Gastric pacing is a new surgical treatment for gastroparesis

Efficacy of gastric stimulator as an adjunct to pyloroplasty for gastroparesis: characterizing patients suitable for single procedure vs dual procedure approach

BACKGROUND

Pyloroplasty is an effective surgery for gastroparesis. However, some patients fail to improve after pyloric drainage and may require subsequent gastric electric stimulation. There is a paucity of data on the efficacy of gastric stimulator as an adjunct to failed pyloroplasty. This study aimed to describe our experience with pyloroplasty, determine the efficacy of gastric stimulator for failed pyloroplasty, and compare the final outcomes of those who required pyloroplasty with and without gastric stimulator for gastroparesis.

METHODS

Records of patients who underwent primary pyloroplasty for gastroparesis at our institution were reviewed. Patients with poor symptomatic improvement after pyloroplasty underwent subsequent gastric stimulator. Symptoms were assessed using the gastroparesis cardinal symptom index (GCSI) preoperatively and after each surgery. Severe gastroparesis was defined as GCSI total score ≥3. Outcomes were assessed after pyloroplasty in all patients and after stimulator in patients who failed pyloroplasty. Final outcomes were then compared between those who did and did not require adjunct gastric stimulator.

RESULTS

The study population consisted of 104 patients (89.4% females) with a mean (SD) age of 42.2 years (11) and body mass index of 26.9 kg/m2 (7). Gastroparesis etiologies were 71.2% idiopathic, 17.3% diabetic, and 11.5% postsurgical. At 18.7 months (12) after pyloroplasty, there was a decrease in the GCSI total score (3.5 [1] to 2.7 [1.2]; P = .0012) and the rate of severe gastroparesis (71.9%-29.3%; P < .0001). Gastric emptying scintigraphy (GES) 4-hour retention decreased (36.5 [24] to 15.3 [18]; P = .0003). Adjunct gastric stimulator was required by 30 patients (28.8%) owing to suboptimal outcomes with no improvement in GCSI (P = .201) or GES (P = .320). These patients were younger (40.5 [10.6] vs 49.6 [15.2] years; P = .0016), with higher baseline GCSI total scores (4.3 [0.7] vs 3.7 [1.1]; P < .001) and more severe gastroparesis (100% vs 55.6%; P < .001). All other preoperative characteristics were similar. At 21.7 months (15) after gastric stimulator, there was improvement in GCSI (4.1 [0.7] to 2.6 [1.1]; P < .0001), severe gastroparesis (100%-33.3%; P < .0001), and GES 4-hour retention (21.2 [22] to 7.6 [10]; P = .054). Before gastric stimulator, those who failed pyloroplasty had significantly worse GCSI (P = .0009) and GES (P = .048). However, after gastric stimulator, GCSI and GES improved and were comparable with those who only required pyloroplasty (P > .05).

CONCLUSION

Pyloroplasty improved gastroparesis symptoms and gastric emptying, yet 28% failed, requiring gastric stimulator. Younger patients and those with preoperative GCSI scores ≥3 were more likely to fail. Gastric stimulator improved outcomes after failed pyloroplasty, with comparable final GCSI and GES with those who did not fail.

A global bibliometric and visualized analysis of the status and trends of gastroparesis research

BACKGROUND

Gastroparesis has a substantial impact on the quality of life but has limited treatment options, which makes it a public health concern. No bibliometric studies on gastroparesis have been published thus far. Thus, this article aims to summarize and analyze research hotspots to provide a reference for clinical researchers.

MATERIALS AND METHODS

Gastroparesis-related research articles were searched in the Web of Science Core Collection (WOSCC), and relevant information was extracted after screening. A total of 1033 documents were analyzed with the bibliometric method using Microsoft Excel, Citespace, and VOSviewer.

RESULTS

Overall, our search retrieved 1033 papers contributed by 966 research institutions from 53 countries. Since 1980, publications in this field have increased rapidly. United States (n = 645) and Temple University (n = 122) were the most productive country and institution, respectively. Parkman, with 96 publications, was the most prominent author.

CONCLUSIONS

Research hotspots in gastroparesis can be summarized into four domains: innovation in diagnostic modalities, change of oral therapeutic agents, choice of surgical interventions, and pathological mechanisms. Future research on gastroparesis should focus on the quality of life of patients, diagnostic techniques, pyloromyotomy, and transpyloric stent placement.

Optical Mapping of Virtual Electrode Polarization Pattern and Its Relationship with Pacemaker Location during Gastric Pacing. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023;2023:1-4. [PMID: 38082999 DOI: 10.1109/embc40787.2023.10340002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Gastric rhythmic contractions are regulated by bioelectrical events known as slow waves (SW). Abnormal SW activity is associated with gastric motility disorders. Gastric pacing is a potential treatment method to restore rhythmic SW activity. However, to date, the efficacy of gastric pacing is inconsistent and the underlying mechanisms of gastric pacing are poorly understood. Optical mapping is widely used in cardiac electrophysiology studies. Its immunity to pacing artifacts offers a distinct advantage over conventional electrical mapping for studying pacing. In the present study, we first found that optical mapping can image pacing-induced virtual electrode polarization patterns in the stomach (adjacent regions of depolarized and hyperpolarized tissue). Second, we found that elicited SWs usually (15 of 16) originated from the depolarized areas of the stimulated region (virtual cathodes). To our knowledge, this is the first direct observation of virtual electrode polarization patterns in the stomach. Conclusions: Optical mapping can image virtual electrode polarization patterns during gastric pacing with high spatial resolution.Clinical Relevance- Gastric pacing is a potential therapeutic method for gastric motility disorders. This study provides direct observation of virtual electrode polarization pattern during gastric pacing and improves our understanding of the mechanisms underlying gastric pacing..

Gastroparesis in geriatrics population: A United States population study

BACKGROUND

Older patients with upper gastrointestinal diseases may lack disease-specific symptoms that are required to make the correct diagnosis. This study aimed to compare the gastroparesis demographics, clinical presentation, and surgical management between the older adult and young populations.

METHODS

The National Inpatient Sample database was used between the years 2012 and 2014 with the primary diagnosis of gastroparesis. Patients were further divided based on their age into two groups: 70 years or older and younger than 70 years.

RESULTS

The older adults were more likely to have early satiety and bloating compared to younger population with an odds ratio (OR) = 3.79; 95% Confidence Interval (95%CI) 2.80- 5.11, p < 0.0001 and OR = 2.80, 95%CI 2.07-3.78, p<0.0001 respectively. Older adults had low odds of having nausea with vomiting (OR = 0.86, 95%CI 0.76-0.95, p = 0.003), or abdominal pain (OR = 0.56, 95%CI 0.50-0.63, p<0.0001).

CONCLUSIONS

Older adults had more early satiety and bloating, whereas younger patients had more nausea with vomiting and abdominal pain.

