This is the first report of clinical performance and safety of the rechargeable InterStimTM Micro sacral neuromodulation (SNM) system in subjects with fecal incontinence (FI).  SNM is an established advanced therapy for treatment of symptoms of overactive bladder, nonobstructive urinary retention, and FI supported by studies with long-term follow up. The ELITE trial is an ongoing global, prospective, post-market study to confirm the clinical performance and safety of the InterStim Micro SNM system in all indicated conditions. This report includes results from the FI cohort through 3 months follow-up.

Subjects provided informed consent and completed a baseline assessment to determine eligibility for SNM. Eligible subjects with symptoms of FI (greater than or equal to 2 incontinent episodes on a 7-day bowel diary) were enrolled following successful therapy evaluation and neurostimulator implant. Subjects completed bowel diaries and questionnaires at baseline and 3-months follow up. Questionnaires included the Cleveland Clinic Incontinence Score (CCIS; also known as Wexner Score), which is an established 5-item questionnaire that was developed to assess the frequency and severity of fecal incontinence ‎[1]. The primary objective was improvement in CCIS at 3 months post-implant compared to baseline. Safety was evaluated by collection of reportable adverse events (AE). Data are reported as mean ± standard deviation or with 95% confidence intervals (CI).

Of 53 subjects enrolled and implanted with InterStim Micro in the FI cohort, most were female (90.6%). The mean age was 58±11 years and BMI was 29±6.1 kg/m2.  Of the implanted patients, 51% (27/53) had a basic evaluation, 45% (24/53) had an advanced evaluation, and 4% (2/53) had both basic and advanced evaluation. The mean CCIS at baseline was 14±2.9. There was a significant improvement in CCIS at 3-months vs baseline with a mean change of -4±3.7 (p≤0.001, n=52) (Figure 1). At baseline, subjects had an average of 2.04±2.0 incontinent episodes per day (Figure 2). At the 3-month follow up, the average number of incontinent episodes per day was 0.49±0.7, and the average percent change in incontinent episodes per day compared to baseline was –72% (95% CI: -81% to -62%).  The incidence of device-, procedure-, or therapy- related AEs in enrolled subjects was 15.1% (8/53) and serious AEs was 1.9% (1/53) at the time of database snapshot; the serious AE was not related to the device, procedure, or therapy. There were no unanticipated adverse device effects.

The primary objective of the FI cohort was met, with a statistically significant improvement in CCIS at 3-months post-implant. Furthermore, the mean change in CCIS can be considered clinically meaningful as it exceeded the previously estimated minimally important improvement which ranges from 2 to 3‎ [2].  The change in symptoms is consistent with previous reports and rate of adverse events is similar compared to previously reported rates for SNM thereby confirming the safety and clinical performance of InterStim Micro for subjects with FI. These data add to the established SNM evidence with data from the rechargeable InterStim Micro. Follow-up of enrolled patients is ongoing.

These data confirm the clinical performance and safety for a rechargeable SNM device through 3-months post implant for FI.

Jorge JMN, Wexner SD. Etiology and management of fecal incontinence. DIS COLON RECTUM. 1993;36(1):77-97.
Bols EMJ, Hendriks HJM, Berghmans LCM, Baeten CGMI, de Bie RA. Responsiveness and interpretability of incontinence severity scores and FIQL in patients with fecal incontinence: A secondary analysis from a randomized controlled trial. Int Urogynecol J Pelvic Floor Dysfunct. 2013;24(3):469-478.

Continence 7S1 (2023) 100893
DOI: 10.1016/j.cont.2023.100893