Prospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Jun 15, 2021; 13(6): 612-624
Published online Jun 15, 2021. doi: 10.4251/wjgo.v13.i6.612
Gastrointestinal function testing model using a new laryngopharyngeal pH probe (Restech) in patients after Ivor-Lewis esophagectomy
Benjamin Babic, Dolores T Müller, Florian Gebauer, Lars Mortimer Schiffmann, Rabi R Datta, Wolfgang Schröder, Christiane J Bruns, Jessica M Leers, Hans F Fuchs
Benjamin Babic, Dolores T Müller, Florian Gebauer, Lars Mortimer Schiffmann, Rabi R Datta, Wolfgang Schröder, Christiane J Bruns, Jessica M Leers, Hans F Fuchs, Department of General, Visceral, Cancer and Transplant Surgery, University of Cologne, Cologne 50931, Germany
Author contributions: Fuchs HF contributed to the study concept and design; Fuchs H and Müller DT acquired the data; Fuchs HF, Babic B, Leers JM, Schröder W and Bruns CJ contributed to analysis and interpretation of data; Fuchs HF and Babic B drafted the manuscript; Fuchs HF, Babic B, Müller DT, Gebauer F, Schiffmann LM, Datta RR, and Bruns CJ critically revised the manuscript for important intellectual content; Fuchs HF performed statistical analysis; Fuchs HF was charge of administrative, technical, or material support; Leers JM and Fuchs HF supervised the study.
Supported by Cologne Fortune Scientific Grant Project, No. 176/2016.
Institutional review board statement: The study was conducted with approval from the institutional review board at the University of Cologne (IRB reference 16-727).
Clinical trial registration statement: Our prospective clinical study has been registered in the “German Clinical Trial Register” and can be found under the following link: The study number is DRKS00011123.
Informed consent statement: All study participants provided written consent prior to study enrollment.
Conflict-of-interest statement: The authors of this manuscript having no conflicts of interest to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Hans Friedrich Fuchs, MD, Assistant Professor, Surgeon, Department of General, Visceral, Cancer and Transplant Surgery, University of Cologne, Kerpener Straße 62, Cologne 50931, Germany.
Received: December 6, 2020
Peer-review started: December 6, 2020
First decision: January 29, 2021
Revised: February 11, 2021
Accepted: May 19, 2021
Article in press: May 19, 2021
Published online: June 15, 2021
Research background

There is no established correlation between 24-h esophageal pH-metry (Eso-pH) and the new laryngopharyngeal pH-monitoring system (Restech) as only small case series exist. Eso-pH was not designed to detect laryngopharyngeal reflux (LPR) and Restech may detect LPR better. We have previously published a dataset using the two techniques in a large patient collective with Gastroesophageal Reflux Disease. Anatomically, patients after esophagectomy were reported to represent an ideal human reflux model as no reflux barrier exists.

Research motivation

Patients after esophagectomy ideally serve as a human reflux model, as they show an impaired esophageal motility and no reflux barrier. This study aims to use this human reflux model to examine a previously established correlation between esophageal and laryngopharyngeal pH testing and to further validate laryngopharyngeal pH testing.

Research objectives

Previous validation studies tried to prove corresponding results in laryngopharyngeal and esophageal pH-metry. We, however, believe that a variety of different reflux scenarios exist and that those can be logically explained by our human reflux model in patients after Ivor-Lewis esophagectomy. Group A (abnormal Eso-pH, normal Restech) can easily be explained by reflux episodes that do not reach the oropharynx and are therefore not measured by laryngopharyngeal pH testing. Group B (normal Eso-pH, abnormal Restech) is not explainable from a pathophysiological standpoint. Results from our last paper indicated that acidic vapor or other factors may cause abnormal Restech results with simultaneous normal Eso-pH results. Previous studies showed only a weak correlation between esophageal and laryngopharyngeal pH measurement resulting in the conclusion that the Restech device adds no or little value as a diagnostic device in the evaluation of Gastroesophageal reflux disease (GERD) and LPR. However, only small numbers of patients were included in those studies and esophageal pH monitoring was either not performed simultaneously or not performed at all, leading to an insufficient comparison of results.

Research methods

A prospective analysis of patient data during follow-up after hybrid minimally invasive Ivor Lewis esophagectomy for cancer was performed. To obtain a homogenous population, only patients at least 3 mo out of surgery and disease-free survival were included in this study to eliminate immediate postoperative effects. Demographics, endoscopic findings, biopsies at different follow-up time points, as well as tumor histology and stage were recorded in the prospective database. Additionally, symptoms were recorded at all times of follow-up. Only patients that presented with reflux-related symptoms or those showing endoscopic proof of mucosal damage in the esophageal remnant were offered inclusion in this study. Gastrointestinal function testing (simultaneous esophageal and laryngopharyngeal pH testing) as well as upper GI endoscopy was completed. No HRM or barium swallow was performed in this study. Subsequently, the relationship between the two techniques was evaluated.

Research results

A total of 43 patients from May 2016 - November 2018 were included. All patients presented with mainly typical reflux symptoms such as heartburn (74%), regurgitation (84%), chest pain (58%), and dysphagia (47%). Extraesophageal symptoms such as cough, hoarseness, asthma symptoms, and globus sensation were also present. Esophageal 24-hour pH-metry was abnormal in 88% of patients with a mean DeMeester Score of 229.45 [range 26.4-319.5]. Restech evaluation was abnormal in 61% of cases in this highly selective patient cohort. All patients with abnormal supine LPR were also abnormal for supine esophageal reflux measured by conventional eso-pH.

Research conclusions

Patients following esophagectomy and reconstruction with gastric interposition can ideally serve as a human reflux model, as a large proportion suffers from severe postoperative GERD. Interestingly, laryngopharyngeal reflux phases occur mainly in the upright position, and acidity of the gastric conduit is already nearly normalized shortly after surgery. In this human volume-reflux model, esophageal pH-metry correlated precisely with an abnormal laryngopharyngeal pH-metry (Restech).

Research perspectives

Overall, the current level of evidence using the Restech device is limited by rather small case studies concluding that more research regarding the new reflux measurement device needs to be done. In addition, patients after esophagectomy can ideally serve as a human reflux model for further investigations and validation studies.