Gastric Pacing / Electrical Stimulation and Gastric Per Oral Endoscopic Myotomy

Number: 0678

Policy

Aetna considers gastric pacing (gastric pacemaker) and gastric electrical stimulation medically necessary for the treatment of symptoms of nausea and vomiting from chronic gastroparesis, where the diagnosis is confirmed by gastric emptying scintigraphy, that is refractory to medical management (including dietary modification, antiemetics, and prokinetics).

Aetna considers revision or replacement of a previously approved gastric stimulator implant medically necessary for complications associated with gastric pacing (eg, bowel obstruction, gastric wall perforation, infection, lead dislodgement or lead erosion into the small intestine).

Aetna considers gastric pacing and gastric electrical stimulation experimental and investigational for all other indications including the following because their effectiveness for these indications has not been established (not an all-inclusive list):

  • As an initial treatment for gastroparesis
  • For the treatment of autonomic nervous system disorders other than gastroparesis
  • For the treatment of cyclic vomiting syndrome
  • For the treatment of diabetes mellitus in persons without gastroparesis
  • For the treatment of gastrointestinal dysmotility disorders other than gastroparesis
  • For the treatment of obesity.

Note: The use of a second gastric electrical stimulator for the treatment of symptoms of nausea and vomiting from chronic gastroparesis is considered experimental and investigational.

Aetna considers gastric per-oral endoscopic myotomy (G-POEM) experimental and investigational for the following indiations because its effectiveness for these indications has not been established (not an all-inclusive list):

  • Treatment of congenital hypertrophic pyloric stenosis
  • Treatment of gastroparesis.

Background

Gastroparesis is a chronic gastric motility disorder of diabetic (both type 1 and type 2 diabetes) or idiopathic etiology.  It is characterized by delayed gastric emptying of solid meals.  Patients with gastroparesis exhibit bloating, distension, nausea, and/or vomiting.  In severe and chronic cases, patients may suffer dehydration, poor nutritional status, and poor glycemic control (in diabetics).  Although gastroparesis is often associated with diabetes, it is also found in chronic pseudo-obstruction, connective tissue disorders, Parkinson disease, and psychological pathology.  Therapeutic options of gastroparesis include prokinetic agents such as metoclopramide, and anti-emetic agents such as metoclopramide, granisetron, or odansetron.  Patients with severe gastroparesis may require enteral or total parenteral nutrition. 

Gastric pacing (gastric stimulation) is utilized to treat individuals with chronic, intractable or drug-refractory nausea and vomiting secondary to gastroparesis. A gastric pacing system delivers electrical stimulation to the gastric muscles by means of two leads that are implanted directly into the stomach and connected to a generator that is implanted into the abdominal area. The device is regulated by an external programmer that noninvasively adjusts the level of gastric stimulation and also allows the device to be completely turned off at any time. Internal battery replacement is required every five to ten years.

Gastric pacing (gastric pacemaker) entails the use of a set of pacing wires attached to the stomach and an external electrical device that provides a low-frequency, high-energy stimulation to entrain the stomach at a rhythm of 3 cycles per minute. However, the gastric pacemaker is cumbersome and problematic for chronic use because of external leads. 

Thus, a newer, implantable device (the Enterra Therapy System by Medtronic, Minneapolis, MN) was developed to provide gastric electrical stimulation (GES).  Unlike gastric pacing, the Enterra delivers a high-frequency (12 cycles per minute), low-energy stimulation to the stomach.  This stimulating frequency does not entrain the stomach, and therefore does not normalize gastric dysrhythmias; hence, the term GES is employed to differentiate between the Enterra and gastric pacing. The Enterra Therapy II system is the only gastric electrical stimulation system approved for marketing by the US Food and Drug Administration (FDA). It is approved under a Humanitarian Device Exemption (HDE). 

The Enterra System was designed to treat intractable nausea and vomiting secondary to gastroparesis.   Electrodes are implanted in the serosa of the stomach laparoscopically or during a laparotomy, and are connected to the pulse generator that is implanted in a subcutaneous pocket.  The Enterra Therapy System (Medtronic, Minneapolis, MN) is currently the only GES that has received approval from the U.S. Food and Drug Administration (FDA).  It was cleared by the FDA as a humanitarian use device.  Thus, the manufacturer was not required to submit the level of evidence that would be required to support a pre-market approval application.  The data presented to the FDA documenting the "probable benefit" of GES (Gastric Electrical Stimulation System) were based on a multi-center double-blind cross-over study (FDA, 2000), which included 33 patients with intractable idiopathic or diabetic gastroparesis.  In the initial phase of the study, all patients underwent implantation of the stimulator and were randomly assigned to stimulation-ON or stimulation-OFF for the first month, with cross-over to OFF and ON during the second month.  The baseline vomiting frequency was 47 episodes per month, which significantly declined in both ON and OFF groups to 23 to 29 episodes, respectively.  However, there were no significant differences in the number of vomiting episodes between the two groups, suggesting a placebo effect.  Thus, long-term results of GES must be validated in longer term randomized studies.  It is important to note that GES did not return gastric emptying to normal in the majority of the treated-patients. 

There exist preliminary data that suggested gastric pacing may be beneficial to patients with refractory gastroparesis.  Forster et al (2001) reported the findings of 25 patients who underwent gastric pacemaker placement.  Both the severity and frequency of nausea and vomiting improved significantly at 3 months and improvements were sustained for 12 months.  Gastric emptying time was also numerically faster over the 12-month period.  Three of the devices were removed and 1 patient died of causes unrelated to the pacemaker 10 months post-operatively.  The authors stated that after placement of the gastric pacemaker, patients rated significantly fewer symptoms and had a modest acceleration of gastric emptying.

Abell et al (2002) performed GES in 33 patients with intractable gastroparesis.  Patients were assessed 3, 5 and 12 months following permanent implantation.  These researchers reported that 97 % of patients experienced greater than 80 % reduction in nausea and vomiting.  For 24 patients who were followed for 1 year, the average weight gain was 5.5 % and 9 of 14 patients receiving enteral or parenteral nutrition were able to discontinue it.  The authors stated that while symptoms improved in the majority of patients following implantation of gastric stimulators, a properly randomized study is needed to ascertain the extent of a favorable placebo response. 

Bortolotti (2002) noted that there are currently 3 principal methods of GES:
  1. gastric electrical pacing,
  2. high-frequency GES, and
  3. sequential neural electrical stimulation. 

The first method aims to reset a regular slow-wave rhythm, but is unable to re-establish efficient contractions and a normal gastric emptying.  High-frequency GES, although inadequate to restore a normal gastric emptying, nevertheless strikingly improves the dyspeptic symptoms, such as nausea and vomiting, giving the patients a better quality of life and a more satisfactory nutritional status.  The last method, neural electrical gastric stimulation, consists of a microprocessor-controlled sequential activation of a series of annular electrodes which encircle the distal 2/3 of the stomach and induce propagated contractions resulting in a forceful emptying of the gastric content.  The latter method is the most promising, but it has so far only been tested in animals and would need to be tested in patients with gastroparesis before it can be used as a solution for this disease.  All the afore-mentioned clinical studies, however, are not controlled and nearly all were published in abstract form.  Thus, further controlled studies are needed to ascertain which of these techniques is more useful for the treatment of gastroparesis.  This is in agreement with Rabine and Barnett (2001) who considered gastric pacing as an experimental technique for the management of patients with gastroparesis.  Additionally, Smith and Ferris (2003) stated that gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation.  Furthermore, in a systematic review of evidence of therapies for gastroparesis, Jones and Maganti (2003) concluded that gastric neurostimulation improves symptoms of nausea and vomiting, but therapeutic gain beyond placebo has not been demonstrated.

