Sacral neuromodulation (SNM) delivered by the InterStim™ system is an FDA-approved therapy doctors have trusted to treat chronic fecal incontinence (FI) for nearly 10 years. More than 300,000 people have received SNM. It is the only surgical treatment with a strong recommendation and moderate quality evidence according to the American College of Gastroenterology (ACG) Guidelines.


The InterStim™ therapy for bowel control prospective clinical study demonstrates a statistically significant decline in FI 12 months after implant.

  • 41% of patients achieve complete continence*2
  • 83% of patients achieve ≥50% reduction in incontinent episodes per week†2,3
  • 83% of patients achieve ≥50% reduction in incontinent days per week†2,3
  • 80% of patients achieve ≥50% reduction in urge incontinent episodes per week‡2,3

This study uses two statistical analyses: per-protocol analysis and intent-to-treat analysis (see below for definition). Results are similar, demonstrating a statistically significant and clinically relevant reduction in fecal incontinence severity for subjects implanted with the InterStim™ Therapy system (p<0.0001).

Per-protocol analysis (also referred to as “completers analysis”): conducted with patients who had complete data at baseline and annual follow-up visits.

Intent-to-treat analysis (also referred to as “modified worst case analysis”): assumed no improvement for patients who were missing bowel diaries (tool used to measure symptom improvement from baseline) at follow-up visits, unless a subsequent bowel diary was available.


Adverse events that occurred in at least 5% of patients after implantation included implant site pain, paresthesias, implant site infection, change in sensation of stimulation, urinary incontinence, and diarrhea.


  • 89% of bowel patients achieved clinical success at five years§||1
  • 36% of bowel patients achieved complete continence1
Medtronic chart stating QOL improvement with InterStim.

Study data demonstrate signifcant improvement in patient quality of life for patients with chronic FI, including physical and psychological well-being, as determined by a variety of accepted measures.³ Mean FIQOL component scales at each visit for patients with at least fve years of follow-up (higher score indicates better quality of life).

Medtronic chart stating long-term efficacy with InterStim.

The most common adverse events through fve years (≥ 5% of patients, n=120) are implant site pain, parasthesia, change in sensation of stimulation, implant site infection, urinary incontinence, neurostimulator battery depletion, diarrhea, pain in extremity, undesirable change in stimulation, and buttock pain.¹


A study by Hetzer et al. demonstrates signifcant improvement across all QOL scores. Sacral neuromodulation delivered by the InterStim™ system significantly improves median Wexner scores at six months (69%, p<0.001). Patients show a reduction of incontinence symptoms, significantly enhancing QOL, including their social life.4

Sacral neuromodulation delivered by the InterStim™ system significantly improves generic and incontinence-specific QOL at six-month follow-up:4

  • SF-36 QOL Questionnaire: Scores improve in all eight categories and significantly improve for physical functioning, social function, mental health, and vitality (p<0.05).
  • Gastrointestinal QOL Index Score: Median preoperative score improves from a preoperative score of 96 to a postoperative score of 107 (0-144 rated, p=0.02).
  • Bowel-Specific Royal London Hospital QOL Questionnaire: All median subscores of this bowel-specific questionnaire improve (lifestyle, coping and behavior, depression and self-perception, and embarrassment). See table below.
  • Adverse events in the Hetzer study include infection, seroma and loss of effect. Eight patients (22% or 8 out of 37 implanted patients) experienced complications that required surgical intervention. (A successful restimulation was possible for five of these patients.) Adverse effects of SNM were remedied in five patients by reprogramming the stimulator.

Complications reported in patients with long-term stimulation included infection/seroma, pain/sleeping disturbance, and loss of effect/dislocation.


Sacral neuromodulation delivered by the InterStim™ system improves all subscores of the Bowel-Specific Royal London Hospital QOL Questionnaire at six-month follow-up (p<0.05).4 Score range 0-100.

Medtronic chart stating change in QOL based on Royal London Hospital questionnaire.


Get detailed information about the InterStim™ II neurostimulator for bowel control.

Medtronic InterStim II Device for sacral neuromodulation.


Take convenient courses specifically designed for clinicians treating patients with OAB, non-obstructive urinary retention, and chronic FI.


41% in per-protocol analysis (n=106) and 36% for intent-to-treat analysis (n=120) for complete continence.

83% in per-protocol analysis (n=106) and 73% for intent-to-treat analysis (n=120) for both weekly incontinent episodes and days per week (p<0.0001).

80% in per-protocol analysis (n=106) and 71% for intent-to-treat analysis (n=120) for urge incontinent episodes per week (p<0.0001).


Clinical success defined as ≥ 50% reduction in episodes/week.


Numbers reflect Completers analysis which included patients who had complete data at baseline and at annual visits. Clinical success was 69% and complete continence was 28% in the Adjusted worst case analysis in which patients with missing data due to lack of efficacy, device or therapy-related adverse events, or death were assumed no change from baseline. If data was missing for any other reason at 5 years, the last observation was used.


Hull T, Giese C, Wexner SD, Mellgren A, Devroede G, et al. Long-term durability of sacral nerve stimulation therapy for chronic fecal incontinence. Dis Colon Rectum. 2013;56:234–245.


Medtronic InterStim Clinical Summary, 2018.


Wexner SD, Coller JA, Devroede G, et al. Sacral nerve stimulation for fecal incontinence: results of a 120-patient prospective multicenter study. Ann Surg. 2010 Mar;251(3):441-449.


Hetzer F, Hahnloser D, Clavien P, Demartines N. Quality of life and morbidity after permanent sacral nerve stimulation for fecal incontinence. Archives of Surgery. 2007;142:8-13.