Functional morphology of the lower esophageal sphincter and crural diaphragm determined by three-dimensional high-resolution esophago-gastric junction pressure profile and CT imaging

Regurgitation, eructation, and supragastric belch: retrograde esophageal motility, disorders, and treatment

PURPOSE OF REVIEW

This review describes pathologic conditions of retrograde flow into the esophagus along with recent therapeutic advances and treatment options.

RECENT FINDINGS

The esophagus facilitates anterograde and retrograde movement of contents, the latter of which is mediated by transient lower esophageal sphincter relaxations (TLESRs). Gastroesophageal reflux disease (GERD) often includes esophageal-specific symptoms such as heartburn or regurgitation. Volume regurgitation responds less frequently to acid suppression with proton pump inhibitors (PPIs) than heartburn, given its relationship with incompetence of the esophagogastric junction (EGJ) and increased frequency of TLESRs. Therefore, although the refluxate pH can be altered with PPIs, the frequency of reflux episodes is generally not reduced and surgical and endoscopic treatments may be favored. Other instances of abnormal retrograde esophageal flow respond better to medical therapy, or lifestyle interventions. Compared to gastric belching because of increased stomach distension, supragastric belching is caused by intake of air from pharynx into the esophagus followed by rapid expulsion of air. These conditions can be distinguished on esophageal tests such as high-resolution manometry and are likely to respond to behavioral modifications.

SUMMARY

Retrograde flow into the esophagus can be a normal occurrence, but diagnostic testing to distinguish causes can guide appropriate intervention.

Automatic three-dimensional reconstruction of the oesophagus in achalasia patients undergoing POEM: an innovative approach for evaluating treatment outcomes

BACKGROUND AND AIMS

Peroral endoscopic myotomy (POEM) is a standard treatment option for achalasia patients. Treatment response varies due to factors such as achalasia type, degree of dilatation, pressure and distensibility indices. We present an innovative approach for treatment response prediction based on an automatic three-dimensional (3-D) reconstruction of the tubular oesophagus (TE) and the lower oesophageal sphincter (LES) in patients undergoing POEM for achalasia.

METHODS

A software was developed, integrating data from high-resolution manometry, timed barium oesophagogram and endoscopic images to automatically generate 3-D reconstructions of the TE and LES. Novel normative indices for TE (volume×pressure) and LES (volume/pressure) were automatically integrated, facilitating pre-POEM and post-POEM comparisons. Treatment response was evaluated by changes in volumetric and pressure indices for the TE and the LES before as well as 3 and 12 months after POEM. In addition, these values were compared with normal value indices of non-achalasia patients.

RESULTS

50 treatment-naive achalasia patients were enrolled prospectively. The mean TE index decreased significantly (p<0.0001) and the mean LES index increased significantly 3 months post-POEM (p<0.0001). In the 12-month follow-up, no further significant change of value indices between 3 and 12 months post-POEM was seen. 3 months post-POEM mean LES index approached the mean LES of the healthy control group (p=0.077).

CONCLUSION

3-D reconstruction provides an interactive, dynamic visualisation of the oesophagus, serving as a comprehensive tool for evaluating treatment response. It may contribute to refining our approach to achalasia treatment and optimising treatment outcomes.

TRIAL REGISTRATION NUMBER

22-0149.

Influence of Achalasia on the Spirometry Flow-Volume Curve and Peak Expiratory Flow

BACKGROUND

Achalasia is an esophageal motor disorder characterized by aperistalsis and the failure of the relaxation of the lower esophageal sphincter. We want to find out whether external compression or recurrent micro-aspiration of undigested food has a functional effect on the airway.

METHODS

The aim of this research was to analyze the influence of achalasia on the peak expiratory flow and flow-volume curve. All of the 110 patients performed spirometry.

RESULTS

The mean diameter of the esophagus was 5.4 ± 2.1 cm, and nine of the patients had mega-esophagus. Seven patients had a plateau in the inspiratory part of the flow-volume curve, which coincides with the patients who had mega-esophagus. The rest of the patients had a plateau in the expiration part of the curve. The existence of a plateau in the diameter of the esophagus of more than 5 cm was significant (p 0.003). Statistical significance between the existence of a plateau and a lowered PEF (PEF < 80) has been proven (p 0.001). Also, a statistical significance between the subtype and diameter of more than 4 cm has been proved. There was no significant improvement in the PEF values after operation. In total, 20.9% of patients had a spirometry abnormality finding. The frequency of the improvement in the spirometry values after surgery did not differ significantly by achalasia subtype. The improvement in FEV1 was statistically significant compared to the FVC values.

CONCLUSIONS

Awareness of the influence of achalasia on the pulmonary parameters is important because low values of PEF with a plateau on the spirometry loop can lead to misdiagnosis. The recognition of various patterns of the spirometry loop may help in identifying airway obstruction caused by another non-pulmonary disease such as achalasia.

