Abstract In Sacral Neuromodulation(SNM), the stimulation intensity is set at the sensory threshold(ST) level. However, subsensory stimulation at 50% of ST has proven effective in reducing faecal incontinence episodes.Aim: To explore the relationship between functional outcomes and varying subsensory stimulation amplitude in newly implanted patients.Method: This randomised, double-blinded study was designed to include patients with ≥ 1faecal incontinence episodes/week despite maximal conservative therapy. As part of another trial, patients were offered a one-stage procedure. Postoperatively, patients were randomised into two groups. G-1: Received stimulation at 0.05 volts, 50 and 90% of ST in 3x4-week periods, followed by 12-weeks stimulation at the ST. G-2: Received stimulation with 90% of the ST in in 3x4-week periods, followed by 12-weeks stimulation at ST. Patients were evaluated after each period using St. Marks’s Incontinence Score, Visual-Analog-Scale(VAS) for patient satisfaction regarding social function, bowel function and quality-of-life, along with a bowel habit diary.Results: Seventy-three patients with a median age of 60(IQR:50–69) completed the trial. Faecal incontinence episodes were significantly reduced at all follow-ups, with no differences between groups. The only statistical difference between groups was deltaVAS for bowel function after 4-weeks. In G-1 with ultralow stimulation amplitude (0.05 volts - equivalent to 9.6(IQR:6.5–13.4)% of ST) the improvement compared to baseline was 30(IQR:10–50) points significantly lower than G-2 with an improvement of 50(IQR:10–70) points (p-value: 0.05).Conclusion: Subsensory stimulation is feasible in newly implanted patients with faecal incontinence. An amplitude of 0.05 volts, is as effective on the functional outcomes as stimulation with higher amplitudes.
Duelund‐Jakobsen et al. (Thu,) studied this question.