Effect of Sacral Neuromodulation Rate on Overactive Bladder Symptoms: A Randomized Crossover Feasibility Study

Objectives: This was a single-center, institutional review board-approved study, conducted in the USA that used a 3 × 3 orthogonal Latin squares crossover design to assess variability in overactive bladder symptoms and adverse events when subjects were exposed to three rate settings of sacral neuromodulation. Methods: Thirteen female subjects who had urgency frequency and urinary urge incontinence were enrolled into the study. Twelve subjects completed the study. Upon enrollment, each subject was randomized to one of three rate-setting sequences: 5.2, 14, and 25 Hz. Each rate setting was tested for 1 week in every subject. Results: When subjects were programmed to 5.2, 14, and 25 Hz, they had an average of 3.83 ± 2.27, 2.37 ± 1.83, and 2.82 ± 2.1 incontinence episodes per day and an average of 2.61 ± 1.64, 1.84 ± 1.43, and 1.94 ± 1.61 pad changes per day, respectively. Rate had a statistically significant effect on the number of incontinent episodes (P < 0.001) and number of pad changes (P = 0.039) with more incontinent episodes in the 5.2-Hz setting compared to the 14- and 25-Hz settings (P < 0.04) for both measurements. Nine subjects reported 21 adverse events. None of the adverse events was considered either a serious or an unanticipated adverse device effect (UADE). Conclusion: Rate significantly affected the number of incontinence episodes and pad changes per day. The number of adverse events was similar across the three rate settings with programming-related adverse events lowest in the 14 Hz group.