Impaired sliding between the lower esophageal sphincter and crural diaphragm (esophageal hiatus) in patients with achalasia esophagus

Swallow-related axial shortening of the esophagus results in the formation of phrenic ampulla in normal subjects; whether it is the case in achalasia esophagus is not known. The goal is to study axial shortening of the esophagus and relative movement between the lower esophageal sphincter (LES) and crural diaphragm (CD) in normal subjects and patients with achalasia. A novel method, isoimpedance contour excursion at the lower edger of LES, as a marker of axial esophageal shortening was validated using X-ray fluoroscopy (n = 5) and used to study axial shortening and separation between the LES and CD during peristalsis in normal subjects (n = 15) and patients with achalasia type 2 esophagus (n = 15). Abdominal CT scan images were used to determine the nature of tissue in the esophageal hiatus of control (n = 15) and achalasia patients (n = 15). Swallow-induced peristalsis resulted in an axial excursion of isoimpedance contours, which was quantitatively similar to the metal clip anchored to the LES on X-ray fluoroscopy (2.3 ± 1.4 vs. 2.1 ± 1.4 cm with deep inspiration and 2.7 ± 0.6 cm vs. 2.7 ± 0.6 cm with swallow-induced peristalsis). Esophageal axial shortening with swallows in patients with achalasia was significantly smaller than normal (1.64 ± 0.5 cm vs. 3.59 ± 0.4 cm, P < 0.001). Gray-level matrix analysis of CT images suggests more "fibrous" and less fat in the hiatus of patients with achalasia. Lack of sliding between the LES and CD explains the low prevalence of hiatus hernia, and low compliance of the LES in achalasia esophagus, which likely plays a role in the pathogenesis of achalasia.NEW & NOTEWORTHY Swallow-related axial shortening of the esophagus is reduced, and there is no separation between the lower esophageal sphincter and crural diaphragm (CD) with swallowing in patients with achalasia esophagus. Fat in the hiatal opening of the esophagus appears to be replaced with fibrous tissue in patients with achalasia, resulting in tight anchoring between the LES and CD. The above findings explain low prevalence of hiatus hernia and the low compliance of the LES in achalasia esophagus.

Hiatal reconstruction is safe and effective for control of reflux after laparoscopic sleeve gastrectomy

Background

Gastroesophageal reflux is a known complication following laparoscopic sleeve gastrectomy (LSG) as anatomical changes predispose to reduced lower esophageal sphincter pressure and development of hiatus hernia. The mainstay of surgical management has been Roux-en-Y gastric bypass (RYGB) which is not without risk. Hiatus hernia repair (HHR) with surgical reattachment of the oesophagus to the crura, recreating the phreno-esophageal ligament is a simple procedure specifically targeting a number of anatomical changes responsible for reflux in this population.

Methods

We conducted a single centre retrospective analysis of adult patients with post-sleeve reflux refractory to medical treatment, managed with either HHR, RYGB or One-anastomosis Duodenal switch (OADS). PPI use and symptoms of reflux were assessed at early and mid-term time points via validated questionnaires.

Results

99 patients were included, of these the surgical procedure was HHR alone in 58, RYGB in 29 and OADS in 12. At early follow-up control of reflux symptoms was achieved in 72.4% after HHR, 82.1% after RYGB and 100% after OADS with no significant difference between groups (p = 0.09). At mid-term followup (median 10 months IQR 7–21) there was no significant difference in the presence of symptomatic reflux as determined by post-op Visick score nor a difference in PPI use. The GerdQ score was significantly lower after OADS as compared to HHR and RYGB (4.6 ± 2.3 vs 7.7 ± 2.2 vs 8.7 ± 3.5, p = 0.006).

Conclusion

HHR with reconstruction of the phreno-esophageal ligament is a safe and effective procedure for patients with reflux after LSG, that avoids more complex operations such as RYGB and OADS and their associated long-term sequelae.

A fully resolved multiphysics model of gastric peristalsis and bolus emptying in the upper gastrointestinal tract

Over the past few decades, in silico modeling of organ systems has significantly furthered our understanding of their physiology and biomechanical function. In spite of the relative importance of the digestive system in normal functioning of the human body, there is a scarcity of high-fidelity models for the upper gastrointestinal tract including the esophagus and the stomach. In this work, we present a detailed numerical model of the upper gastrointestinal tract that not only accounts for the fiber architecture of the muscle walls, but also the multiphasic components they help transport during normal digestive function. Construction details for 3D models of representative stomach geometry are presented along with a simple strategy for assigning circular and longitudinal muscle fiber orientations for each layer. We developed a fully resolved model of the stomach to simulate gastric peristalsis by systematically activating muscle fibers embedded in the stomach. Following this, for the first time, we simulate gravity-driven bolus emptying into the stomach due to density differences between ingested contents and fluid contents of the stomach. Finally, we present a case of retrograde flow of fluid from the stomach into the esophagus, resembling the phenomenon of acid reflux. This detailed computational model of the upper gastrointestinal tract provides a foundation for future models to investigate the biomechanics of acid reflux and probe various strategies for gastric bypass surgeries to address the growing problem of obesity.

