The pressure area: a variable for the assessment of anal sphincter function

Area of Science:

• Physiology
• Gastroenterology
• Urogynecology

Background:

• Anorectal manometry is essential for assessing anal sphincter function.
• Interpreting manometry requires understanding pressure dynamics and spatial characteristics.
• Sex-based differences in anal sphincter function are recognized but require precise quantification.

Purpose of the Study:

• To evaluate the diagnostic contribution of pressure-area measurements versus peak pressures in anal sphincter function.
• To compare resting and squeeze pressure-area calculations with maximal pressures in healthy volunteers.
• To determine if pressure-area metrics enhance the differentiation of anal sphincter function between sexes.

Main Methods:

• An open study involving 106 healthy volunteers (73 women, 33 men) was conducted.
• Anorectal manometry was performed using a microtransducer.
• Maximal resting and squeeze pressures, along with their respective pressure-area integrals (0-5 cm from the anal verge), were recorded.

Main Results:

• No significant difference in mean resting pressure (mmHg) between men and women.
• A significant difference was observed in mean resting pressure area (units) between sexes.
• Squeeze pressure and squeeze pressure area were significantly higher in men compared to women, with greater sex-based differentiation in pressure-area values.

Conclusions:

• Both peak pressure values and the high-pressure zone are important for anorectal manometry interpretation.
• Pressure-area measurements integrate both pressure magnitude and spatial extent, offering a more comprehensive assessment.
• Pressure-area metrics demonstrate superior ability to distinguish anal sphincter function between men and women compared to peak pressure alone.