Two-year results of intermittent electrical stimulation of the lower esophageal sphincter treatment of gastroesophageal reflux disease

Pulmonary and esophageal function in lung transplantation: Fundamental principles and clinical application

The lungs and esophagus have a close anatomical and physiological relationship. Over the years, reflux-induced pulmonary injury has gained wider recognition, but the full effects of pulmonary disease on esophageal function are still unknown. Intrathoracic pressure dynamics potentially affect esophageal function, especially in patients with end-stage lung disease, both obstructive and restrictive. Lung transplantation is the only viable option for patients with end-stage pulmonary disease and has provided us with a unique opportunity to study these effects as transplantation restores the intrathoracic environment. Esophageal and foregut functional testing before and after transplantation provide insights into the pathophysiology of the foregut-pulmonary axis, such as how underlying pulmonary disease and intrathoracic pressure changes affect esophageal physiology. This review summarizes the available literature and shares the research experience of a lung transplant center, covering topics such as pre- and posttransplant foregut function, esophageal motility in lung transplant recipients, immune-mediated mechanisms of graft rejection associated with gastroesophageal reflux, and the role of antireflux surgery in this population.

Wirelessly powered deformable electronic stent for noninvasive electrical stimulation of lower esophageal sphincter

Electrical stimulation is a promising method to modulate gastrointestinal disorders. However, conventional stimulators need invasive implantation and removal surgeries associated with risks of infection and secondary injuries. Here, we report a battery-free and deformable electronic esophageal stent for wireless stimulation of the lower esophageal sphincter in a noninvasive fashion. The stent consists of an elastic receiver antenna infilled with liquid metal (eutectic gallium-indium), a superelastic nitinol stent skeleton, and a stretchable pulse generator that jointly enables 150% axial elongation and 50% radial compression for transoral delivery through the narrow esophagus. The compliant stent adaptive to the dynamic environment of the esophagus can wirelessly harvest energy through deep tissue. Continuous electrical stimulations delivered by the stent in vivo using pig models significantly increase the pressure of the lower esophageal sphincter. The electronic stent provides a noninvasive platform for bioelectronic therapies in the gastrointestinal tract without the need for open surgery.

Updates on Surgical Treatment for Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a common condition that is on the rise. Obesity is one risk factor that has increased in parallel with the rise of GERD. Typical symptoms include heartburn, regurgitation, dysphagia, cough, and chest pain. Patients with typical symptoms are empirically treated with proton pump inhibitors (PPIs). If the diagnosis is not clear, further evaluation is performed with endoscopy, pH monitoring, and esophageal manometry. Untreated GERD increases the risk of esophagitis, esophageal stricture, Barrett's esophagus, and esophageal adenocarcinoma. Treatment begins with lifestyle modification and medical therapy. If these fail, surgical and endoscopic surgical techniques are available, to provide treatment, symptom relief, and reduce long-term PPI use.

Effect of the transcutaneous electrical stimulation system on esophageal-acid exposure in patients non-responsive to once-daily proton-pump inhibitor: proof-of-concept study

Background

Gastroesophageal reflux disease (GERD) is a common disorder. Overall, ≤35% of GERD patients fail the standard dose of proton-pump-inhibitor (PPI) treatment. Due to the high prevalence and low satisfaction rate with treatment failure, there is an unmet need for new treatment. Our aim was to evaluate whether the use of the transcutaneous electrical stimulation system (TESS) can reduce esophageal-acid exposure in GERD patients unresponsive to standard-dose PPI.

Methods

We enrolled 10 patients suffering from heartburn and regurgitation with an abnormal esophageal-acid exposure (off PPIs) who failed standard-dose PPI. After the placement of a wireless esophageal pH capsule, all patients were treated with TESS. The primary end point was the reduction in the baseline (pretreatment) 24-hour percent total time pH <4 and/or DeMeester score by 50%.

Results

Seven GERD patients (five females and two males, aged 49.3 ± 10.1 years) completed the study. At baseline, the mean percent total time pH <4 was 12.0 ± 4.9. Following TESS, the mean percent total time pH <4 dropped to 5.5 ± 3.4, 4.5 ± 2.6, 3.7 ± 2.9, and 4.4 ± 2.5 on Days 1, 2, 3, and 4, respectively. At baseline, the mean DeMeester score was 39.0 ± 18.5. After TESS, the mean DeMeester score dropped to 15.8 ± 9.2, 13.2 ± 6.8, 11.2 ± 9.4, and 12.0 ± 6.8 on Days 1, 2, 3, and 4, respectively.

Conclusion

TESS is a safe and potentially effective modality in reducing esophageal-acid exposure in GERD patients unresponsive to standard-dose PPI. A larger and prospective controlled study is needed to verify these preliminary results.

Electrical stimulation therapy of the lower esophageal sphincter in GERD patients—a prospective single-center study

Background

Electrical stimulation therapy (EST) of the lower esophageal sphincter (LES) for gastro esophageal reflux disease (GERD) treatment increases LES pressure through chronic stimulation, with a low risk for gastrointestinal side effects and preservation of hiatal anatomy. The aim of this study was to evaluate the efficacy and safety of this novel technique in a high-output specialized reflux center.

Methods

This is a prospective single-center study including GERD patients indicated for anti-reflux therapy who consented to undergo LES-EST. Patients underwent prospective scheduled follow-up visits including interrogation of the stimulation device, clinical examination, and assessment of health-related quality of life (HRQL).