Endoscopic Management of GERD

Gastroesophageal reflux disease (GERD) has consistently been the most frequently diagnosed gastrointestinal malady in the USA. The mainstay of therapy has traditionally been medical management, including lifestyle and dietary modifications as well as antacid medications. In those patients found to be refractory to medical management or with a contraindication to medications, the next step up has been surgical anti-reflux procedures. Recently, though innovative advancements in therapeutic endoscopy have created numerous options for the endoscopic management of GERD, in this review, we discuss the various endoscopic therapy options, as well as suggested strategies we use to recommend the most appropriate therapy for patients.

Current Advancement on the Dynamic Mechanism of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a common clinical disease associated with upper gastrointestinal motility disorders. Recently, with improvements in living standards and changes in lifestyle and dietary habits, the incidence of GERD has been increasing yearly. However, the mechanism of GERD has not been fully elucidated due to its complex pathogenesis, and this had led to unsatisfactory therapeutic outcomes. Currently, the occurrence and development of GERD involve multiple factors. Its pathogenesis is mainly thought to be related to factors, such as lower esophageal sphincter pressure, transient lower esophageal sphincter relaxation, crural diaphragmatic dysfunction, hiatus hernia, and impaired esophageal clearance. Therefore, explaining the pathogenesis of GERD more clearly and systematically, exploring potential and effective therapeutic targets, and choosing the best treatment methods have gradually become the focus of scholars' attention. Herein, we reviewed current advancements in the dynamic mechanism of GERD to better counsel patients on possible treatment options.

Chicago Classification update (v4.0): Technical review of high-resolution manometry metrics for EGJ barrier function

Esophagogastric junction (EGJ) barrier function is of fundamental importance in the pathophysiology of gastroesophageal reflux disease. Impaired EGJ barrier function leads to excessive distal esophageal acid exposure or, in severe cases, esophagitis. Hence, proposed high-resolution manometry (HRM) metrics assessing EGJ integrity are clinically important and were a focus of the Chicago Classification (CC) working group for inclusion in CC v4.0. However, the EGJ is a complex sphincter comprised of both crural diaphragm (CD) and lower esophageal sphincter (LES) component, each of which is subject to independent physiological control mechanisms and pathophysiology. No single metric can capture all attributes of EGJ barrier function. The working group considered several potential metrics of EGJ integrity including LES-CD separation, the EGJ contractile integral (EGJ-CI), the respiratory inversion point (RIP), and intragastric pressure. Strong recommendations were made regarding LES-CD separation as indicative of hiatus hernia, although the numerical threshold for defining hiatal hernia was not agreed upon. There was no agreement on the significance of the RIP, only that it could localize either above the LES or between the LES and CD in cases of hiatus hernia. There was agreement on how to measure the EGJ-CI and that it should be referenced to gastric pressure in units of mmHg cm, but the numerical threshold indicative of a hypotensive EGJ varied widely among reports and was not agreed upon. Intragastric pressure was endorsed as an important metric worthy of further study but there was no agreement on a numerical threshold indicative of abdominal obesity.

Various Kinds of Functional Digestive Tract Reconstruction Methods After Proximal Gastrectomy

The incidence of proximal gastric cancer has shown a rising trend in recent years. Surgery is still the main way to cure proximal gastric cancer. Total gastrectomy with D2 lymph node dissection was considered to be the standard procedure for proximal gastric cancer in the past several decades. However, in recent years, many studies have confirmed that proximal gastrectomy can preserve part of the stomach function and can result in a better quality of life of the patient than total gastrectomy. Therefore, proximal gastrectomy is increasingly used in patients with proximal gastric cancer. Unfortunately, there are some concerns after proximal gastrectomy with traditional esophagogastrostomy. For example, the incidence of reflux esophagitis in patients who underwent proximal gastrectomy with traditional esophagogastrostomy is significantly higher than those patients who underwent total gastrectomy. To solve those problems, various functional digestive tract reconstruction methods after proximal gastrectomy have been proposed gradually. In order to provide some help for clinical treatment, in this article, we reviewed relevant literature and new clinical developments to compare various kinds of functional digestive tract reconstruction methods after proximal gastrectomy mainly from perioperative outcomes, postoperative quality of life and survival outcomes aspects. After comparison and discussion, we drew the conclusion that various functional reconstruction methods have their own advantages and disadvantages; large scale high-level clinical studies are needed to choose an ideal reconstruction method in the future. Besides, in clinical practice, surgeons should consider the condition of the patient for individualized selection of the most appropriate reconstruction method.