Abell et al (2003) reported on a 2-phase clinical study of GES for gastroparesis: in the first phase, lasting 2 months, the investigators attempted to blind participants to stimulation.  In the first phase, 33 patients with gastroparesis (17 diabetic, 16 idiopathic) were randomized to stimulation either ON or OFF for 1 month, then crossed-over to the other mode for 1 month.  During the second uncontrolled phase of the study, all patients had their stimulator turned ON and were followed at 6 and 12 months.  The investigators reported that, during the first phase of the study, vomiting frequency was significantly less in the ON position, than in the off position, with weekly vomiting frequencies of 6.8 and 13.5 episodes, respectively (p < 0.05).  Total symptom score (mean sum of 6 symptoms, rated from 0 (absent) to 4 (severe) was also slightly less in the ON position than the OFF position, with scores of 12.5 + 1.0 and 13.9 + 1.1, respectively.  The investigators noted that 21 patients preferred the ON mode and 7 patients preferred the OFF mode.  An assessment by the National Institute for Clinical Excellence (NICE, 2004) commented that the results of this study are based on short-term follow-up of a small number of patients.  The assessment noted that one of the difficulties in interpreting the evidence on this procedure in this and other studies is the reliance on self-reported measures of symptom relief.   Furthermore, given the nature of the GES procedure, it is possible that patients experienced a placebo response.  The investigators reported that, during the second phase, there were significant improvements from baseline in weekly vomiting frequency, total symptom score, and measures of gastric emptying.  However, only 24 subjects included in this study were followed for 12 months, and gastric emptying data were available for only 20 subjects at 12 months. 

More recent studies have examined the effectiveness of gastric pacing in refractory gastroparesis.  These studies are limited by the lack of a control group, so that the effect of GES on gastroparesis can not be distinguished from the effects of the waxing and waning nature of these symptoms and the effects of concurrent interventions that the patient may be receiving for this condition.  Lin et al (2004) reported on the results of an uncontrolled study of GES in diabetic patients (n = 48) with refractory gastroparesis.  The investigators reported that, after application of high-frequency GES by a permanently implanted system, improvements were observed in upper gastrointestinal symptoms, health-related quality of life, nutritional status, glucose control, and hospitalizations.  van der Voort and colleagues (2005) reported improvements in symptom control and decreases in gastric retention (measured scintigraphically) after 12-months of continuous high-frequency/low-energy GES in a small group (n = 17) of insulin-dependent diabetic subjects suffering from drug-refractory gastroparesis.  The lack of a control group limits the strength of conclusions that can be drawn from these studies.

MaCallum et al (2005) reported on 12 month outcomes of GES in an uncontrolled study of a small group (n = 16) of subjects with post-surgical gastroparesis.  The investigators reported that, after application of GES, there was significant improvement in upper gastrointestinal symptoms, quality of life, nutritional status, and hospitalization requirements.  Lin et al (2005) reported significant reductions in the use of prokinetic/anti-emetic medications and the need for hospitalization after application of GES in an uncontrolled study of refractory gastroparetic patients (n = 37).  The authors also reported that subjects clinical and quality of life outcomes significantly improved after 1 year follow-up.  Other long-term uncontrolled studies include those of Oubre et al (2005) (46 month follow-up) and Cutts et al (2005) (3 year follow-up).

An assessment by the National Institute for Clinical Excellence (2004) concluded that "[c]urrent evidence on the safety and efficacy of gastroelectrical stimulation for gastroparesis does not appear adequate to support the use of this procedure without special arrangements for consent and for audit or research".  The assessment explained that “[c]urrent evidence on the efficacy of the procedure relates mainly to relief from nausea and vomiting, which occurs in some patients. There is little evidence that the procedure improves gastric emptying.”  The assessment reported that one of the difficulties in interpreting the evidence on this procedure is that most studies lack a comparision group, and rely on self-reported measures of symptom relief.

Evidence-based guidelines on gastroparesis from the American Gastroenterological Association (Parkman et al, 2004) state: “Gastric electric stimulation is an emerging therapy for refractory gastroparesis …. Studies to better evaluate the efficacy of gastric electric stimulation are ongoing.  As this type of treatment evolves, further delineation of the overall effectiveness, the type of patient who will likely respond, optimal electrode placement, and stimulus parameters should be explored.”

In a case series study, Filichia and Cendan (2008) assessed the response of transplant patients with gastroparesis to GES (Enterra therapy) and compared to non-transplant recipients.  A questionnaire consisting of 11 questions was administered to investigate symptoms.  Patients were asked to score these symptoms before and after surgery using a 0 to 5 Likert scale.  A total of 13 consecutive patients underwent placement of the Enterra device with a mean follow-up of 12 +/- 6.1 months.  Transplant recipients were as likely as diabetic or idiopathic patients to show improvements in symptoms of nausea, vomiting, as well as retching and prandial symptoms following Enterra therapy.  In fact, transplant patients reported improvement in appetite and bloating symptoms more frequently than diabetics (p = 0.055 and p = 0.037, respectively).  The authors concluded that post-transplantation gastroparesis responds to Enterra therapy as well as in patients with idiopathic or diabetic gastroparesis.  They stated that Enterra therapy should be prospectively investigated in this population of patients.

An UpToDate review on “Electrical stimulation for gastroparesis” (Hasler, 2015) states that “Patients with severe nausea and vomiting (occurring on average at least once-daily), which have proven refractory to aggressive anti-emetic and prokinetic drug therapy for at least 1 year in duration may be candidates for gastric neurostimulation. In the United States, the gastric electrical neurostimulator (Enterra Therapy system, Medtronic, Inc., Minneapolis, MN) has been approved as a humanitarian exemption device only for diabetic and idiopathic gastroparesis”.

Obesity is a major health problem among adults in the United States.  It is also an increasing health concern among American children as well as adolescents.  Various methods are employed in the management of obesity.  One of the new approaches is gastric pacing, which is intended to induce early satiety through electrical stimulation of the gastric wall.  However, the effectiveness of this technique in treating obesity has not been established.  Buchwald and Buchwald (2002) considered gastric pacing as an experimental procedure for the management of morbid obesity.

An assessment of gastric pacing for obesity by the Swedish Council on Technology Assessment in Healthcare (SBU, 2004) found that "[t]here is insufficient scientific evidence on the short-term patient benefit of gastric pacing" for obesity, and that "[t]here is no scientific evidence on the long-term patient benefit of gastric pacing" for this indication.  The assessment concluded:

“Gastric pacing is still an experimental method and should be used only in scientific studies that have been approved by a research ethics committee.  Trials that include adequate control groups are very much needed.”

Yao et al (2005) stated that acute retrograde gastric pacing at a tachygastrial frequency results in a significant reduction of water and food intake and a delay in gastric emptying without inducing any unacceptable symptoms.  The investigators concluded that it is worthy to explore its therapeutic potential for obesity.  In a review on the potential role of new therapies in modifying cardiovascular risk in over-weight patients with metabolic risk factors, Jensen (2006) noted that surgically implanted gastric pacemaker systems that modulate vagus nerve activity and delay gastric emptying are under study.

Salvi et al (2009) reported their 2-year experience on gastric pacing in the treatment of morbid obesity.  From August 2005 to January 2006, a total of 4 patients (mean age of 44 years) underwent placement for implantable gastric stimulation (IGS) therapy.  The mean bone mass index (BMI) was 41.8, mean weight 117.2 kg.  The IGS was activated 30 days after implantation.  Fasting and post-prandial plasma ghrelin concentrations after a test meal were measured before and 1, 2, 3 and 6 months after implantation.  All procedures were successfully completed laparoscopically.  There were no major operative complications.  Post-operative course was uneventful in all cases.  One patient was lost to follow-up after 6 months.  Post-operative lead dislodgement and cutaneous decubitus occurred in another patient, making necessary the removing of the device.  For the remaining 2 patients, there was a significant weight loss (49 kg) in 1, while weight was unchanged in the other.  Plasma ghrelin concentrations were not correlated among patients.  The authors concluded that morbid obese patients can undergo IGS implantation by laparoscopy with minimal peri-operative complications.  Attention to technical details is essential.  In accordance with the manufacturer, these data demonstrated that gastric pacing is a safe procedure for selected patients supported by adequate psychological treatment, but outcome about weight loss should be evaluated among bigger trial.  According to these investigators, their experience with IGS didn't provide satisfactory results, thus discouraging them to carry on with the study.