Results

Within a 4-year period, 37 LES-EST implantations were performed. The majority of patients were male (54.1%), mean BMI was 25.8 (SD 4.4), and mean age was 54.0 (SD 15.8). The median GERD HRQL composite score was 41 (IQR 21–49). Median total % of pH <4 was 10.1 (IQR 4.4–17.3). Six (16.2%) individuals underwent explantation of the entire system (IPG and leads) due to technical defect (n = 4) or failure of therapy (n = 2). HRQL score improved from 41 (IQR 21–49) to 8.50 (IQR 4.25–20.5, p < 0.001) and 9 (23.7%) patients were on at least occasional PPI treatment.

Conclusion

Due to the low rate of GI side effects and its minimal invasive character preserving the hiatal anatomy, this novel technique might find its place in anti-reflux surgery. However, the considerably high rate of device dysfunction needs further investigation.

Effect of electrical stimulation therapy of the lower esophageal sphincter in GERD patients with ineffective esophageal motility

BACKGROUND

Electrical stimulation therapy (EST) of the lower esophageal sphincter (LES) is a novel technique in antireflux surgery. Due to the minimal alteration at the LES during surgery, LES-EST is meant to be ideal for patients with gastroesophageal reflux disease (GERD) and ineffective esophageal motility (IEM). The aim of this prospective trial (NCT03476265) is to evaluate health-related quality of life and esophageal acid exposure after LES-EST in patients with GERD and IEM.

METHODS

This is a prospective non-randomized open-label study. Patients with GERD and IEM undergoing LES-EST were included. Follow-up (FUP) at 12 months after surgery included health-related quality of life (HRQL) assessment with standardized questionnaires (GERD-HRQL) and esophageal functional testing.

RESULTS

According to the study protocol, 17 patients fulfilled eligibility criteria. HRQL score for heartburn and regurgitation improved from 21 (interquartile range (IQR) 15-27) to 7.5 (1.25-19), p = 0.001 and from 17 (11-23.5) to 4 (0-12), p = 0.003, respectively. There was neither significant improvement of esophageal acid exposure nor reduction of number of reflux events in pH impedance measurement. Distal contractile integral improved from 64 (11.5-301) to 115 (IQR 10-363) mmHg s cm, p = 0.249. None of the patients showed any sign of dysphagia after LES-EST. One patient needed re-do surgery and re-implantation of the LES-EST due to breaking of the lead after one year.

CONCLUSION

Although patient satisfaction improved significantly after surgery, this study fails to demonstrate normalization or significant improvement of acid exposure in the distal esophagus after LES-EST.

State of Evidence in Minimally Invasive Management of Gastroesophageal Reflux: Findings of a Scoping Review

BACKGROUNDS & AIMS

Endoscopic management of gastroesophageal reflux disease (GERD) is being employed increasingly. The aim of this scoping review was to assess the volume of available evidence on the benefits of endoscopic and minimally invasive surgical therapies for GERD.

METHODS

criteria were used to perform an extensive literature search of data regarding the reported benefit of endoscopic therapies in GERD. Randomized controlled studies were utilized when available; however, data from observational studies were also reviewed.

RESULTS

A formal review of evidence was performed in 22 studies. Inclusion and exclusion criteria and study duration were noted and tabulated. Assessment of outcomes was based on symptoms and objective criteria reported by investigators. Reported outcomes for the interventions were tabulated under the heading of subjective (symptom scores, quality of life metrics, and change in proton pump inhibitor use) and objective metrics (pH parameters, endoscopic signs, and lower esophageal sphincter pressure changes). Adverse events were noted and tabulated. The majority of studies showed symptomatic and objective improvement of GERD with the device therapies. Adverse events were minimal. However, normalization of acid exposure occurred in about 50% of patients and, for some modalities, long-term durability is uncertain.

CONCLUSIONS

This scoping review revealed that the endoluminal and minimally invasive surgical devices for GERD therapy are a promising alternative to proton pump inhibitor therapy. Their place in the treatment algorithm for GERD will be better defined when important clinical parameters, especially durability of effect, are better understood.

Endoscopic and Surgical Treatments for Achalasia: Who to Treat and How?

Achalasia is a progressive neurodegenerative disorder characterized by failure of relaxation of the lower esophageal sphincter (LES) and altered motility of the esophagus. The traditional, highly effective, surgical approach to relieve obstruction at the LES includes cardiomyotomy. Fundoplication is added to decrease risk of postoperative reflux. Per oral endoscopic myotomy is a new endoscopic procedure that allows division of the LES via transoral route. It has several advantages including less invasiveness, cosmesis, and tailored approach to the length on the myotomy. However, it is associated with increased rate of post-procedural reflux. Various endoscopic interventions are used to address this problem.

[Current aspects of surgical treatment of gastro-esophageal reflux disease]

Gastroesophageal reflux disease (GERD) is characterized by abnormal reflux of gastric content into the esophagus, pharynx, respiratory tract and oral cavity. In recent years, there has been a significant increase of the incidence of this disease, that significantly aggravates quality of life of the population. The 'gold standard' for treating GERD is anti-secretory therapy with proton pump inhibitors (PPIs). However, up to 40% of patients are unresponsive to PPIs even after dose adjustment. Advantages and disadvantages of modern surgical approaches for this pathology are reviewed. Laparoscopic fundoplication including Nissen (360°), Toupet (270°) and Dor procedures (180°) is the most common anti-reflux operation. In addition, new alternative surgical options are also discussed. For example, these are minimally invasive methods such as LINX reflux control system, electrical stimulation of the lower esophageal sphincter and transoral incisionless fundoplication (TIF). These methods are less aggressive and have less side effects. A comparative assessment of modern methods of surgical treatment of GERD is made.

