Introduction
Constipation is a common anorectal symptom that causes significant changes in the patients' quality of life. Anorectal manometry (ARM) and magnetic resonance (MR) defecography are important tools in diagnosing disorders associated with constipation, which are mainly structural and/or functional. Pelvic floor dyssynergia is diagnosed in the presence of alterations in 2 of the following: defecation kinetics in ARM, balloon expulsion test (BET) and/or MR defecography.
Aims & Methods
Compare the findings in ARM and MR defecography, in patients with constipation.
Retrospective cohort study including patients who fulfilled the Roma IV criteria for functional constipation, who were submitted to ARM and MR defecography. The London classification was used to describe the findings in ARM, establishing 3 groups of patients: Group 1 with those who had normal anorectal coordination and normal BET, Group 2 had altered anorectal coordination and altered BET, and Group 3 with those who had inconclusive findings: altered anorectal coordination and normal BET or normal anorectal coordination with abnormal BET. The structural alterations considered significant in MR defecography were those described as moderate to severe, which lead to defecation obstruction.
Results
A total of 51 patients were included, most were female (98.0%), with a mean age of 55 ± 12 years. Regarding the ARM findings, 16 patients were in Group 1 (31.4%), 11 in Group 2 (21.6%) and 24 in Group 3 (47.1%). Forty-three patients had alterations in MR defecography (84.3%), with 42 patients having at least one structural alteration and the most common being rectocele (72.5%) and descending perineum syndrome (66.7%). Pelvic floor dyssynergia was diagnosed by MR defecography in 9 patients (17.6%).
In the group of patients with normal anorectal coordination in ARM and normal BET (Group 1: n=16), 14 had significant structural alterations in MR defecography (87.5%) and 2 patients had no alterations (12.5%). In the group of patients with altered anorectal coordination in ARM and altered BET (Group 2: n=11), 8 also had structural alterations in MR defecography (72.7%). In the group of patients with inconclusive findings in ARM (Group 3: n= 24), 20 had structural alterations (83.3%) and 3 patients had pelvic floor dyssynergia diagnosed by MR defecography (12.5%), 2 of whom had both alterations (8.3%). In this group, 3 patients had no alterations in MR defecography (12.5%).
Patients with pelvic floor dyssynergia, with or without structural alterations, had a significantly lower rectoanal pressure differential than those with solely structural alterations (-25.0 ± 27.1 vs 5.7 ± 30.0 mmHg, p=0.004). There were no statistically significant differences in the values of anal pressure at rest and voluntary contraction pressure between patients with pelvic floor dyssynergia and those with solely structural alterations (p=0.350 and p=0.833), as well as in the values of residual anal pressure, intrarectal pressure and percentage of relaxation during defecation (p=0.267, p=0.257 and p=0.348).
Conclusion
Most patients had alterations in MR defecography, regardless of the ARM findings. Therefore, it is important to interpret the results of the ARM in conjunction with an imaging test capable of identifying structural alterations that may condition defecation in patients with functional constipation. In addition, those with pelvic floor dyssynergia, with or without associated structural alterations, had a lower rectoanal pressure differential than those with solely structural alterations.