In a prospective, randomized, placebo-controlled, double-blind, multi-center study, Shikora et al (2009) compared IGS therapy with a standard diet and behavioral therapy regimen in a group of class 2 and 3 obese subjects by evaluating the difference in the percentage of excess weight loss (EWL) between the control and treatment groups.  The primary endpoint was the percentage of EWL from baseline to 12 months after randomization.  A total of 190 subjects were enrolled in this study.  All patients underwent implantation with the implantable gastric stimulator and were randomized to one of the following two groups:
  1. the control group (stimulation off) or
  2. treatment group (stimulation on). 

Patients were evaluated on a monthly basis.  All individuals who enrolled in this study agreed to consume a diet with a 500-kcal/day deficit and to participate in monthly support group meetings.  The procedure resulted in no deaths and a low complication rate.  The primary endpoint of a difference in weight loss between the treatment and control groups was not met.  The control group lost 11.7 % +/- 16.9 % of excess weight and the treatment group lost 11.8 % +/- 17.6 % (p = 0.717) according to an intent-to-treat analysis.  The authors concluded that IGS as a surgical option for the treatment of morbid obesity is a less complex procedure than current bariatric operations.  However, the results of the present study do not support its application.  They stated that additional research is needed to understand the physiology and potential benefits of this therapy.

Policker and colleagues (2009) noted that the TANTALUS System (MetaCure Limited) is a minimally invasive implantable device for the treatment of type 2 diabetes (T2DM).  The system detects food intake by sensing gastric electrical variations and applies electrical stimulation to the gut synchronized to natural gastric activity.  It is commercially available in Europe and Israel and is in clinical trials in the United States.  It has been tested in 132 patients worldwide to date.  These researchers re-analyzed previously reported data from different studies.  This retrospective analysis of the type 2 diabetes sub-population analyzed the expected benefit and characterized the significance of baseline A1c in the determination of the expected clinical outcome.  From the total cohort of 132 patients implanted with the TANTALUS device in 10 different centers in Europe and the United States, these investigators identified 50 subjects (27 females, 23 males) who were obese with uncontrolled T2DM on a stable regime of oral medication for 3 months before implantation of the device.  This population had similar inclusion/exclusion criteria as well as treatment protocols and were all treated for at least 24 weeks.  The analysis was based on the A1c change compared to baseline.  Data after 24 weeks demonstrated a reduction in A1c in 80 % of the patients with average drop in A1c of 1.1 +/- 0.1 %.  The average weight loss was 5.5 +/- 0.7 kg.  The authors concluded that these findings suggested that the TANTALUS stimulation regime can improve glucose levels and induce moderate weight loss in obese T2DM patients.

In an European multi-center, open-label clinical study, Bohdjalian and associates (2009) prospectively investigated the potential effect of the TANTALUS system on glycemic control and weight in over-weight subjects with T2DM.  A total of 13 T2DM obese (7 females, 6 males, BMI of 37.2 +/- 1.0 kg/m(2), range of 30.4-44.0 kg/m(2)) subjects treated with oral anti-diabetic medications but with poor glycemic control (HbA1c greater than or equal to 7 %, range of 7.3 to 9.5 %) were implanted laparoscopically with the TANTALUS system.  Thirteen subjects that had completed 3 months of treatment showed a significant reduction in HbA1c from 8.0 +/- 0.2 % to 6.9 +/- 0.1 % (p < 0.05), whereas fasting blood glucose decreased from 175 +/- 6 mg/dL to 127 +/- 8 mg/dL (p < 0.05).  The glycemic improvement was accompanied by reduction in weight from 104.4 +/- 4.4 kg to 99.7 +/- 4.8 kg, and in waist circumference from 122.3 +/- 3.2 cm to 117.0 +/- 3.0 cm.  The authors concluded that interim results with the TANTALUS system suggest that this stimulation regime can potentially improve glucose levels and induce moderate weight loss in obese T2DM subjects on oral anti-diabetic therapy with poor glycemic control.  They stated that further evaluation is needed to ascertain if this effect is due to induced weight loss and/or due to direct signal-dependent mechanisms.

Thazhath et al (2013) noted that delayed gastric emptying affects a substantial proportion of patients with long-standing diabetes, and when associated with symptoms and/or disordered glycemic control, affects quality of life adversely.  Important clinic-pathological insights have recently been gained by the systematic analysis of gastric biopsies from patients with severe diabetic gastroparesis, which may stimulate the development of new therapies in the coming decade.  The authors stated that experience with prokinetic therapies and treatments, such as pyloric botulinum toxin injection and GES, has established that relief of symptoms does not correlate closely with acceleration of delayed gastric emptying, and that well-designed randomized controlled trials are essential to determine the effectiveness of emerging therapies.

Cha and colleagues (2014) evaluated the current state-of-the-art of GES to treat obesity. These investigators performed systematic reviews of all studies to evaluate the effect of different types of GES on obesity. A total of 31 studies consisting of a total of 33 different trials were included in the systematic review for data analysis. Weight loss was achieved in most studies, especially during the first 12 months, but only very few studies had a follow-up period longer than 1 year. Among those that had a longer follow-up period, many were from the Transcend (Implantable Gastric Stimulation) device group and maintained significant weight loss. Other significant results included changes in appetite/satiety, gastric emptying rate, blood pressure and neuro-hormone levels or biochemical markers such as ghrelin and HbA1c. The authors concluded that GES holds great promises to be an effective obesity treatment. Moreover, they stated that stronger evidence is needed through more studies with a standardized way of carrying out trials and reporting outcomes, to determine the long-term effect of GES on obesity.

Gastric Pacing and Gastric Electrical Stimulation for Gastro-Intestinal Dysmotility

Sallam and associates (2014) stated that patients with gastro-intestinal (GI) dysmotility of systemic sclerosis (SSc, scleroderma) require careful evaluation and intervention. The lack of effective prokinetic drugs motivate researchers to search for alternative treatments. These researchers presented an overview of the pathophysiology of SSc GI dysmotility and the advances in its management, with particular focus on acupuncture-related modalities and innovative therapies. Original research articles were identified based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline methodology. These investigators have searched the MEDLINE database using Medical Subject Heading (MeSH) for all English and non-English articles with an English abstract from 2005 to October 2012. Key words used included gastric electrical stimulation. Only 4 original articles of various study designs were found studying complementary and alternative medicine (CAM) therapies for SSc patients. Despite the small patient study numbers, CAM treatments, acupressure, and transcutaneous electro-acupuncture, showed self-reported and physiologic evidence of improvement of GI functioning and/or symptoms in SSc patients. The authors concluded that CAM therapies include experimental modalities with the potential to offer relief of symptoms from GI dysmotility. They stated that larger studies are needed to investigate their optimal use in patient subsets to tailor therapies to patient needs.

