Prospective Randomized Feasibility Study Assessing the Effect of Cyclic Sacral Neuromodulation on Urinary Urge...

The aim of this prospective, randomized, multicenter, single-blind, 4 × 4 crossover study was to estimate the effect of 4 InterStim cycling settings (continuous, 16 seconds on/8 seconds off, 10 minutes on/10 minutes off, and 30 minutes on/23.5 hours off) on efficacy, Global Response Assessment, and safety.

Eligible women implanted for at least 3 months for urgency urinary incontinence (UI) were enrolled, and daily diaries were collected. General linear mixed models were used to estimate the cycling effect on efficacy. Quality of life measured by Global Response Assessment (subjects' perception of effectiveness) and safety were summarized.

Primary efficacy analysis was based on the first 24 subjects who completed unique randomization sequences. Mean age was 64 years, and mean implant duration was 2.8 years. Results showed no significant cycling (P = 0.3773) or period (P = 0.0800) effect on UI. There was a statistically significant interaction between cycling and period (P = 0.0032). In the first period, subjects on 10 minutes on/10 minutes off had significantly fewer UI episodes compared with subjects on 16 seconds on/8 seconds off (P = 0.0026); this difference was not observed in any other period or sensitivity analyses. No cycling effect was found on urgency or pad usage. When programmed to 10 minutes on/10 minutes off, 54% of subjects felt their incontinence symptoms improved compared with when they entered the study, followed by 42% on 30 minutes on/23.5 hours off, 38% on 16 seconds on/8 seconds off, and 29% on continuous. Safety was similar across cycling settings.

The results suggest that patients with overactive bladder who have been implanted with sacral neuromodulation devices and are receiving substantial benefit may perceive further optimization by switching to cycling settings.