Tailored modern GERD therapy - steps towards the development of an aid to guide personalized anti-reflux surgery

As the incidence of gastroesophageal reflux disease (GERD) is rising, surgical treatment is continuously advancing in an effort to minimize side effects, whilst maintaining efficacy. From a database of patients that underwent anti-reflux surgery at our institution between 2015 and 2018, the last 25 consecutive patients that underwent electrical stimulation (ES), magnetic sphincter augmentation (MSA) and Nissen fundoplication (NF), following a personalized treatment decision aid, were included in a comparative analysis. After preoperative evaluation each patient was referred for an ES, MSA or NF based on esophageal motility, hiatal hernia (HH) size and the patients’ preferences. Postoperative gastrointestinal symptoms and GERD-Health-related-Quality-of-Life were assessed. Preoperatively the median DCI (299 ES vs. 1523.5 MSA vs. 1132 NF, p = 0.001), HH size (0.5 cm ES vs. 1 cm MSA vs. 2 cm NF, p = 0.001) and presence of GERD-related symptoms differed significantly between the groups. The highest rate of postoperative dysphagia was seen after MSA (24%, p = 0.04), while the median GERD HRQL total score was equally distributed between the groups. The positive short-term postoperative outcome and patient satisfaction indicate that such an aid in treatment indication, based on esophageal motility, HH size and patient preference, represents a feasible tool for an ideal choice of operation and an individualized therapy approach.

Use of Bioelectronics in the Gastrointestinal Tract

Gastrointestinal (GI) motility disorders are major contributing factors to functional GI diseases that account for >40% of patients seen in gastroenterology clinics and affect >20% of the general population. The autonomic and enteric nervous systems and the muscles within the luminal GI tract have key roles in motility. In health, this complex integrated system works seamlessly to transport liquid, solid, and gas through the GI tract. However, major and minor motility disorders occur when these systems fail. Common functional GI motility disorders include dysphagia, gastroesophageal reflux disease, functional dyspepsia, gastroparesis, chronic intestinal pseudo-obstruction, postoperative ileus, irritable bowel syndrome, functional diarrhea, functional constipation, and fecal incontinence. Although still in its infancy, bioelectronic therapy in the GI tract holds great promise through the targeted stimulation of nerves and muscles.

A Wireless Implantable System for Facilitating Gastrointestinal Motility

Gastrointestinal (GI) electrical stimulation has been shown in several studies to be a potential treatment option for GI motility disorders. Despite the promising preliminary research progress, however, its clinical applicability and usability are still unknown and limited due to the lack of a miniaturized versatile implantable stimulator supporting the investigation of effective stimulation patterns for facilitating GI dysmotility. In this paper, we present a wireless implantable GI modulation system to fill this technology gap. The system consists of a wireless extraluminal gastrointestinal modulation device (EGMD) performing GI electrical stimulation, and a rendezvous device (RD) and a custom-made graphical user interface (GUI) outside the body to wirelessly power and configure the EGMD to provide the desired stimuli for modulating GI smooth muscle activities. The system prototype was validated in bench-top and in vivo tests. The GI modulation system demonstrated its potential for facilitating intestinal transit in the preliminary in vivo chronic study using porcine models.

Colonic electrical stimulation improves colonic transit in rotenone-induced Parkinson's disease model through affecting enteric neurons

AIMS

The aims of this study were to investigate the effect of colonic electrical stimulation (CES) on delayed colonic transit in Parkinson's disease (PD) model induced by rotenone and its possible mechanisms.

MAIN METHODS

Sprague-Dawley male rats were implanted with a pair of electrodes on the serosa at the proximal colon and rotenone was subcutaneously injected for 6 weeks to induce the PD model. Behavior activity, stool volume and open-field test were recorded during the injection. Colonic propulsion rate was measured 6 weeks after rotenone injection. Colon samples of all rats were collected for the measurement of phosphorylated alpha-synuclein, choline acetyltransferase (CHAT), neuronal nitric oxide synthase (nNOS), and tyrosine hydroxylase (TH). The protocols of control rats were the same as the PD rats except that no electrodes were implanted and no rotenone was injected.

KEY FINDINGS

(1) Rotenone-induced PD rats demonstrated weight loss, significant decrease of the dopaminergic neurons in substantia nigra, and impairment of colon movement. (2) CES significantly accelerated the delayed colonic transmit (91.67 ± 5.58% vs 51.33 ± 4.18%), superior to Macrogol-4000. (3) CES significantly upregulated the expression of CHAT, nNOS and TH protein in colon of PD rats. (4) In colon of PD rats, the phosphorylated alpha-synuclein was significantly upregulated, but CES had no significant effect on phosphorylated alpha-synuclein.

SIGNIFICANCE

Our data show that CES can normalize the delayed colonic transit and this normalization may attribute to affecting enteric excitatory and inhibitory neurons.

