Basic testing of an artificial pacemaker in the normal and incontinent anorectum

Area of Science:

• Gastroenterology
• Neurology
• Biomedical Engineering

Background:

• Idiopathic fecal incontinence affects numerous individuals, often linked to diminished external anal sphincter (EAS) electromyography (EMG) activity.
• Current treatments for fecal incontinence have limitations, necessitating novel therapeutic strategies.

Purpose of the Study:

• To investigate the efficacy of an artificial pacemaker (AP) in controlling idiopathic fecal incontinence.
• To assess the impact of electrical stimulation of the internal anal sphincter (IAS) and EAS on rectal pressures and continence mechanisms.

Main Methods:

• A study involving 15 healthy volunteers and 11 patients with idiopathic fecal incontinence.
• Electrical stimulation of the IAS and EAS using a custom-built pacemaker.
• Measurement of rectal and rectal neck pressures, and rectal distension using a catheter and balloon expulsion test.

Main Results:

• In healthy subjects, IAS or EAS pulsing significantly increased rectal neck pressure, with EAS pulsing yielding a greater increase.
• In incontinent subjects, IAS pulsing significantly increased rectal neck pressure, whereas EAS pulsing did not.
• IAS pulsing, even with rectal distension, increased rectal neck pressure and decreased rectal pressure without causing balloon expulsion in incontinent patients.

Conclusions:

• Artificial pacemaker stimulation of the IAS demonstrates potential in enhancing rectal neck pressure, offering a possible mechanism for managing fecal incontinence.
• IAS stimulation appears more effective than EAS stimulation in improving continence parameters in patients with idiopathic fecal incontinence.