Gastric Pacing and Gastric Electrical Stimulation for Cyclic Vomiting Syndrome

Grover and colleagues (2016) stated that cyclic vomiting syndrome (CVS) is a disabling migraine variant manifesting as severe episodes of nausea and vomiting and often refractory to many therapies. Gastric electrical stimulation, which can reduce nausea and vomiting in gastroparesis, may provide symptomatic relief for drug-refractory CVS.  In a 1-year, non-randomized, clinical study, these researchers examined the effects of GES in reducing the symptoms of CVS and improving quality of life.  A total of 11 consecutive patients with drug-refractory CVS based on Rome III criteria and North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN), underwent treatments with temporary GES (Temp GES) and permanent GES (Perm GES).  Post-treatment follow-up was carried out up to 1 year after Perm GES therapy.  Total symptom score decreased by 68 % and 40 % after Temp GES and Perm GES therapies, respectively.  Hospital admission events significantly decreased to 1.50 (± 1.00) events from 9.14 (± 7.21) annual admissions prior to treatment with Perm GES.  Vomiting episodes fell by 83 % post-Temp GES, and 69 % post-Perm GES treatments.  Mucosal electrogram values also changed after temporary stimulation.  The authors concluded that in a small group of drug-refractory CVS patients, treatments with Temp GES and Perm GES significantly reduced the severity of GI symptoms and frequency of hospital admissions.  These preliminary findings need to be validated by well-designed studies.

Gastric Pacing and Gastric Electrical Stimulation for Autonomic Nervous System Disorders

Lee and Abd-Elsayed (2016) stated that neuromodulation (e.g., GES, cavernous nerve 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.  These researchers discussed the evidence of using neuromodulation for treating some important disorders involving the autonomic nervous system (ANS) that are not currently FDA approved.  This was a review article that included a systematic online web search for human clinical studies testing the effectiveness of neuromodulation in treating asthma, erectile dysfunction, gastroparesis, gastro-esophageal reflux disease (GERD), heart failure, and obesity.  This review included all feasibility studies, non-randomized clinical trials, and randomized controlled trials (RCTs).  The systematic literature search found 3, 4, 5, 4, 1, and 4 clinical studies relating to erectile dysfunction, gastroparesis, GERD, obesity, asthma, and heart failure, respectively.  The authors concluded that this review article showed preliminary support based on clinical studies that neuromodulation can be of benefit for patients with important ANS disorders that are not currently approved by the FDA.  They stated that all of these investigational uses are encouraging; further studies are needed for all indications discussed in this review before achieving FDA approval.

Gastric Pacing and Gastric Electrical Stimulation for the Treatment of Obesity

Morales-Conde and colleagues (2018) noted that weight regain following bariatric surgery is not uncommon.  Safe, effective weight loss treatment up to 1 year has been reported with the closed-loop GES (CLGES) system.  Continuous recording of eating and activity behavior by onboard sensors is one of the novel features of this closed-loop electrical stimulation therapy, and may provide improved long-term weight maintenance by enhancing aftercare.  Four centers participating in a 12-month prospective multi-center randomized study monitored all implanted participants (n = 47) up to 24 months after laparoscopic implantation of a CLGES system.  Weight loss, safety, quality of life (QOL), and cardiac risk factors were analyzed.  Weight regain was limited in the 35 (74 %) participants remaining enrolled at 24 months.  Mean percent total body weight loss (%TBWL) changed by only 1.5 % between 12 and 24 months, reported at 14.8 % (95 % confidence interval [CI]: 12.3 to 17.3) and 13.3 % (95 % CI: 10.7 to 15.8), respectively.  The only serious device-/procedure-related adverse events (AEs) were 2 elective system replacements due to lead failure in the first 12 months, while improvements in QOL and cardiovascular risk factors were stable through 24 months.  The authors concluded that during the 24 month follow-up, CLGES was shown to limit weight regain with strong safety outcomes, including no serious AEs in the 2nd year.  These investigators hypothesized that CLGES and objective sensor-based behavior data combined to produce behavior change.  The findings of this study support CLGES as a safe obesity treatment with potential for long-term health benefits.

Busetto and associates (2018) analyzed behavior changes using sensor-based food intake and activity data in participants treated with the CLGES system.  Food intake and activity data (3-D accelerometer) were down-loaded at baseline and monthly/bimonthly for 12 months in a subset of patients with obesity (n = 45) participating in a multi-center trial with CLGES.  Measured food intake parameters included the number of intakes during allowed and disallowed periods, night-time intakes, and between-meal snacks (average/day).  Activity parameters included time in different levels of physical activity (mins/day), sleep/sedentary (hours/day), and estimated energy expenditure (EE).  Weight loss at 12 months averaged 15.7 ± 7.7 % of the baseline body weight.  Stable reduction in the number of disallowed meals and between-meal snacks (p < 0.05), an increase in all levels of physical activity (p < 0.001), and an increase in activity-based EE (303 ± 53 kcal/day on average, p < 0.001) were observed.  The authors concluded that significant and consistent positive changes in eating behavior and physical activity were observed in a small group of patients with severe obesity treated with CLGES therapy for 12 months.  These lifestyle modifications led to a clinically significant 15 % weight loss.  There is an increasing interest today in the use of modern advanced technology in behavioral therapy.  The potential of digital technology, including Web‐based tools, mobile phones and smartphone applications, virtual reality, and gaming technologies, has been reviewed in relation to both general obesity management and specifically in bariatric surgery.  Electronic activity monitor systems have been increasingly studied and have yielded positive results in clinical practice.  The CLGES system used in this study coupled effective and tailored GES with an extensive use of modern technology for behavioral self‐monitoring and modifications.  They stated that this new form of a combined weight loss approach appears promising and warrants further testing and application.

The authors stated that this study had several drawbacks.  First, food intake and physical activity down-loaded from the device at the 1st follow‐up visit, which was 2 weeks following implantation and before CLGES activation, were used as baseline data.  This raised the possibility that the behavior of the patients in this period could be influenced by the recent surgery and not be representative of normal behavior before the surgery.  However, device implantation required only minimal surgery, and patients usually did not experience significant problems or limitations in the early post-operative period.  Second, the follow‐up in this study was limited to 12 months, and this short period of observation raised some concern regarding the durability of behavioral changes and weight loss.  Weight loss has been reported to remain stable until 27 months in a small sample of patients treated with CLGES therapy, but controlled studies with a more extended follow‐up time are needed.  These investigators stated that one of the major issues raised by this study was what part of the effect of the CLGES system was due to the electrical stimulation and what part was due to the behavioral modifications determined by data monitoring.  The magnitude of the weight loss observed in this study was larger than the weight loss usually reported after behavioral programs, suggesting an additive effect between GES and behavioral modifications.  However, the design of this study precluded definitive conclusion.  The exact role played by each of the 2 components could be disentangled only by a specifically designed double‐blind study comparing weight loss in patients having the stimulation turned on or off.

Maisiyiti and Chen (2019) examined the feasibility of GES as a potential therapy for obesity.  These investigators presented several GES methods for treating obesity and their effects on food intake and body weight.  Possible mechanisms involved in the anti-obesity effect of GES were discussed.  They provided comments on the potential of GES for obesity and expectations for future development of the GES therapy.  The PubMed central data-base was searched from inception to May 2019.  The literature search used the following terms: “Gastric electrical stimulation” combined with “obesity” and “Implantable gastric stimulation” and “pharmaceutical therapy” and “bariatric surgery”.  The authors concluded that there is a potential to use GES for treating obesity.  However, more efforts are needed to develop appropriate stimulation devices and to design an adequate therapy for treating obesity in humans.

