Investigation of Colonic and Rectal Sensory Properties and Compliance and Its Reproducibility in Humans

Abstract

Purpose: Assessment of colonic and rectal sensory function and compliance can provide both mechanistic understanding and diagnostic information in IBS, chronic constipation and other functional GI disorders. However, these two properties have not been investigated in the same individual and whether they are reproducible is unknown. The aims of this study were to systematically examine the colonic and rectal sensory properties and compliance in the same individual, and to test its reproducibility. Methods: A six sensor solid state manometry probe with a 10 cm long highly compliant balloon was placed under endoscopic and fluoroscopic guidance such that the center of balloon was located in the mid descending colon in 7 healthy subjects. 24 hours after probe placement, balloon distentions were performed with a barostat; using 2 mmHg intermittent balloon distention protocol, until maximum tolerance. After 30 minutes, the probe and balloon were pulled down and repositioned in the rectum, and intermittent balloon distentions were performed after reassessing IOP. Pressure and volume thresholds for first sensation, desire to defecate/discomfort and urgency to defecate or pain were assessed at each site. Studies were repeated after two week intervals. Subjects scored their sensations using a scoring chart. Results: (see Table – Mean ± s.d.) Rectal sensory pressure and volume thresholds for first sensation, desire to defecate and urgency to defecate together with urgency to defecate were similar between study 1 and study 2 with a Kappa statistic of. Likewise, colonic sensory thresholds were similar between the two studies. There was greater variability in volume thresholds but there was no difference (Table). The rectal wall compliance (dv/dp) for Study 1 was 11.9 ± vs. 12.2 ± and for colonic wall compliance was 5.56 ± vs. 6.8 ± respectively.TableConclusion: Both colonic and rectal sensory thresholds and can be assessed in the same subject and are reproducible. Volume-based sensory thresholds appear to be less reproducible than pressure-based thresholds. These data provide evidence that measurements of both colonic and rectal sensation and colonic and rectal wall compliance are robust and valid.