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.