Gastric Electrical Stimulation: Role and Clinical Impact on Chronic Nausea and Vomiting

Gastric electrical stimulation (GES) is currently used as an alternative treatment for medically refractory gastroparesis. GES has been initially developed to accelerate gastric motility, in order to relieve the symptoms of the patients. Subsequent studies, unfortunately, failed to demonstrate the acceleration of gastric emptying using high-frequency stimulation - low energy stimulation although the technique has shown a clinical impact with a reduction of nausea and vomiting for patients with gastroparesis. The present review details the clinical efficacy of GES in gastroparesis as well as its putative mechanisms of action.

New device for active gastric mechanical stimulation

BACKGROUND

Gastroparesis is a chronic stomach disorder and effective treatment is the aim of different strategies. Alternative therapies consist of an electrical stimulation of the stomach to evoke a response in the gastric activity. We present the development and in vivo application of an electromagnet system to induce a mechanical stimulus in the stomach aiming for gastric contractile responses.

METHODS

The electromagnet system consisted of an implantable magnet and an external drive coil. We implanted the magnet at the greater curvature of the gastric body in rats. We applied an alternating current to the drive coils, inducing mechanical stimulation of the gastric wall. We measured the gastric contraction activity and gastric electrical activity in response to the stimulus using AC biosusceptometry and electrogastrography. Moreover, we used the phenol red to evaluate the stimulus effects on gastrointestinal transit.

KEY RESULTS

The stimulus increased the spectral intensity and signal-to-noise ratio significantly of gastric contraction activity and gastric electrical activity. Furthermore, we found a lower phenol red retention in the stomach in rats without stimulus. No significant differences were found in frequency and root mean square amplitude.

CONCLUSIONS & INFERENCES

We developed a new simple electromagnet system that evoked a contraction and gastric electrical response using a mechanical stimulus and decreased gastric emptying time. The system is an accessible tool and may contribute to gastroparesis studies in animals.

Gastric neurons in the nucleus tractus solitarius are selective to the orientation of gastric electrical stimulation

Objective.Gastric electrical stimulation (GES) is a bioelectric intervention for gastroparesis, obesity, and other functional gastrointestinal disorders. In a potential mechanism of action, GES activates the nerve endings of vagal afferent neurons and induces the vago-vagal reflex through the nucleus tractus solitarius (NTS) in the brainstem. However, it is unclear where and how to stimulate in order to optimize the vagal afferent responses.Approach.To address this question with electrophysiology in rats, we applied mild electrical currents to two serosal targets on the distal forestomach with dense distributions of vagal intramuscular arrays (IMAs) that innervated the circular and longitudinal smooth muscle layers. During stimulation, we recorded single and multi-unit responses from gastric neurons in NTS and evaluated how the recorded responses depended on the stimulus orientation and amplitude.Main results.We found that NTS responses were highly selective to the stimulus orientation for a range of stimulus amplitudes. The strongest responses were observed when the applied current flowed in the same direction as the IMAs in parallel with the underlying smooth muscle fibers. Our results suggest that gastric neurons in NTS may encode the orientation-specific activity of gastric smooth muscles relayed by vagal afferent neurons.Significance.This finding suggests that the orientation of GES is critical to effective engagement of vagal afferents and should be considered in light of the structural phenotypes of vagal terminals in the stomach.

Miniaturized wireless gastric pacing via inductive power transfer with non-invasive monitoring using cutaneous Electrogastrography

BACKGROUND

Gastroparesis is a debilitating disease that is often refractory to pharmacotherapy. While gastric electrical stimulation has been studied as a potential treatment, current devices are limited by surgical complications and an incomplete understanding of the mechanism by which electrical stimulation affects physiology.

METHODS

A leadless inductively-powered pacemaker was implanted on the gastric serosa in an anesthetized pig. Wireless pacing was performed at transmitter-to-receiver distances up to 20 mm, frequency of 0.05 Hz, and pulse width of 400 ms. Electrogastrogram (EGG) recordings using cutaneous and serosal electrode arrays were analyzed to compute spectral and spatial statistical parameters associated with the slow wave.

RESULTS

Our data demonstrated evident change in EGG signal patterns upon initiation of pacing. A buffer period was noted before a pattern of entrainment appeared with consistent and low variability in slow wave direction. A spectral power increase in the EGG frequency band during entrainment also suggested that pacing increased strength of the slow wave.

CONCLUSION

Our preliminary in vivo study using wireless pacing and concurrent EGG recording established the foundations for a minimally invasive approach to understand and optimize the effect of pacing on gastric motor activity as a means to treat conditions of gastric dysmotility.

Endoscopic and Surgical Treatments for Gastroparesis: What to Do and Whom to Treat?

Gastroparesis is a complex chronic debilitating condition of gastric motility resulting in the delayed gastric emptying and multiple severe symptoms, which may lead to malnutrition and dehydration. Initial management of patients with gastroparesis focuses on the diet, lifestyle modification and medical therapy. Various endoscopic and surgical interventions are reserved for refractory cases of gastroparesis, not responding to conservative therapy. Pyloric interventions, enteral access tubes, gastric electrical stimulator and gastrectomy have been described in the care of patients with gastroparesis. In this article, the authors review current management, indications, and contraindications to these procedures.

Status of Brain Imaging in Gastroparesis

The pathophysiology of nausea and vomiting in gastroparesis is complicated and multifaceted involving the collaboration of both the peripheral and central nervous systems. Most treatment strategies and studies performed in gastroparesis have focused largely on the peripheral effects of this disease, while our understanding of the central nervous system mechanisms of nausea in this entity is still evolving. The ability to view the brain with different neuroimaging techniques has enabled significant advances in our understanding of the central emetic reflex response. However, not enough studies have been performed to further explore the brain–gut mechanisms involved in nausea and vomiting in patients with gastroparesis. The purpose of this review article is to assess the current status of brain imaging and summarize the theories about our present understanding on the central mechanisms involved in nausea and vomiting (N/V) in patients with gastroparesis. Gaining a better understanding of the complex brain circuits involved in the pathogenesis of gastroparesis will allow for the development of better antiemetic prophylactic and treatment strategies.

Effectiveness of gastric electrical stimulation in gastroparesis: Results from a large prospectively collected database of national gastroparesis registries

BACKGROUND

Gastric electrical stimulation (GES) for treating gastroparesis symptoms is controversial.

METHODS

We studied 319 idiopathic or diabetic gastroparesis symptom patients from the Gastroparesis Clinical Research Consortium (GpCRC) observational studies: 238 without GES and 81 with GES. We assessed the effects of GES using change in GCSI total score and nausea/vomiting subscales between baseline and 48 weeks. We used propensity score methods to control for imbalances in patient characteristics between comparison groups.