Recovery of lower oesophageal barrier function: a pilot study comparing a mixture of atropine and neostigmine and sugammadex: A randomised controlled pilot study

BACKGROUND

The lower oesophageal sphincter (LOS) barrier serves to prevent regurgitation of gastric contents. Although general anaesthesia depresses its function, its recovery process during emergence from anaesthesia has not been systematically examined.

OBJECTIVE

To explore whether recovery of lower oesophageal barrier function differed between patients receiving a mixture of 1 mg atropine and 2 mg neostigmine and those receiving 2 mg kg-1 sugammadex during emergence from anaesthesia.

DESIGN

An unblinded randomised controlled pilot study.

SETTING

A single university hospital from January 2016 to December 2018.

PATIENTS

A total of 20 non-obese adult females undergoing minor surgery.

INTERVENTION

The patients were randomly assigned to a group either receiving atropine and neostigmine or sugammadex for reversal of rocuronium.

MAIN OUTCOME MEASURES

Through use of the high-resolution manometry technique, the lower oesophageal barrier pressure (PBAR: primary variable) defined as a pressure difference between pressures at the LOS and the stomach was measured at five distinguishable time points during emergence from total intravenous anaesthesia. A mixed effects model for repeated measures was used to test the hypothesis.

RESULTS

In all patients baseline PBAR values were positive even under muscle paralysis and general anaesthesia before administration of reversal agents, and did not differ between the groups (P = 0.299). During recovery from muscle paralysis and general anaesthesia, PBAR (mean ± SD) significantly increased (P = 0.004) from 17.0 ± 2.9 to 21.0 ± 5.0 mmHg in the atropine and neostigmine group (n = 8) and from 19.1 ± 9.0 to 24.5 ± 12.7 mmHg in the sugammadex group (n = 11). PBAR significantly increased immediately after return of consciousness in both groups, whereas return of muscle tone, lightening of anaesthesia and tracheal extubation did not change it.

CONCLUSION

Recovery of the lower oesophageal barrier function does not differ between patients receiving either atropine and neostigmine or sugammadex and is completed after recovery of consciousness from general anaesthesia.

TRIAL REGISTRATION

UMIN Clinical Trials Registry: UMIN000020500: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&recptno=R000023594&type=summary&language=E.

Evaluation of the Esophagogastric Junction on High Resolution Manometry

The esophagogastric junction (EGJ) is a complex barrier between the thoracic and abdominal luminal gut compartments, comprised primarily of the lower esophageal sphincter (LES) and crural diaphragm. Although closed at rest, the EGJ relaxes to allow antegrade bolus transit and retrograde venting of air. Abnormal relaxation is the hallmark of achalasia spectrum disorders, while increased frequency of transient lower esophageal sphincter relaxations and/or EGJ disruption are seen in gastroesophageal reflux disease. High resolution manometry (HRM) is the modern day gold standard for assessment of EGJ morphology and function, with better performance characteristics compared with endoscopy and barium esophagography. Conventional LES metrics defining EGJ function include resting LES pressure as well as postswallow residual pressures. Newer HRM-based metrics include EGJ contractile integral, which measures static barrier function at rest, and EGJ morphology, which characterizes the relationship between LES and crural diaphragm. Provocative maneuvers assess dynamic EGJ function during physiological or pharmacologic stress. The most useful of these maneuvers, the rapid drink challenge, assesses for latent obstruction, while multiple rapid swallows evaluate adequacy of deglutitive inhibition. Amyl nitrate and cholecystokinin administration can segregate motor from structural obstruction. Newer provocative tests (straight leg raise maneuver, abdominal compression) and novel diagnostic tools (functional lumen imaging probe) complement HRM evaluation of the EGJ. Although current HRM metrics and maneuvers show promise in identifying clinically relevant EGJ abnormalities, future investigations evaluating management outcomes will improve segregation of normal from abnormal EGJ morphology and function.

Esophageal motility disorders on high-resolution manometry: Chicago classification version 4.0©

Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). Fifty-two diverse international experts separated into seven working subgroups utilized formal validated methodologies over two-years to develop CCv4.0. Key updates in CCv.4.0 consist of a more rigorous and expansive HRM protocol that incorporates supine and upright test positions as well as provocative testing, a refined definition of esophagogastric junction (EGJ) outflow obstruction (EGJOO), more stringent diagnostic criteria for ineffective esophageal motility and description of baseline EGJ metrics. Further, the CCv4.0 sought to define motility disorder diagnoses as conclusive and inconclusive based on associated symptoms, and findings on provocative testing as well as supportive testing with barium esophagram with tablet and/or functional lumen imaging probe. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification and provide more standardized and rigorous criteria for patterns of disorders of peristalsis and obstruction at the EGJ.

