Sacral nerve stimulation for the treatment of faecal incontinence related to dysfunction of the internal anal sphincter

In patients with faecal incontinence related to isolated internal anal sphincter (IAS) disruption, conservative management is the mainstay of treatment. Surgical repair of the internal sphincter is not successful. This study evaluated the use of sacral nerve stimulation (SNS) in those with faecal incontinence and IAS disruption in whom medical and behavioural treatments had failed. Nine patients (seven women, median age 44 years, range 39-62 years), with a history of obstetric or iatrogenic anal sphincter trauma, underwent a trial of SNS. All had passive faecal incontinence, low resting anal sphincter pressure and full thickness IAS muscle disruption of greater than 30A degrees radial extent. The effect of SNS on symptoms was measured by a bowel habit diary and validated questionnaires used to assess impact on quality of life. Eight (89%) patients benefited from temporary stimulation and proceeded to permanent device implantation. Follow-up was at a mean of 46 months (range 2-81). Faecal incontinence decreased from a mean (SD) of 9.9 (10.9) to 1.0 (2.4) episodes per week (p = 0.031), and soiling decreased from 6.1 (1.6) to 1.7 (2.4) episodes per week (p = 0.031), with chronic stimulation. At latest follow-up, three patients had no incontinence, three patients had episodes of minor soiling only, one patient had > 75% reduction of incontinent episodes, and two patients remained incontinent. Sacral nerve stimulation is effective in treating faecal incontinence related to a structurally and functionally abnormal internal anal sphincter. Treatment should not be refused on the basis of IAS disruption.