KEY RESULTS

GES patients were clinically worse (40% severe vs. 18% for non-GES; P < .001); worse PAGI-QOL (2.2. vs. 2.6; P = .003); and worse GCSI total scores (3.5 vs. 2.8; P < .001). We observed improvements in 48-week GCSI total scores for GES vs. non-GES: improvement by ≥ 1-point (RR = 1.63; 95% CI = (1.14, 2.33); P = .01) and change from enrollment (difference = -0.5 (-0.8, -0.3); P < .001). When adjusting for patient characteristics, symptom scores were smaller and not statistically significant: improvement by ≥ 1-point (RR = 1.29 (0.88, 1.90); P = .20) and change from the enrollment (difference = -0.3 (-0.6, 0.0); P = .07). Of the individual items, the nausea improved by ≥ 1 point (RR = 1.31 (1.03, 1.67); P = .04). Patients with GCSI score ≥ 3.0 tended to improve more than those with score < 3.0. (Adjusted P = 0.02).

CONCLUSIONS AND INFERENCES

This multicenter study of gastroparesis patients found significant improvements in gastroparesis symptoms among GES patients. Accounting for imbalances in patient characteristics, only nausea remained significant. Patients with greater symptoms at baseline improved more after GES. A much larger sample of patients is needed to fully evaluate symptomatic responses and to identify patients likely to respond to GES.

Cajal Cell Counts are Important Predictors of Outcomes in Drug Refractory Gastroparesis Patients With Neurostimulation

BACKGROUND AND AIMS

Cajal cells serve as the pacemaker cells of the gastrointestinal tract and regulates peristalsis. On the baisis of that fact, it has been hypothesized that a decrease in Cajal cells can lead to gastroparesis and other motility issues. Treatment with medications has a limited efficacy and most resort to gastric electrical stimulation (GES) devices for symptomatic relief. We believe that the number of Cajal cells present is directly proportional to symptomatic relief with GES.

MATERIALS AND METHODS

Twenty-three (white female) subjects were recruited from the gastric motility clinic University of Mississipi for this study with the criteria of drug refractory gastropersis. Symptoms were measured using Likert scale and gastric emptying times were measured pre-GES and post-GES. Serosal electrogram measurements were recorded during surgical placement of permanent electrical stimulator under various modes. Cajal cell count scoring via immunohistochemistry were performed during the implantaion of the GES.

RESULTS

The data were grouped in 2 categories based on the Cajal cells that is ≥2.00 and <2.00. Subjects with higher Cajal cells reported a statiscially improvement in gastroperesis symptoms. Significant differences were also noted in the first hour gastric emptying study. The mean group difference is 17.5 (95% confidence interval, 1.41-33.58; P=0.035). Serosal amplitude differences were noted being significantly higher in the group with ≥2 cajal cells.

CONCLUSIONS

Electrograms obtained after GES demonstrates immediate improvement in gastric electrical activity and gastroparesis symptoms in patients with relatively higher Cajal cell counts when compared with patients with extensive loss of Cajal cells.

Minimally-invasive temporary gastric stimulation: A pilot study to predict the outcome of electronic gastric stimulation with the Enterra™ system

INTRODUCTION

Gastroparesis (GP) is defined as delayed gastric emptying (GE) without any obstruction of the pylorus. It can be divided into idiopathic, diabetic, post surgical and rare causes. Electronic gastric stimulation (EGS) - Enterra Medtronic™ - is a part of GP therapy. Although its positive impact has been reported in open label trials, randomized controlled trials failed in demonstrating a positive outcome. The aim of this pilot study was to establish a reliable prediction for permanent gastric stimulation.

PATIENTS AND PROCEDURE

6 female patients underwent laparoscopic implantation of 2 temporary electrodes. The Enterra™ system was connected and taped to the skin. Baseline and postoperative gastroparesis cardinal symptom index (GCSI), a validated index for GP therapy, was assessed. Response to EGS was defined as a 50% decrease of baseline GCSI.

RESULTS

4 of 6 patients responded to temporary EGS. 3 of 4 responders underwent permanent implantation. 1 non-responder received a permanent Enterra™ at another institution. After a median follow up time of 9months the responder group GCSI remained low, whereas the non-responder GCSI had increased. Moreover, the health care system was saved € 30,678.03 by this test stimulation concept.

CONCLUSION

Laparoscopic implantation of a temporary EGS system predicts the outcome of permanent gastric stimulation and is cost-saving.

Study on effects of electrical stimulation on rabbit esophageal body motility in vivo

Electric stimulation (ES) could induce contraction of intestinal smooth muscle. The aim of this study was to analyze the effects of ES on esophageal motility and the underlying mechanism in vivo. Twenty-eight rabbits were equipped with a pair of subserosa electrodes (connected to an electrical stimulator) in the lower segment of the esophagus. The ES signal consisted of bipolar rectangular pulse trains, lasting for 3 s, with different amplitudes (1 mA, 3 mA, 5 mA and 10 mA), and frequencies (10 Hz, 20 Hz and 50 Hz). The amplitude of the contraction was recognized by high-resolution manometry. The effect of ES was tested under anesthesia and following administration of atropine, phentolamine or L-NAME. ES induced esophageal contraction at the stimulated site. A statistically significant increase in esophageal pressure was observed when the stimulation amplitude was above 3 mA. The increase in esophageal pressure was associated with the amplitude of stimulus as well as the frequency. During stimulation, atropine, phentolamine and L-NAME had no effect on the increase of esophageal pressure induced by ES. These findings implied that ES induced esophageal contraction were not mediated via the NANC, adrenergic or cholinergic pathway. The amplitude of esophageal contraction was current and frequency dependent.

Gastric Mixing During Food Digestion: Mechanisms and Applications

Gastric mixing is a complex process that is governed by meal properties, such as food buffering capacity, physical properties, and the rate of breakdown as well as physiological factors, such as the rate of gastric secretions, gastric emptying, and gastric motility. Gastric mixing processes have been studied through the use of experimental and computational methods. Gastric mixing impacts the intragastric pH distribution and residence time in the stomach for ingested materials. Development of a fundamental understanding of the advective and diffusion processes and their roles in gastric mixing will be important in furthering our understanding of food breakdown, microbial survival, and drug dissolution during gastric digestion.

Gastric Electrical Stimulation for Gastroparesis and Chronic Unexplained Nausea and Vomiting

OPINION STATEMENT

Gastroparesis is a heterogeneous clinical syndrome. Some patients have debilitating vomiting, weight loss, and dehydration, while others have effortless regurgitation of undigested foods or postprandial distress suggestive of functional dyspepsia. Gastric electrical stimulation (GES) has been proposed as an effective treatment option for patients with gastroparesis refractory to medical therapy. Evidence suggests that the clinically available device, a low-energy high-frequency GES, activates the vagal afferent pathways to influence the central control mechanisms for nausea and vomiting. Myoelectrical effects of the stomach are also involved. The results of randomized controlled trials (RCTs) for adults with diabetic and idiopathic gastroparesis are conflicting. There are no RCTs in adults with chronic unexplained nausea and vomiting (CUNV) with normal gastric emptying or in children with gastroparesis. However, there is increasing evidence from large unblinded studies showing the long-term efficacy in selected adults with gastroparesis. Selection criteria should be based on three categories: (a) underlying etiology, (b) clinical presentation and predominant symptoms, and (c) potential risk for complication. Significant abdominal pain, daily opiate use, and idiopathic gastroparesis are identified as negative predictors of success. Temporary GES has been utilized to identify patients who may benefit from surgical GES, but this strategy has yet to be proven in controlled studies. Objectives for this review are to highlight the mechanisms of action for GES, to look at the evidence for clinical efficacy, and to select patients who are likely to benefit.