Wirelessly Powered Endoscopically Implantable Devices into the Submucosa as the Possible Treatment of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a rather common disease with a prevalence reaching up to 10 or 20% in the western world. The most specific symptoms which point to the diagnosis of GERD are feelings of heartburn and the regurgitation of acidic stomach contents into the esophagus. However, a certain number of patients do not respond to standard therapy, and in these cases, it is necessary to resort to other treatment methods, such as laparoscopic fundoplication or electrostimulation of the lower esophageal sphincter. The aim of our work was to design and manufacture a miniature, battery-less stimulator to provide electric stimulation of the lower esophageal sphincter, which could be implanted deep into the submucosa of the distal esophagus. The main goal was to provide a battery-less system as opposed to traditional battery neurostimulators to reduce the size and weight of the device. An electronic prototype of a wirelessly powered implantable device was developed. We used animal models for the experiments. The device is designed to treat GERD via electrical stimulation of the muscularis propria. It is implanted into the submucosal pocket by the lower esophageal sphincter with an endoscope. This method of implantation is superior to esophageal stimulators used today because of very low invasiveness of the surgery. Bipolar neurostimulation via two gold-plated leads is provided. The device does not have any source of energy; it is powered wirelessly which reduces the risk of potential battery leakage and reduces the overall dimensions.

Autonomous and Rechargeable Microneurostimulator Endoscopically Implantable into the Submucosa

Gastric dysmotility can be a sign of common diseases such as longstanding diabetes mellitus. It is known that the application of high-frequency low-energetic stimulation can help to effectively moderate and alleviate the symptoms of gastric dysmotility. The goal of the research was the development of a miniature, endoscopically implantable device to a submucosal pocket. The implantable device is a fully customized electronic package which was specifically designed for the purpose of experiments in the submucosa. The device is equipped with a lithium-ion battery which can be recharged wirelessly by receiving an incident magnetic field from the charging/transmitting coil. The uplink communication is achieved in a MedRadio band at 432 MHz. The device was endoscopically inserted into the submucosal pocket of a live domestic pig used as an in vivo model, specifically in the stomach antrum. The experiment confirmed that the designed device can be implanted into the submucosa and is capable of bidirectional communication. The device can perform bipolar stimulation of muscle tissue.

Comparison of the outcome of laparoscopic procedures for GERD

A total laparoscopic fundoplication has become the procedure of choice for the surgical treatment of gastroesophageal reflux disease in patients with normal esophageal motility, with reduced postoperative pain, faster recovery and similar long-term outcomes compared to conventional open total fundoplication. Most controversial surgical aspects are the division of the short gastric vessels and the insertion of a bougie to calibrate the wrap. The anterior 180° and the posterior partial fundoplications lead to similar control of heartburn when compared to total fundoplication with lower risk of dysphagia. However, when performed, 24-h pH monitoring shows pathologic reflux more frequently after partial than total fundoplication. Disappointing results are achieved by anterior 90° partial fundoplication. More recently, a magnetic sphincter augmentation with the LINX Reflux Management System (Torax Medical) and the lower esophageal sphincter Electrical Stimulation (EndoStim) have been developed, seeking for a durable and effective minimally invasive alternative to laparoscopic fundoplication for the treatment of reflux. Both devices seem to be promising, with very low postoperative complications and good short-term functional outcomes. Large randomized controlled trials comparing them with laparoscopic fundoplication over a long period of follow-up are needed to verify their indications and outcomes.

Medical Therapy of Gastroesophageal Reflux Disease Beyond Proton Pump Inhibitors: Where Are We Heading?

Proton pump inhibitors (PPI) have greatly improved the treatment of gastroesophageal reflux disease. However, recent investigations have revealed that reflux symptoms persist in a substantial number of patients. Therefore, treatment strategies beyond PPI are urgently required. One such strategy may involve more reliable acid suppression, e.g., with new acid inhibitory drugs. Furthermore, the rapid appearance of an acidic compartment in the proximal stomach after a meal, which is largely responsible for postprandial heartburn, requires a specific kind of therapy in addition to PPI which still needs to be established. Pharmacological augmentation of the lower esophageal sphincter may represent another approach to diminish reflux, but the clinical efficacy of compounds tested so far is limited. Altered e-sophageal perception represents a major component involved in the generation of reflux symptoms, particularly in non-erosive reflux disease, but effective pharmacological intervention is largely lacking. Presumed reflux-induced respiratory symptoms (cough, laryngitis, etc.) in the absence of typical esophageal symptoms (e.g., heartburn) remain a hot topic, but recent research points towards a hypersensitivity syndrome and only a minor role of gastroesophageal reflux. Treatment options for this condition are still pending.

Novel Surgical Treatments for Gastroesophageal Reflux Disease: Systematic Review of Magnetic Sphincter Augmentation and Electric Stimulation Therapy

Electric stimulation therapy (EST) and magnetic sphincter augmentation (MSA) represent novel methods for the surgical treatment of gastroesophageal reflux disease (GERD). The aim of this review was to assess the effectiveness and safety of EST and magnetic sphincter augmentation device (MSAD) comapred to laparoscopic fundoplication (LF) and proton pump inhibitor therapy (in case of EST). We performed a systematic literature search without restrictions on publication dates in five electronic databases (MEDLINE, EMBASE, the Cochrane library, PubMed, and Centre for Reviews and Dissemination), complemented by hand search, search in trial registries, and documentation provided by the manufacturers. No study passed inclusion criteria for analyzing EST effectiveness. Concerning safety, lead erosion through the esophagus and trocar perforation of the small bowel occurred in 2.4% of patients (in one study). Only the registry study fulfilled inclusion criteria for effectiveness analysis of MSAD. The crucial outcome of GERD-health-related quality of life (HRQL) score improved from 20 to 3 points in MSAD patients, and from 23 to 3.5 points in LF patients. However, the LF patients were in a more severe stage of the disease. The results yield indefinite conclusions about the use of both MSAD and EST. Clinical effectiveness and safety of both MSAD and EST are not sufficiently proven and are yet to be supported by high quality evidence from randomized controlled trials.

