Active Versus Passive Anal Sphincter Training in Patients With Fecal Incontinence

This prospective randomized controlled trial will compare two home-based rehabilitation approaches for fecal incontinence. Eligible adult patients with urge, passive, or mixed fecal incontinence will be enrolled at study site: University Hospital Martin, Slovakia. Possibility to incorporate another study centre with be allowed. Participants will be randomized in a 1:1 ratio to one of two treatment arms.

In the active treatment arm, participants will use anal electrical stimulation combined with active voluntary anal sphincter contraction. Electrical stimulation will be delivered using the commercially available NeuroTrac Continence device with a frequency of 40 Hz, pulse width of 250 µs, 5-second ON and 10-second OFF cycles, 1-second ramp-up, and a session duration of 25 minutes. Stimulation intensity will be adjusted by the patient up to the maximum tolerable level without pain. Participants will be instructed to perform a maximum voluntary anal sphincter contraction for 5 seconds at the start of each stimulation ON cycle and to relax during the rest phase.

In the control intervention arm, participants will use identical electrical stimulation parameters but will remain relaxed during stimulation and will not perform active voluntary sphincter contractions. Both groups will receive standardized patient education, including device training and written instructions.

The intervention period will last 12 weeks. Study assessments will include the Vaizey/St. Mark's Incontinence Score, Fecal Incontinence Quality of Life scale, 14-day bowel diary, adherence assessment, adverse event monitoring, and high-resolution anorectal manometry. Optionally patients will be also assessed by endoanal ultrasound to detect possible structural abnormalities where clinical suspicion of these will be present. Assessments will be performed at baseline, week 12, and week 36 (as a post treatment follow up), with interim phone or secure online follow-up for adherence and safety. The primary endpoint is the mean change in Vaizey/St. Mark's Incontinence Score from baseline to week 12. Secondary endpoints include changes in weekly fecal incontinence episodes, FIQL subscales, anorectal manometry parameters, treatment adherence, adverse events, and sustained clinical improvement during follow-up.

Inclusion criteria

• Signed informed consent
• Age ≥18 years
• Diagnosis of fecal incontinence (urge, passive, or mixed type) with at least 1 episode of involuntary stool leakage requiring hygiene intervention or underwear change per month for ≥3 months
• Vaizey (St. Mark's) Incontinence Score ≥8
• Ability to understand study procedures and comply with the 12-week home intervention
• Willingness to attend all study visits and assessments
• Stable medical management for fecal incontinence for at least 4 weeks prior to enrollment

Exclusion criteria

• Complete spinal cord injury above the conus medullaris
• Active inflammatory bowel disease flare requiring systemic therapy or not in clinical remission
• Rectal prolapse requiring surgical intervention
• Severe symptomatic hemorrhoids interfering with anorectal assessments or device use
• Active anal fissure or perianal fistula
• Active colorectal cancer or history of colorectal cancer within 5 years
• Colorectal surgery within the previous 6 months
• Pregnancy or planned pregnancy during study participation
• Implanted cardiac pacemaker or defibrillator
• Other implanted electrical devices contraindicating electrical stimulation
• Previous specialized pelvic floor physiotherapy, biofeedback therapy, EMG-guided rehabilitation, or anal electrical stimulation within 3 months prior to randomization
• Cognitive impairment preventing understanding of study procedures or informed consent
• Uncontrolled severe diarrhea (>5 liquid stools/day)
• Anal stenosis preventing probe insertion
• Severe anal sphincter defect (>120° on ultrasound) requiring surgical repair
• Isolated severe rectal sensory dysfunction without significant sphincter dysfunction
• Previous pelvic radiotherapy
• Concurrent participation in another interventional clinical trial