Anal acoustic reflectometry predicts the outcome of percutaneous nerve evaluation for faecal incontinence.

BACKGROUND: Sacral nerve stimulation (SNS) is effective for some patients with faecal incontinence. Before insertion of a costly implant, percutaneous nerve evaluation (PNE) is undertaken to identify patients likely to report success from SNS. The aim of this study was to determine whether variables of anal sphincter function measured by anal acoustic reflectometry (AAR) could predict the outcome of PNE for faecal incontinence. METHODS: Women with faecal incontinence undergoing PNE were recruited. AAR, followed by anal manometry, was performed on the day of surgery, immediately before PNE. The outcome of PNE was determined by bowel diary results and incontinence severity score. Patients with a successful PNE outcome were compared with those with an unsuccessful outcome; logistic regression analysis was used to identify any independent predictors of success. RESULTS: Fifty-two patients were recruited, of whom 32 (62 per cent) had a successful PNE outcome and 20 (38 per cent) an unsuccessful outcome. The AAR variable opening pressure was significantly greater in patients who subsequently had a successful PNE result compared with the pressure in patients who did not (28 versus 17 cmH2 O; P = 0·008). No difference was seen in the manometric equivalent, maximum resting pressure. Opening pressure was an independent predictor of success with an odds ratio of 1·08 (95 per cent confidence interval 1·01 to 1·16; P = 0·018). CONCLUSION: AAR is a sensitive test of sphincter function and can identify differences between patients who respond to PNE and those who do not. Opening pressure is an independent predictor of success in PNE, and may be of value in the selection of patients for this expensive treatment option.

Insertion under local anaesthetic of temporary electrodes for sacral nerve stimulation testing is reliable and cost effective.

AIM: The aim of this study was to determine whether temporary electrode implantation under local anaesthesia (LA), with reliance on sensory response rather than motor response, gives as good a result as implantation under general anaesthesia (GA). METHOD: A retrospective review of a prospectively maintained database of patients with faecal incontinence treated with sacral nerve stimulation (SNS) was performed. RESULTS: A total of 111 consecutive patients underwent a 2-week trial of SNS. Forty-seven (42%) had the temporary electrode implanted under LA and 64 (58%) under GA. There was no significant difference between the two groups in relation to the improvement in Vaizey score (P = 0.15), incontinent episodes per day (P = 0.73) and incontinent episodes per week (P = 0.93). There was no significant difference (P = 0.14) in the percentage of successful trials between the LA group (64%) and the GA group (77%); however, only 62% of the GA group were discharged home on the same day when compared with 89% of the LA group (P < 0.0001). CONCLUSION: Similar success rates for temporary trial with SNS can be achieved with LA and GA. Insertion under LA is associated with reduced cost, shorter hospital stay and quicker recovery, and it avoids the risk of general anaesthesia.