Gastric Electrical Stimulation with the Enterra System: A Systematic Review

Background. Gastric electrical stimulation (GES) is a surgically implanted treatment option for refractory gastroparesis. Aim. To systematically appraise the current evidence for the use of gastric electrical stimulation and suggest a method of standardisation of assessment and follow-up in these patients. Methods. A systematic review of PubMed, Web of Science, DISCOVER, and Cochrane Library was conducted using the keywords including gastric electrical stimulation, gastroparesis, nausea, and vomiting and neuromodulation, stomach, central nervous system, gastric pacing, electrical stimulation, and gastrointestinal. Results. 1139 potentially relevant articles were identified, of which 21 met the inclusion criteria and were included. The quality of studies was variable. There was a variation in outcome measures and follow-up methodology. Included studies suggested significant reductions in symptom severity reporting over the study period, but improvements in gastric emptying time were variable and rarely correlated with symptom improvement. Conclusion. The evidence in support of gastric electrical stimulation is limited and heterogeneous in quality. While current evidence has shown a degree of efficacy in these patients, high-quality, large clinical trials are needed to establish the efficacy of this therapy and to identify the patients for whom this therapy is inappropriate. A consensus view on essential preoperative assessment and postoperative measurement is needed.

Effects of intestinal electrical stimulation on postprandial small-bowel motility and transit in dogs

BACKGROUND

Intestinal electrical stimulation (IES) with long pulses has been reported to inhibit motility as well as accelerate transit of continuous infusion. However, it is unknown whether there is a correlation between the IES-induced alterations in motility and transit and whether there is a difference in transit during IES between continuous infusion and bolus infusion.

METHODS

The study was performed in 2 postprandial sessions (control and stimulation) in dogs with 2 pairs of serosal electrodes and 2 intestinal cannulas. Intestinal motility and transit with and without IES were measured by manometry and phenol red, respectively.

RESULTS

IES significantly decreased intestinal motility and increased transit time. There was a significant correlation between motility index and transit during IES.

CONCLUSIONS

IES inhibits both intestinal bolus motility and transit. There is correlation between motility and transit during IES.

Gastric electrical stimulation with Enterra therapy improves symptoms of idiopathic gastroparesis

BACKGROUND

Gastric electrical stimulation (GES) is a therapeutic option for intractable symptoms of gastroparesis (GP). Idiopathic GP (ID-GP) represents a subset of GP.

AIMS

A prospective, multicenter, double-blinded, randomized, crossover study to evaluate the safety and efficacy of Enterra GES in the treatment of chronic vomiting in ID-GP.

METHODS

Thirty-two ID-GP subjects (mean age 39; 81% F, mean 7.7 years of GP) were implanted with GES. The stimulator was turned ON for 1½ months followed by double-blind randomization to consecutive 3-month crossover periods with the device either ON or OFF. ON stimulation was followed in unblinded fashion for another 4.5 months. Twenty-five subjects completed the crossover phase and 21 finished 1 year of follow-up.

KEY RESULTS

During the unblinded ON period, there was a reduction in weekly vomiting frequency (WVF) from baseline (61.2%, P < 0.001). There was a non-significant reduction in WVF between ON vs OFF periods (the primary outcome) with median reduction of 17% (P > 0.10). Seventy-five percent of patients preferred the ON vs OFF period (P = 0.021). At 1 year, WVF remained decreased (median reduction = 87%, P < 0.001), accompanied by improvements in GP symptoms, gastric emptying and days of hospitalization (P < 0.05).

CONCLUSIONS & INFERENCES

(i) In this prospective study of Enterra GES for ID-GP, there was a reduction in vomiting during the initial ON period; (ii) The double-blind 3-month periods showed a non-significant reduction in vomiting in the ON vs OFF period, the primary outcome variable; (iii) At 12 months with ON stimulation, there was a sustained decrease in vomiting and days of hospitalizations.

Treatments for severe gastroparesis

Severe gastroparesis is a kind of gastroparesis that is refractory to conventional drug therapy and requires nutritional support and frequently emergency hospitalization. The selection of treatment for severe gastroparesis has always been a dilemma for clinicians. Currently, there have been limited reports on the treatment of severe gastroparesis. This article sums up the primary treatments, drug treatments and other kinds of treatments for severe gastroparesis and discusses the prospects for the treatment of this refractory disease.

Gastric electrical stimulation for the treatment of obesity: from entrainment to bezoars-a functional review

GROWING WORLDWIDE OBESITY EPIDEMIC HAS PROMPTED THE DEVELOPMENT OF TWO MAIN TREATMENT STREAMS: (a) conservative approaches and (b) invasive techniques. However, only invasive surgical methods have delivered significant and sustainable benefits. Therefore, contemporary research exploration has focused on the development of minimally invasive gastric manipulation methods featuring a safe but reliable and long-term sustainable weight loss effect similar to the one delivered by bariatric surgeries. This antiobesity approach is based on placing external devices in the stomach ranging from electrodes for gastric electrical stimulation to temporary intraluminal bezoars for gastric volume displacement for a predetermined amount of time. The present paper examines the evolution of these techniques from invasively implantable units to completely noninvasive patient-controllable implements, from a functional, rather than from the traditional, parametric point of view. Comparative discussion over the available pilot and clinical studies related to gastric electrical stimulation outlines the promises and the fallacies of this concept as a reliable alternative anti-obesity strategy.

The addition of pyloroplasty as a new surgical approach to enhance effectiveness of gastric electrical stimulation therapy in patients with gastroparesis

BACKGROUND

Improvement of gastroparesis (GP) symptoms has been documented in patients treated with gastric electrical stimulation (GES), but acceleration of gastric emptying (GET) is unpredictable. The aim of our study was to evaluate the advantage of adding surgical pyloroplasty (PP) to GES for improvement of GET and control of symptoms in diabetes mellitus (DM), idiopathic (ID), and postvagotomy (P-V) GP.

METHODS

A total of 49 (17 - DM, 9 - ID, 23 - P-V) consecutive GP patients: 38 female; mean age 42 (21-73 years); mean weight 158 lbs (102-245), underwent GES implantation, and 26 (53%) additionally received PP. Total Symptoms Score, 4-h GET, adverse events (AEs), and days of hospitalizations were captured at baseline and at the last visit.

