Women with defecatory disorders (DDs) suffer from anorectal dysfunction indicated by inadequate rectal pressurization, anal relaxation, or abdominopelvic-rectoanal coordination, according to a study published in Gastroenterology.

DDs may result from inadequate rectal propulsive force, impaired anal relaxation, and structural disturbances; however, diagnostic tests for DD show limited agreement. Therefore, researchers analyzed anorectal pressures, anorectal and abdominal motion, and evacuation in healthy controls and women with constipation using supine magnetic resonance defecography and anorectal manometry. They defined evacuators as those who attained at least 25% rectal evacuation. Supervised and unsupervised analyses were conducted to identify abdominal and anorectal variables that predict evacuation.

In total, 60 women were enrolled in the study; 30 with constipation and 30 healthy controls. The mean age and body mass index (BMI) of patients with constipation vs healthy controls was 36 years and 27 kg/m2 vs 38 years and 26 kg/m2, respectively. Thirty percent of patients met criteria for irritable bowel syndrome and 70% met criteria for functional constipation.


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Measurements of anorectal pressures and rectal emptying were recorded for 28 healthy controls and 26 women with constipation, with more healthy controls (73%) meeting criteria for evacuation vs those with constipation (31%). The researchers found that defecation was initiated by abdominal wall expansion, anorectal descent, increased rectal and anal pressure, and then anal relaxation and rectal evacuation. Compared with evacuators, nonevacuators had smaller anal diameters, and lower rectal pressure, anorectal junction descent, and abdominopelvic-rectoanal coordination during evacuation (P <.05).

An unsupervised cluster analysis identified 3 clusters that were associated with evacuators; 10 patients (83%) in cluster 1, 16 patients (73%) in cluster 2, and 1 patient (5%) in cluster 3 (P <.01). Each cluster had distinct characteristics (eg, maximum abdominosacral distance, rectal pressure, anorectal junction descent, anal diameter) and correlates that were more (clusters 1-2) or less (cluster 3) conducive to evacuation. However, even within a cluster, the percent evacuation was determined by the interaction of several variables.

This study included a women-only cohort, limiting its generalizability. 

“Women with DDs and a modest proportion of healthy women have specific patterns of anorectal dysfunction that are characterized by inadequate rectal pressurization, anal relaxation, or abdominopelvic-rectoanal coordination (or a combination thereof),” the authors concluded. “These observations may help to guide individualized therapy for women with DDs in the future.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference

Deb B, Sharma M, Fletcher JG, et al. Inadequate rectal pressure and insufficient relaxation and abdominopelvic coordination in defecatory disorders. Gastroenterol. Published online December 22, 2021. doi: 10.1053/j.gastro.2021.12.257