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Sacral Nerve Stimulation at Subsensory Threshold Does Not Compromise Treatment Efficacy: Results From a Randomized, Blinded Crossover Study

Duelund-Jakobsen, Jakob MD; Buntzen, Steen MD, DMSc; Lundby, Lilli MD, PhD; Laurberg, Søren MD, DMSc

doi: 10.1097/SLA.0b013e318269d493
Randomized Controlled Trials

Background and Objective: Stimulation amplitude used in sacral nerve stimulation (SNS) is at or just above the sensory threshold (ST). This randomized, blinded crossover study aimed to document if stimulation at 75% or 50% of the ST would be as effective as stimulation at the ST for fecal incontinence (FI).

Method: FI patients treated with SNS, who were satisfied with current treatment results and had a minimum symptom reduction of 75%, were eligible. Patients were randomized into 3 periods of 4-week stimulation: ST, 75% of the ST, and 50% of the ST. Patients completed a bowel habit diary and questionnaires on bowel functions and patient satisfaction at the study baseline and in each study period.

Results: Nineteen patients (18 females) with a mean follow-up of 51.7 ± 29.9 months were included from January to April 2010. The mean FI episodes per 3 weeks decreased from pre-SNS therapy 33.6 ± 31.6 to 1.1 ± 2.2 at the study baseline (P < 0.001). Decreasing the stimulation amplitude to as low as 50% of the ST did not affect the overall number of incontinent episodes (P = 0.078). The Wexner incontinence score dropped from 16.5 ± 2.5 for pre-SNS therapy to 7.4 ± 3.1 at the study baseline (P < 0.001). Decreasing the stimulation amplitude to ST, 75% of the ST or 50% of the ST, did not change the Wexner score when compared with the study baseline (P = 0.581). In general, patient satisfaction was high at the study baseline and did not deteriorate as the stimulation amplitude was decreased to 50% of the ST (P = 0.932).

Conclusions: Subsensory stimulation as low as 50% of the ST is as effective as stimulation at or above the ST. The study was approved by the Regional Committee on Biomedical Research Ethics, Denmark, and registered at ClinicalTrials.gov (NCT01130870).

This randomized, blinded crossover study documented that the treatment efficacy of sacral nerve stimulation for fecal incontinence at a subsensory stimulation amplitude as low as 50% of the sensory threshold, is as effective as stimulation at or above the sensory threshold.

Surgical Research Unit, Department of Surgery P, Aarhus University Hospital, Tage-Hansens Gade, Aarhus C, Denmark.

Reprints: Jakob Duelund-Jakobsen, MD, Surgical Research Unit, Department of Surgery P, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark. E-mail: Jakob_Jakobsen@hotmail.com.

Disclosure: S.B., L.L., and S.L. have received honoraria from Medtronic as speakers at meetings and/or as members of the medical advisory board. The study design, performance, analysis, and reporting have been conducted without the influence of Medtronic.

Presented at the ESCP-2011 Meeting in Copenhagen, Denmark.

© 2013 Lippincott Williams & Wilkins, Inc.