Rectal motility after sacral nerve stimulation for faecal incontinence

Area of Science:

• Gastroenterology
• Neurology
• Pelvic Floor Disorders

Background:

• Sacral nerve stimulation (SNS) is a recognized treatment for fecal incontinence.
• The precise mechanism by which SNS improves fecal incontinence remains unclear.
• Understanding SNS effects on rectal motility is crucial for elucidating its mode of action.

Purpose of the Study:

• To investigate the impact of sacral nerve stimulation (SNS) on rectal motility during fasting and postprandial states.
• To differentiate between the effects of SNS on rectal tone versus phasic rectal contractions.
• To provide insights into the neurophysiological mechanisms underlying SNS efficacy in fecal incontinence.

Main Methods:

• The study involved 16 patients (14 female) with fecal incontinence.
• Rectal cross-sectional area and ano-rectal pressures were measured using impedance planimetry and manometry.
• Measurements were taken during 1-hour fasting and 1-hour postprandial periods, both before and during SNS.

Main Results:

• Sacral nerve stimulation (SNS) did not significantly alter fasting or postprandial phasic rectal motility parameters.
• SNS significantly reduced postprandial changes in rectal tone (P < 0.02).
• Rectal cross-sectional area showed no significant changes during SNS in either fasting or postprandial states.

Conclusions:

• Sacral nerve stimulation (SNS) for fecal incontinence does not influence phasic rectal motility.
• SNS appears to modulate rectal tone, particularly in the postprandial period.
• These findings suggest that alterations in rectal tone, rather than phasic motility, may be a key mechanism in SNS treatment for fecal incontinence.