Prospective Randomized Crossover Trial Comparing Continuous and Cyclic Stimulation in InterStim Therapy

Abstract

The aim of this study was to assess a difference in efficacy and patient preference in cyclic versus continuous stimulation with InterStim therapy for urge incontinence or urinary frequency. Patients with refractory urge incontinence/urinary frequency and with recent implantation of the InterStim system were randomized to continuous or cyclic InterStim stimulation after institutional review board-approved consent. They completed a 3-day voiding diary after 1 month of stimulation. They were then switched to the alternative setting for 1 month and completed another voiding diary. Subjective responses were evaluated with the Urinary Incontinence Impact Questionnaire and the Urinary Distress Inventory. Patient preference of stimulation setting was assessed. Statistical analysis was performed with paired t tests and repeated-measures analysis of variance. Data were available for 32 patients. Indication for InterStim: urge incontinence = 24, frequency = 8. No differences were noted in the number of urgency or urge incontinence episodes (mild, moderate, severe, or total) with cyclic or continuous stimulation. No differences were noted in the number of number of pads per day or the number of daytime or nighttime voids. The Urinary Incontinence Impact Questionnaire and Urinary Distress Inventory symptoms scores showed no significant differences between cyclic and continuous stimulation. No significant difference was noted in measured parameters based on the order of stimulation. Continuous stimulation was preferred by 17 patients, 9 preferred cyclic stimulation, and 6 had no preference. No significant differences were noted in voiding diaries and subjective responses between cyclic and continuous stimulation in InterStim therapy for patients with urge incontinence or frequency.