Reflux Barrier Research Articles

A multidisciplinary approach to identifying and managing heterotopic gastric inlet patches.

Gastric inlet patches are often incidental, but can also be a treatable cause of laryngo-esophageal symptoms. We retrospectively reviewed all patients whose gastric inlet patches were diagnosed following assessment for laryngopharyngeal and swallowing symptoms. Improvement following Argon Plasma Coagulation (APC) was assessed using Minimum Clinically-Important Difference methodology combining voice, throat, and swallowing domains. Correlations between APC response and measures of reflux and mucosal barrier integrity, measured during 24-h pH-impedance manometry, were obtained. Proximal and Distal Mean Nocturnal Baseline Impedance (MNBI) values were separately calculated and the novel variable of Mucosal Impedance Gradient was derived as [((Distal MNBI-Proximal MNBI)/((Distal MNBI + Proximal MMBI)/2)) x 100]. Inlet patches were detected in 57 of 651 patients who had Transnasal Panendoscopy (8.7 ± 2.2%). There were 34 males. Mean age was 58 years. Mean duration of symptoms was 2 years. The commonest symptoms were hoarseness (n = 33), throat symptoms (n = 24), and dysphagia (n = 21), respectively. APC was used to ablate patches in 34 patients. Treatment response was 71% at a mean followup of 5.5 months. MIG > - 25% predicted response to APC, with area under the receiver operating characteristic curve of 0.875 (Sensitivity = 81%; Specificity = 100%; p < 0.0001). Gastric inlet patches are common and under-recognized. They can cause protracted pharyngo-esophageal symptoms. Patch ablation is an effective treatment for carefully selected patients. Optimal patient selection requires multidisciplinary teamwork. Mucosal Impedance Gradient could further refine patient selection.

Endoscopy and Antireflux Surgery: A Technical Review of Pre- and Postoperative Evaluation and Recognizing Patterns of Failure

Endoscopic evaluation after antireflux surgery is a challenge, due to the complexity of anatomy, variations in anatomical repairs, and the various patterns of failure. Studies have demonstrated that endoscopy reports of postoperative examinations are often inaccurate and inconsistent. The key to consistent high quality endoscopic examinations of the integrity of an antireflux surgery is a sound foundation in the native anatomical gastroesophageal junction and an understanding of the anatomy of the various postoperative configurations. This review will clarify the critical details necessary to perform a detailed endoscopic evaluation of the patient with suspected gastroesophageal reflux, and highlight key features to distinguish the intact repair from the dysfunctional one. It first explores the anatomical components of the native gastroesophageal junction and the unique geometric architecture that manifests in the physiologic reflux barrier. Then details the essential structures to evaluate and techniques to perform in an endoscopic examination prior to an antireflux surgery. It then systematically examines the altered anatomy and postoperative changes in endoscopic appearance after Nissen, Toupet, and Dor fundoplication, Collis gastroplasty, magnetic sphincter augmentation, and transoral incisionless fundoplication. Finally, to aid in the endoscopic diagnosis of specific dysfunction, it discusses the various patterns of failure after antireflux surgery, their characteristic endoscopic appearances, and the most useful adjunct testing modalities to augment the endoscopic examination when diagnosis is unclear.

Gastroesophageal reflux disease in children: What's new right now?

Gastroesophageal reflux (GER) in children is very common and refers to the involuntary passage of gastric contents into the esophagus. This is often physiological and managed conservatively. In contrast, GER disease (GERD) is a less common pathologic process causing troublesome symptoms, which may need medical management. Apart from abnormal transient relaxations of the lower esophageal sphincter, other factors that play a role in the pathogenesis of GERD include defects in esophageal mucosal defense, impaired esophageal and gastric motility and clearance, as well as anatomical defects of the lower esophageal reflux barrier such as hiatal hernia. The clinical manifestations of GERD in young children are varied and nonspecific prompting the necessity for careful diagnostic evaluation. Management should be targeted to the underlying aetiopathogenesis and to limit complications of GERD. The following review focuses on up-to-date information regarding of the pathogenesis, diagnostic evaluation and management of GERD in children.

Evolution in the treatment of gastroesophageal reflux disease over the last century: from a crural-centered to a lower esophageal sphincter-centered approach and back.

