John E. Pandolfino, MD, MSci, Editor

In addition, a review on esophageal function testing is also timely as there have been major advances in most of the older techniques, and new novel methodologies have been developed that allow for a more visual and accurate description of physiologic and anatomical data. My goals for this issue are to provide a comprehensive review of all of the available technologies and to focus the discussion on how these techniques can impact clinical practice and research into the pathogenesis of esophageal diseases. In addition, I’ve also asked my collaborators of this issue to provide background on the technical aspects of these devices as this is extremely important in determining which test is most appropriate for a specific complaint.

With this in mind, the issue begins with a description of the technical aspects of manometry as this is the quintessential esophageal function test, and there have been dramatic improvements in this technology over the last decade. The introduction of high-resolution manometry by Ray Clouse and his team at Washington University, St. Louis, has revolutionized our evaluation of esophageal motor disorders. This is highlighted in the second article, which provides an update on a new classification scheme, “The Chicago Classification,” that utilizes esophageal pressure topography to display and analyze esophageal motor function. Although the next article appears to be a step backwards as it focuses on an older technique, one must recognize that the barium esophagram is still an important tool in the assessment of esophageal diseases, and it sometimes can be an important arbiter of equivocal cases.

The next two articles focus on techniques to study gastroesophageal reflux. Impedance monitoring provides an alternative to techniques that require radiation to study bolus transit and thus is a useful tool for ambulatory reflux testing. This technique has become important in the assessment of patients not responding to proton pump inhibitor therapy. However, pH testing still remains an important component in the evaluation of gastroesophageal reflux disease and the accompanying article focuses on the value of this surrogate marker for reflux and how adapting this into a wireless modality and combined impedance–pH system could help improve accuracy. Complementing these two articles is an important review of postprandial symptoms that may mimic refractory reflux, and this article highlights how rumination and supragastric belching can be differentiated from gastroesophageal reflux disease using novel techniques that combine manometry and impedance.

This issue also emphasizes new technologies that are less mainstream and are more prominently used in research. The functional lumen imaging probe represents a high-resolution impedance planimetry system that can provide information regarding the mechanical properties of the esophageal wall and the esophagogastric junction. In addition, new testing modalities and imaging techniques such as sensitivity testing and functional MRI are providing exciting information regarding the role of visceral hypersensitivity and central processing of esophageal stimuli in symptom generation. The role of these techniques is emerging and it is likely that this work will give rise to a new generation of esophageal function tests.

Anchoring the issue are three final articles that seek to provide a cohesive approach to patients presenting with dysphagia and reflux and a glimpse into the future beyond manometry and impedance. Dysphagia is a complaint that typically begins with endoscopy to rule out mechanical causes for dysphagia, and a systematic approach is provided to help guide decisions focused on managing these patients. Similarly, the management of GERD is also approached in the context of a negative endoscopy as reflux testing and manometry should be performed after a negative examination to look for an alternative diagnosis or documentation that the patient is truly refractory to medical management. Each of these reviews also highlights the limitations of our current strategies, and this is a nice segue into the final article that looks at novel techniques that could potentially complement our current strategies in the future.

I hope that you will find the information in this issue both informative and useful in terms of improving the management of patients with a negative endoscopy or equivocal findings. This issue of Gastrointestinal Endoscopy Clinics of North America would not have been possible without the excellent contributions of my friends and colleagues, and I am eternally grateful for their effort and time.