Approaches to driving the evolving understanding of lower oesophageal sphincter mechanical function

Abstract

This article reviews and places into context the development of lower oesophageal sphincter (LOS) manometry, the key technique for researching the mechanics of this region. The first of two major challenges, being able to record sphincter pressure accurately with generally available equipment, was solved by the advent of perfused manometry in the 1960s. The other main challenge was to achieve reliable, continuous recording of LOS pressure, despite the constant movements of the LOS relative to the manometric catheter. Though well documented, this challenge is still poorly understood and prioritised, as many clinical/diagnostic and research manometric studies use methods for LOS manometry that are invalidated by LOS movement. There are two techniques that can record continuously from the LOS, despite its movements: high resolution manometry (HRM), which uses multiple point pressure sensors spaced at 1 cm interval or less, and the sleeve, which is a single long sensor. HRM provides valuable additional information on the varied topography of pressure patterns across the gastro-oesophageal junction and how this can change in an individual, second to second. HRM especially, but also sleeve manometry continue to advance understanding of the mechanics of gastro-oesophageal reflux, to unravel the mysteries of the mechanics of hiatus hernia and the diaphragmatic hiatus, to define why antireflux surgery fails or causes dysphagia, to recognise patients with dysphagia due to isolated defects of LOS relaxation and to test novel therapies for reflux disease directed at LOS function. Ample evidence now exists that accurate monitoring of LOS and gastro-oesophageal junction pressures is important for the diagnostic assessment of many patients and for advancing research into several aspects of the mechanical function of the LOS and its surrounding structures. This evidence now needs to be better reflected in the methods used for routine clinical practice and research.

Esophageal motility, vagal function and gastroesophageal reflux in a cohort of adult asthmatics

“…Stationary pull-through method was employed according to the available facilities in our unit. The gold standard for measurement of LES pressure is use of a Dent Sleeve [36,37]. However this technique was not available to us at the time of the study.…”

Oesophageal high-resolution manometry: moving from research into clinical practice

“…In 1956, Fyke and colleagues introduced the station pull-through technique to ensure that LOS pressure was sampled reliably as the sensor passed through the high-pressure zone 3. This method is still in wide use; however, the pull-through is time-consuming, not well tolerated, has effects on LOS pressure, and cannot be used to assess LOS movement or relaxation 4. This problem was solved first in 1976 by Dent with the introduction of a perfused sleeve sensor that signals the greatest pressure along its length, so that maximum LOS pressure is measured continuously 5.…”

High-resolution Esophageal Manometry: Using Technical Advances for Clinical Advantages

“…16 The dynamic function of the LES has been studied by using the perfused sleeve described by Dent. 17,18 As the techniques were refined, it became clear that phasic contraction of the crura of the diaphragm also contributed to the pressure at the LES, a concept popularly described as the "double sphincter" hypothesis. 19 In normal subjects, the LES is surrounded by the muscle of the crura, and this is easily recognizable as abrupt inspiratory spikes of pressure when the transducer is lying within the crura.…”

“…It has been postulated that HRM may be able to identify whether persistent or recurrent symptoms after surgical treatment of reflux disease or achalasia are due to persistent esophageal dysmotility or functional obstruction at the level of gastroesophageal junction induced by the surgery. 18 Other Diagnostic Possibilities…”