Inadequate Rectal Pressure and Insufficient Relaxation and Abdominopelvic Coordination in Defecatory Disorders.

BACKGROUND & AIMS: Diagnostic tests for defecatory disorders (DDs) asynchronously measure anorectal pressures and evacuation and show limited agreement; thus, abdominopelvic-rectoanal coordination in normal defecation and DDs is poorly characterized. We aimed to investigate anorectal pressures, anorectal and abdominal motion, and evacuation simultaneously in healthy and constipated women. METHODS: Abdominal wall and anorectal motion, anorectal pressures, and rectal evacuation were measured simultaneously with supine magnetic resonance defecography and anorectal manometry. Evacuators were defined as those who attained at least 25% rectal evacuation. Supervised (logistic regression and random forest algorithm) and unsupervised (k-means cluster) analyses identified abdominal and anorectal variables that predicted evacuation. RESULTS: We evaluated 28 healthy and 26 constipated women (evacuators comprised 19 healthy participants and 8 patients). Defecation was initiated by abdominal wall expansion that was coordinated with anorectal descent, increased rectal and anal pressure, and then anal relaxation and rectal evacuation. Compared with evacuators, nonevacuators had lower anal diameters during simulated defecation, rectal pressure, anorectal junction descent, and abdominopelvic-rectoanal coordination (P < .05). Unsupervised cluster analysis identified 3 clusters that were associated with evacuator status (P < .01), that is, 10 evacuators (83%), 16 evacuators (73%), and 1 evacuator (5%) in clusters 1, 2, and 3, respectively. 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. Cluster 2 had 16 evacuators (73%) and intermediate characteristics (eg, lower anal resting pressure and relaxation during evacuation; P < .05). CONCLUSIONS: Women with DDs and a modest proportion of healthy women had specific patterns of anorectal dysfunction, including inadequate rectal pressurization, anal relaxation, and abdominopelvic-rectoanal coordination. These observations may guide individualized therapy for DDs in the future.

Abdomino-anal Dyscoordination in Defecatory Disorders.

BACKGROUND & AIMS: The contribution of the abdominal muscles to normal defecation and disturbances thereof in defecatory disorders (DDs) are unknown. METHODS: In 30 healthy and 60 constipated women with normal rectal balloon expulsion time (BET) (n = 26) or prolonged BET (ie, DD; n = 34), seated anorectal pressures (manometry) and thickness (ultrasound) of the external and internal oblique and transversus abdominis muscles were measured simultaneously at rest, during hollowing, squeeze, evacuation, and a Valsalva maneuver. RESULTS: Compared with healthy women with a normal BET, DD women had a lower rectal and greater anal pressure increase during evacuation (P ≤ .05), and more activation of the internal oblique and the transversus abdominis muscles during squeeze (P < .05). The change in transversus abdominis thickness during a Valsalva maneuver vs hollowing (rho = 0.5; P = .002) and separately vs evacuation (rho = 0.7; P < .0001) were correlated in DD but not in healthy women with a normal BET. A principal component (PC) analysis of anorectal pressures and muscle thicknesses during evacuation uncovered a PC (PC3) that was associated with a prolonged BET. Higher PC3 scores were associated with low rectal and high anal pressures at rest and during evacuation, thinner external oblique muscle, and thicker internal oblique muscle during evacuation. A greater PC3 score was associated with increased odds for DD vs health (odds ratio, 1.84; 95% CI, 1.05-3.23), and separately vs constipation with a normal BET (odds ratio, 3.64; 95% CI, 1.73-7.69). CONCLUSIONS: Taken together, these findings show 3, possibly inter-related, disturbances suggestive of dyscoordination in DD: aberrant activation of abdominal muscles during squeeze in DD, dyscoordination of the abdominal muscles during various tasks in constipated women, and abdomino-anal dyscoordination.

A comparison of rectoanal pressures during Valsalva maneuver and evacuation uncovers rectoanal discoordination in defecatory disorders.

BACKGROUND: It is suggested that patients with defecation disorders (DD) strain excessively or do a Valsalva maneuver (VM) during evacuation, resulting in rectoanal discoordination, which hinders rectal evacuation. However, definitive data are lacking. METHODS: Rectoanal pressures during evacuation and a VM were measured with seated high-resolution manometry (HRM) in 64 healthy and 136 constipated women with a normal (84 women, C-normal) or prolonged (52 women, C-abnormal) balloon expulsion time (BET). The number of abnormal rectoanal parameters during evacuation and the joint distribution of pressures during evacuation and a VM were used to discriminate between controls and C-abnormal BET patients. KEY RESULTS: The peak anal pressure (5 s) during a VM accounted for 0%, 26%, and 49% of the variance in anal pressure during evacuation in healthy women, C-normal BET, and C-abnormal BET. The association between anal pressure during a VM and evacuation was stronger in C-abnormal BET than in healthy women and C-normal BET (p for interaction <0.001). Fifty-eight of 64 controls and 33 of 52 C-abnormal BET patients had no or one abnormal parameter during evacuation; hence, the probability of C-abnormal BET was 33/91 (36%). In patients with no or one abnormal parameter during evacuation, a logistic model based on anal pressures during evacuation and a VM discriminated between controls and patients with C-abnormal BET with a sensitivity and a specificity of 67% and 75%. CONCLUSIONS: Assessment of rectoanal pressures during evacuation and a VM uncovers rectaoanal discoordination and facilitates the diagnosis of DD in selected patients.

Participation of rural patients in clinical trials at a multisite academic medical center.

OBJECTIVE: Clinical trials, which are mainly conducted in urban medical centers, may be less accessible to rural residents. Our aims were to assess participation and the factors associated with participation of rural residents in clinical trials. METHODS: Using geocoding, the residential address of participants enrolled into clinical trials at Mayo Clinic locations in Arizona, Florida, and the Midwest between January 1, 2016, and December 31, 2017, was categorized as urban or rural. The distance travelled by participants and trial characteristics was compared between urban and rural participants. Ordinal logistic regression analyses were used to evaluate whether study location and risks were associated with rural participation in trials. RESULTS: Among 292 trials, including 136 (47%) cancer trials, there were 2313 participants. Of these, 731 (32%) were rural participants, which is greater than the rural population in these 9 states (19%, P < 0.001). Compared to urban participants, rural participants were older (65 ± 12 years vs 64 ± 12 years, P = 0.004) and travelled further to the medical center (103 ± 104 vs 68 ± 88 miles, P < 0.001). The proportion of urban and rural participants who were remunerated was comparable. In the multivariable analysis, the proportion of rural participants was lower (P < 0.001) in Arizona (10%) and Florida (18%) than the Midwest (38%) but not significantly associated with the study-related risks. CONCLUSIONS: Approximately one in three clinical trial participants were rural residents versus one in five in the population. Rural residents travelled further to access clinical trials. The study-associated risks were not associated with the distribution of rural and urban participants in trials.