The surgical management of gastroesophageal reflux disease (GERD) has evolved significantly over the past century, driven by increased understanding of the physiology of the reflux barrier, its anatomic components, and surgical innovation. Initially, emphasis was on reduction of hiatal hernias and crural closure as the etiology behind GERD was felt to be solely related to the anatomic alterations caused by hiatal hernias. With persistence of reflux-related changes in some patients despite crural closure, along with the development of what is now modern manometry and the discovery of a high-pressure zone at the distal esophagus, focus evolved to surgical augmentation of the lower esophageal sphincter (LES). With this transition to an LES-centric approach, attention shifted to reconstruction of the angle of His, ensuring sufficient intra-abdominal esophageal length, development of the now commonly employed Nissen fundoplication, and creation of devices that directly augment the LES such as magnetic sphincter augmentation. More recently, the role of crural closure in antireflux and hiatal hernia surgery has again received renewed attention due to the persistence of postoperative complications including wrap herniation and high rates of recurrences. Rather than simply preventing transthoracic herniation of the fundoplication as was originally thought, diaphragmatic crural closure has been documented to have a key role in re-establishing intra-abdominal esophageal length and contributing to the restoration of normal LES pressures. This progression from a crural-centric to a LES-centric approach and back has evolved along with our understanding of the reflux barrier and will continue to do so as more advances are made in the field. In this review, we will discuss the evolution of surgical techniques over the past century, highlighting key historical contributions that have shaped our management of GERD today.

156. ANTI-REFLUX RADIOFREQUENCY THERAPY USING STRETTA FOR REFRACTORY GORD IS FEASIBLE AND REDUCES THE NEED FOR MINIMALLY INVASIVE SURGERY

Abstract Radiofrequency (RF) therapy of the lower oesophageal sphincter using STRETTA strengthens the reflux barrier across the gastro-oesophageal junction. Numerous studies have shown improvement in reflux symptoms, reduction in proton pump inhibitor (PPI) dependence and need for surgical treatment for gastro-oesophageal reflux disease (GORD). We present the largest series from Europe, and aim to assess long term outcomes of STRETTA for patients with medically refractory GORD. Data for all patients who underwent STRETTA from October 2014 till April 2021 were prospectively maintained on a database and was analysed retrospectively. Patients and primary care doctor practices were contacted to obtain information on PPI free period (PFP) after STRETTA therapy, which was defined as the time between STRETTA and recommencement of prescribed and daily consumption of PPI medication. As required medication use was not considered for PFP calculation. Statistical analysis and graphical presentation were carried out using Minitab® and GraphPad Prism®. Mann–Whitney test was used to compare two sets of non-parametric data and a p &amp;lt; 0.05 was considered significant. From 195 patients (median age 55, 116 females (59%)) who underwent STRETTA, PFP data were available for 144 (74%) patients. Sixty-six patients (45%) remained without PPI after a median follow-up of 4.5 years (52 months). Six patients (3%) went on to have a further intervention. There was a significant negative correlation between PFP and age (p = 0.023) with no differences between the genders (p = 0.90). Patients &amp;lt;55 years had a longer PFP than &amp;gt;55 years (p = 0.012). Younger males had a significantly longer PFP than older males (0.03). However, this was not observed in the female cohort (p = 0.14). Our findings suggest STRETTA as a safe and feasible option for treating medically refractory GORD, especially in younger patients. STRETTA does reduce the need for long term PPI and lessens the frequency of further interventions such as surgery. Further studies are required to investigate the mechanisms by which STRETTA is beneficial in the younger patient.

State of evidence and future perspectives in minimally invasive management of gastroesophageal reflux disease (GERD)

