When You Gotta Go: A High Resolution Anal Manometry Study Evaluating the Urge to Defecate in Patients with Mixed Fecal Incontinence and Obstructed Defecation

Elyse LeeVan, MD1, Aaron Lewis, MD2, Alex Huang1, Gabriel Akopian, MD1, Howard Kaufman, MD1. 1Huntington Hospital, 2City of Hope

Objectives: In the past 5 years, three-dimensional high resolution anorectal manometry (3D HRAM) has replaced traditional perfusion catheters in the evaluation of defecatory disorders. Our objectives were to utilize 3D HRAM to identify physiologic differences between groups of female patients with fecal incontinence (FI), obstructed defecation, and mixed disorders (both obstructive and incontinent symptoms), to evaluate these relationships in male patients, and to determine the relationship between the rectal sensory threshold urge to defecate and sphincter function, specifically, mean resting sphincter tone, residual anal pressure, and percent anal relaxation.   

Methods: A retrospective chart review of of 77 females and 27 males was performed using anorectal physiology reports for patients undergoing 3D HRAM for evaluation of defecatory disorders between January 1, 2013 and April 1, 2015 at a single institution.  Exclusion criteria included patients with rectal cancer and ileal j-pouches. Remaining patients were categorized into three groups: incontinent, obstructed, and mixed based on presenting symptoms. Physiologic values including mean resting sphincter pressure, maximal squeeze pressure, residual anal sphincter pressure, percent anal relaxation, and sensory threshold of urge to defecate were recorded. Kruskal-Wallis tests were performed to assess differences with regards to physiologic variables between groups. Bivariate correlation tests were performed to assess the relationship between these variables within groups. SPSS was utilized for statistical analysis.

Results: Women with mixed defecatory disorders had mean resting pressures and maximum squeeze pressures that were significantly different from patients with pure FI or obstruction. Men with mixed defecatory disorders had only mean resting pressures that were significantly different from patients with pure FI or obstruction. In females with mixed defecatory disorders there was a positive correlation between the rectal sensory threshold urge to defecate and the resting mean sphincter pressure, residual anal bear down pressure, and percent anal relaxation (p values 0.021, 0.036, 0.006 respectively). These relationships were not demonstrated in the incontinent or obstructed defecation groups.    

Conclusion: Females and males with mixed defecatory disorders demonstrate unique, but distinct physiologic profiles that can be characterized using 3D HRAM. The female mixed defecatory group demonstrates relationships between physiologic parameters that are not seen in the incontinent or obstructed groups. These relationships provide further insight into the etiology of this poorly described disease process and may aid in developing treatment regimens. 

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