Pressure tension, and force of closure of the human lower esophageal sphincter and esophagus.

Abstract

A B S T R A C T The mechanical characteristics of the circular muscle of the human lower esophageal sphincter and esophagus were studied in subjects with competent and incompetent sphincters. Pressure-diameter curves were constructed by producing various degrees of circumferential stretch with pressure-measuring probes of increasing diameter. The circumferential membrane tension (force of closure) and the circumferential stress (muscle tension) of the circular muscle layer were also calculated from these data.The pressure-diameter curves of competent and incompetent sphincters were different in magnitude and shape. Incompetent sphincters had lower pressures at all diameters, with pressures gradually increasing with larger probe diameter. In contrast for competent sphincters the pressure was highest near closure, with an initial decline and then an increase in pressure with increasing probe diameter. Both shape and magnitude of pressure-diameter curves of competent and incompetent sphincters were interchangeable when manipulated by pharmacologic agents. Urecholine increased the pressures and changed the incompetent pressure-diameter curve to the levels of the competent sphincter; conversely, Pro-Banthine decreased pressures and changed the shape of the competent pressure-diameter curve to the levels of the incompetent sphincter.Force of closure and circular muscle tension curves of competent and incompetent sphincters were similar in shape but were higher at all diameters for competent sphincters. Force of closure and circular muscle tension increased with larger probe diameter. However, the diameter of optimal tension development was larger than the largest probe used and certainly far from closure.Fundoplication increased the magnitude and changed the shape of the incompetent pressure-diameter curve

A Mathematical Model for Estimating Muscle Tension in vivo during Esophageal Bolus Transport

“…Whereas previous investigators have used the Laplace equation to relate total tension to intraluminal pressure (e.g. Biancani et al, 1975), we have developed a model based on the full equations of motion for a thick-walled two-layer muscle wall with anisotropic fiber distribution.…”

“…The bolus tail, bolus head and manometric catheter are indicated. In our model, we approximate the esophageal wall in the bolus head region as a straight tube so that aE@a=@zE0: M. A. NICOSIA AND J. G. BRASSEUR measurements of intraluminal pressure and thickness data from cadavers (Biancani et al, 1975;Orvar et al, 1993). No attempt was made in these studies to separate the active and passive components of muscle tension.…”

Relationship between esophageal muscle thickness and intraluminal pressure in patients with esophageal spasm

“…We found a significant correlation between peak pressure and peak muscle thickness during esophageal contractions in a given individual as well as among normal subjects (17). The Laplace's equation states that wall stress is directly proportional to the intraluminal pressure and inversely proportional to the vessel thickness-to-radius ratio (2,7). We proposed that a positive correlation between esophageal thickness and intraluminal pressure serves to maintain a constant wall stress.…”

Myoarchitectural and functional alterations in rabbit external anal sphincter muscle following experimental surgical trauma

“…Injury to the muscle is an important cause of impairment in its length-tension function; for example, injury to myocardium and limb muscles impairs their length-tension property (9,12,18). Lower esophageal sphincter function, as assessed by its length-tension measurement, is impaired in patients with gastroesophageal reflux disease (5).…”