The future of minimally invasive treatment of gastroesophageal reflux disease (GERD) will be realized through collaborative precision medicine more than any foreseeable new technology. Multidisciplinary foregut societies are fostering the collaboration and expertise needed to provide a personalized treatment of GERD. Patient-centric therapy will consider combination therapies’ clinical successes. Taking a patient uncontrolled on medication to controlled via a combination of medicine and a procedure will replace the historical mutual exclusivity of acid-suppressive medication or surgery as a treatment for GERD. Research directed at precision medicine will focus on subgroup analysis rather than randomized controlled trials. Recognition of the crural diaphragm as a reflux barrier which fails in GERD patients regardless of the presence of an axial hernia has resulted from modalities such as 3-D high-resolution impedance manometry, endoscopic ultrasound, functional luminal impedance planimetry. More precise patient selection for purely endoscopic therapies will be possible.The concept of hernia reduction will be replaced by calibration of the crural repair to restore its sphincteric function. Partnering a surgically calibrated hernia repair partnered with interventional gastrointestinal endoscopic reinforcement of the lower esophageal sphincter will foster physician alliances and offer patient-centric alternatives to traditional fundoplication. As such, laparoscopic Nissen Fundoplication will lose its historical primacy and be relegated to the most severe GERD. Magnetic sphincter augmentation (LINX®), varing degrees of partial fundoplication, and endoluminal therapies with or without hiatal hernia repair will become the mainstay of GERD AntiReflux Procedures. Radio Frequency modulation (Stretta®) may be an alternative to neuromodulators in treating the acid-sensitive esophagus. The nascent era of endoscopic robotics will improve precision, reproducibility and revive natural orifice transluminal endoscopic surgery.

Gastrointestinal function testing model using a new laryngopharyngeal pH probe (Restech) in patients after Ivor-Lewis esophagectomy.

BACKGROUNDThere 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. AIMTo use a human reflux model to examine our previously published correlation in these patients. METHODSPatients after Ivor Lewis esophagectomy underwent our routine follow-up program with surveillance endoscopies, computed tomography scans and further exams following surgery. Only patients with a complete check-up program and reflux symptoms were offered inclusion into this prospective study and evaluated using Restech and simultaneous Eso-pH. Subsequently, the relationship between the two techniques was evaluatedRESULTSA 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. CONCLUSIONPatients following esophagectomy and reconstruction with gastric interposition can ideally serve as a human reflux model. Interestingly, laryngopharyngeal reflux phases occur mainly in the upright position. In this human volume-reflux model, results of simultaneous esophageal and laryngopharyngeal (Restech) pH-metry showed 100% correlation as being explicable by one of our reflux scenarios.

Food and Gastroesophageal Reflux Disease.

Gastroesophageal reflux disease is a chronic condition with a high prevalence in western countries. Transient lower esophageal sphincter relaxation episodes and a decreased lower esophageal sphincter pressure are the main mechanisms involved. Currently used drugs are efficient on reflux symptoms, but only as long as they are administered, because they do not modify the reflux barrier. Certain nutrients or foods are generally considered to increase the frequency of gastroesophageal reflux symptoms, therefore physicians recommend changes in diet and some patients avoid bothering foods. This review summarizes current knowledge regarding food and gastroesophageal reflux. For example, fat intake increases the perception of reflux symptoms. Regular coffee and chocolate induce gastroesophageal reflux and increase the lower esophageal exposure to acid. Spicy foods might induce heartburn, but the exact mechanism is not known. Beer and wine induce gastroesophageal reflux, mainly in the first hour after intake. For other foods, like fried food or carbonated beverages data on gastroesophageal reflux is scarce. Similarly, there are few data about the type of diet and gastroesophageal reflux. Mediterranean diet and a very low carbohydrate diet protect against reflux. Regarding diet-related practices, consistent data showed that a "short-meal-to-sleep interval" favors reflux episodes, therefore some authors recommend that dinner should be at least four hours before bedtime. All these recommendations should consider patient's weight, because several meta-analyses showed a positive association between increased body mass index and gastroesophageal reflux disease.

The acid pocket - a novel target for the treatment of gastro-esophageal reflux disease

