Gastric electrical stimulation (GES) is a surgically implanted treatment option for treating gastroparesis resistant to medical therapy. Gastroparesis is characterised by a delay in gastric emptying in the absence of any physical obstruction [
Three principal methods are currently available: gastric low-frequency/high-energy GES with long pulse stimulation, high-frequency/low-energy GES with short pulse stimulation, and neural sequential GES [
Insertion of GES device involves the surgical placement of several electrodes into the muscle layer of the stomach, typically delivering two short pulses with an interval of 72 ms, width of about 0.3 ms, and amplitude of about 5 mA7 [
A review protocol was devised regarding search strategy and data extraction. Studies published since 1993 were identified using PubMed, Web of Knowledge, DISCOVER, and the Cochrane Library. The search terms included those used originally by Zhang and Chen (2006) [
Data were extracted from reports by the authors using a preprepared spreadsheet. The data extracted was as follows: study year, sample size, participant demographics and aetiology of gastroparesis, study design and methods, follow-up duration, and outcome measures: symptom scores, gastric emptying time, nutritional status, quality of life, medication usage, weight, and BMI. Risk of bias was assessed using Cochrane Review guidelines [
Through database searching of PubMed, DISCOVER, Web of Knowledge, and the Cochrane Library 1139 papers were identified. Of these, 52 were deemed potentially relevant based on assessment of their title and abstract. After removal of reviews, small sample-sized studies, and irrelevant papers as judged by full text review (Figure
Summary of studies.
Study | Methods |
|
Participants | Follow-up |
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Forster et al., 2001 [ |
Cohort-observational | 25 | 19 DG, 3 IG, and 3 PSG | 12 months |
Abell et al., 2002 [ |
Cohort-observational | 38 | 9 DG, 24 IG, and 5 PSG | 11 months |
Abell et al., 2003 [ |
Crossover and then observational | 33 | 17 DG, 16 IG | 12 months |
Abell et al., 2003 [ |
Cohort-observational | 12 | 3 DG, 9 IG | 60 months |
Forster et al., 2003 [ |
Cohort-observational | 55 | 39 DG, 7 IG, and 9 PSG | 12 months |
Lin et al., 2004 [ |
Cohort-observational | 48 | 48 DG | 12 months |
McCallum et al., 2005 [ |
Cohort-observational | 16 | 16 PSG | 12 months |
van der Voort et al., 2005 [ |
Cohort-observational | 17 | 17 DG | 12 months |
Lin et al., 2005 [ |
Cohort-observational | 37 | 24 DG, 8 IG, and 5 PSG | 12 months |
Mason et al., 2005 [ |
Cohort-observational | 29 | 24 DG, 5 IG | 20 months |
Lin et al., 2006 [ |
Cohort-observational | 55 | 39 DG, 9 IG, and 6 PSG | 36 months |
Anand et al., 2007 [ |
Cohort-observational | 214 | 146 IG, 45 DG, and 23 PSG | 48 months |
Lin et al., 2008 [ |
Cohort-observational | 63 | 38 DG, 11 IG, and 14 PSG | 12 months |
McKenna et al., 2008 [ |
Cohort-observational | 19 | 10 DG, 6 IG, and 3 PSG | 9.5 months |
Brody et al., 2008 [ |
Cohort-observational | 50 | 20 DG, 25 IG, 2 PSG, and 3 CTG | 12 months |
McCallum et al., 2010 [ |
Crossover and then observational | 55 | 55 DG | 12 months |
McCallum et al., 2011 [ |
Cohort-observational | 221 | 142 DG, 48 IG, and 31 PSG | 56 months |
O’Loughlin et al., 2013 [ |
Cohort-observational | 17 | 9 DG, 7 IG, and 1 PSG | 14 months |
McCallum et al., 2013 [ |
Crossover and then observational | 32 | 32 IG | 12 months |
Ross et al., 2014 [ |
Cohort-observational | 25 | 15 DG, 10 IG | 6 months |
Brody et al., 2015 [ |
Cohort-observational | 79 | 43 IG, 37 DG | 12 months |
DG: diabetic gastroparesis; IG: idiopathic gastroparesis; PSG: postsurgical gastroparesis; WVF: Weekly Vomiting Frequency; WNF: Weekly Nausea Frequency; GET: gastric emptying; SAQ: self-administered questionnaire; M: months; Y: years; W: weeks; TSS: Total Symptom Score; PCS: Physical Composite Score; MCS: Mental Composite Score (PCS and MCS are aspects of QOL assessment); EFT: enteral feeding tube; TPN: total parenteral nutrition; N: nausea; V: vomiting; PK: prokinetics; AE: antiemetics; PPF: postprandial fullness; ILM: isotope labelled meal.
