Factors affecting the outcome of temporary sacral nerve stimulation for faecal incontinence. The value of the new tined lead electrode.

AIM: Sacral nerve stimulation (SNS) is an effective but expensive treatment for faecal incontinence. About 50% of the patients are unresponsive for unknown reasons, hence knowledge of any factors predictive of success would be highly desirable. The aim of this study was to analyse the potential factors associated with a successful outcome of the temporary test of electrostimulation. METHOD: Eighty-five patients with faecal incontinence were tested for SNS. The cause was idiopathic in 45, iatrogenic or obstetric in 28, spinal lesion or neurological diseases in nine and anal malformation in three patients; 43 were tested with a unipolar electrode and 42 with a quadripolar electrode. The severity of faecal incontinence was evaluated using the American Medical System (AMS) score and Wexner's score. RESULTS: A positive response was obtained in 45 patients (53%); 40 (47%) were implanted with a permanent pulse generator. Responders and nonresponders were comparable in age, duration of incontinence, anal manometry, pudendal nerve terminal motor latency and diabetes. Unipolar electrode test (PNE test) was able to elicit positive responses in 18 of 43 (42%) and the quadripolar in 27 of 42 patients (P < 0.001). Type of incontinence and gender did not affect the success rate. Patients with idiopathic incontinence had a significantly higher response rate (P =0.022). Multivariate regression analysis indicated use of a quadripolar electrode as the only independent variable predicting the success of SNS (OR = 5.58, P = 0.009). CONCLUSION: Use of the quadripolar electrode is the only factor significantly related to the success of SNS.

Fecal incontinence: up to date on pathophysiology and treatment.

This study analyzes the most recent insight into the pathophysiology of fecal incontinence considering each of the factors contributing to the mechanism of fecal continence both during urgency to defecate and in resting state. In fact different types of incontinence are caused by different damage to one or more of these physiologic factors. The second part of the study focuses on the therapeutic choices of fecal incontinence. The recent introduction of sacral nerve electrostimulation and the progressive broadening of its clinical indications is progressively replacing and challenging other traditional surgical techniques because of their disappointing long-term results and because they are much more invasive. An emerging new treatment based on the injection of anal bulking agents is nowadays even more preferred for the less severe cases of fecal incontinence. An increasing number of materials is now proposed by the industry in order to identify the best biocompatible material to be injected trans-anally. Traditional surgery could be reserved for patients non-responding to these new treatments.