Bilateral compared with unilateral sacral nerve stimulation for faecal incontinence: results of a randomized, single‐blinded crossover study

Aim This randomized single-blinded crossover study aimed to investigate whether bilateral sacral nerve stimulation (SNS) is more efficient than unilateral stimulation for faecal incontinence (FI). Method Patients with FI who responded during a unilateral test stimulation, with a minimum improvement of 50% were eligible. Twenty-seven patients who were accepted to enter the trial were bilaterally implanted with two permanent leads and pacemakers. Patients were randomized into three periods of 4weeks' stimulation including unilateral right, unilateral left and bilateral stimulation. Symptoms scores and bowel habit diaries were collected at baseline and in each study period. A 1-week washout was introduced between each study period. Results Twenty-seven (25 female) patients with a median age of 63 (36-84) years were bilaterally implanted from May 2009 to June 2012. The median number of episodes of FI per 3weeks significantly decreased from 17 (3-54) at baseline to 2 (0-20) during stimulation on the right side, 2 (0-42) during stimulation on the left side and 1 (0-25) during bilateral stimulation. The Wexner incontinence score improved significantly from a median of 16 (10-20) at baseline to 9 (0-14) with right-side stimulation, 10 (0-15) with left-side stimulation and 9 (0-14) with bilateral stimulation. The differences between unilateral right or unilateral left and bilateral stimulation were non-significant, for FI episodes (P=0.3) or for Wexner incontinence score (P=0.9). Conclusion Bilateral SNS therapy for FI is not superior to standard unilateral stimulation in the short term. Equal functional results can be obtained regardless of the side of implantation.