In a multi-center, open prospective cohort, phase-1 clinical trial, Paulus and associates (2020) examined the safety of the Exilis GES system and determined if the settings can be adjusted for comfortable chronic use in subjects with morbid obesity.  Gastric emptying and motility and meal intake were evaluated.  A total of 20 morbidly obese subjects (17 female, mean BMI of 40.8 ± 0.7 kg/m2) were implanted with the Exilis system.  Amplitude of the Exilis system was individually set during titration visits.  Subjects underwent 2 blinded baseline test days (GES ON versus OFF), after which long-term, monthly follow-up continued for up to 52 weeks.  The procedure was safe, and electrical stimulation was well-tolerated and comfortable in all subjects.  No significant differences in gastric emptying half-time (203 ± 16 versus 212 ± 14 mins, p > 0.05), food intake (713 ± 68 versus 799 ± 69 kcal, p > 0.05), insulin area under the curve (AUC) (2,448 ± 347 versus 2,186 ± 204, p > 0.05), and glucose AUC (41 ± 2 versus 41 ± 2, p > 0.05) were found between GES ON and OFF.  At week 4, 13, and 26, a significant (p < 0.01) reduction in weight loss was observed but not at week 52.  At this time-point, the mean EWL was 14.2 ± 4.5 %.  The authors concluded that GES with the Exilis system can be considered as safe.  No significant effect on food intake, gastric emptying, or gastric motility was observed.  The reduction in weight loss with Exilis GES was significant but short-lasting.  These researchers stated that further electrophysiological research is needed to gain more insight in optimal stimulation parameters and lead localization.

The authors stated that this study had several limitations.  Due to the aims and deliverables of this study -- to assess safety and preliminary effectiveness of the Exilis system -- a control group was not included.  In all studies and trials on interventions for weight loss, a control group is needed to fully evaluate efficacy.  Several studies have shown between 12 and 14 % of EWL in the control groups, which is comparable with what these investigators observed with the present study.  Thus, they concluded that the additional effect of GES with the Exilis system with its current settings was limited.  Up to now, substantial work with GES for the treatment of obesity has been performed, and results varied considerably.  More essential basic research has to be carried out before this approach can be applied clinically.  Pacing protocols should be optimized to achieve physiologically and clinically useful outcomes.  Essential electrophysiological knowledge of the human stomach is still lacking, and more basic electrophysiological research work should be conducted before proceeding to new pacing protocols.  Potentially, high resolution mapping of gastric slow-wave activity and the effects of gastric pacing on these waves may be a method to examine if pacing protocols will be effective.  When optimal stimulation parameters have been assessed, these researchers recommended that they will be examined in a blinded, randomized, placebo-controlled trial.

Gastric Per Oral Endoscopic Myotomy (G-POEM) for the Treatment of Gastroparesis

Kristensen and colleagues (2014) performed a case-series study of 3 patients who underwent per-oral endoscopic myotomy (POEM)  for nutcracker esophagus.  At 3 months, 6 months and 1 year post-operatively, all patients had clinical follow-up, barium swallow and high-resolution manometry.  All patients displayed marked improvement with a significant reduction in Eckardt score at follow-up after 1 year, from 10, 10 and 11 to 3, 1 and 1, respectively.  During follow-up, the patients were diagnosed with increased reflux index and 1 patient was diagnosed with gastroparesis.  The authors concluded that POEM may be considered as a therapeutic option for severe nutcracker esophagus; however, these researchers stated that further studies are needed.

Mekaroonkamol and co-workers (2016) stated that gastric POEM (G-POEM) is an emerging novel endoscopic technique as an incisionless pyloroplasty for refractory gastroparesis; and effective information of G-POEM on different types of gastroparesis is sparse.  These researchers retrospectively evaluated cases of gastric POEM (G-POEM) in refractory gastroparesis.  The G-POEM procedures were performed by a single expert endoscopist under a certain protocol.  Gastroparesis Cardinal Symptoms Index (GCSI) and GES were evaluated before and after the procedure.  Procedures related AEs were also recorded.  All procedures were successfully completed without complications.  Each case in this series was different in demography and etiology of gastroparesis, namely post-surgical, post-infectious, and idiopathic gastroparesis in an elderly men and 2 women.  All cases were refractory to conventional treatment but demonstrated obvious success after G-POEM as a salvage therapy both clinically and on GES.  The authors concluded that their cases revealed that G-POEM as a salvage therapy improved symptoms and gastric emptying in patients with different types of refractory gastroparesis; however, more data are needed to determine which subgroup of patients would benefit most from this novel procedure.

Gonzalez and associates (2017) conducted a single-center, case-series study to examine G-POEM in refractory gastroparesis.  These investigators evaluated 29 patients operated on between January 2014 and April 2016, with disturbed GES and/or elevated GCSI.  The primary end-point was the efficacy at 3 and 6 months, based on GCSI and symptoms.  The secondary end-points were GES evolution, procedure reproducibility and safety, and identification of predictive factors for success.  The median follow-up was 10 ± 6.4 months.  The clinical success rate was 79 % at 3 months, 69 % at 6 months, with a significant decrease in the mean GCSI compared to pre-operatively (3.3 ± 0.9 versus 1 ± 1.2 and 1.1 ± 0.9 respectively).  The GES (n = 23) normalized in 70 % of cases, with a significant improvement of the mean half emptying time and retention at 2 hours, and a discordance in 21 % of the cases.  In univariate analysis, diabetes and female gender were significantly associated with risk of failure, but not confirmed in multivariate analysis.  Mid-term efficacy of G-POEM reached 70 % at 6 months.  The authors concluded that the procedure remained reproducible and safe, and that diabetes and female gender were predictive of failure.

Xu and colleagues (2018) noted that G-POEM has been regarded as a novel and minimally invasive therapy for refractory gastroparesis.  In a retrospective, single-center study, these researchers reported the long-term outcomes and possible predictive factors for successful outcomes after G-POEM in an Asian population.  This trial enrolled 16 patients (11 males and 5 females) who underwent G-POEM for refractory gastroparesis from August 2016 to October 2017.  In addition, 13 patients had post-surgical gastroparesis, and 3 patients had diabetes.  Subjects had severe and refractory gastroparesis, as indicated by a GCSI score of greater than or equal to 20, and evidence of a delay on GES.  The primary outcome parameter was an assessment of the long-term clinical efficacy of the procedure.  The secondary outcome parameter was the detection of possible predictive factors for success and the determination of cut-off values for such predictors.  Technical success was achieved in 100 % of the patients, with a mean procedure time of 45.25 ± 12.96 mins.  The long-term clinical response was assessed in all patients during a median follow-up of 14.5 months.  Clinical success was achieved in 13 (81.25 %) patients.  There was a significant reduction in the GCSI scores and GES values after the procedure compared to the baseline values, with p values of < 0.0001 and 0.012, respectively.  Univariate regression analysis showed that the GCSI and gastric emptying scintigraphy had significant associations with the future clinical outcomes of the patients, but this finding was not confirmed in multivariate analysis.  A GCSI cut-off score of less than or equal to 30 had a high sensitivity and a negative predictive value (NPV) of 100 % for predicting a successful procedure; GES (half emptying time of less than or equal to 221.6 mins and 2-hour retention of less than or equal to 78.6 %) had a high specificity and a positive predictive value (PPV) of 100 %.  The authors concluded that this study presented a promising long-term clinical outcome for G-POEM, with a high technical success rate and few AEs; GCSI score and GES values could be used as predictors of favorable outcomes.  Moreover, these researchers stated that prospective, multi-center RCTs are needed to confirm these findings and determine the exact factors that predict patient responsiveness to G-POEM.

In a review on “Current and emerging therapeutic options for gastroparesis”, Myint et al (2018) concluded that novel endoscopic therapeutic options such as G-POEM have shown some efficacy in small trials; further investigation is needed to identify new and effective therapeutic options.