Increased acid reflux after meals is a key feature of gastro-esophageal reflux disease (GERD) and is the most important cause for patient symptoms, particularly heartburn and acid regurgitation. Chronic acid exposure also predisposes to associated pathologies including reflux esophagitis, esophageal stricture, Barrett's esophagus, and Barrett's carcinoma (esophageal adenocarcinoma). The severity of esophageal symptoms and mucosal damage is related to two key factors, (i) the acidity of the refluxate, which depends primarily on the gastric secretory output and its distribution within the stomach, and (ii) the frequency and duration of reflux events which depends on the efficacy of the reflux barrier at the gastro-esophageal junction and the esophageal clearance function. The concept of the acid pocket is an attempt to bring these two factors into a unified patho-mechanism.The acid pocket describes an area of unbuffered, highly acidic, gastric secretion in the proximal stomach adjacent to the esophago-gastric junction (GEJ) which forms in the postprandial period and is the source of acid refluxate into the esophagus. It is observed both in healthy individuals as well as in reflux patients. However, the presence of a hiatus hernia and/or a weak lower esophageal sphincter in patients allows the acid pocket to encroach on the gastro-esophageal junction. This results in very high acid exposure of the squamous epithelium of the distal esophagus, leading to mucosal damage and symptoms. Recently, the acid pocket has been proposed as a target for pharmacological and surgical therapies of GERD. Proton pump inhibitors and related medications reduce its acidity; whereas, alginate preparations, prokinetics, and fundoplication displace it away from the gastro-esophageal junction.

FA02.07: BARRIER STRUCTURE AND FUNCTION OF THE NEO-SQUAMOUS EPITHELIUM FOLLOWING SUCCESSFUL BARRETT’S ENDOTHERAPY IS IMPAIRED

Abstract Background The neo-squamous epithelium that replaces columnar epithelium after successful endoscopic ablation of Barrett's esophagus (BE) has not been fully characterized in regard to its structural and functional integrity. Intercellular space is a surrogate marker for epithelial structural integrity and mucosal impedance (MI) is a surrogate for transepithelial resistance and thus epithelial functional integrity. Impairment of the structural and functional integrity may influence recurrence following successful ablation. We aimed to measure the esophageal epithelial intercellular space diameter and MI in the neo-squamous and normal squamous epithelium of patients who underwent successful radiofrequency ablation for dysplastic BE. Methods Forty patients with complete remission of intestinal metaplasia (CRIM) (defined as two negative surveillance endoscopies for intestinal metaplasia) were prospectively recruited. Patients were excluded if they had endoscopic evidence of esophagitis. MI measurements were taken at 1 cm above the GE junction and 2 cm above the prior BE segment (targeting uninvolved squamous epithelium), using a novel through the scope MI probe. Endoscopic biopsies were also taken at these corresponding sites to assess intercellular space diameter using transmission electron microscopy (TEM) using standard techniques. Results 80% of patients were male with a mean age of 69 years. Mean follow since achieving CRIM was 30 months. 39 patients underwent RFA for dysplasia. The mean intercellular space diameter was higher in the neo-squamous epithelium (1.01 μm) when compared to the untreated native squamous epithelium (0.96 μm) [Difference of 0.056 μm, 95% CI of -0.036 to 0.148, P = 0.228]. The mean MI was significantly lower in the neosquamous epithelium (4001.3 Ω) when compared to the untreated native epithelium (5168.1 Ω) [Difference of 1166.7 Ω, 95% CI 418.8 to 1914.6, P = 0.003]. Conclusion Neo-squamous epithelium that replaces BE epithelium following successful endoscopic therapy for BE appears to be functionally and likely structurally deficient with regards to acid reflux barrier function, when compared to native squamous esophageal epithelium. This impairment may be associated with recurrence following successful ablation. Disclosure All authors have declared no conflicts of interest.

Feasibility and effectiveness of laparoscopic transgastric stapler-assisted circumferential esophageal mucosectomy and simultaneous fundoplication in a pig model.

Laparoscopic transgastric stapler-assisted mucosectomy (SAM) has been described for minimally invasive circumferential en bloc resection of Barrett's esophagus (BE). Conceivably long-term disease control might be achieved by adding antireflux surgery after resection of BE by SAM. The aim of this study was to assess the feasibility of combined SAM and fundoplication in one laparoscopic procedure in six pigs. Furthermore, the competence of the gastroesophageal junction (GEJ) was assessed at baseline, after SAM, and after subsequent laparoscopic fundoplication. At each measuring point reflux measurements were repeated 6 times in each pig. Blue-colored water was infused into the stomach to provoke reflux. Intragastric yield pressure and volume were recorded until drainage of blue solution (DBS) was noted. Time to reflux was measured by DBS and by multichannel intraluminal impedance (MII). In all animals SAM followed by laparoscopic fundoplication was feasible in a single session. A weakening of the GEJ was found after SAM, indicated by decreased yield pressure (11.5 mmHg vs. 8.5 mmHg; P<0.001), time to DBS (90 seconds vs. 60 seconds; P=0.008) and MII (80 seconds vs. 33 seconds; P<0.001). After additional Nissen fundoplication the GEJ competence was restored, with measurements returning to baseline values (time to DBS 99 seconds; P=0.15; MII 76 seconds; P=0.84). The yield pressure increased from 11.5 mmHg at baseline to 19.7 mmHg after SAM and fundoplication (P<0.001). Laparoscopic fundoplication and SAM may be combined in a single laparoscopic session. Although the GEJ was weakened after SAM, Nissen fundoplication restored the GEJ as an effective reflux barrier in this experiment. For clinical validation, the results need to be confirmed in a prospective human trial.

