Introduction

This abstract describes the rate of complete urinary continence at 5 years in this prospective, multicenter post-approval study of sacral neuromodulation (SNM) with the InterStim® System. Subjects with bothersome symptoms of overactive bladder (OAB) including urinary urge incontinence (UI) and/or urgency-frequency (UF), who had not exhausted all medication options (failed at least 1 anticholinergic medication and had at least 1 medication not tried) were included in the InSite study.

Methods

Subjects with successful test stimulation received an InterStim implant. Implanted subjects were followed at 3 months, 6 months, and annually to 5 years post-implant. Therapeutic success for UI subjects was defined as a ≥50% improvement in average leaks/day from baseline. Complete continence was defined as 100% improvement in leaks/day compared to the baseline. Therapeutic success and complete urinary continence through 5 years were evaluated for all implanted UI subjects with diary data at baseline and follow-up visits (completers analysis).

Results

Of 272 OAB subjects that were implanted, 91% were female and the mean age was 57 years. Of these, 202 subjects qualified as having UI based on the baseline voiding diary and they had an average of 3.1±2.7 leaks/day. As shown in the figure, over time the UI therapeutic responder rate was consistently high, ranging from 76% through 83% through different follow-up visits. The UI therapeutic responder rate at 5 years was 76% (95% CI: 69-84%). From 3 months through 5 year follow-up, a range of 33% through 46% of UI subjects achieved complete urinary continence at different follow-up visits. At 5 years, 45% of UI subjects achieved complete urinary continence. For all implanted subjects the most common device-related AEs were undesirable change in stimulation (60/272, 22%), implant site pain (40/272, 15%), and therapeutic product ineffective (36/272, 13%).

Conclusions

This multicenter study shows that SNM is an effective and sustainable therapy for UI subjects through 5 years of follow-up. A large portion of subjects were able to achieve complete continence at 5 years.

Funding

This study was sponsored by Medtronic