Khoury and co-workers (2018) stated that gastroparesis significantly impacts a patient's life with limited and challenging treatments available.  Although the pathogenesis is multi-factorial, pyloro-spasm is believed to have a major underlying role.  Several therapeutic interventions directed to the pylorus have been developed over the past 10 years, including intra-pyloric injections of botulinum toxin (BTX), trans-pyloric stenting, and surgical pyloroplasty.  All of these therapeutic options had limited and disappointing results.  More recently, G-POEM has been reported as a treatment for refractory gastroparesis.  In this review article, these investigators provided an overview on gastroparesis with a focus on the therapeutic interventions.  In addition, they provided a literature summary and pool analysis of the clinical efficacy, scintigraphic efficacy, and safety profile of all studies that evaluated G-POEM in gastroparesis.  A total of 7 studies have reported on the use of G-POEM in gastroparesis, and the pooled analysis of these studies showed a technical success of 100 %, with clinical efficacy as assessed by the GCSI of 81.5 %, GES normalization in approximately 55.5 % of the cases, peri-operative complications in 7.6 %, and intra-operative complications in 6.6 %.  The authors concluded that this suggested that G-POEM is a new promising therapeutic intervention for the treatment of gastroparesis with durable effect and limited potential AEs.

Kahaleh and associates (2018) stated that G-POEM has been offered as a novel therapy in the treatment of refractory gastroparesis.  These researchers presented a multi-center case-series study of their experience with G-POEM.  The severity of gastroparesis was assessed by delayed GES and an elevated GCSI.  Patients then underwent G-POEM using the submucosal tunneling technique.  The primary end-point was improvement in the GCSI score and improvement in gastric emptying on repeat scintigraphy.  Secondary end-points were technical success, complication rate, procedure duration, and length of hospital stay (LOS) post-procedure.  G-POEM was technically successful in all 33 patients.  Symptomatic improvement was observed in 28/33 patients (85 %), with a decrease in symptom score by GCSI from 3.3 to 0.8 at follow-up (p < 0.001).  The mean procedure duration was 77.6 mins (37 to 255 mins).  Mean GES improved significantly from 222.4 mins to 143.16 mins (p < 0.001).  Complications were minimal and included bleeding (n = 1) and an ulcer (n = 1) treated conservatively.  The mean LOS post-procedure was 5.4 days (1 to 14 days).  The mean follow-up duration was 11.5 months (2 to 31 months).  The authors concluded that G-POEM is a technically feasible, safe, and successful procedure for the treatment of refractory gastroparesis.  Moreover, these researchers stated that a further comparative, multi-center study should be performed to compare this technique to laparoscopic pyloromyotomy.

Malik and co-workers (2018) reported their experience in performing G-POEM for refractory gastroparesis of different etiologies and determine symptom improvement.  A total of 13 patients undergoing G-POEM were reported.  Pre- and post-procedure GES and PAGI-SYM for symptom severity were obtained.  Patients underwent G-POEM by creating a submucosal tunnel starting in the greater curvature of the distal antrum and extending it to the beginning of the duodenal bulb, followed by a full thickness pyloromyotomy.  All 13 gastroparesis patients successfully underwent G-POEM (1 diabetic [DGp], 4 idiopathic [IGp], 8 post-surgical [PSGp]).  Post-surgical patients included 4 s/p esophagectomy for esophageal cancer, 3 s/p Nissen fundoplication, and 1 s/p esophagectomy for achalasia.  There were no procedure-related side effects.  Of 11 patients completing follow-up questionnaires, 8 were improved subjectively (4 patients reported considerably better, 4 patients somewhat better, 1 unchanged, and 2 worse).  Individual symptom severity scores tended to improve, particularly vomiting, retching, and loss of appetite.  Of 6 patients that had post-G-POEM GES; GES improved in 4, unchanged in 1, and worsened in 1).  The authors concluded that G-POEM for treatment of refractory gastroparesis appeared to be a feasible and safe technique that can be successfully performed in patients with a variety of etiologies including different types of post-surgical gastroparesis.  The authors’ initial experience suggested that the majority of patients reported some improvement in symptoms, particularly symptoms of vomiting, retching, and loss of appetite.  These researchers stated that further experience is needed to determine the safety and efficacy of G-POEM and predict those who best respond to this treatment.

Mekaroonkamol and colleagues (2019) noted that G-POEM is a novel procedure with promising potential for the treatment of gastroparesis but with limited data regarding predictors of clinical response.  In a retrospective, longitudinal, single-center study, these researchers examined the safety and efficacy of the procedure and explored the impact of duration and etiology (diabetic versus non-diabetic) of gastroparesis on clinical outcome as measured by the GCSI.  This trial was carried out at a tertiary care hospital over an 18-month period.  A total of 40 patients with refractory gastroparesis (25 non-diabetic and 15 diabetic patients) were included; GCSI significantly improved throughout the study period (F (2.176, 17.405) = 10.152, p = 0.001).  The nausea/vomiting subscale showed sustained improvement through 18 months (F (2.213, 17.704) = 15.863, p =< 0.00001).  There was no significant improvement in bloating (F (2.099, 16.791) = 1.576, p = 0.236).  Gastric scintigraphy retention was significantly reduced by 41.7 % (t = -7.90; p < 0.00001).  Multivariate linear regression modeling revealed a significant correlation between the duration of disease and a GCSI improvement at 12 months (p = 0.02), with a longer duration of disease being associated with a poorer long-term response.  The etiology of gastroparesis was not associated with clinical improvement (p = 0.16); AEs (7.5 %) included 1 capno-peritoneum, 1 peri-procedure COPD exacerbation, and 1 mucosotomy closure site disruption.  The authors concluded that G-POEM appeared to be a safe and effective minimally invasive therapy for refractory gastroparesis, especially for patients with predominant nausea/vomiting and shorter duration of disease, regardless of the etiology.  These researchers proposed the clinical criteria for undergoing G-POEM should be a GSCI of at least 2.0 and a gastric retention of greater than 20 %.  This was a relatively small (n = 40) retrospective study; its findings need to be further investigated.

Aghaie Meybodi and associates (2019) stated that G-POEM has been recently introduced as a minimally invasive approach for the treatment of refractory gastroparesis.  These investigators carried out a meta-analysis to examine the feasibility and efficacy of this technique in the management of patients with refractory gastroparesis.  PubMed, Embase, and Scopus databases were searched to identify relevant studies published through May 2018.  Weighted pool rates (WPR) of the clinical resolution were calculated.  Pooled values of GCSI before and after the procedure were compared.  Pooled difference in means comparing gastric emptying before and after the procedure was calculated.  Fixed or random effect model was used according to the level of heterogeneity.  A total of 7 studies with 196 patients were included in the meta-analysis.  The mean value of procedure duration was 69.7 (95 % CI: 39  to 99 mins) and average estimate of LOS  was 1.96 (95 % CI: 1.22  to 2.95) days.  The WPR for clinical success was 82 % (95 % CI: 74 %  to  87 %, I2  = 0).  Compared with pre-procedure GCSI values, mean values of GCSI were reduced significantly at 5 days (-1.57 (95 % CI: -2.2 to -0.9), I2  = 80 %) (p< 0.001).  Mean values of gastric emptying were significantly decreased 2 to 3 months after the procedure (-22.3 (95 % CI: -32.9 to - 11.6), I2 = 67 %) (p < 0.05).  The authors concluded that the findings of this meta-analysis suggested that G-POEM is an effective therapeutic intervention for management of patients with refractory gastroparesis in terms of clinical response and scintigraphic studies.  Moreover, these researchers stated that large controlled trials are needed to identify the subset of patients who would benefit the most from this technique.

Tao and co-workers (2019) noted that G-POEM is a technically demanding endoscopic procedure.  As of yet, there is no consensus on the technique.  A variety of techniques have been reported in published studies.  The essential technical steps of the procedure are establishment of submucosal tunnel in gastric antrum, identification of the pyloric muscular ring, selective circular myotomy, and a 2.5-cm to 3.0-cm length of myotomy.  The authors stated that there are still some technical questions unanswered, and more studies are needed to establish standardized techniques and possible improvement of outcomes.

