Assessment of Obstructive Defecation by High-Resolution Anorectal Manometry Compared With Magnetic Resonance...

Area of Science:

• Gastroenterology and Colorectal Surgery
• Diagnostic Imaging and Functional Assessment

Background:

• Obstructive defecation is linked to anorectal functional and structural abnormalities.
• Conventional anorectal manometry (ARM) shows only fair agreement with defecography.
• High-resolution ARM (HR-ARM) may enhance diagnostic accuracy for obstructive defecation.

Purpose of the Study:

• To compare HR-ARM findings with magnetic resonance (MR) defecography.
• To assess HR-ARM's utility in diagnosing obstructive defecation defined by Rome III criteria.

Main Methods:

• HR-ARM assessed anal sphincter function and pressure during simulated defecation in 188 patients.
• Findings were classified using the Rao system and compared against MR defecography as the reference standard.

Main Results:

• HR-ARM revealed lower resting and squeeze pressures in patients with structural pathology versus dyssynergia.
• A higher rectoanal pressure gradient was observed in patients with structural pathology.
• HR-ARM identified intra-anal intussusception in 24 patients with high intrarectal pressure and a positive pressure gradient; diagnostic accuracy for dyssynergia was 82%.

Conclusions:

• HR-ARM demonstrates high diagnostic agreement with MR defecography for obstructive defecation.
• Pressure measurements via HR-ARM accurately identify recto-anal dyssynergia and structural outlet obstruction.