Electrical Stimulation of the Lower Esophageal Sphincter to Treat Gastroesophageal Reflux After POEM

As per-oral endoscopic myotomy (POEM) is not followed by any anti-reflux procedure, a common concern is the risk of postoperative gastro-esophageal reflux disease (GERD). Electrical stimulation of the lower esophageal sphincter (LES-EST) could be an option for post-POEM GERD. A 68-year old male obese patient underwent successful POEM but developed GERD not responsive to proton pump inhibitors. Consecutively, the patient had implanted an electrical LES stimulation device, consisting of bipolar LES-electrodes connected to a subcutaneous pulse generator. POEM reduced the Eckardt score (9 vs. 0), the LES resting pressure (52.0 vs. 16.4 mmHg), and the Integrated Relaxation Pressure (62.0 vs. 10.0 mmHg). LES-EST substantially reduced post-POEM GERD symptoms. GERD-HRQL scores indicated the elimination of heartburn (26 vs. 7) and regurgitation (24 vs. 3) at three months. A reduced total number refluxes (82 vs. 14) was observed. The %-time of pH below 4 was only slightly reduced (8.6% to 6.2%).LES-EST appears to be a feasible option to symptomatically treat post-POEM GERD for patients not ideal for conventional anti-reflux surgery.

Proton pump inhibitor-refractory gastroesophageal reflux disease: challenges and solutions

A significant percentage of patients with gastroesophageal reflux disease (GERD) will not respond to proton pump inhibitor (PPI) therapy. The causes of PPI-refractory GERD are numerous and diverse, and include adherence, persistent acid, functional disorders, nonacid reflux, and PPI bioavailability. The evaluation should start with a symptom assessment and may progress to imaging, endoscopy, and monitoring of esophageal pH, impedance, and bilirubin. There are a variety of pharmacologic and procedural interventions that should be selected based on the underlying mechanism of PPI failure. Pharmacologic treatments can include antacids, prokinetics, alginates, bile acid binders, reflux inhibitors, and antidepressants. Procedural options include laparoscopic fundoplication and LINX as well as endoscopic procedures, such as transoral incisionless fundoplication and Stretta. Several alternative and complementary treatments of possible benefit also exist.

A Wireless Implant for Gastrointestinal Motility Disorders

Implantable functional electrical stimulation (IFES) has demonstrated its effectiveness as an alternative treatment option for diseases incurable pharmaceutically (e.g., retinal prosthesis, cochlear implant, spinal cord implant for pain relief). However, the development of IFES for gastrointestinal (GI) tract modulation is still limited due to the poorly understood GI neural network (gut⁻brain axis) and the fundamental difference among activating/monitoring smooth muscles, skeletal muscles and neurons. This inevitably imposes different design specifications for GI implants. This paper thus addresses the design requirements for an implant to treat GI dysmotility and presents a miniaturized wireless implant capable of modulating and recording GI motility. This implant incorporates a custom-made system-on-a-chip (SoC) and a heterogeneous system-in-a-package (SiP) for device miniaturization and integration. An in vivo experiment using both rodent and porcine models is further conducted to validate the effectiveness of the implant.

Surgical Anti-Reflux Options Beyond Fundoplication

PURPOSE OF REVIEW

This paper provides an overview of current and future surgical interventions available for the management of gastroesophageal reflux disease (GERD) beyond the well established and recognized fundoplication. Review the current indications and outcomes of these surgical procedures.

RECENT FINDINGS

Fundoplication has been a cornerstone of the surgical management of GERD. However, other effective surgical options exist and can be considered based on prior interventions as well as patient, anatomical or other factors. These options are intended to address some of the shortcomings or potential complications of fundoplication such as symptom recurrence, dysphagia, or gas bloating, for example. Alternative procedures to fundoplication include magnetic sphincter augmentation, electrical stimulation and Roux-en-Y gastric bypass. The indication for surgical management remains failure of or inability to tolerate medical therapy.

System design and experimental research of lower esophageal sphincter stimulator for treatment of gastroesophageal reflux disease

Electrical stimulation therapy (EST) of lower esophageal sphincters (LES) is a new technique for the treatment of gastroesophageal reflux disease (GERD). In this paper, an implantable LES stimulator with wireless power transmission is proposed for the treatment of GERD. The LES stimulator is composed of an implantable pulse generator (IPG), an external controller, and a wireless power transmission module. The IPG, whose area is 31×21 mm², is designed to generate voltage-regulated constant-current stimulation pulses. The external controller allows for wireless programming of the IPG via a Bluetooth Low Energy (BLE) module. The wireless power transmission module provides power for the IPG. According to the measurement of output stimulus waveforms, the proposed LES stimulator is capable of delivering electrical stimulations with a current ranging between 0 and 8 mA. To evaluate the safety and efficacy of the proposed LES stimulator, experiments were performed on 12 male New Zealand white rabbits. Esophageal manometry was performed before and after the procedure and the LES pressure (LESP) has been recorded. The mean LESP is increased significantly in the stimulation group than the sham group (stimulation group: 9.25±1.24 mmHg vs 13.99 ±1.28 mmHg, p<;0.05; sham group: 9.00±1.22 mmHg vs 9.23±1.27 mmHg, p=0.267). The results show that the electrical stimulation delivered by the LES stimulator can safely and effectively increase resting LES pressure in acute animal models, suggesting that the implantable LES stimulator is a perspective approach for treating GERD in clinics.