Concomitant hiatal hernia repair during bariatric surgery: does the reinforcement make the difference?

BACKGROUND

Hiatal hernia repair (HHR) is still controversial during bariatric procedures, especially in case of laparoscopic sleeve gastrectomy (LSG).

AIMS

to report the long-term results of concomitant HHR, evaluating the safety and efficacy of posterior cruroplasty (PC), simple or reinforced with biosynthetic, absorbable Bio-A^® mesh (Gore, Flagstaff, AZ, USA). Primary endpoint: PC's failure, defined as symptomatic HH recurrence, nonresponding to medical treatment and requiring revisional surgery.

METHODS

The prospective database of 1876 bariatric operations performed in a center of excellence between 2011-2019 was searched for concomitant HHR. Intraoperative measurement of the hiatal surface area (HSA) was performed routinely.

RESULTS

A total of 250 patients undergone bariatric surgery and concomitant HHR (13%). Simple PC (group A, 151 patients) was performed during 130 LSG, 5 re-sleeves and 16 gastric bypasses; mean BMI 43.4±5.8 kg/m², HSA mean size 3.4±2 cm². Reinforced PC (group B) was performed in 99 cases: 62 primary LSG, 22 LGB and 15 revisions of LSG; mean BMI 44.6±7.7 kg/m2, HSA mean size 6.7±2 cm². PC's failure, with intrathoracic migration (ITM) of the LSG was encountered in 12 cases (8%) of simple vs. only 4 cases (4%) of reinforced PC (P=0.23); hence, a repeat, reinforced PC and R-en-Y gastric bypass (LRYGB) was performed laparoscopically in all cases. No mesh-related complications were registered perioperatively or after long-term follow-up (mean 50 months). One case of cardiac metaplasia without goblet cells was detected 4 years postoperatively; conversion to LRYGB, with reinforced redo of the PC was performed. The Cox hazard analysis showed that the use of more than four stitches for cruroplasty represents a negative factor on recurrence (HR=8; P<0.05).

CONCLUSIONS

An aggressive search for and repair of HH during any bariatric procedure seems advisable, allowing a low HH recurrence rates. Additional measures, like mesh reinforcement of crural closure with biosynthetic, absorbable mesh, seem to improve results on long term follow-up, especially in case of larger hiatal defects. In our experience, reinforcement of even smaller defects seems advisable in obese population.

Three-Dimensional Pressure Profile of the Lower Esophageal Sphincter and Crural Diaphragm in Patients with Achalasia Esophagus

BACKGROUND & AIMS

Smooth muscles of the lower esophageal sphincter (LES) and skeletal muscle of the crural diaphragm (esophagus hiatus) provide the sphincter mechanisms at the esophagogastric junction (EGJ). We investigated differences in the 3-dimensional (3D) pressure profile of the LES and hiatal contraction between healthy subjects and patients with achalasia esophagus.

METHODS

We performed a prospective study of 10 healthy subjects (controls; 7 male; mean age, 60 ± 15 years; mean body mass index, 25 ± 2) and 12 patients with a diagnosis of achalasia (7 male; mean age, 63 ± 13 years; mean body mass index, 26 ± 1), enrolled at a gastroenterology clinic. Participants underwent 3D high-resolution manometry (3DHRM) with a catheter equipped with 96 transducers (for the EGJ pressure recording). A 0.5-mm metal ball was taped close to the transducer number 1 of the 3DHRM catheter. EGJ pressure was recorded at end-expiration (LES pressure) and at the peak of forced inspiration (hiatal contraction). Computed tomography (CT) scans were performed to localize the circumferential location of the metal ball on the catheter. Esophagus, LES, stomach, right and left crus of the diaphragm, and spine were segmented in each CT scan slice images to construct the 3D morphology of the region.

RESULTS

The metal ball was located at the 7 o'clock position in all controls. The circumferential orientation of metal ball was displaced 45 to 90 degrees in patients with achalasia compared with controls. The 3D-pressure profile of the EGJ at end-expiration and forced inspiration revealed marked differences between the groups. The LES turns to the left as it entered from the chest into the abdomen, forming an angle between the spine and LES. The spine-LES angle was smaller in patients with achalasia (104°) compared with controls (124°). Five of the 10 subjects with achalasia had physical breaks in the left crus of the diaphragm CONCLUSIONS: Besides LES, the 3D pressure profile of the EGJ can indicate anatomic and functional abnormalities of the crural diaphragm muscle in patients with achalasia esophagus. Further studies are needed to define the nature of hiatal and crural diaphragm dysfunction in patients with achalasia of the esophagus.