Study characteristics.
Study | Follow-up | Measure | Outcome at 12 months (unless otherwise stated) |
---|---|---|---|
Forster et al., 2001 [ |
12 M | Symptoms | Significant improvement in N and V |
GE | No significant improvement | ||
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Abell et al., 2002 [ |
3 M | Symptoms | MVF: 21 to 0; MNF: 21 to 2 |
GE | No significant improvement | ||
12 M | Symptoms | WVF down to average 90%; WNF: 28 to 1 | |
GE | No significant improvement reported | ||
Medication | Significant decrease in use of AE/PK; patients requiring none rose 5 to 14 | ||
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Abell et al., 2003 [ |
2 M | Symptoms | WVF in combined group (all patients) significantly reduced |
12 M | Symptoms | WNF down to 64% baseline in combined group | |
GE | 78% to 56% 2-hour retention of ILM ( | ||
Quality of life | PCS: 25.8 to 32.4; MCS: 36.1 to 45.1 (combined group) | ||
Nutrition | 9 out of 14 discontinued nutrition | ||
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Abell et al., 2003 [ |
60 M | Symptoms | Mean TSS scores: 35.6 to 16.6; at 60 M TSS score mean at 20.3 ( |
Quality of life | Overall score increased by mean 2.1 points by 60 M | ||
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Forster et al., 2003 [ |
12 M | Symptoms | TSS severity mean: 20 to 9.1; frequency mean: 21 to 10 |
Quality of life | MCS: 37 to 48; PCS: 24 to 33 | ||
GE | No change | ||
BMI | BMI and body weight increased significantly | ||
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Lin et al., 2004 [ |
12 M | Symptoms | TSS severity mean: 17.6 to 7.9; frequency mean: 18.5 to 8.9 ( |
GE | No significant change (significance seen at 6 M) | ||
Quality of life | MCS: 36.9 to 46; PCS: 23.8 to 33.5 ( | ||
Days in hospital | Mean hospital stay reduced by 52 days compared to the prior year | ||
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McCallum et al., 2005 [ |
12 M | Symptoms | TSS severity: 17.1 to 8.6; frequency: 19.2 to 9.89 ( |
GE | No significant change | ||
Quality of life | PCS: 28.6 to 37.7; MCS: 39.7 to 49.6 ( | ||
Days in hospital | Reduced by a mean of 25 days compared to the prior year | ||
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van der Voort et al., 2005 [ |
12 M | Symptoms | WVF: 26 to 4; WNF: 34 to 12 ( |
GE | 2-hour retention of ILM: 83 to 25%; 4-hour retention of ILM: 38 to 17% ( | ||
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Lin et al., 2005 [ |
12 M | Symptoms | On PK: TSS: 18.1 to 7.4; off PK: TSS: 17 to 2.6 |
On AE: TSS: 19.1 to 9.9; off AE: TSS: 17.7 to 5 | |||
Quality of life | On medication at follow-up: PCS: 21.3 to 33.8; MCS: 36.4 to 50.2 | ||
Days in hospital | 50 to 14.9 patients had no admissions | ||
Medication | Patients requiring PK reduced from 27 to 19; patients requiring AE reduced from 26 to 17 | ||
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Mason et al., 2005 [ |
20 M | Symptoms | No significance reported |
GE | Rate of emptying: 0.17% to 0.38% per minute ( | ||
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Lin et al., 2006 [ |
36 M | Symptoms | TSS: 21 to 6 ( |
Days in hospital | 31 to 5 ( | ||
Medication | Medication use significantly reduced | ||