Electrical therapies for gastrointestinal motility disorders

Gastrointestinal (GI) motility disorders are common in clinical settings, including esophageal motility disorders, gastroesophageal reflux disease, functional dyspepsia, gastroparesis, chronic intestinal pseudo-obstruction, post-operative ileus, irritable bowel syndrome, diarrhea and constipation. While a number of drugs have been developed for treating GI motility disorders, few are currently available. Emerging electrical stimulation methods may provide new treatment options for these GI motility disorders. Areas covered: This review gives an overview of electrical therapies that have been, and are being developed for GI motility disorders, including gastroesophageal reflux, functional dyspepsia, gastroparesis, intestinal motility disorders and constipation. Various methods of gastrointestinal electrical stimulation are introduced. A few methods of nerve stimulation have also been described, including spinal cord stimulation and sacral nerve stimulation. Potentials of electrical therapies for obesity are also discussed. PubMed was searched using keywords and their combinations: electrical stimulation, spinal cord stimulation, sacral nerve stimulation, gastrointestinal motility and functional gastrointestinal diseases. Expert commentary: Electrical stimulation is an area of great interest and has potential for treating GI motility disorders. However, further development in technologies (devices suitable for GI stimulation) and extensive clinical research are needed to advance the field and bring electrical therapies to bedside.

Laparoscopic alternatives to fundoplication for gastroesophageal reflux: the role of magnetic augmentation and electrical stimulation of the lower esophageal sphincter

Reflux symptoms are very common, and despite modern medication they are a major cause of disease burden and loss of quality of life worldwide. Laparoscopic anti-reflux surgery is the only current effective alternative but suffers from the risks of long-term side effects. Surgery also suffers variation in standards and outcomes. Magnetic augmentation and electrical stimulation of the lower esophageal sphincter represent promising innovative procedures in the field.

The virtual esophagus: investigating esophageal functions in silico

Esophageal and gastroesophageal junction (GEJ) diseases are highly prevalent worldwide and are a significant socioeconomic burden. Recently, applications of multiscale mathematical models of the upper gastrointestinal tract have gained attention. These in silico investigations can contribute to the development of a virtual esophagus modeling framework as part of the larger GIome and Physiome initiatives. There are also other modeling investigations that have potential screening and treatment applications. These models incorporate detailed anatomical models of the esophagus and GEJ, tissue biomechanical properties and bolus transport, sensory properties, and, potentially, bioelectrical models of the neural and myogenic pathways of esophageal and GEJ functions. A next step is to improve the integration between the different components of the virtual esophagus, encoding standards, and simulation environments to perform more realistic simulations of normal and pathophysiological functions. Ultimately, the models will be validated and will provide predictive evaluations of the effects of novel endoscopic, surgical, and pharmaceutical treatment options and will facilitate the clinical translation of these treatments.

Diagnosis and treatment of gastroesophageal reflux disease: recommendations of the Asociación Mexicana de Gastroenterología

Emerging concepts in the pathophysiology of gastroesophageal reflux disease (GERD) and the constant technologic advances in the diagnosis and treatment of this clinical condition make it necessary to frequently review and update the clinical guidelines, recommendations, and official statements from the leading academic groups worldwide. The Asociación Mexicana de Gastroenterología (AMG), aware of this responsibility, brought together national experts in this field to analyze the most recent scientific evidence and formulate a series of practical recommendations to guide and facilitate the diagnostic process and efficacious treatment of these patients. The document includes algorithms, figures, and tables for convenient consultation, along with opinions on GERD management in sensitive populations, such as pregnant women and older adults.

How can we deal with the GERD treatment gap?

Patients experiencing heartburn and acid regurgitation despite proton pump inhibition therapy who are averse to antireflux surgery fall into what is called the gastroesophageal reflux disease (GERD) treatment gap. This gap may be potentially addressed by several endoscopic and laparoscopic techniques, including gastric bypass surgery for those patients who are obese. These novel techniques do not significantly alter the anatomy of the esophagogastric junction, minimizing short- and long-term adverse effects. This review provides an overview of the assessment of patients with refractory GERD and highlights the strengths and weaknesses of these minimally invasive therapies.

Electrical stimulation therapy of the lower esophageal sphincter is successful in treating GERD: long-term 3-year results

BACKGROUND

Electrical stimulation of the lower esophageal sphincter (LES) has been shown to improve outcomes in patients with gastroesophageal reflux disease (GERD) at 2 years. The aim of the study was to evaluate the safety and efficacy of LES stimulation in the same cohort at 3 years.

METHODS

GERD patients with partial response to PPI, with % 24-h esophageal pH < 4.0 for >5 %, with hiatal hernia <3 cm and with esophagitis ≤LA grade C were treated with LES stimulation in an open-label 2-year trial. All patients were on fixed stimulation parameter of 20 Hz, 220 μs, 5 mA delivered in twelve, 30-min sessions. After completing the 2-year open-label study, they were offered enrollment into a multicenter registry trial and were evaluated using GERD-HRQL, symptom diaries and pH testing at their 3-year follow-up.