Esophageal physiology-an overview of esophageal disorders from a pathophysiological point of view

The esophagus serves the principal purpose of transporting food from the pharynx into the stomach. A complex interplay between nerves and muscle fibers ensures that swallowing takes place as a finely coordinated event. Esophageal function can be tested by a variety of methods, endoscopy, manometry, and reflux monitoring being some of the most important. Regarding pathophysiology, motor disorders, such as achalasia, often cause dysphagia and/or chest pain. Functional esophageal disorders are a heterogeneous group with hypersensitivity as a dominant pathophysiological factor. Gastroesophageal reflux disease often causes symptoms, such as heartburn and regurgitation, and a spectrum of disease, ranging from minimal mucosal damage visible only in the microscope to esophageal ulcers and strictures in the most severe cases. Eosinophilic esophagitis is an immune-mediated condition that can result in significant dysphagia and associated luminal narrowing. In the following, we will provide an overview of the most common esophageal disorders from a combined pathophysiological and clinical view.

Tissue engineering of the gastroesophageal junction

The gastroesophageal junction has been of clinical interest for some time due to its important role in preventing reflux of caustic stomach contents upward into the esophagus. Failure of this role has been identified as a key driver in gastroesophageal reflux disease, cancer of the lower esophagus, and aspiration-induced lung complications. Due to the large population burden and significant morbidity and mortality related to reflux barrier dysfunction, there is a pressing need to develop tissue engineering solutions which can replace diseased junctions. While good progress has been made in engineering the bodies of the esophagus and stomach, little has been done for the junction between the two. In this review, we discuss pertinent topics which should be considered as tissue engineers begin to address this anatomical region. The embryological development and adult anatomy and histology are discussed to provide context about the native structures which must be replicated. The roles of smooth muscle structures in the esophagus and stomach, as well as the contribution of the diaphragm to normal anti-reflux function are then examined. Finally, engineering considerations including mechanics and current progress in the field of tissue engineering are presented.

Mechanism and Pathophysiology of Gastroesophageal Reflux Disease

Gastroesophageal reflux (GER) describes a process in which gastric contents travel retrograde into the esophagus. GER can be either a physiologic phenomenon that occurs in asymptomatic individuals or can potentially cause symptoms. When the latter occurs, this represents GER disease (GERD). The process by which GER transforms into GERD begins at the esophagogastric junction. Impaired clearance of the refluxate also contributes to GERD. Reflux causes degradation of esophageal mucosal defense. The refluxate triggers sensory afferents leading to symptom generation.

Three-Dimensional High-Resolution Esophageal Manometry Study of the Esophagogastric Junction in Patients with Achalasia

BACKGROUND

A novel three-dimensional high-resolution esophageal manometry provides a dynamic 360° representation of the pressure at the esophagogastric junction.

AIMS

To describe the three-dimensional high-resolution esophageal manometry patterns of achalasia.

METHODS

We retrospectively included all consecutive patients who underwent three-dimensional high-resolution esophageal manometry before and after treatment (pneumatic dilatation or per-oral endoscopic myotomy) for achalasia between November 2016 and July 2017. The distribution of the pressures at the esophagogastric junction on three-dimensional high-resolution esophageal manometry was determined.

RESULTS

Eighteen patients were included. Mean integrated relaxation pressure was 20.7 mmHg, and median (range) Eckardt score was 7 (4-10). Nine patients were treated by pneumatic dilatation and seven by myotomy. Nine patients underwent three-dimensional high-resolution esophageal manometry after treatment. Before treatment, the esophagogastric junction pressure distribution was best observed at end expiration and during the 4 s of the integrated relaxation pressure measurement. During the integrated relaxation pressure, the lower esophageal sphincter was asymmetric in 12 patients with a high-pressure zone between the left and the posterior side of the esophagogastric junction. After treatment, five patients had a residual high-pressure point on the left or the posterior side of the esophagogastric junction.

CONCLUSIONS

Three-dimensional high-resolution esophageal manometry allows a simple assessment of the pressure topography at the EGJ. In patients with achalasia, we found the esophagogastric junction pressure to be asymmetric with a peak pressure on the greater curvature side. Three-dimensional high-resolution esophageal manometry has the potential to guide initial and redo treatments.

Transoral Incisionless Fundoplication

GERD is a spectrum disorder, and treatment should be individualized to the patient's anatomic alterations. Trans-oral incisionless fundoplication (TIF 2.0) is an endoscopic procedure which reduces EGJ distensibility, thereby decreasing tLESRs, and also creates a 3-cm high pressure zone at the distal esophagus in the configuration of a flap valve. As it produces a partial fundoplication with a controlled valve diameter, gas can still escape from the stomach, minimizing the side-effect of gas-bloat. Herein we discuss the rationale, mechanism of action, patient selection, step-by-step procedure, safety and efficacy data, it's use with concomitant laparoscopic hernia repair, and future emerging indications.