KEY RESULTS

The mean follow-up was 7 months. Total Symptoms Score in patients who received Enterra and PP or GES alone significantly improved compared to their baseline scores (P < 0.001). GET improved by 64% at 4 h (P < 0.001) in patients with Enterra and PP, compared to 7% observed after GES therapy alone (ns). The most impressive acceleration of GET was seen in the P-V group, who received both therapies (P = 0.004) and 8 (60%) of them normalized GET. No AEs accompanied the addition of PP to the Enterra surgery.

CONCLUSIONS & INFERENCES

(i) In drug-refractory GP the addition of PP to GES substantially accelerated GET; (ii) The GET response in P-V group was the most impressive; (iii) Significant symptom reductions were achieved by both procedures; and (iv) PP added to GES may sustain better long-term symptoms control particularly in the P-V setting.

Clinical guideline: management of gastroparesis

This guideline presents recommendations for the evaluation and management of patients with gastroparesis. Gastroparesis is identified in clinical practice through the recognition of the clinical symptoms and documentation of delayed gastric emptying. Symptoms from gastroparesis include nausea, vomiting, early satiety, postprandial fullness, bloating, and upper abdominal pain. Management of gastroparesis should include assessment and correction of nutritional state, relief of symptoms, improvement of gastric emptying and, in diabetics, glycemic control. Patient nutritional state should be managed by oral dietary modifications. If oral intake is not adequate, then enteral nutrition via jejunostomy tube needs to be considered. Parenteral nutrition is rarely required when hydration and nutritional state cannot be maintained. Medical treatment entails use of prokinetic and antiemetic therapies. Current approved treatment options, including metoclopramide and gastric electrical stimulation (GES, approved on a humanitarian device exemption), do not adequately address clinical need. Antiemetics have not been specifically tested in gastroparesis, but they may relieve nausea and vomiting. Other medications aimed at symptom relief include unapproved medications or off-label indications, and include domperidone, erythromycin (primarily over a short term), and centrally acting antidepressants used as symptom modulators. GES may relieve symptoms, including weekly vomiting frequency, and the need for nutritional supplementation, based on open-label studies. Second-line approaches include venting gastrostomy or feeding jejunostomy; intrapyloric botulinum toxin injection was not effective in randomized controlled trials. Most of these treatments are based on open-label treatment trials and small numbers. Partial gastrectomy and pyloroplasty should be used rarely, only in carefully selected patients. Attention should be given to the development of new effective therapies for symptomatic control.

Is symptom relief associated with reduction in gastric retention after gastric electrical stimulation treatment in patients with gastroparesis? A sensitivity analysis with logistic regression models

BACKGROUND

Enterra gastric electrical stimulation (GES) is an alternative treatment for gastroparesis (GP) when standard medical therapy fails. The aims of this study were to evaluate the association between total symptom score (TSS) and reduction in gastric retention (GR) after GES by GP etiology and to examine the sensitivity of the association to varying cutpoints used to define GR and TSS improvement.

METHODS

Gastric retention assessed with a standardized (99m) Tc radio-labeled egg meal and TSS measured by a five-point Likert scale in 221 GP patients treated with Enterra GES therapy for at least 1 year were analyzed. Bivariate chi-square test and multivariable logistic regression with all possible cutpoints were used to assess the consistency of association and quantitate the relationship across three GP etiologies.

KEY RESULTS

Symptom relief in diabetic GP was more likely attributable to GR reduction as indicated by the consistently significant odds ratios (P < 0.01) across all cutpoints. The association in idiopathic GP was inconclusive because odds ratios were sensitive to cutpoints with P-values ranging from 0.01 to 0.47. No association was found for patients with post surgical gastroparesis (P > 0.1 for all cutpoints). Patient age, gender, baseline TSS and baseline GR had no significant effect at 5% level on clinical improvement regardless of cutpoints for GR.

CONCLUSIONS & INFERENCES

Association between clinical improvements and GR reduction following GES treatment depends on patient etiology and was able to be demonstrated in diabetic GP. The association for idiopathic GP was inconclusive and no such association was found for post surgical GP across all possible cutpoint combinations.

Gastric electrical stimulation for the treatment of diabetic gastroparesis

Diabetic gastroparesis is a component of autonomic neuropathy, and is the most common manifestation of gastrointestinal neuropathy. Diabetes is responsible for about one quarter of gastroparesis. The upper gastrointestinal symptoms are often non-specific and dominated by nausea, vomiting, early satiety, fullness, bloating. We also have to look for diabetic gastroparesis in case of metabolic instability, such as postprandial hypoglycaemia. The pathophysiology of diabetic gastroparesis is complex, partly due to a vagus nerve damage, but also to changes in secretion of hormones such as motilin and ghrelin. A decrease in the stem cell factor (SCF), growth factor for cells of Cajal (gastric pacemaker), was found in subjects with diabetic gastroparesis. These abnormalities lead to an excessive relaxation in the corpus, a hypomotility of antrum, a desynchronization antrum-duodenum-pylorus, and finally an abnormal duodenal motility. The treatment of diabetic gastroparesis is based on diabetes control, and split meals by reducing the fiber content and fat from the diet. The antiemetic and prokinetic agents should be tested primarily in people with nausea and vomiting. Finally, after failure of conventional measures, the use of gastric neuromodulation is an effective alternative, with well-defined indications. Introduced in the 1970s, this technology works by applying electrical stimulation continues at the gastric antrum, particularly in patients whose gastric symptoms are refractory to other therapies. Its efficacy has been recently reported in different causes of gastroparesis, especially in diabetes. Gastric emptying based on gastric scintigraphy, gastrointestinal symptoms, biological markers of glycaemic control and quality of life are partly improved, but not normalized. Finally, a heavy nutritional care is sometimes necessary in the most severe forms. The enteral route should be preferred (nasojejunal and jejunostomy if possible efficiency). However, in case of failure especially in patients with small bowel neuropathy, the long-term parenteral nutrition is sometimes required.

Treatment of high-frequency gastric electrical stimulation for gastroparesis

BACKGROUND AND AIMS

The aim of this study was to assess the effects of gastric electrical stimulation (GES) on symptoms and gastric emptying in patients with gastroparesis, and the effects of GES on the three subgroups of gastroparesis.

METHODS

A literature search of clinical trials using high-frequency GES to treat patients with gastroparesis from January 1995 to January 2011 was performed. Data on the total symptom severity score (TSS), nausea severity score, vomiting severity score, and gastric emptying were extracted and analyzed. The statistic effect index was weighted mean differences.

RESULTS

Ten studies (n = 601) were included in this study. In the comparison to baseline, there was significant improvement of symptoms and gastric emptying (P < 0.00001). It was noted that GES significantly improved both TSS (P < 0.00001) and gastric retention at 2 h (P = 0.003) and 4 h (P < 0.0001) in patients with diabetic gastroparesis (DG), while gastric retention at 2 h (P = 0.18) in idiopathic gastroparesis (IG) patients, and gastric retention at 4 h (P = 0.23) in postsurgical gastroparesis (PSG) patients, did not reach significance.

