Study of the Corticoanorectal Neurophysiology in Women With Fecal Incontinence.

INTRODUCTION

Fecal incontinence (FI) is a prevalent condition that disproportionately affects women. Although sphincter biomechanics are well studied, the integrity of the corticoanal motor pathway remains elusive. We evaluated the corticospinoanorectal pathway in women with FI against age-matched (AM-HV) and young healthy (Y-HV) volunteers.

METHODS

Observational study with 18 women with FI (mean age: 63.4 ± 11.1), 15 AM-HV (60.7 ± 9.01), and 15 Y-HV (24.2 ± 5.39) conducted in a tertiary hospital. Patients underwent clinical evaluation, high-resolution anorectal manometry, endoanal ultrasound, and transcranial/translumbosacral magnetic stimulation to assess anorectal motor-evoked potentials (MEP). Clinical severity was measured with St. Mark score and quality of life with Fecal Incontinence Quality of Life and EQ5D.

RESULTS

Patients had longer MEP latencies than AM-HV in the cortico-anal (25.93 ± 3.67 ms vs 22.89 ± 1.38 ms) and right lumbo-rectal segments (5.64 ± 1.35 ms vs 4.39 ± 1.27 ms; P < 0.05), but not in the tibial segment (control) (33.35 ± 2.88 ms vs 32.08 ± 2.05 ms; P > 0.05). However, tibial latencies were longer in AM-HV compared with Y-HV (32.08 ± 2.05 ms vs 29.21 ± 2.75 ms; P = 0.003). In FI, 41.1% had corticoanorectal impairments, 50% lumboanal, and 44.4% sacral. Overall, 82.4% showed delayed latencies in at least one of the 12 segments. High-resolution anorectal manometry revealed 83.24% had external anal sphincter dysfunction, 40% internal sphincter dysfunction, and 23.57% both. MEP latencies inversely correlated with external anal sphincter squeeze strength. FI patients had significantly poorer EQ5D scores compared with both control groups.

DISCUSSION: Women with FI show significant neuropathy in the corticospinoanorectal pathway linked to impaired anorectal function. These findings underscore the brain-gut axis's role in FI pathophysiology, advocating for advanced neurophysiological diagnostics and targeted interventions.