RESULTS

Fifteen patients completed their 3-year evaluation [mean (SD) age = 56.1 (9.7) years; men = 8] on LES stimulation. At 3 years, there was a significant improvement in their median (IQR) GERD-HRQL on electrical stimulation compared to both their on PPI [9 (6-10) vs. 1 (0-2), p = 0.001] and off PPI [22 (21-24) vs. 1 (0-2), p < 0.001]. Median 24-h distal esophageal acid exposure was significantly reduced from [10.3 (7.5-11.6) % at baseline vs. 3 (1.9-4.5) %, p < 0.001] at 3 years. Seventy-three % (11/15) patients had normalized their distal esophageal acid exposure at 3 years. Remaining four patients had improved their distal esophageal acid exposure by 39-48 % from baseline. All but four patients reported cessation of regular PPI use (>50 % of days with PPI use); three had normal esophageal pH at 3 years. There were no unanticipated device- or stimulation-related adverse events or untoward sensation reported during the 2- to 3-year follow-up.

CONCLUSION

LES-EST is safe and effective for treating patients with GERD over long-term, 3-year duration. There was a significant and sustained improvement in esophageal acid exposure and reduction in GERD symptoms and PPI use. Further, no new GI side effects or adverse events were reported.

Some Non-FDA Approved Uses for Neuromodulation in Treating Autonomic Nervous System Disorders: A Discussion of the Preliminary Support

INTRODUCTION

Neuromodulation, including cavernous nerve stimulation, gastric electrical stimulation, deep brain stimulation, and vagus nerve stimulation, has been used with success in treating several functional disease conditions. The FDA has approved the use of neuromodulation for a few indications. We discuss in our review article the evidence of using neuromodulation for treating some important disorders involving the autonomic nervous system that are not currently FDA approved.

METHODS

This was a review article that included a systematic online web search for human clinical studies testing the efficacy of neuromodulation in treating erectile dysfunction, gastroparesis, gastroesophageal reflux disease, obesity, asthma, and heart failure. Our review includes all feasibility studies, nonrandomized clinical trials, and randomized controlled trials.

RESULTS

Our systematic literature search found 3, 4, 5, 4, 1, and 4 clinical studies relating to erectile dysfunction, gastroparesis, gastroesophageal reflux disease, obesity, asthma, and heart failure, respectively.

CONCLUSION

This review article shows preliminary support based on clinical studies that neuromodulation can be of benefit for patients with important autonomic nervous system disease conditions that are not currently approved by the FDA. All of these investigational uses are encouraging; further studies are necessary and warranted for all indications discussed in this review before achieving FDA approval.

[Insufficient symptom control under long-term treatment with PPI in GERD - fact or fiction?]

BACKGROUND

Randomized controlled trials show that patients with gastroesophageal reflux disease (GERD) and treatment with proton pump inhibitors (PPI) in about 30% of the cases complain about persisting reflux symptoms (heartburn, regurgitation). The aim of the study was to evaluate the efficacy of PPI long-term treatment in patients with GERD in the family doctor's office.

METHOD

Patients with GERD and a PPI therapy of at least one year participated in a prospective, multicenter observational study. The patients obtained a questionnaire together with a further prescription of PPI. They were asked about the intensity and frequency of heartburn, regurgitation and sleep disorders due to reflux symptoms, satisfaction with PPI therapy, diagnostics performed up to now (endoscopy, pH monitoring, manometry) and surgical consultation. The questionnaire included a validated instrument for the diagnosis of GERD (GerdQ). Patients with the diagnosis "GERD " according to the questionnaire who were very dissatisfied with their current PPI therapy (score 1 or 2 on a 5-point Likert scale) were defined as "lost patients " (LOPA).

RESULTS

39% of the patients still suffered from heartburn at least two days a week, 30% of regurgitation. In 22% of the patients, reflux symptoms led to sleep disorder at least two days a week. 20% of the patients were very dissatisfied with the current PPI therapy. 70% of them (= 14% of the total patient population) were "lost patients " according to the definition. An endoscopy was performed in 86% of the patients and function diagnosis (pH monitoring ± manometry) in 8%. A surgeon was consulted in 8% of the patients, a third of which had received function diagnosis before.

CONCLUSIONS

A poor symptom control can often be found in GERD patients with PPI long-term therapy, but does not stand out in the daily routine. So diagnosis will not continue and treatment alternatives will not be searched for. In the future quality of treatment should be verified e. g. by questionnaires.

Management of refractory typical GERD symptoms

The management of patients with refractory GERD (rGERD) is a major clinical challenge for gastroenterologists. In up to 30% of patients with typical GERD symptoms (heartburn and/or regurgitation), acid-suppressive therapy does not provide clinical benefit. In this Review, we discuss the current management algorithm for GERD and the features and management of patients who do not respond to treatment (such as those individuals with an incorrect diagnosis of GERD, inadequate PPI intake, persisting acid reflux and persisting weakly acidic reflux). Symptom response to existing surgical techniques, novel antireflux procedures, and the value of add-on medical therapies (including prokinetics and reflux inhibitors) for rGERD symptoms are discussed. Pharmaceutical agents targeting oesophageal sensitivity, a condition that can contribute to symptom generation in rGERD, are also discussed. Finally, on the basis of available published data and our expert opinion, we present an outline of a current, usable algorithm for management of patients with rGERD that considers the timing and diagnostic use of pH-impedance monitoring on or off PPI, additional diagnostic tests, the clinical use of baclofen and the use of add-on neuromodulators (tricyclic agents and selective serotonin reuptake inhibitors).