CONCLUSIONS

Based on this meta-analysis, the substantial and significant improvement of symptoms and gastric emptying, and the good safety we observed, indicate that high-frequency GES is an effective and safe method for treating refractory gastroparesis. DG patients seem the most responsive to GES, both subjectively and objectively, while the IG and PSG subgroups are less responsive and need further research.

Temporary gastric neuromodulation for intractable nausea and vomiting

INTRODUCTION

Gastric neuromodulation (GNM) has been advocated for the treatment of drug refractory gastroparesis or persistent nausea and vomiting in the absence of a mechanical bowel obstruction. There is, however, little in the way of objective data to support its use, particularly with regards to its effects on gastric emptying.

METHODS

Six patients (male-to-female ratio: 4:2, mean age: 49 years, range: 44-57 years) underwent the GNM between April and August 2010. Three patients had confirmed slow gastrointestinal transit. Aetiology included previous gastric surgery in two, diabetes in one and idiopathic nausea and vomiting in three patients. GNM pacing wires were placed endoscopically and left in situ for seven days. Patients underwent gastric scintigraphy before and 24 hours after the commencement of GNM. Total gastroparesis symptom scores (TSS), weekly vomiting frequency scores (VFS), health-related quality of life (using the SF-12(®) questionnaire), gastric emptying, nutritional status and weight were compared before and after GNM.

RESULTS

TSS improved after GNM in comparison with baseline data. VFS improved in three of four symptomatic patients. The SF-12(®) physical composite score improved in four patients (27.5 vs 34.3) and the mental composite score improved in five patients (34.9 vs 35.9). All patients reported an improvement in oral intake. A significant weight gain (mean: 1kg, range: 0.3-2.4kg) was observed over seven days. Gastric emptying half-time improved in four patients.

CONCLUSIONS

GNM improved upper gastrointestinal symptoms, quality of life and nutritional status in patients with intractable nausea and vomiting. GNM merits further investigation.

Two-channel gastric pacing in patients with diabetic gastroparesis

BACKGROUND

Our primary goals were to investigate the effects of two-channel gastric pacing on gastric myoelectrical activity, and energy consumption with the secondary intent to monitor gastric emptying and symptoms in patients with severe diabetic gastroparesis.

METHODS

Four pairs of temporary pacing wires were inserted on the serosa of the stomach at the time of laparotomy to place the Enterra™ System in 19 patients with severe gastroparesis not responding to standard medical therapies. Two of the pairs were for electrical stimulation and the other two for recording. Five days after surgery the optimal pacing parameters for the entrainment of gastric slow waves in each patient were identified by serosal recordings. Two-channel gastric pacing was then initiated for 6 weeks using a newly developed external multi-channel pulse generator. Electrogastrogram (EGG), Total Symptom Score (TSS), and a 4-h gastric emptying test were assessed at baseline and after 6 weeks of active gastric pacing. Enterra™ device was turned OFF during the duration of this study.

KEY RESULTS

Two-channel gastric pacing at 1.1 times the intrinsic frequency entrained gastric slow waves and normalized gastric dysrhythmia. After 6 weeks of gastric pacing, tachygastria was decreased from 15 ± 3 to 5 ± 1% in the fasting state and from 10 ± 2 to 5 ± 1% postprandially (P < 0.05), mean TSS was reduced from 21.3 ± 1.1 to 7.0 ± 1.5 (P < 0.05) and mean 4-h gastric retention improved from 42 to 28% (P = 0.05).

CONCLUSIONS & INFERENCES

Two-channel gastric pacing is a novel treatment approach which is able to normalize and enhance gastric slow wave activity as well as accelerate gastric emptying in patients with diabetic gastroparesis with a goal safety profile.

Design, implementation and testing of an implantable impedance-based feedback-controlled neural gastric stimulator

Functional neural gastrointestinal electrical stimulation (NGES) is a methodology of gastric electrical stimulation that can be applied as a possible treatment for disorders such as obesity and gastroparesis. NGES is capable of generating strong lumen-occluding local contractions that can produce retrograde or antegrade movement of gastric content. A feedback-controlled implantable NGES system has been designed, implemented and tested both in laboratory conditions and in an acute animal setting. The feedback system, based on gastric tissue impedance change, is aimed at reducing battery energy requirements and managing the phenomenon of gastric tissue accommodation. Acute animal testing was undertaken in four mongrel dogs (2 M, 2 F, weight 25.53 ± 7.3 kg) that underwent subserosal two-channel electrode implantation. Three force transducers sutured serosally along the gastric axis and a wireless signal acquisition system were utilized to record stimulation-generated contractions and tissue impedance variations respectively. Mechanically induced contractions in the stomach were utilized to indirectly generate a tissue impedance change that was detected by the feedback system. Results showed that increasing or decreasing impedance changes were detected by the implantable stimulator and that therapy can be triggered as a result. The implantable feedback system brings NGES one step closer to long term treatment of burdening gastric motility disorders in humans.

Temporary percutaneous and permanent gastric electrical stimulation in children younger than 3 years with chronic vomiting

BACKGROUND

The aim was to investigate whether young children with drug-refractory nausea and vomiting can be treated with gastric electrical stimulation (GES) in a similar way as adults and to evaluate whether temporary percutaneous gastric electrical stimulation (TPGES) can be used in the pediatric population to select the patients who are responders to GES treatment. We report the clinical results in 3 children between 2 and 3 years of age. To the best of our knowledge, these are the youngest patients treated with GES.

METHODS

Three patients younger than 3 years with intractable vomiting underwent TPGES. Custom-made leads were percutaneously implanted in the gastric wall under gastroscopic guidance. Symptoms were recorded daily during the TPGES stimulation time (12-40 days). Responders were offered permanent GES treatment.

RESULTS

There were no technical problems. All 3 patients were responders to TPGES. They are now treated with surgically implanted permanent GES and reported greater than 50% vomiting reduction at last visit.

CONCLUSION

Children younger than 3 years can be treated with GES in a similar way as adolescents and adults. Temporary percutaneous GES is a safe, feasible technique even in small children, with the possibility to perform the test over several weeks to select responders to GES treatment.

Gastric electrical stimulation improves outcomes of patients with gastroparesis for up to 10 years

BACKGROUND & AIMS

We assessed the long-term clinical outcomes of gastric electrical stimulation (GES) therapy with Enterra (Enterra Therapy System; Medtronic, Minneapolis, MN) in a large cohort of patients with severe gastroparesis.

