Clinical Application of the London Classification in 3D High-Definition Anorectal Manometry: Prevalence, Limitations,...

Area of Science:

• Gastroenterology
• Colorectal Surgery
• Physiology

Background:

• The London classification (LC) standardizes anorectal manometry interpretation.
• Real-world data using high-definition 3D anorectal manometry (3D HD-ARM) are limited.

Purpose of the Study:

• Characterize anorectal manometric patterns in a large 3D HD-ARM cohort using the LC.
• Assess functional parameters beyond the current LC.

Main Methods:

• Retrospective analysis of 300 consecutive 3D HD-ARM studies with balloon expulsion testing (BET).
• Clinical subgroups defined using validated questionnaires for anal incontinence (AI) and chronic constipation (CC).

Main Results:

• High prevalence of AI (81.7%) and CC (56.7%).
• Rectal hyposensitivity (43.3%) and anal normotension with hypocontractility (16.3%) were most frequent.
• Anal normotension with hypocontractility correlated with AI; anal hypertension was more frequent in CC.
• Defecatory coordination disorders were common (54.4% inconclusive).
• Additional parameters like reduced anal canal length and shorter squeeze duration were noted in women with AI.

Conclusions:

• The LC enables consistent phenotyping of anorectal dysfunction.
• Frequent minor and inconclusive findings, especially in defecatory coordination, highlight limitations of the current LC.
• Refinement of the LC is needed for improved diagnostic precision.