Effect on anal pressure of percutaneous posterior tibial nerve stimulation for faecal incontinence

Abstract

AIM: Previous studies on percutaneous posterior tibial nerve stimulation (PTNS) for faecal incontinence do not report anal pressure changes. In the present study the effect of percutaneous PTNS on anal manometry was determined. METHOD: This was a prospective observational study of patients with faecal incontinence. They underwent one 30-min session of PTNS weekly for 12 consecutive weeks. Patients who showed improvement were given six more sessions at 2-weekly intervals. Anal manometry was performed before and after treatment. Clinical data including the Wexner score, psychological testing, quality of life using the Fecal Incontinence Quality of Life Score and the contents of a continence diary were recorded before and after the procedure. RESULTS: Twenty-four patients were included in the study of whom 17 (70.83%) demonstrated some degree of clinical or manometric improvement at 3 months. Before treatment 18 patients had urgency of <1 min. At 3 and 6 months this had risen to 5 min in 62.5% and 70.83% (P < 0.001). The anal resting pressure increased from 21.7 to 37.6 mmHg (P = 0.021), the maximum squeeze pressure from 58.2 to 72.2 mmHg (P = 0.045) and the Wexner score fell from 15 to 10 (P = 0.018) at 6 months. Predictive factors for a response included fewer than three incontinent episodes per week (P = 0.027). Negative predictive factors included episiotomy and an initial Wexner score of > 12 (P = 0.035). CONCLUSION: Percutaneous PTNS was effective in over 70% of patients in the present study with improvements in urgency, anal pressures and Wexner score.