Nutrition | Patients requiring nutrition reduced from 15 to 8 ( | ||
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Anand et al., 2007 [ |
48 M | Symptoms | TSS: 15.6 to 10.9; WVF down to 62%; WNF down to 59%, by 4 years |
GE | 2-hour retention of ILM: 55 to 42%; 4-hour retention of ILM: 26 to 17% by 4 Y | ||
Survival | No significant differences in survival | ||
Quality of life | IDIOMS score from 16.3 to 10.6 ( | ||
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Lin et al., 2008 [ |
12 M | Symptoms | TSS decreased from 19.9 to 9.1 ( |
GE | 2-hour ILM retention: 73% to 63%; 4-hour retention from 46% to 34% ( | ||
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McKenna et al., 2008 [ |
9.5 M | Symptoms | TSS: 17.1 to 7.7; DG: 16.9 to 5.6 ( |
GE | No significant change reported | ||
Quality of life | No significant change | ||
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Brody et al., 2008 [ |
12 M | Symptoms | TSS severity: 19.05 to 14.05; frequency: 20.39 to 15.71 |
GE | 2-hour retention of ILM: 66% to 50% ( | ||
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McCallum et al., 2010 [ |
3 M | Symptoms | No significant findings |
12 M | Symptoms | WVF: 19.5 to 4.25; TSS frequency: 18.74 to 11.95; severity: 17.08 to 10.69 | |
GE | 2-hour retention: 76.5 to 51%; 4-hour retention of ILM: 46.5 to 20.5% | ||
Quality of life | MCS: 29.53 to 36.43; PCS: 33.53 to 40.35 | ||
Days in hospital | 40 to 10 | ||
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McCallum et al., 2011 [ |
56 M | Symptoms | TSS: 19.4 to 9.2; DG: 19.8 to 8.7; IG: 18.6 to 9.7; PSG: 19.1 to 10.9 at 56 M |
GE | 2-hour retention: 70 to 66%; 4-hour retention of ILM: 37 to 30% at 56 M | ||
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O’Loughlin et al., 2013 [ |
14 M | Symptoms | Total GCSI from 13.4 to 6.6 |
GE | Correlation between GCSI and preoperative gastric emptying | ||
Medication | Significance not reported | ||
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McCallum et al., 2013 [ |
12 M | Symptoms | WVF and TSS reduction between ON and OFF not significant |
TSS frequency score from 21.74 ± 1.75 to 13 ± 7.92; |
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TSS severity score from 18.75 ± 6.34 to 10.26 ± 7.09; |
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TSS reduction for epigastric pain and burning not significant | |||
GE | 2 hr ILM retention reduction from 63.5% to 49% ( | ||
Median from 2 to 0 ( | |||
Days in hospital | 26.96 to 24.74 ( | ||
BMI | PCS from 32.66 ± 8.8 to 37.86 ± 13.28 ( | ||
Quality of life | SF, MH, and RP |
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Ross et al., 2014 [ |
6 M | Quality of life | Improvement in overall GSRS score, |
Median MHC score from 29.15 to 46.6, |
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Median PHC score from 28.5 to 31.1, |
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Brody et al., 2015 [ |
12 M | Symptoms | TSS functional from 3.2 ± 0.6 to 2.4 ± 0.8; |
TSS pain from 2.8 ± 0.8 to 2.1 ± 0.8; |
DG: diabeticgastroparesis; IG: idiopathicgastroparesis; PSG: postsurgicalgastroparesis; CTG: connective tissue disorder.
Flow chart of paper selection and analysis.
