Sacral Nerve Stimulation for Fecal Incontinence: How Long Should the Test Phase Be?

Background Decision-making for pulse generator implantation for sacral nerve stimulation in the management of fecal incontinence is based on the results of a test phase. Its duration is still a matter of debate. Objective The purpose of this study was to determine whether an early positive response during the test phase could predict implantation of a permanent sacral nerve pulse generator. Design This was a short-term observational cohort study. A positive response was defined as a >50% decrease of fecal leaks compared with baseline. A multivariate logistic regression was computed to predict pulse generator implantation after the first week of the test phase. Settings The study was conducted in 3 national referral centers. Patients From January 2006 to December 2012, 144 patients with fecal incontinence enrolled in a prospectively maintained database completed a 2- to 3-week bowel diary, at baseline and during test phase. Main outcome measures The primary outcome was the clinical decision to implant a pulse generator. The primary predictor was a calculated score including the number of leak episodes, bowel movements, and urgencies and the time to defer defecation expressed in minutes during the first screening test week. Results After the first, second and third week of the test phase, 81 (56%) of 144, 96 (67%) of 144, and 93 (70%) of 131 patients had a positive test. A permanent pulse generator was implanted in 114. Time to defer defecation increased during the 3 weeks of screening. Urgencies were unchanged. The computed score was predictive of a permanent pulse generator implantation (Se = 72.6% (95% CI, 59.8-83.1); Sp = 100% (95% CI, 78.2-100); c-index = 0.86 (95% CI, 0.78-0.94)). Limitations No cost analysis or projection based on our proposal to reduce the test phase has been made. Conclusions Permanent pulse generator implantation can be safely proposed early (1-week screening) to fast responders. Nonetheless, permanent implantation may be decided as well in patients exhibiting a delayed response. Whether a rapid response to sacral nerve stimulation could be predictive of a long-term response remains to be determined. See Video Abstract at http://links.lww.com/DCR/A452.