Mo2013 Predictability of Functional Defecation Disorder in Patients With Chronic Constipation Using a Standardized Constipation Symptom Questionnaire

Abstract

Introduction Anorectal manometry is a commonly used technique to assess patients with fecal incontinence, but is known to have low reproducibility and poor validation in assessment of anal sphincter function. We report a pilot study on a novel technique using Functional Lumen Imaging Probe (FLIP) to improve assessment. Although FLIP has been used in upper GI studies its use in anorectal region is limited to three published studies, all of which used a 16 cm probe (as in upper GI studies). We used a purpose built shorter catheter to demonstrate bio-mechanical properties of the anus. Methods 19 healthy volunteers were recruited (9 females), mean age 34 (20-75). Catheters were purpose built, incorporating an anal and rectal balloon, each with its own separate inflation point. Anal canal balloon was made in three different sizes (2, 3 and 4cm long). Appropriate sized catheter corresponding to the length of subject's anal canal (based on manometry) was used. 3 cross sectional area (CSA) readings were obtained with 2cm balloon, 5 with 3cm and 10 with 4cm balloon. In order to obtain meaningful results, the anal canal balloon was required to be touching the lumen wall. This was achieved by varying inflation volumes according to the balloon size. Results Participants underwent standard water-perfused anal manometry followed by FLIP on the same day. To test repeatability the FLIP was repeated after 30 minutes on the same day. The parameters checked for repeatability included CSA during rest, squeeze, endurance squeeze and cough in addition to the intra balloon pressure during these phases. Anal canal was divided into three partsdistal, mid and proximal based on anatomy and preliminary data analysis. Study established the test-retest and intra-observer repeatability for CSA using Bland-Altman plot and Intra-class correlation coefficient (ICC). Pearson correlation coefficient (PCC) was used to establish correlation between CSA and pressure. Bland Altmans plots showed measurement points for all parameters to be within 2 SD of line of equality. ICC calculated individually for each part of anal canal showed high levels of repeatability for CSA measurements (Table 1). Pressure readings were also repeatable (Table 1). Pearson correlation coefficient showed a negative correlation, between CSA and pressure, at all the balloon volumes apart from the highest (Table 2). Conclusions By allowing determination of serial CSAs during distension EndoFLIP allows detailed and segmental description of geometric and mechanical properties of the anal canal. The CSA and pressure reading were repeatable and lower CSA was associated with higher pressure across all balloon volumes apart from the highest. Possible cause for this was excessive distension of anal canal at higher balloon volumes. Validity and repeatability of EndoFLIP has been proved by this study. Intra-class correlation coefficient values