Pathophysiology and treatment of achalasia in a muscle mechanical perspective.

This review provides a biomechanical perspective on the pathophysiology and treatment of achalasia. The esophagus is efficient in transporting ingested material to the stomach in healthy subjects. A fine balance exists between the peristaltic forces generated in the esophageal body (which herein is defined as the preload) and the resistance in the outlet, the esophago-gastric junction (which is defined as the afterload). Achalasia is a rare esophageal disease that progressively over many years challenges esophageal efficacy. Clinical features and current literature are interpreted using well-known muscle mechanics models and terms from cardiac mechanophysiology. The preload, afterload, length-tension, and strain softening concepts in particular are useful for understanding the remodeling induced by achalasia. The concepts are also useful in understanding the treatment that aim to reduce the lower esophageal sphincter pressure that does not relax sufficiently in achalasia. These treatments cover endoscopic or laparoscopic myotomy, pneumatic balloon dilation, and Botox injections. In addition to the intended reduction of the afterload for aboral transport of ingested materials, the treatments tend to induce gastroesophageal reflux in some patients because they obliterate an important component in the reflux barrier.

Network of breathing. Multifunctional role of the diaphragm: a review.

The diaphragm is the primary muscle involved in active inspiration and serves also as an important anatomical landmark that separates the thoracic and abdominal cavity. However, the diaphragm muscle like other structures and organs in the human body has more than one function, and displays many anatomic links throughout the body, thereby forming a 'network of breathing'. Besides respiratory function, it is important for postural control as it stabilises the lumbar spine during loading tasks. It also plays a vital role in the vascular and lymphatic systems, as well as, is greatly involved in gastroesophageal functions such as swallowing, vomiting, and contributing to the gastroesophageal reflux barrier. In this paper we set out in detail the anatomy and embryology of the diaphragm and attempt to show it serves as both: an important exchange point of information, originating in different areas of the body, and a source of information in itself. The study also discusses all of its functions related to breathing.

Diagnosis and treatment of benign inflammatory esophageal diseases

Nowadays, benign inflammatory esophageal diseases represent a rising socioeconomic burden. Recently, novel therapeutic approaches have been introduced to enrich personalized surgical options. A PubMed research was conducted and merged with institutional guidelines and data. Magnetic sphincter augmentation strengthens the lower esophageal sphincter and therefore recreates the natural reflux barrier. Electrical sphincter stimulation offers the possibility to personalize minimal invasive treatment and considers even changing lifestyles. Endoscopic antireflux procedures try to mimic the outcome of laparoscopic fundoplication and aim to improve the angle of His. However, laparoscopic fundoplication remains the surgical treatment of choice in advanced reflux disease. Reflux can also cause eosinophilic infiltration and therefore hinders diagnosis of eosinophilic esophagitis. Once diagnosis is established, dietary modifications and topical steroids offer relevant relief. Reflux produces Barrett’s esophagus, a neoplastic progression, which is commonly treated with radiofrequency ablation. Novel therapeutic options are facing the rising incidence of benign inflammatory diseases.

