Anorectal manometry: Should it be performed in a seated position?

Area of Science:

• Gastroenterology
• Physiology
• Medical Device Technology

Background:

• Anorectal manometry (ARM) is typically performed in a non-physiological lateral position.
• This position can lead to inaccurate rectoanal pressure gradient (RAPG) measurements, even during normal defecation.

Purpose of the Study:

• To compare ARM parameters using water-perfused versus solid-state sensors.
• To evaluate differences between lateral and seated positions for ARM.
• To determine the predictive value of ARM parameters for balloon expulsion.

Main Methods:

• ARM was conducted in 18 healthy volunteers and 60 functional constipation patients.
• Three conditions were tested: water-perfused (lateral), solid-state (lateral), and solid-state (seated).
• A balloon expulsion test was performed in the seated position.

Main Results:

• Solid-state sensors yielded higher rectal pressure and RAPG than water-perfused sensors in the lateral position.
• The seated position with solid-state sensors showed significantly higher rectal pressure and RAPG compared to the lateral position.
• Seated solid-state ARM RAPG predicted balloon expulsion with 82% specificity and 77% sensitivity.

Conclusions:

• Seated anorectal manometry with solid-state sensors offers a more accurate assessment of rectal pressure.
• Rectoanal pressure gradient measured in this configuration predicts successful balloon expulsion in functional constipation.