An UpToDate review on “Peroral endoscopic myotomy (POEM)” (Khashab) states that “Gastric peroral endoscopic myotomy (G-POEM), which is an endoscopic equivalent of surgical pyloroplasty, has been performed in a few centers for severe refractory diabetic gastroparesis … Several case reports show that G-POEM is safe, feasible, and effective in treating severe refractory gastroparesis”.

Furthermore, an UpToDate review on “Treatment of gastroparesis” (Camilleri, 2019) does not mention G-POEM as a therapeutic option.

Shen and colleagues (2020) compared the long-term clinical outcomes of G-POEM versus GES in the treatment of patients with refractory gastroparesis.  These investigators retrospectively evaluated 111 consecutive patients between January 2009 and August 2018.  To overcome selection bias, they used propensity score matching (1:1) between G-POEM and GES treatment.  The primary outcome was the duration of clinical response.  After propensity score matching, 23 patients were included in each group.  After a median follow-up of 27.7 months, G-POEM had a significantly better and longer clinical response than GES (hazard ratio [HR] for clinical recurrence 0.39, 95 % CI: 0.16 to 0.95; p = 0.04).  The median duration of response was 25.4 months (95 % CI: 8.7 to 42.0) in the GES group and was not reached in the G-POEM group.  The Kaplan-Meier estimate of 24-month clinical response rate was 76.6 % with G-POEM versus 53.7 % with GES.  GES appeared to have little effect on idiopathic gastroparesis (HR for recurrence with G-POEM versus GES 0.35, 95 % CI: 0.13 to 0.95; p = 0.05).  The incidence of AEs was higher in the GES group (26.1 % versus 4.3 %; p = 0.10).  The authors concluded that among patients with refractory gastroparesis, clinical response was better and lasted longer with G-POEM than with GES.  The positive outcomes with G-POEM were likely to derive from the superior clinical response in patients with idiopathic gastroparesis.  Moreover, these researchers stated that further studies are needed to confirm these findings.

Gastric Peroral Endoscopic Myotomy for the Treatment of Congenital Hypertrophic Pyloric Stenosis

Kozlov and colleagues (2019) noted that traditionally, a laparoscopic approach is used for treatment of congenital hypertrophic pyloric stenosis (CHPS) in newborns and infants.  The novel technique, G-POEM, had been proposed as an alternative method.  In this study, these researchers demonstrated for the first time the performance of G-POEM in an infant and its short-term results.  G-POEM was performed in the Center of Newborn Surgery in Irkutsk (Russia) in August 2018 for a 1-month old infant, whose weight was 4,200 g.  The patient had vomiting for 5 days before admission and a slight deficiency of body weight.  The diagnosis of CHPS was confirmed by ultrasound (US) examination of the abdominal cavity.  The pyloric muscle thickness was 7 mm.  The operative technique of the performed G-POEM was performed by creation of a submucosal tunnel with a distance of 4 cm toward the pylorus and dissection of the hypertrophied muscle layer in a form of the Ramstedt's incision by using an electrocautery knife.  At the end of the procedure, the mucosal membrane incision was closed by special clamps.  The operating time was 65 mins.  There were no intra-operative complications such as bleeding and/or mucosal perforation.  The patient began to eat 6 hours after the procedure.  The transition time to full enteral nutrition was 24 hours.  The infant was discharged from the hospital the next day in good condition.  These investigators did not observe early or late post-operative complications such as recurrence of pyloric stenosis and incomplete myotomy during post-operative observation.  There were not even minimal scars on the patient's body.  The authors concluded that G-POEM is a technically feasible, safe, and successful procedure for treatment of CHPS in newborns and infants.  Moreover, these investigators stated that an additional study is needed to perform the comparison between this technique and laparoscopic pyloromyotomy.

Diverticular Peroral Endoscopic Myotomy (D-POEM) for the Treatment of Esophageal Diverticulum

In a retrospective, international, multi-center study, Yang and associates (2019) reported their experience with the diverticular peroral endoscopic myotomy (D-POEM) technique in the management of esophageal diverticula; D-POEM was carried out using the principles of submucosal endoscopy.  A total of 11 patients with an esophageal diverticulum (Zenker's 7, mid-esophagus 1, epiphrenic 3) were included.  The mean size of the esophageal diverticula was 34.5 mm.  The overall technical success rate of D-POEM was 90.9 %, with a mean procedure time of 63.2 mins, and there were no AEs.  Clinical success was achieved in 100 % (10 /10), with a decrease in mean dysphagia score from 2.7 to 0.1 (p < 0.001) during a median follow-up of 145 days (interquartile range [IQR] of 126 to 273).  The authors concluded that endoscopic management of esophageal diverticula using the novel technique of D-POEM appeared promising.  This 1st case-series study on D-POEM suggested that the procedure was feasible, safe, and effective in the management of esophageal diverticula; D-POEM offered the distinct advantage of ensuring a complete septotomy.  Moreover, these investigators stated that larger studies are needed to confirm these preliminary findings.

Maydeo and co-workers (2019) noted that submucosal tunneling diverticular septotomy by D-POEM has emerged as an alternative to surgery for symptomatic esophageal diverticula, however, its medium- to long-term outcomes are currently unexplored.  In this study, D-POEM for patients with symptomatic esophageal diverticula was prospectively studied to examine its safety and the 12-month outcomes.  A total of 25 patients (72 % men; median age of 61 years [range of 48 to 88]) with a Zenker's diverticulum (n = 20) or epiphrenic diverticulum (n = 5) were included.  Major indications were dysphagia, recurrent broncho-aspiration, and foreign body sensation in 20 patients (80 %), with a mean symptom duration of 2.5 years (range  of 1 to 4).  Complete submucosal tunneling septotomy was achieved in a mean of 36 mins (range of 25 to 45), with 100 % technical success.  The median hospitalization was 5 days (range of 4 to 10).  The mean (standard deviation) Eckardt Score improved significantly from 13.2 (1.0) at baseline to 3.2 (1.4) at 12 months (p < 0.001) with clinical success in 19/22 patients (86 %) and no long-term AEs.  The authors concluded that D-POEM appeared safe and durable in patients with esophageal diverticula.  Moreover, these researchers stated that further multi-center studies with a larger patient cohort are needed.

Sato et al (2019) stated that esophageal diverticula are rare conditions that cause esophageal symptoms, such as dysphagia, regurgitation, and chest pain.  They are classified according to their location and characteristic pathophysiology into 3 types: epiphrenic diverticulum, Zenker's diverticulum, and Rokitansky diverticulum.  The former 2 disorders take the form of protrusions, and symptomatic cases require interventional treatment.  However, the esophageal anatomy presents distinct challenges to surgical resection of the diverticulum, especially when it is located closer to the oral orifice.  Since the condition itself is not malignant, minimally invasive endoscopic approaches have been developed with a focus on alleviation of symptoms.  Several types of endoscopic devices and techniques are currently employed, including POEM.  However, the use of minimally invasive endoscopic approaches, like POEM, has allowed the development of new disorder called iatrogenic esophageal diverticula.  Furthermore, these investigators stated that no RCTs comparing the difference between endoscopic treatment and surgery, or among the different endoscopic techniques have been performed.  Also, such studies of long-term follow-up results, including esophageal motility outcomes, are needed to decide the best intervention modality for esophageal diverticulum.  Another issue is the risk of esophageal carcinoma in the remnant diverticulum.  Although the absolute risk of esophageal carcinoma is rather low, surveillance endoscopy is necessary after treatment.