Overall the risk of bias was considered medium to high in the majority of studies with low risk being suggested only in Abell et al., 2003 [
In addition it was noted that six of the studies used the same hospital and time period (Kansas University Medical Centre between 1998 and 2002) [
There is a variation in the methods used to assess the improvement in symptoms in the patients with GES implants. Most commonly used measures were Total Symptom Score (TSS) [
To date there have been just three studies fulfilling employing a blinded period of study [
In the second example, McCallum et al., 2010 [
Additionally, several large scale nonrandomised studies have displayed similar results in terms of symptom improvements. Most notably, McCallum et al., 2011 [
All studies investigating gastric emptying used a 2-hour and 4-hour Gastric Emptying Test (GET) after a low fat meal. Seven studies [
Abell et al. (2003) [
Pyloroplasty was only rarely carried out in conjunction with insertion of GES. Only 4 (0.73%) patients out of 545 patients who were reviewed for GE in the studies included in the review had pyloroplasty during the assessment. From the 3 studies that included patients with pyloroplasty, only Mason et al. [
Papers reported an increase in quality of life as analysed mainly via Short Form 36 (SF-36) [
The number of days spent in the hospital in the year after GES is commenced is reported to be between 13 and 31% of the number spent in the year before the surgery [
None of the included studies reported a death associated with GES implantation. One study analysed long-term survival in implanted patients. Anand et al., 2007 [
Adverse events can be noted in patients after GES insertion, although serious adverse events such as migration of the leads and infections of the pocket of the pulse generator are infrequent. Typically complications occur between 5 and 14% [
These studies included in the review used a variety of outcome measures and variety of preoperative assessments, making it difficult to combine data and offer firm conclusions. The evidence base for the use of GES in gastroparesis is limited with a total of just five months of blinded, randomised study including only 83 patients [
The absence of a standardised approach to symptom reporting and preoperative assessment means comparison between studies is challenging, and combining results in a meta-analysis is not possible. The commonest symptom assessments used include Total Symptom Score (TSS) and Gastroparesis Cardinal Symptom Index (GCSI) for scoring symptoms. Some solely measured weekly vomiting and nausea frequency. For example, Abell et al., 2002 [
Gastric emptying was mainly measured using standardised scintigraphy analysis of retention of an isotope labelled meal. There was a discrepancy in the definition of delayed gastric emptying employed in the included studies [
Only two studies suggested a correlation between gastric emptying and symptoms [
McCallum et al., 2011 [
The crossover trials offer conflicting views. While Abell et al., 2003 [
Patient study populations also pose significant confounding within the literature. Many of the study patients were recruited at the same study centre during the same time period (Kansas University Medical Centre between 1998 and 2003) [
Follow-up reporting was not consistent, and many papers did not state mean or median follow-up time or at which stage of follow-up the results presented reflected. In one instance a mean follow-up of 56 months referred to a range of 12 to 123 months [
A dominant financial support within the literature was Medtronic (Minneapolis, USA), with 14 of the 21 studies included in this review reported being financially supported, either in part or in full, by it [
Given the absence of high-quality data to support the efficacy of GES for gastroparesis, there is a need for a randomised crossover study, which based on the safety record of the intervention and analysis of long-term survival in patients postoperatively [
A better understanding of preoperative patient factors that contribute to outcome is needed to improve selection of patients for this therapy and consequently outcomes. GES does appear to offer a significant benefit to a subset of patients, and future research should be aimed at identifying this subset preoperatively. Limited research into this has suggested potential predictive factors that need further exploration [
Investigation into novel surgical approaches could include the addition of pyloroplasty during GES insertion which was suggested to improve gastric emptying when compared to patients who were given GES alone (64% GES + PP improvement versus 7% GES,
Gastroparesis has a significant impact on a patient’s quality of life and is associated with significant economic cost. Although its supporting evidence base is limited, GES does seem to offer significant improvement in quality of life and symptom control to a subset of patients. The limited current use of this intervention lends itself to easily implementable strategy for the improvement of data quality. To facilitate improved understanding of GES and who it may benefit, an international registry, with standardised preoperative assessment (Table
Minimum criteria for insertion and reporting outcomes of gastric electrical stimulation (GES).
Assessment | Measure |
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Quality of life | Short Form 36 (SF-36) |
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|
Symptoms | Total Symptom Score (TSS) |
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Days in hospital | Days in hospital in the last 12 |
months | |
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Medication | Is the patient on any prokinetics or |
antiemetics? | |
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Gastric emptying | Standardised scintigraphy analysis of retention of an isotope labelled meal. |
The authors declare no conflict of interests.