Short-Term Outcomes Using Magnetic Sphincter Augmentation Versus Nissen Fundoplication for Medically Resistant Gastroesophageal Reflux Disease

In 2012 the United States Food and Drug Administration approved implantation of a magnetic sphincter to augment the native reflux barrier based on single-series data. We sought to compare our initial experience with magnetic sphincter augmentation (MSA) with laparoscopic Nissen fundoplication (LNF). A retrospective case-control study was performed of consecutive patients undergoing either procedure who had chronic gastrointestinal esophageal disease (GERD) and a hiatal hernia of less than 3 cm. Sixty-six patients underwent operations (34 MSA and 32 LNF). The groups were similar in reflux characteristics and hernia size. Operative time was longer for LNF (118 vs 73 min) and resulted in 1 return to the operating room and 1 readmission. Preoperative symptoms were abolished in both groups. At 6 months or longer postoperatively, scores on the Gastroesophageal Reflux Disease Health Related Quality of Life scale improved from 20.6 to 5.0 for MSA vs 22.8 to 5.1 for LNF. Postoperative DeMeester scores (14.2 vs 5.1, p=0.0001) and the percentage of time pH was less than 4 (4.6 vs 1.1; p=0.0001) were normalized in both groups but statistically different. MSA resulted in improved gassy and bloated feelings (1.32 vs 2.36; p=0.59) and enabled belching in 67% compared with none of the LNFs. MSA results in similar objective control of GERD, symptom resolution, and improved quality of life compared with LNF. MSA seems to restore a more physiologic sphincter that allows physiologic reflux, facilitates belching, and creates less bloating and flatulence. This device has the potential to allow individualized treatment of patients with GERD and increase the surgical treatment of GERD.

Esophagogastric Junction pressure morphology: comparison between a station pull‐through and real‐time 3D‐HRM representation

Esophagogastric junction (EGJ) competence is the fundamental defense against reflux making it of great clinical significance. However, characterizing EGJ competence with conventional manometric methodologies has been confounded by its anatomic and physiological complexity. Recent technological advances in miniaturization and electronics have led to the development of a novel device that may overcome these challenges. Nine volunteer subjects were studied with a novel 3D-HRM device providing 7.5mm axial and 45° radial pressure resolution within the EGJ. Real-time measurements were made at rest and compared to simulations of a conventional pull-through made with the same device. Moreover, 3D-HRM recordings were analyzed to differentiate contributing pressure signals within the EGJ attributable to lower esophageal sphincter (LES), diaphragm, and vasculature. 3D-HRM recordings suggested that sphincter length assessed by a pull-through method greatly exaggerated the estimate of LES length by failing to discriminate among circumferential contractile pressure and asymmetric extrinsic pressure signals attributable to diaphragmatic and vascular structures. Real-time 3D EGJ recordings found that the dominant constituents of EGJ pressure at rest were attributable to the diaphragm. 3D-HRM permits real-time recording of EGJ pressure morphology facilitating analysis of the EGJ constituents responsible for its function as a reflux barrier making it a promising tool in the study of GERD pathophysiology. The enhanced axial and radial recording resolution of the device should facilitate further studies to explore perturbations in the physiological constituents of EGJ pressure in health and disease.

The gastro‐esophageal reflux barrier: biophysical analysis on 3D models of anatomy from magnetic resonance imaging

The function and structure of the gastro-esophageal junction (GEJ) determine its efficacy as a reflux barrier. This study presents a novel methodology for the quantitative assessment of GEJ and proximal gastric morphology from magnetic resonance (MR) imaging. Based on this data we propose a new conceptualization of the hypothesis that a flap valve mechanism contributes to reflux protection. 3D models of the GEJ and proximal stomach were reconstructed from MR images in 12 healthy volunteers during respiration and on eating a test meal to maximum satiation. A rotating plane analysis measured the gastro-esophageal insertion angle and span of contact. An ellipsoid fit provided quantitative assessment of gastric shape and orientation relative to a fixed anatomical reference point. Position of the esophageal insertion on the 'gastric ellipse' was noted. An ellipsoid-cylinder model was designed to analyze the relationships among parameters describing the GEJ morphology. The insertion angle became more acute on expiration, but did not change with meal ingestion. In contrast the span of contact did not vary with respiration, but increased with gastric filling. Changes in gastric morphology with distension further augmented the span of gastro-esophageal contact in almost 70% of the studies. Novel MR imaging and biophysical analysis of the GEJ and proximal stomach provide a quantitative description of structures contributing to the reflux barrier. Changes in these parameters during respiration and on eating support the hypothesis that structural components of a functional 'flap valve' like mechanism contribute to reflux protection.

