Introduction

Faecal incontinence (FI) is prevalent, being associated with a high biopsychosocial burden and considerable health costs. The pathophysiology of FI is varied and often multifactorial, representing a diagnostic and therapeutic challenge. Anorectal manometry is the first recommended diagnostic method, although its utility is debatable due to overlapping findings between healthy individuals and patients.

Aims & Methods

The aim of this study is to establish a relationship between FI clinical presentation, manometric findings, and imaging.
We prospectively included all patients undergoing high-resolution anorectal manometry, according to the London protocol, at a tertiary centre, who agreed to respond to a questionnaire to characterize their FI, between August 2021 and March 2023. Clinical records were consulted, in order to access demographic data and past imaging reports. Statistical analysis was performed using IBM SPSS Statistics version 26®.

Results

Forty-seven patients were included with a mean age of 63.5±11.6 years, 87.2% women, of whom 73.2% had an obstetric history. Depressive/anxious symptoms were described in 59.6%, previous perineal surgery in 38.3%, and concomitant urinary incontinence in 40.0%. Mean FI duration was 5.4±5.2 years, with 51.1% reporting daily complaints and a bowel movement median of 2.0 (IQR 3.0). Males tended to have more bowel movements than females (3.5 (IQR 5.0) vs 2.0 (IQR 2.0); p-value 0.03). FI for flatus and faeces was present in 57.4%, for faeces alone in 34.0%, and for flatus alone in 8.5%. Urgency FI was verified in 37.0%, passive FI in 37.0%, and mixed FI in 26.1%. Mean Wexner score was 10±5. Rectal examination revealed hypotonicity in 15.9%. Mean resting pressure on anorectal manometry was 55.9±22.5 mmHg, dyssynergy was identified in 16.7% and altered balloon expulsion in 19.5%. The mean value of first sensation, first urge to defecate, and maximum tolerated volume were within the normal range. Imaging was performed in 19 patients (40.4%), with external anal sphincter injury in 15.8% and internal sphincter injury in 10.5%. Mean thickness of the internal anal sphincter (IAS) was 2.3±1.0 cm. Patients with hypotonicity in rectal examination had lower anal resting pressure (35.7±16.0 mmHg vs 60.3±22.4 mmHg; p-value 0.09) and lower IAS thickness (1.6±0.8 mm vs 2.6±0.9 mm; p-value 0.07), although not statistically significant. Patients with depressive/anxious symptoms showed lower maximum incremental pressure (56.6±34.0 mmHg vs 81.2±46.2 mmHg; p-value 0.045), as well as females when compared to males (60.0±34.9 mmHg vs 108.7±53.2 mmHg; p-value 0.005). No other statistically significant results were found, especially correlating clinical findings with manometry or imaging.

Conclusion

Our study showed, as previously replicated, that clinical, manometric and imaging findings have low correlation in the assessment of FI, reflecting its pathophysiological complexity.