Dynamic functional luminal imaging probe analysis of the anal sphincter opening function during straining in healthy volunteers

The objective of the present study was to introduce a novel method of assessing anal canal opening in healthy volunteers (HV) using the EndoFLIP system. By analyzing dynamic loops during push maneuvers, the study aimed to identify the most reliable markers of anal canal opening function during this maneuver. Forty HV women were recruited and underwent anal canal assessments with the EndoFLIP system, both at rest and during push maneuvers. Cross-sectional area (CSA)-pressure loops were constructed for each HV at distension volumes of 40 mL and 50 mL. Key parameters (pressure and CSA) derived from these loops were identified as potential markers of anal function to reduce dimensionality. Anal opening function during push maneuver was quantified in both percentage (relative variation) and absolute (absolute variation) values for pressure and CSA. The direction of the CSA-pressure loops during the push maneuver at 40 mL and 50 mL of distension was upward and to the right, indicating an increase in both pressure and CSA during straining. None of the demographic data were significant predictors of any characteristics of the CSA-pressure loops at 40 mL and 50 mL of distension. The mean relative variation in pressure and CSA at 50 mL of distension and, to a lesser extent, the maximal relative variation pressure and CSA, were identified as markers with the lowest variability. This pilot study points to potential markers for assessing anal opening function during push maneuvers. Further confirmatory studies are necessary to establish the clinical utility of these markers.<b>NEW & NOTEWORTHY</b> In the present study, we generated a bioinformatics pipeline for analyzing anal EndoFLIP data in healthy volunteers using automated data reprocessing to identify potential markers of anal opening function during the push maneuver. Mean relative variations in pressure and CSA at 50 mL of distension were identified as the most indicative parameters. Given that this was a pilot study, our findings warrant further confirmatory research to establish the clinical relevance of these markers.