Anorectal volume-pressure relations, contraction work, and flow during defecation

Area of Science:

• Gastroenterology and Biomedical Engineering
• Physiology of Defecation
• Medical Device Technology

Background:

• Assessing anorectal function is crucial for understanding defecation disorders.
• Existing methods for evaluating defecation dynamics can be invasive or limited in scope.
• Fecobionics offers a novel, integrated approach to visualize and quantify defecatory patterns.

Purpose of the Study:

• To evaluate a wireless Fecobionics prototype for assessing anorectal function.
• To visualize defecatory patterns and compute key functional parameters.
• To analyze the relationship between rectal distension, anal diameter, and defecatory dynamics.

Main Methods:

• A wireless Fecobionics probe (10 cm) with pressure sensors and impedance planimetry electrodes was used.
• Twelve healthy subjects underwent rectal bag distension to the point of defecatory urge.
• Data on pressure, diameter, volume, contraction work, and flow were collected and analyzed during voluntary evacuation.

Main Results:

• The minimum anal diameter during evacuation was 17.6 ± 1.5 mm.
• Rectal bag volume at the urge correlated with minimum anal diameter (r=0.63).
• Defecatory contraction work was 3520 ± 480 mL×cmH2O, and maximum flow was 302 ± 33 mL/s, associated with anal diameter (r=0.84).

Conclusions:

• The wireless Fecobionics prototype effectively visualizes defecatory patterns and quantifies functional parameters.
• Findings provide insights into the mechanics of defecation, including the interplay of pressure, volume, and anal diameter.
• This technology holds potential for clinical applications in diagnosing and managing defecatory disorders.