Effect of electrical stimulation of the lower esophageal sphincter in gastroesophageal reflux disease patients refractory to proton pump inhibitors

AIM: To evaluate the efficacy of lower esophageal sphincter (LES)-electrical stimulation therapy (EST) in a subgroup of patients that reported only partial response to proton pump inhibitors (PPIs) therapy, compared to a group of patient with complete response.

METHODS: Bipolar stitch electrodes were laparoscopically placed in the LES and connected to an implantable pulse generator (EndoStim BV, the Hague, the Netherlands), placed subcutaneously in the anterior abdominal wall. Stimulation at 20 Hz, 215 μsec, 3-8 mAmp in 30 min sessions was delivered starting on day 1 post-implant. Patients were evaluated using gastroesophageal reflux disease (GERD)-HRQL, symptom diaries; esophageal pH and esophageal manometry before and up to 24 mo after therapy and results were compared between partial and complete responders.

RESULTS: Twenty-three patients with GERD on LES-EST were enrolled and received continuous per-protocol stimulation through 12 mo and 21 patients completed 24 mo of therapy. Of the 23 patients, 16 (8 male, mean age 52.1 ± 12 years) had incomplete response to PPIs prior to LES-EST, while 7 patients (5 male, mean age 52.7 ± 4.7) had complete response to PPIs. In the sub-group with incomplete response to PPIs, median (IQR) composite GERD-HRQL score improved significantly from 9.5 (9.0-10.0) at baseline on-PPI and 24.0 (20.8-26.3) at baseline off-PPI to 2.5 (0.0-4.0) at 12-mo and 0.0 (0.0-2.5) at 24-mo follow-up (P < 0.05 compared to on-and off-PPI at baseline). Median (IQR) % 24-h esophageal pH < 4.0 at baseline in this sub-group improved significantly from 9.8% (7.8-11.5) at baseline to 3.0% (1.9-6.3) at 12 mo (P < 0.001) and 4.6% (2.0-5.8) at 24 mo follow-up (P < 0.01). At their 24-mo follow-up, 9/11 patients in this sub-group were completely free of PPI use. These results were comparable to the sub-group that reported complete response to PPI therapy at baseline. No unanticipated implantation or stimulation-related adverse events, or any untoward sensation due to stimulation were reported in either group and LES-EST was safely tolerated by both groups.

CONCLUSION: LES-EST is safe and effective in controlling symptoms and esophageal acid exposure in GERD patients with incomplete response to PPIs. These results were comparable to those observed PPI responders.

Electrical stimulation for gastroesophageal reflux disease: current state of the art

Patients with gastroesophageal reflux disease (GERD) who are not satisfied with acid suppression therapy can benefit primarily from fundoplication, a surgical intervention. Fundoplication has been the standard surgical procedure for GERD. It is effective but is associated with adverse effects, resulting in a declining number of interventions, creating a need for alternative interventions that are effective, yet have a better adverse effect profile. One such alternative involves the application of electrical stimulation to the lower esophageal sphincter. A number of animal studies showed that such stimulation can increase resting lower esophageal sphincter pressure. An acute human study confirmed this effect, and was followed by two open-label studies, with a follow-up of up to 3 years. Results thus far show that the therapy is associated with a significant improvement in symptoms, a significant reduction in esophageal acid exposure, and a very good safety profile. This review will describe the evolution of electrical stimulation therapy for GERD, as well as the safety and efficacy of this intervention.

Electrical stimulation therapy of the lower oesophageal sphincter for refractory gastro-oesophageal reflux disease - interim results of an international multicentre trial

BACKGROUND

A previous single-centre study showed that lower oesophageal sphincter electrical stimulation therapy (LES-EST) in gastro-oesophageal reflux disease (GERD) patients improves reflux symptoms and decreases oesophageal acid exposure.

AIM

To evaluate safety and efficacy of LES-EST in GERD patients with incomplete response to proton pump inhibitors (PPIs) in a prospective, international, multicentre, open-label study.

METHODS

GERD patients, partially responsive to PPIs, received LES-EST. GERD health-related quality of life (GERD-HRQL), daily symptom diaries, quality of life scores, oesophageal acid exposure, and LES resting and residual pressure were measured before and after initiation of LES-EST. Stimulation sessions were optimised based on residual symptoms and oesophageal acid exposure.

RESULTS

Forty-four patients were enrolled and 6-month data from 41 patients are available. Hiatal repair was performed in 16 patients. One device-related, one procedure-related and one unrelated severe adverse event were reported. GERD-HRQL improved from 31.0 (IQR 26.2-36.8) off-PPI and 16.5 (IQR 9.0-22.8) on-PPI to 4 (IQR 1-8) at 3-month and 5 (IQR 3-9) at 6-month follow-up (P < 0.0001 vs. on- and off-PPI). Oesophageal acid exposure (pH < 4.0) improved from 10.0% (IQR 7.5-12.9) to 3.8% (IQR 1.9-12.3) at 3 months (P = 0.0027) and 4.4% (IQR 2.2-7.2) at 6 months (P < 0.0001).

CONCLUSIONS

These interim results show an acceptable safety record of LES-EST to date, combined with good short-term efficacy in GERD patients who are partially responsive to PPI therapy. A remarkable reduction in regurgitation symptoms, without the risk of intervention-requiring dysphagia may prove to be an advantage compared with other anti-reflux procedures. ClinicalTrials.gov Identifier: NCT01574339.