Predictive factors for successful sacral nerve stimulation in the treatment of faecal incontinence: a 10-year cohort analysis

Objective Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence. We aimed to identify specific factors that could predict the outcome of temporary and permanent stimulation. Method A cohort analysis was performed to identify potential predictive factors in 81 patients who underwent temporary SNS at a single institution over a 10-year period (June 1996 to June 2006). Data were obtained from prospectively collected patient symptom diaries and quality of life questionnaires, operation reports, anorectal physiological studies, endoanal ultrasound images and radiology of lead placement. Results Clinical outcome of temporary screening was not affected by patient gender, age, body mass index, severity or length of symptoms. The need for a repeated temporary procedure was associated with subsequent failure during screening (P = 0.008). A low threshold to obtain a motor response during temporary lead insertion was associated with improved outcome (P = 0.048). Evidence of anal sphincter trauma was associated with a greater risk of failure (P = 0.040). However, there was no difference in medium-term outcome between patients with external anal sphincter (EAS) defects and patients with intact anal sphincter muscles. Conclusion Variables have been identified that help to predict the outcome of SNS. The presence of an EAS defect should not preclude treatment.