Postoperative Impedance–pH Testing is Unreliable After Nissen Fundoplication With or Without Giant Hiatal Hernia Repair

IntroductionCombined 24-h multichannel intralumenal impedance–pH monitoring (MII-pH) is gaining popularity as a diagnostic tool for gastroesophageal reflux. Since the surgical reduction of hiatal hernias and creation of a fundoplication anatomically restores the gastroesophageal reflux barrier, one would assume that it effectively stops all reflux regardless of composition. Our aim is to evaluate the results of routine MII-pH testing in successful Nissen fundoplication patients. Material and MethodsSixty-two patients with normal acid exposure, confirmed by 24-h pH testing, after Nissen fundoplication were evaluated with symptomatic questionnaire, esophageal manometry and MII-pH testing more than 6 months after surgery. Patients were grouped into normal and abnormal based on postoperative impedance results. Patients with Nissen alone were separately compared to patients with Nissen + giant hiatal hernia (GHH). ResultsTwenty-nine (47%) patients exhibited abnormal impedance after successful Nissen fundoplication. Abnormal impedance was associated with GHH repair, lower bolus pressures, and lower distal esophageal contraction amplitudes. ConclusionPostoperative testing with the standard MII-pH catheters using published normative values seems to be clinically irrelevant. Clinicians should analyze the results of routine MII-pH testing in the setting of a fundoplication critically as the current technology is associated with a high false positive rate.

Gastroesophageal Junction: Structure and Function as Assessed by Using MR Imaging

To develop and validate magnetic resonance (MR) imaging protocols for quantitative assessment of the structural and functional properties of the gastroesophageal junction (GEJ) and to compare MR imaging detection of reflux events against concurrent manometry as a reference method. The local ethics committee approved this study, and written informed consent was obtained. Twelve healthy volunteers were examined. Three-dimensional models of the GEJ and proximal portion of the stomach were reconstructed from high-spatial-resolution anatomic MR images to assess the insertion angle of the esophagus into the stomach and proximal stomach distention before and after ingestion of a large test meal. A linear mixed-effects model was used to detect differences in the insertion angle and proximal stomach distention with respect to the respiratory cycle and gastric filling. Additionally, dynamic MR imaging at high temporal resolution was used to detect reflux events. The esophageal insertion angle, given in units of plane angle (radians), was more acute in expiration than in inspiration (0.57 vs 0.73 radian, P = .004) but was not affected by feeding. Progressive distention of the proximal stomach was observed from baseline compared with the postprandial period (0.95 vs 0.65 radian(-1), P < .05). Eighteen reflux events detected by using MR imaging were also detected by using manometry. MR imaging methods were developed and validated for the assessment of GEJ structure and function (a) to describe the effects of respiration and feeding on the reflux barrier and (b) to detect reflux events in real time. Anatomic and dynamic MR imaging may be useful techniques in the assessment of GEJ physiology and reflux.

Endoscopic lower esophageal sphincter bulking for the treatment of GERD: safety evaluation of injectable polymethylmethacrylate microspheres in miniature swine

Endoscopic therapy for GERD is an appealing, minimally invasive alternative to medical treatment and surgery. Various materials have been tested to augment the lower esophageal sphincter (LES), with limited success. To our knowledge, safety and migration of polymethylmethacrylate (PMMA) microspheres has never been evaluated. To assess the safety, migration, inflammatory reaction, and durability of PMMA injected into the LES of miniature swine to create a reflux barrier. Animal study. Approved animal research facilities. Injection of the LES of miniature swine with PMMA. Histopathology of the injected site at certain intervals and postnecropsy microsphere counts of various organs. Minimal inflammatory reaction at the injection site, persistent bulking effect of the material, and no migration of microspheres. Injection of LES with PMMA caused a mild inflammatory reaction. The bulking effect of the injected material was persistent. Migration of microspheres was eliminated with the use of larger-sized microspheres. Animal model. Our phase I study documented that 40-microm polymethylmethacrylate microspheres are biocompatible and that PMMA microspheres are resistant to degradation when injected submucosally into the wall of the esophagus. The detection of 40-microm PMMA microspheres in local lymph nodes, liver, and lungs of some animals in the phase I study clearly documented transport of PMMA away from the injection site. This finding was eliminated by increasing the size of microspheres to 125 microm. The potential therapeutic effects of these larger microspheres for humans with GERD remains to be evaluated.