METHODS

Gastroparesis patients (n=221; 142 diabetic, 48 idiopathic, and 31 postsurgical) treated with Enterra (Medtronic) for 1-11 years were retrospectively assessed; 188 had follow-up visits and data were collected for at least 1 year (mean 56 months, range 12-131 months). Total symptom scores (TSSs), gastric emptying, nutritional status, weight, hospitalizations, use of prokinetic and/or antiemetic medications, levels of HbA1c levels (in diabetic patients), and adverse events were evaluated at the beginning of the study (baseline) and during the follow-up period.

RESULTS

TSS, hospitalization days, and use of medications were significantly reduced among all patients (P<.05). More patients with diabetic (58%) and postsurgical gastroparesis (53%) had a greater than 50% reduction in TSS than those with idiopathic disease (48%; P=.32). Weight significantly increased among all groups, and 89% of J-tubes could be removed. At end of the follow-up period, all etiological groups had similar, abnormal delays in mean gastric retention. Thirteen patients (7%) had their devices removed because of infection at the pulse generator site.

CONCLUSIONS

GES therapy significantly improved subjective and objective parameters in patients with severe gastroparesis; efficacy was sustained for up to 10 years and was accompanied by good safety and tolerance profiles. Patients with diabetic or postsurgical gastroparesis benefited more than those with idiopathic disease.

Botulinum toxin type A for the treatment of gastroparesis in Parkinson's disease patients

Gastroparesis is a very common non-motor feature in Parkinson's disease (PD) patients. However, treatment options are limited and difficult. We present 2 cases of PD patients with excellent response to botulinum toxin type A as treatment for PD-related gastroparesis.

Duodenum electrical stimulation delays gastric emptying, reduces food intake and accelerates small bowel transit in pigs

Duodenum electrical stimulation (DES) has been shown to delay gastric emptying and reduce food intake in dogs. The aim of this study was to investigate the effects of DES on gastric emptying, small bowel transit and food intake in pigs, a large animal model of obesity. The study consisted of three experiments (gastric emptying, small bowel transit, and food intake) in pigs implanted with internal duodenal electrodes for DES and one or two duodenal cannulas for gastric emptying and small bowel transit. We found that (i) gastric emptying was dose-dependently delayed by DES of different stimulation parameters; (ii) small bowel transit was significantly accelerated with continuous DES in proximal intestine but not with intermittent DES; (iii) DES significantly reduced body weight gain with 100% duty cycle (DC), but not with DES with 40% DC. A marginal difference was noted in food intake among 100% DC session, 40% DC session, and control session. DES with long pulses energy-dependently inhibits gastric emptying in pigs. DES with appropriate parameters accelerates proximal small bowel transit in pigs. DES reduces body weight gain in obese pigs, and this therapeutic effect on obesity is mediated by inhibiting gastric emptying and food intake, and may also possibly by accelerating intestinal transit. DES may have a potential application to treat patients with obesity.

Gastric electrical stimulation with Enterra therapy improves symptoms from diabetic gastroparesis in a prospective study

BACKGROUND & AIMS

Gastric electrical stimulation (GES) treats refractory gastroparesis by delivering electric current, via electrodes, to gastric smooth muscle. Enterra therapy (Medtronic, Inc, Minneapolis, MN) uses an implantable neurostimulator with a high-frequency, low-energy output. We performed a controlled, multicenter, prospective study to evaluate the safety and efficacy of Enterra therapy in patients with chronic intractable nausea and vomiting from diabetic gastroparesis (DGP).

METHODS

Patients with refractory DGP (n = 55; mean age, 38 y; 66% female, 5.9 years of DGP) were given implants of the Enterra gastric stimulation system. After surgery, all patients had the stimulator turned on for 6 weeks and then they randomly were assigned to groups that had consecutive 3-month, cross-over periods with the device on or off. After this period, the device was turned on in all patients and they were followed up, unblinded, for 4.5 months.

RESULTS

The median reduction in weekly vomiting frequency (WVF) at 6 weeks, compared with baseline, was 57% (P < .001). There was no difference in WVF between patients who had the device turned on or off during the cross-over period (median reduction, 0%; P = .215). At 1 year, the WVF of all patients was significantly lower than baseline values (median reduction, 67.8%; P < .001). Patients also had significant improvements in total symptom score, gastric emptying, quality of life, and median days in the hospital.

CONCLUSIONS

In patients with intractable DGP, 6 weeks of GES therapy with Enterra significantly reduced vomiting and gastroparetic symptoms. Patients had improvements in subjective and objective parameters with chronic stimulation after 12 months of GES, compared with baseline.

Enterra Therapy: gastric neurostimulator for gastroparesis

Gastroparesis is a chronic disorder of gastric motility characterized by delayed gastric empting in the absence of mechanical obstruction, which can lead to symptoms of nausea, vomiting, bloating, abdominal pain, postprandial fullness and weight loss. Although there are many etiologies, the primary causes are diabetes or are idiopathic. The mainstay of treatment is dietary and drug therapies. However, many patients will continue to suffer intractable symptoms despite these treatments. Gastric neurostimulation with the Enterra Therapy system has been approved for use under the Humanitarian Device Exemption by the US FDA. The device produces pulses of electrical stimulation that are delivered to the stomach continuously. One randomized clinical trial and multiple nonrandomized unblinded clinical trials and case series have documented improvement of symptoms in intractable diabetic and idiopathic gastroparesis. The purpose of this article is to introduce the Enterra Therapy gastric neurostimulator. Gastroparesis and its pathophysiology will be discussed in this clinical context to enhance the understanding of the device and its development. We will analyze the device in detail, its placement and the results of studies evaluating its efficacy.

Effects and mechanisms of electrical stimulation of the stomach, duodenum, ileum, and colon on gastric tone in dogs

Previous studies have shown that gastric tone is inhibited by the electrical stimulation of some parts of the gut. The aims of this study were to investigate the effects of gastric electrical stimulation (GES), duodenal electrical stimulation (DES), ileal electrical stimulation (IES), and colonic electrical stimulation (CES) on gastric tone and the possible mechanism of electrical stimulation on gastric tone. Experiments were performed to study: (1) the effects of the four stimulations (GES, DES, IES, CES) on gastric tone; (2) the role of the nitrergic pathway's involvement in the effect of IES on gastric tone. Each dog was implanted with one pair of gastric, duodenal, ileal, and colonic electrodes and a gastric cannula. A computerized barostat was used to assess gastric tone by measuring the gastric intra-balloon volume. We found that: (1) all methods of stimulation significantly inhibited gastric tone; (2) the percentage of increase in gastric volume was highest with CES and lowest with DES; however, there was no significant difference in the percentage of inhibition among the four stimulations; (3) the inhibitory effect of IES on gastric tone was abolished by intravenous nitric oxide synthase inhibitor. It was concluded that electrical stimulation of the stomach, intestine, or colon with long pulses has an inhibitory effect on gastric tone, and the most effective stimulation is CES. The inhibitory effect is not organ-specific and is unrelated to the distance between the stimulation site and the affected organ. The inhibitory effect of IES on gastric tone is mediated by the nitrergic pathway.