Morphology of the Esophageal Hiatus: Is It Different in 3 Types of Hiatus Hernias?

Background/Aims

The esophageal hiatus is formed by the right crus of the diaphragm in the majority of subjects. Contraction of the hiatus exerts a sphincter-like action on the lower esophageal sphincter (LES). The aim is to study the hiatal anatomy (using CT scan imaging) and function (using high-resolution manometry [HRM]), and esophageal motor function in patients with sliding and paraesophageal hiatal hernia.

Methods

We assessed normal subjects (n = 20), patients with sliding type 1 hernia (n = 18), paraesophageal type 2 hernia (n = 19), and mixed type 3 hernia (n = 19). Hernia diagnosis was confirmed on the upper gastrointestinal series. The hiatal morphology was constructed from the CT scan images. The LES pressure and relaxation, percent peristalsis, bolus pressure, and hiatal squeeze pressure were assessed by HRM.

Results

The CT images revealed that the esophageal hiatus is formed by the right crus of the diaphragm in all normal subjects and 86% of hernia patients. The hiatus is elliptical in shape with a surface area of 1037 mm² in normal subjects. The hiatal dimensions were larger in patients compared to normal subjects. The HRM revealed impaired LES relaxation and higher bolus pressure in patients with paraesophageal compared to the sliding hernia. The hiatal pinch on HRM was recognized in significantly higher number of patients with sliding as compared to paraesophageal hernia.

Conclusions

Using a novel approach, we provide details of the esophageal hiatus in patients with various kinds of hiatal hernia. Impaired LES relaxation in paraesophageal hernia may play a role in its pathophysiology and genesis of symptoms.

Asymmetrical elevation of esophagogastric junction pressure suggests hiatal repair contributes to antireflux surgery dysphagia

The radial distribution of esophago-gastric junction (EGJ) pressures with regard to troublesome dysphagia (TDysph) after antireflux surgery is poorly understood. Before and after antireflux surgery, end-expiratory and peak-inspiratory EGJ pressures were measured at eight angles of 45° radial separation in patients with reflux disease. All 34 patients underwent posterior crural repair, then either 90° anterior (N = 13) or 360° fundoplication (N = 21). Dysphagia was assessed prospectively using a validated questionnaire (score range 0-45) and TDysph defined as a dysphagia score that was ≥5 above pre-op baseline. Compared with before surgery, for 90° fundoplication, end-expiratory EGJ pressures were highest in the left-anterolateral sectors, the position of the partial fundoplication. In other sectors, pressures were uniformly elevated. Compared with 90° fundoplication, radial pressures after 360° fundoplication were higher circumferentially (P = 0.004), with a posterior peak. Nine patients developed TDysph after surgery with a greater increase in end-expiratory and peak-inspiratory EGJ pressures (P = 0.03 and 0.03, respectively) and significantly higher inspiratory pressure at the point of maximal radial pressure asymmetry (P = 0.048), compared with 25 patients without TDysph. Circumferential elevation of end-expiratory EGJ pressure after 90° and 360° fundoplication suggests hiatal repair elevates EGJ pressure by extrinsic compression. The highly localized focal point of elevated EGJ pressure upon inspiration in patients with TDysph after surgery is indicative of a restrictive diaphragmatic hiatus in the presence of a fundoplication.

Botox injection into the lower esophageal sphincter induces hiatal paralysis and gastroesophageal reflux

Endoscopic intrasphincteric injection of Botox (ISIB) is used routinely for the treatment of achalasia esophagus and other spastic motor disorders. Studies show that the ISIB reduces the smooth muscle lower esophageal sphincter (LES) pressure. The esophageal hiatus, formed by the right crus of diaphragm, surrounds the cranial half of the LES and works like an external LES. We studied the effects of ISIB on the LES and hiatal contraction and gastroesophageal reflux (GER). Fourteen patients treated with ISIB were studied. Esophageal manometry-impedance recordings were performed before and after the ISIB. Hiatal contraction was assessed during tidal inspiration, forced inspiration, Müller's maneuver, and straight leg raise. In 6 subjects, the manometry were repeated 6-12 mo after the ISIB. The esophagogastric junction (EGJ) pressure was measured at end expiration (LES pressure) and at the peak of maneuvers (hiatal contraction). Transdiaphragmatic pressure (pdi; force of diaphragmatic contraction) was measured at the peak of forced inspiration. GER was measured from the impedance recordings. The EGJ pressure at end expiration (LES pressure) decreased significantly after the Botox injection. The peak EGJ pressure at tidal inspiration, forced inspiration, Müller's maneuver, and straight leg raise was also dramatically reduced by the ISIB. There was no effect of Botox on the pdi during forced inspiration. Seven of 10 subjects demonstrated GER during maneuvers following the ISIB. Six to 12 mo after ISIB, the LES and hiatal contraction pressure returned to the pre-ISIB levels. ISIB, in addition to decreasing LES pressure, paralyzes the esophageal hiatus (crural diaphragm) and induces GER.NEW & NOTEWORTHY The sphincter mechanism at the lower end of the esophagus comprises smooth muscle lower esophageal sphincter (LES) and skeletal muscle crural diaphragm (hiatus). Current thinking is that the endoscopic intrasphincteric injection of Botox (ISIB), used routinely for the treatment of achalasia esophagus, reduces LES pressure. Our study shows that ISIB, even though injected into the LES, diffuses into the hiatus and causes its paralysis. These findings emphasize the importance of esophageal hiatus as an important component of the antireflux barrier and that the ISIB is refluxogenic.

