Magnetic resonance defecography assessment of obstructed defecation syndrome in patients with chronic constipation in a tertiary care hospital

Abstract

Background: Obstructed defecation syndrome (ODS) is a subtype of constipation that is considered one of the major pelvic floor dysfunctions affecting the aging population, particularly women over 50 seeking medical care. The condition is characterized by the urge to defecate but an impaired ability to expel the fecal bolus. ODS is associated with various anorectal abnormalities, which are not always apparent during a standard physical examination, requiring specialized imaging techniques for proper diagnosis.

Aim: To study the distribution of causes of ODS in patients with chronic constipation by magnetic resonance defecography (MRD).

Methods: This observational study evaluated the causes of ODS in 57 patients with chronic constipation who presented to Bangabandhu Sheikh Mujib Medical University between July 2020 and June 2021. After obtaining institutional review board approval and informed consent, patients underwent history taking, physical exams, and relevant investigations. ODS was diagnosed using Rome III criteria, with colonoscopy ruling out organic causes. Standard MRD was performed in different phases, and images were analyzed by expert radiologists and reported in a standardized format.

Results: Pelvic floor descent and anorectal junction descent were the most frequent findings, each present in 94.7% of cases. Rectocele was observed in 78.9% of patients, while vaginal or uterine prolapse was seen in 59.4% of females. Less common abnormalities included paradoxical contraction (7%), and there were no cases of sigmoidocele. Functional measurements showed significant differences in pelvic floor dynamics between rest and defecation, particularly in the H-line, M-line, and descent of pelvic organs (P < 0.05).

Conclusion: Pelvic floor descent and anorectal descent were the most common findings in patients suffering from ODS, followed by rectocele. Younger females (< 30 years) were most affected.

Keywords: Chronic constipation; Magnetic resonance defecography; Obstructed defecation syndrome; Pelvic floor disorders; Tertiary care hospital.

Figure 1

Magnetic resonance defecography T2-weighted image depicting the normal pubococcygeal line[14]. Pubococcygeal line (PCL) (yellow line) spans the inferior border of the pubic symphysis to the last visible coccygeal joint. H-line (purple) represents the length of the anterior-posterior levator hiatus. M-line (blue) measures the vertical descent of the anorectal junction below the PCL. Citation: Korula DR, Chandramohan A, John R, Eapen A. Barium Defecating Proctography and Dynamic Magnetic Resonance Proctography: Their Role and Patient's Perception. J Clin Imaging Sci 2021; 11: 31. Copyright ^©The Author(s) 2011. Published by Scientific Scholar LLC (Supplementary material).

Figure 2

Magnetic resonance defecography image showing pelvic organ prolapse across all three pelvic compartments[15]. Anterior compartment: Cystocele (blue); Middle compartment: Uterine prolapse (white); Posterior compartment (orange, anterior rectocele and anorectal junction descent). Citation: Shetty A, Walizai T, Murphy A. MR defaecating proctography. Radiopaedia 2016. Copyright ^©The Author(s) 2016. Published by Radiopaedia[15] (Supplementary material).

Figure 3

Magnetic resonance images indicating an anorectal angle (typically 90°–130° at rest)[10]. Citation: Megha K, Sushil G K, Dilip L L. Applications and Limitations of Magnetic Resonance Defecography in Evaluation of Pelvic Floor Dysfunction Disorders. Int J Radiol Imaging Technol 2019; 5. Copyright ^©The Author(s) 2019. Published by ClinMed International Library (Supplementary material).