The study was presented at the American Urogynecologic Society annual scientific meeting here.
Two caveats appear to be that long-term data are not yet available on the TOT procedure and that TOT introduces the possibility of leg complications that can be avoided with TVT.
Of 180 patients enrolled in the study, 170 actually underwent one of the two procedures, and 166 (92%) returned for follow-up (mean, 18.5±6 months). All subjects had urodynamic stress incontinence and were randomized to TVT or TOT on the day of surgery at one of three academic medical centers. Those with detrusor overactivity or previous sling surgery were excluded.
Evaluation and follow-up consisted of a standing cough stress test (300 mL), 3-day bladder diary, the Incontinence Severity Index, and validated health-related quality of life and sexual function questionnaires. Data collection time points were established at baseline and at 6 months, 1 year, and 2 years after surgery.
The primary outcome of "abnormal bladder function" was assessed 1 year after surgery and was defined by the investigators as the presence of any one of the following:
Dr. Barber and colleagues specifically used a non-inferiority study design to test the hypothesis that TOT is not inferior to TVT.
"When we designed the study, we felt that there was no reason to suggest that the cure rate of TOT would be substantially higher than TVT, given TVT's proven efficacy, but that it was important to demonstrate that TOT was not worse than TVT by a clinically important de gree," Dr. Barber explained.
The study team found that abnormal bladder function occurred in 46% of TVT patients and 42% of TOT patients, with a mean absolute difference of 3.9% favoring TOT (95% CI: –11.0% to +18.6%; p=.64). Negative cough stress test rates and rate of stress incontinence symptoms also were similar between the two groups, as were mean operating time, blood loss, length of stay, and postoperative pain scores.
Bladder perforations occurred in 7% of TVT patients and in no TOT patients (p=.02), which compares well with other studies in the literature that report a 3% to 9% incidence of bladder perforations with TVT.
"That's significant," Dr. Barber acknowledged, "but it's generally not as clinically important as it might sound. If the perforations are identified at the time of TVT surgery, you can remove and replace the trocars and generally don't have to perform any intervention beyond that."
The obvious advantages of the TOT, Dr. Barber noted, are that it is minimally invasive with small incisions, can be performed on an outpatient basis under local anesthesia, and offers quick patient recovery with lower rates of voiding dysfunction than have been seen with some of the more established procedures for stress incontinence, such as fascia slings.
When it comes to deciding which procedure to use, Dr. Barber says the choice largely comes down to patient counseling.
"Even though we have pretty promising results for TOT in our study, the mean follow-up is only about 18 months," he said. "That's the longest follow-up of which I'm aware in the literature. For TVT, we have at least 7-year data, so there needs to be more long-term follow-up on TOT before I can look my patient in the eye and say I know this works.
"These are meant to be permanent operations, so we'd like to be able to show some durability with them."
The study was partially funded by American Medical Systems.