Surgical Anatomy of Paraesophageal Hernias

Paraesophageal hernia represents a complex surgical problem involving significant distortion of the anatomy and function of the esophagus, stomach, gastroesophageal junction, mediastinum, lungs, and heart. Surgeons operating in the area must have deep understanding of the normal anatomy and pathologic derangements in patients with paraesophageal hernias. This article describes the normal anatomy and anatomic abnormalities in application to the various approaches used in the surgical repair of a paraesophageal hernia.

Esophageal A-ring is associated with the severity of gastroesophageal reflux

BACKGROUND

The esophageal A-ring (EAR) is an anatomic finding appreciated on videofluoroscopic esophagram (VFE) at the junction of the tubular esophagus and esophageal vestibule. EARs are appreciated on a small subset (5%) of VFEs. We hypothesize that EARs represent a compensatory mechanism to protect against gastroesophageal reflux (GER).

OBJECTIVE

To evaluate the association between EAR and GER.

STUDY DESIGN

Case control study.

METHODS

All persons having undergone ambulatory pH testing with an EAR identified on VFE between November 1, 2014 and June 30, 2014 were identified. All cases were matched to controls by age, gender, and the presence/absence of hiatal hernia. Subjective dysphagia severity was assessed with the EAT10 and the presence of erosive esophagitis and intestinal metaplasia on esophagoscopy was abstracted.

RESULTS

The mean (±SD) age of the entire cohort (N = 20) was 63 (±7.7) years. 60% was female. The mean composite DeMeester pH score for persons with and without an EAR was 48.9 (±39.6) and 15.4 (±12.3), respectively (P = .033). The mean total % time of pH < 4 for persons with and without an EAR was 26.4 (±21.9) and 7.7 (±6.8), respectively (P = .034). The prevalence of erosive esophagitis among persons with and without an EAR was 70% and 10%, respectively (P = .019).

CONCLUSION

There is a significant association between the presence of esophageal A-rings on esophagography and the severity of acid reflux on endoscopy and ambulatory pH testing. The data suggest that the presence of an esophageal A-ring may be either a compensatory mechanism to protect against gastroesophageal reflux and/or an inflammatory consequence of peptic esophagitis.

LEVEL OF EVIDENCE

3b Laryngoscope, 130:951-954, 2020.

Generation of Spontaneous Tone by Gastrointestinal Sphincters

An important feature of the gastrointestinal (GI) muscularis externa is its ability to generate phasic contractile activity. However, in some GI regions, a more sustained contraction, referred to as "tone," also occurs. Sphincters are muscles oriented in an annular manner that raise intraluminal pressure, thereby reducing or blocking the movement of luminal contents from one compartment to another. Spontaneous tone generation is often a feature of these muscles. Four distinct smooth muscle sphincters are present in the GI tract: the lower esophageal sphincter (LES), the pyloric sphincter (PS), the ileocecal sphincter (ICS), and the internal anal sphincter (IAS). This chapter examines how tone generation contributes to the functional behavior of these sphincters. Historically, tone was attributed to contractile activity arising directly from the properties of the smooth muscle cells. However, there is increasing evidence that interstitial cells of Cajal (ICC) play a significant role in tone generation in GI muscles. Indeed, ICC are present in each of the sphincters listed above. In this chapter, we explore various mechanisms that may contribute to tone generation in sphincters including: (1) summation of asynchronous phasic activity, (2) partial tetanus, (3) window current, and (4) myofilament sensitization. Importantly, the first two mechanisms involve tone generation through summation of phasic events. Thus, the historical distinction between "phasic" versus "tonic" smooth muscles in the GI tract requires revision. As described in this chapter, it is clear that the unique functional role of each sphincter in the GI tract is accompanied by a unique combination of contractile mechanisms.