S167 Comparison of High-Resolution Anorectal Manometry and Magnetic Resonance Defecography in Patients With Obstructive Defecation: Are Both Tests Necessary?

Abstract

Introduction: Investigation of evacuation disorders is often pursued in patients with symptoms of obstructive defecation. High-resolution anorectal manometry (HR-ARM) is a simple, safe and widely available test to diagnose pelvic floor dysfunction. A more costly and less accessible test is magnetic resonance defecography (MRD). This study aims to qualify the added value of MRD in diagnosing pelvic floor disorders. Methods: HR-ARM and MRD performed in patients with a diagnosis of constipation between 1/1/2020 and 5/15/22 at Mayo Clinic were identified using Epic SlicerDicer. Univariate and multivariate analyses were used to compare findings on MRD in patients with and without abnormal HR-ARM. Results: Seventy-six consecutive patients (81.8% female, 94.8% white, age 19-82) who underwent both HR-ARM and MRD were included. The majority had evidence of dyssynergia on HR-ARM (n=49, 64.5%). Patients with dyssynergia on HR-ARM were significantly more likely to have prolonged balloon expulsion at both >60 and >30 seconds (p< 0.00001) and incomplete gel expulsion on MRD (p=0.00008) (Table). However, they were not more likely to have a clinically significant rectocele measuring >2cm (p=0.5093) or evidence of rectal prolapse (p=0.071). An increased number of vaginal deliveries was correlated with a higher likelihood of having a rectocele >2cm (r=0.24, p< 0.05). Conclusion: Anatomic findings on MRD were similar between patients with and without evidence of dyssynergia identified by HR-ARM. In this retrospective review, undergoing MRD in addition to HR-ARM does not appear to provide additional diagnostic information to guide therapeutic recommendations. Large prospective studies to evaluate the added value of MRD are needed. Table 1. - Findings on MRD and balloon expulsion test in patients with and without dyssynergia on HR-ARM Dyssynergia on HR-ARM No dyssynergia on HR-ARM P value n= 49 (64.5%) n = 27 (35.5%) Balloon Expulsion >60 sec 30 (61.2%) 0 (0.0%) p< 0.00001 Balloon Expulsion >30 sec 32 (65.3%) 2 (7.4%) p< 0.00001 < 50% gel expulsion on MR 26 (53.1%) 2 (7.4%) p=0.00008 Rectocele on MR 26 (53.1%) 22 (81.5%) p=0.0139 >2 cm Rectocele on MR 21 (42.9%) 16 (59.3%) p=0.5093 >3 cm Rectocele on MR 10 (20.4%) 9 (33.3%) p=0.2113 >4 cm Rectocele on MR 3 (6.1%) 3 (11.1%) p=0.4413 Rectal Prolapse 5 (10%) 7 (31.8%) p=0.071