Measurement of Anal Cross-Sectional Area and Pressure during Anal Distension in Healthy Volunteers

Abstract

A probe for simultaneous measurement of cross-sectional area and pressure was used to elucidate biomechanical wall properties during anal distension. Measurements in distal sphincter regions demonstrated a high resistance to stretch and a large hysteresis compared to proximal sphincter regions. Resistance to stretch decreased during anal distension indicating an active relaxation mechanism at all recording levels. The zone with high resistance to stretch was located more distal than the high-pressure zone measured by anal-pressure profilometry. In conclusion, biomechanical wall properties of the anal canal cannot be described by classic viscoelastic theories but rather by a loss of sphincter tone caused by reflex mechanism during anal distension.

Closure Mechanism of the Anal Canal in Women: Assessed by Three-Dimensional Ultrasound Imaging

“…The anal canal pressure using different size probes and compliance function of anal canal has been investigated using various techniques. [5][6][7][8] All of these studies show that the anal canal pressure and tension increases with the increase in the probe size and anal distension. Gregerson et al 8 used impedance planimetery technique and found that the distal part of the anal canal has lower compliance than the proximal part, which is similar to the findings of our study.…”

“…Anal canal pressure as measured by manometery measures the anal closure pressure but not the anal canal compliance. Investigators have used the pressure volume relationship of a balloon placed in the anal canal and impedance planimetery to measure the anal canal compliance [5][6][7][8] ; however, these techniques do not allow assessment of the relative role of the IAS, EAS, and PRM to the compliance function of the anal canal. We used the novel 3D US imaging and a waterfilled bag in the anal canal to determine the closure and compliance functions of the anal canal in nullipara women.…”

Functional lumen imaging of the gastrointestinal tract

“…In the case of lumens in the GI tract, this is the CSA in the distending bag at the position of the measurement electrodes. In early studies, impedance planimetry was not considered suitable for studying sphincteric regions owing to the potential for dislocation of the then short bag and the single CSA measurement [8]. Nevertheless, some successful measurements by means of impedance planimetry were made in the LES and the anal sphincter [8,9].…”

“…In early studies, impedance planimetry was not considered suitable for studying sphincteric regions owing to the potential for dislocation of the then short bag and the single CSA measurement [8]. Nevertheless, some successful measurements by means of impedance planimetry were made in the LES and the anal sphincter [8,9]. The barostat, a technology based on pressure-volume measurements, is a competing distension technology that has mainly been used in the stomach and tubular segments of the GI tract.…”

Impedance Planimetry: A New Approach to Biomechanical Intestinal Wall Properties

“…This system had the obvious ad vantage that the current was confined to the liquid in the balloon. Furthermore, it was sufficient for studies of active and passive wall properties of the female urethra [12, 21,22,23], The balloon method was introduced for studies in the gastrointestinal tract in 1988 [ 15] with later application in studies of esophageal [16,24], duodenal [17], and anorectal physiology [25,26].…”