Manometric parameters, when measured with the 3‐dimensional high‐definition anorectal manometry probe, poorly predict prolonged balloon expulsion time

Abstract

Background: There are little data evaluating the performance of the 3-dimensional high-definition anorectal manometry (3D-HDAM) system in the diagnosis of dyssynergic defecation. Physical properties of the thicker, rigid, 3D-HDAM probe may have implications on the measurements of anorectal pressures.Aim: Our aim was to compare 3D-HDAM to balloon expulsion test and magnetic resonance (MR) defecography. Methods: Consecutive constipated patients referred for anorectal function testing atthe Calgary Gut Motility Centre (Calgary, Canada) between 2014 and 2019 were assessed. All patients underwent anorectal manometry with the 3D-HDAM probe, and a subset underwent BET or MR defecography. Anorectal manometric variables were compared between patients who had normal and abnormal BET.Results: Over the study period, 81 patients underwent both 3D-HDAM and BET for symptoms of constipation. 52 patients expelled the balloon within 3 minutes. Patients with abnormal BET had significantly lower rectoanal pressure differential (RAPD) (−61 vs. −31 mmHg for normal BET, p = 0.03) and defecation index (0.29 vs. 0.56, p = 0.03).On logistic regression analysis, RAPD (OR: 0.99, 95% CI: 0.97-0.99, p = 0.03) remained a negative predictor of abnormal BET. On ROC analysis, RAPD had an AUC of 0.65.There was good agreement between dyssynergic patterns on 3D-HDAM and defecographic evidence of dyssynergia (sensitivity 80%, specificity 90%, PLR 9, NLR 0.22, accuracy 85%).Conclusions: Manometric parameters, when measured with the 3D-HDAM probe, poorly predict prolonged balloon expulsion time. RAPD remains the best predictor of prolonged balloon expulsion time. The 3D-HDAM probe may not be the ideal tool to diagnose functional defecatory disorders.

To what extent are anorectal function tests comparable? A study comparing digital rectal examination, anal electromyography, 3-dimensional high-resolution anal manometry, and transperineal ultrasound

“…This was categorized as dyssynergia by the 3D-HRAM in 32% of the cases. In contrast to older studies, more recent studies demonstrated poor agreement between BET and ARM [ 46 , 47 ].…”

Clinical significance and related factors of rectal hyposensitivity in patients with functional defecation disorder

“…A 4-cm long balloon filled with 50 mL of warm water was placed in the patient’s rectum while the patient was seated on a commode and was asked to expel the balloon, in privacy. If the subject could not expel the balloon after 1 min of straining, it was deflated and removed and the result was identified as abnormal ( 13 ).…”

Constipated patients with functional defecatory disorder have secondary rectal hyposensitivity due to altered rectal biomechanics

“…Resting and squeeze anal sphincter pressures, as well as rectoanal pressure differential, residual anal pressure, and intrarectal pressure with push were measured as previously described. 13 Percent anal relaxation was defined as [1 À residual anal pressure/anal resting pressure], where anal resting pressure was measured over the first 1.5 s of the bear-down frame, and residual anal pressure was the subsequent 10 s, with the most positive (normal) of the all the measurement frames taken. Push pressure changes were described by the London classification, which provides a standardized method and nomenclature for describing alteration in anorectal motor and sensory function.…”

“…3D‐HDAM data were analyzed in a blinded fashion by the primary investigator (MW) using ManoViewAR 3.0 ® software (Medtronic, Minneapolis, MN). Resting and squeeze anal sphincter pressures, as well as rectoanal pressure differential, residual anal pressure, and intrarectal pressure with push were measured as previously described 13 …”