Efficacy of gastric electrical stimulation in improving functional vomiting in patients with normal gastric emptying

The objective of this study is to evaluate the utility of gastric electrical stimulation (GES) in the subgroup of patients with refractory nausea and vomiting in the presence of normal gastric emptying. Eighteen patients (15 females) underwent GES implantation for dyspeptic symptoms in the presence of normal gastric emptying. Upper gastrointestinal (UGI) symptom score, health-related quality of life (HR-QOL), nutritional status and weight, and medication use (prokinetics and antiemetics) were assessed at baseline and at 1 year after GES placement. Twelve patients (two males) were included in the final analysis. All patients had normal gastric emptying scintigraphy at baseline. After 1 year of GES, there was a significant reduction in the UGI symptom score from 18 to 10 (P = 0.001). The physical component score (PCS) of the HR-QOL was also significantly increased from 25 to 42 (P = 0.04). Gastric emptying actually became slower in 29% of those who repeated the test after 1 year. No adverse events related to GES placement were recorded. Results of our study suggest that GES improves dyspeptic symptoms in patients with medically refractory nausea and vomiting independent of its effect on gastric emptying and could be considered as a potential therapy in this clinical setting.

Mechanisms of symptomatic improvement after gastric electrical stimulation in gastroparetic patients

The aims were to investigate the effects of gastric electrical stimulation (GES) on autonomic function, gastric distention and tone, and central control mechanisms in gastroparetic patients. Ten gastroparetic patients refractory to standard medical therapy participated in this study and data were collected at baseline, within two weeks before surgery for implantation of GES system, and at follow-up sessions between 6 and 12 weeks after GES therapy was initiated. In each session, electrocardiogram, electrogastrogram (EGG) and gastric barostat measurements were conducted before and after a caloric liquid meal. Positron Emission Tomography (PET) brain scans were performed on a separate day. During GES therapy there was a significant increase in the discomfort threshold for mean pressure from 21 mmHg at baseline to 25 mmHg at follow-up, and for mean volume from 561 mL to 713 mL. A significant increase in the postprandial EGG power (amplitude) was observed between baseline and follow up. The sympathovagal balance was significantly decreased after GES therapy, indicating a significant increase in vagal activity. The cumulative PET data showed an increase in quantitative radioactive counts relative to the standardized data base in both the thalamic and caudate nuclei after chronic GES therapy. We conclude that our data suggest that the symptomatic improvement achieved by GES in gastroparesis is best explained by activation of vagal afferent pathways to influence CNS control mechanisms for nausea and vomiting accompanied by enhanced vagal efferent autonomic function and decreased gastric sensitivity to volume distention which enhances postprandial gastric accommodation.

Gastric emptying function in patients 5 years after pylorus-preserving distal gastrectomy with or without preserving pyloric and hepatic branches of the vagal nerve for early gastric cancer

BACKGROUND

To clarify the significance of preserving pyloric and hepatic branches of the vagal nerve (PHV) after pylorus preserving distal gastrectomy (PPG) for early gastric cancer, the author investigated the postgastrectomy syndrome and gastric emptying function at 5 years in PPG patients with or without preserving the PHV.

METHODS

A total of 18 subjects (mucosal cancers) who underwent PPG with D1 lymph node dissection and preserving the PHV; they comprised group A-12 men and 6 women aged 38-68 years (mean 58.9 years). They were interviewed to inquire about gastrointestinal symptom (appetite, weight loss, gastric fullness, reflux esophagitis, early dumping syndrome) and then were compared with 24 PPG patients (submucosal cancers) with D2 lymph node dissection without preserving the PHV (group B-16 men and 8 women aged 33 to 69 years, mean 60.1 years). Esophagogastric endoscopy, abdominal ultrasonography, and gastric emptying function tests (GET) were undertaken, the latter by both radioisotope (solid diet) and acetaminophen (liquid diet) methods.

RESULTS

There were no differences in the postoperative gastrointestinal symptoms, endoscopic reflux esophagitis, or endoscopic mucosal edema and redness (gastropathy) between groups A and B. However, more cholecystolithiasis (gallbladder stones) was found in group A than in group B, with the difference being significant (P < 0.0391). The GET for solid diet and liquid diet were the almost same among groups A and B.

CONCLUSIONS

There were no significant differences in the postoperative QOL and GET between PPG patients with preserving PHV and those without preserving PHV. Cholecystolithiasis was only found in patients without preserving PHV.

High-frequency gastric electrical stimulation for the treatment of gastroparesis: a meta-analysis

BACKGROUND & AIMS

High-frequency gastric electrical stimulation (GES) is a relatively new treatment for medically refractory gastroparesis. There have been a number of clinical studies based on the use of a high-frequency stimulator (Enterra, Medtronic, Minneapolis, MN). A meta-analysis was performed to evaluate evidence for improved clinical outcome with this device.

METHODS

A literature search of major medical databases was performed for the period January 1992 to August 2008. Clinical studies involving an implanted high-frequency GES device were included and reported a range of clinical outcomes. Studies of external, temporary, and/or low-frequency GES were excluded.

RESULTS

Of 13 included studies, 12 lacked controls and only one was blinded and randomized. Following GES, patients reported improvements in total symptom severity score (3/13 studies, mean difference 6.52 [confidence interval--CI: 1.32, 11.73]; P = 0.01), vomiting severity score (4/13, 1.45 [CI: 0.99, 1.91]; P < 0.0001), nausea severity score (4/13, 1.69 [CI: 1.26, 2.12]; P < 0.0001), SF-36 physical composite score (4/13, 8.05 [CI: 5.01, 11.10]; P < 0.0001), SF-36 mental composite score (4/13, 8.16 [CI: 4.85, 11.47]; P < 0.0001), requirement for enteral or parenteral nutrition (8/13, OR 5.53 [CI: 2.75, 11.13]; P < 0.001), and 4-h gastric emptying (5/13, 12.7% [CI: 9.8, 15.6]; P < 0.0001). Weight gain did not reach significance (3/13, 3.68 kg [CI: -0.23, 7.58]; P = 0.07). The device removal or reimplantation rate was 8.3%.

CONCLUSIONS

Results show substantial benefits for high-frequency GES in the treatment of gastroparesis. However, caution is necessary in interpreting the results, primarily because of the limitations of uncontrolled studies. Further controlled studies are required to confirm the clinical benefits of high-frequency GES.

Clinical management of motility disorders in children

We review the current clinical evaluation and management of the most common esophageal and gastrointestinal motility disorders in children based on the literature and our experience in a pediatric motility center in the United States. The disorders discussed include esophageal achalasia, pre- and post-fundoplication motility disorders, gastroparesis, motility disorders occurring after repair of congenital atresias, motility disorders associated with gastroschisis, chronic intestinal pseudo-obstruction, motility after intestinal transplantation, motility disorders after colonic resection for Hirschsprung's disease, chronic functional constipation, and motility disorders associated with imperforate anus.