Accurate Differentiation of Dyssynergic Defecation Patients from Normal Subjects Based on Abnormal Anorectal Angle in MR Defecography

MR defecography in ano-rectal dysfunction: a clinical-radiological correlation study

“…The etiology of this condition is unclear [21], and its diagnosis depends on both physical examination and ano-rectal physiologic testing, like ano-rectal manometry and anal/ pelvic floor electromyography (EMG), but both have certain limitations as voluntary contraction of puborectalis muscle can occur due to anxiety to rectal examination itself, and the EMG has false-positive results caused by pain from the needle placement [22]; on the other hand, MR defecography can detect this pathological action of puborectalis muscle by measuring ARA during rest and during defecation and if there is less than 15-20°widening or even decrease in the ARA detected in the latter phase diagnosis is made directing those patients to nonsurgical treatment. like biofeedback therapy [9]. In the current study, there was statistically significant difference between clinical assessment and MRD findings, with the capability of the latter to measure changes in ARA during defecation and this was in agreement with the findings of Nikjooy et al [9] that showed abnormal ARA changes had sensitivity of 95%, specificity of 92%, PPV of 95%, and NPN of 92% in differentiating patients with this disorder from normal subjects.…”

“…like biofeedback therapy [9]. In the current study, there was statistically significant difference between clinical assessment and MRD findings, with the capability of the latter to measure changes in ARA during defecation and this was in agreement with the findings of Nikjooy et al [9] that showed abnormal ARA changes had sensitivity of 95%, specificity of 92%, PPV of 95%, and NPN of 92% in differentiating patients with this disorder from normal subjects. Structural causes of ARD include descending perineum syndrome which is abnormal pelvic floor descent during straining, and it is due to weakness of the pelvic floor muscles and ligaments from pudendal nerve injury as a result of obstetric trauma or chronic straining, it can occur in any of the three compartments of the pelvis; most of the times, more than one compartment is simultaneously involved [23].…”

“…For many years, fluoroscopic defecography was used to evaluate different causes of ARD including paradoxcial puborectalis contraction, increased perineal descent, rectocele, enterocele, and rectal intussusception, but this modality has its draw backs, as it cannot detect pelvic floor soft tissues, its projectional nature along with the ionizing radiation hazards [8]. Recently MR defecography emerged as a perfect modality considering its multiplanar capability, superior temporal resolution, and excellent soft tissue contrast in evaluating pelvic organs and soft tissues supporting structures in addition to assessing the defecation process in dynamic way [9].…”