Transvaginal Electrical Stimulation for Treatment of Overactive Bladder Without Incontinence: A Pilot Cross-Over Clinical Trial.

Abstract

Objectives: Few studies look at therapeutic efficacy specifically in the OAB population that lacks urgency incontinence (OAB-dry). Transvaginal electrical stimulation (TES) improves urgency incontinence in OAB-wet by targeting the detrusor muscle by reflex inhibition but has not yet been trialed for the improvement of urgency and frequency symptoms alone without incontinence. This study sought to measure the efficacy of an at-home TES program on urgency and frequency symptoms alone in OAB-dry.

Methods: This was a prospective, randomized, cross-over, controlled trial of women > 18 years old presenting to a urogynecology clinic with urinary urgency and frequency without incontinence. Participants were randomized to receive 4 weeks of sham, followed by a 3-week washout period, and then 4 weeks of intervention (Arm 1), or the reverse (Arm 2). Intervention included 15 min/day of TES using a TENS unit and transvaginal probe with stimulation width of 100 µs, rate of 12 Hz, and amplitude set by participant based on sensation. Baseline bladder symptoms were captured with voiding diaries and standardized questionnaires. Standardized pelvic floor muscle exam was performed at the beginning and end of treatment. Participants were categorized as responders if the participants stated they planned to continue the TES as their primary treatment after study completion. Outcomes were compared using t-tests, χ², and Fisher exact tests.

Results: In total, 19 enrolled and 15 (79%) completed the study and had primary outcomes data available for analysis. There were no demographic differences between arms. Mean OAB-q scores for all at baseline was 25.1, post-sham was 22.9, and post-TES was 17.60, for a mean change of -7.73 points (95% CI, -21.5 to 5.9), p = 0.007). There was a reduction in voids per 24 h from 11.3 (± 3.7) to 9.0 (± 3.6) posttreatment (p = 0.048). Response, defined as continuation of therapy, had a significant association with lack of pelvic floor tenderness on baseline standardized exam (OR 0.96, CI 0.94-0.99).

Conclusions: These data suggest there are two phenotypes within OAB-dry, those with pelvic floor myofascial dysfunction that do not respond to bladder directive therapy, and those who represent a population of less severe OAB-wet with detrusor overactivity, which respond to bladder directive therapy. TES is a viable treatment option for this population, resulting in clinically significant improvements in urinary symptoms and patient-reported disease severity.

Trial registration: ClinicalTrials.gov: NCT04957524.