Zeng and colleagues (2020) noted that with the development of minimally invasive endoscopic approaches for the esophagus in recent years, POEM in the treatment of esophageal diverticulum has been described recently in some reports due to its successful outcomes.  In a retrospective study, these researchers described their experience with the use of D-POEM in the management of esophageal diverticulum.  This trial included consecutive patients with symptomatic esophageal diverticulum who visited the authors’ endoscopy center between April 2014 and January 2019.  D-POEM was carried out based on the principles of submucosal endoscopy.  A new symptomatic scoring system was introduced to evaluate the severity of diverticular symptoms.  A total of 10 patients with esophageal diverticulum (Zenker's 2, mid-esophagus 5, and epiphrenic 3) were included.  The overall technical success rate of D-POEM was 100 %, with a mean procedure time of 38.9 ± 20.5 (range of 16 to 70) mins.  No serious complications occurred.  Clinical improvement was achieved in 90 % (9/10) of patients.  The symptomatic score was significantly decreased from 2.5 (IQR of 2.00 to 3.25) to 1.0 (IQR of 0 to 1.25) (p = 0.007) during a median follow-up period of 11.0 (IQR of 10.25 to 17.25) months.  The authors concluded that the findings of this study suggested complete septotomy by D-POEM.  Moreover, these researchers stated that these preliminary results and experience put forwarded D-POEM as a safe and effective technique for esophageal diverticulum.

Table: CPT Codes / HCPCS Codes / ICD-10 Codes
Code Code Description

Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":

CPT codes covered if selection criteria are met:

0162T Electronic analysis and programming, reprogramming of gastric neurostimulator (ie, morbid obesity)
43647 Laparoscopy, surgical; implantation or replacement of gastric neurostimulator electrodes, antrum
43648     revision or removal of gastric neurostimulator electrodes, antrum
43881 Implantation or replacement of gastric neurostimulator electrodes, antrum, open
43882 Revision or removal of gastric neurostimulator electrodes, antrum, open
64590 Insertion or replacement of peripheral or gastric neurostimulator pulse generator or receiver, direct or inductive coupling
64595 Revision or removal of peripheral or gastric neurostimulator pulse generator or receiver
95980 Electronic analysis of implanted neurostimulator pulse generator system (e.g., rate, pulse amplitude and duration, configuration of wave form, battery status, electrode selectability, output modulation, cycling, impedance and patient measurements) gastric neurostimulator pulse generator/transmitter; intraoperative, with programming
95981     subsequent, without reprogramming
95982     subsequent, with reprogramming

CPT codes not covered for indications listed in the CPB:

Gastric per-oral endoscopic myotomy (G-POEM), Diverticular peroral endoscopic myotomy (D-POEM) - no specific code:

Other CPT codes related to the CPB:

78264 Gastric emptying imaging study (eg, solid, liquid, or both)
78265 Gastric emptying imaging study (eg, solid, liquid, or both); with small bowel transit
78266 Gastric emptying imaging study (eg, solid, liquid, or both); with small bowel and colon transit, multiple days

HCPCS codes covered if selection criteria are met:

C1767 Generator, neurostimulator (implantable), non-rechargeable
C1778 Lead, neurostimulator (implantable)
L8679 Implantable neurostimulator pulse generator, any type
L8680 Implantable neurostimulator electrode, each
L8688 Implantable neurostimulator pulse generator, dual array, non-rechargeable, includes extension

ICD-10 codes covered if selection criteria are met:

E08.43
E09.43
E10.43
E11.43
E13.43
[K31.84 also required]
Diabetic gastroparesis
K31.84 Gastroparesis

ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):

E08.00 - E08.42
E08.44 - E09.42
E09.44 - E10.42
E10.44 - E11.42
E11.44 - E13.42
E13.44 - E13.9
Diabetes mellitus
E66.01 - E66.1
E66.8 - E66.9
Obesity and morbid obesity
F50.81 - F50.89 Other eating disorders [psychogenic cyclic vomiting]
G43.A0 Cyclical vomiting, not intractable
G43.A1 Cyclical vomiting, intractable
G90.01 - G90.9 Disorders of autonomic nervous system
K22.5 Diverticulum of esophagus, acquired
K30 Functional dyspepsia
Q40.0 Congenital hypertrophic pyloric stenosis

The above policy is based on the following references:

Gastric Pacing and Gastric Electrical Stimulation for Gastroparesis

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  6. Cullen JJ, Kelly KA. The future of intestinal pacing. Gastroenterology Clin North Am. 1994;23(2):391-402.
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  8. Filichia LA, Cendan JC. Small case series of gastric stimulation for the management of transplant-induced gastroparesis. J Surg Res. 2008;148(1):90-93.
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  10. Forster J, Sarosiek I, Lin Z, et al. Further experience with gastric stimulation to treat drug refractory gastroparesis. Am J Surg. 2003;186(6):690-695.
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  16. Horowitz M, Su YC, Rayner CK, Jones KL. Gastroparesis: prevalence, clinical significance and treatment. Can J Gastroenterol. 2001;15(12):805-813.
  17. Jones MP, Maganti K. A systematic review of surgical therapy for gastroparesis. Am J Gastroenterol. 2003;98(10):2122-2129.
  18. Kelly KA. Pacing the gut. Gastroenterology. 1992;103(6):1967-1968.
  19. Lin Z, Forster J, Sarosiek I, McCallum RW. Effect of high-frequency gastric electrical stimulation on gastric myoelectric activity in gastroparetic patients. Neurogastroenterol Motil. 2004;16(2):205-212.
  20. Lin Z, Forster J, Sarosiek I, McCallum RW. et al. Treatment of diabetic gastroparesis by high-frequency gastric electrical stimulation. Diabetes Care. 2004;27(5):1071-1076.
  21. Lin Z, Forster J, Sarosiek I, McCallum RW. Treatment of diabetic gastroparesis by high-frequency gastric electrical stimulation. Diabetes Care. 2004;27(5):1071-1076.
  22. Lin Z, McElhinney C, Sarosiek I, et al. Chronic gastric electrical stimulation for gastroparesis reduces the use of prokinetic and/or antiemetic medications and the need for hospitalizations. Dig Dis Sci. 2005;50(7):1328-1334.
  23. Lin ZY, McCallum RW, Schirmer BD, Chen JD. Effects of pacing parameters on entrainment of gastric slow waves in patients with gastroparesis. Am J Physiol. 1998;274(1 Pt 1):G186-G191.
  24. McCallum R, Lin Z, Wetzel P, et al. Clinical response to gastric electrical stimulation in patients with postsurgical gastroparesis. Clin Gastroenterol Hepatol. 2005;3(1):49-54.
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Gastric Pacing and Gastric Electrical Stimulation for Obesity and Diabetes

  1. Aljarallah BM. Management of diabetic gastroparesis. Saudi J Gastroenterol. 2011;17(2):97-104.
  2. Bohdjalian A, Ludvik B, Guerci B, et al. Improvement in glycemic control by gastric electrical stimulation (TANTALUS) in overweight subjects with type 2 diabetes. Surg Endosc. 2009;23(9):1955-1960.
  3. Buchwald H, Buchwald JN. Evolution of operative procedures for the management of morbid obesity 1950-2000. Obes Surg. 2002;12(5):705-717.
  4. Busetto L, Torres AJ, Morales-Conde S, et al. Impact of the feedback provided by a gastric electrical stimulation system on eating behavior and physical activity levels. Obesity (Silver Spring). 2017;25(3):514-521.
  5. Cha R, Marescaux J, Diana M. Updates on gastric electrical stimulation to treat obesity: Systematic review and future perspectives. World J Gastrointest Endosc. 2014;6(9):419.
  6. Cigaina V, Hirschberg AL. Gastric pacing for morbid obesity: Plasma levels of gastrointestinal peptides and leptin. Obes Res. 2003;11(12):1456-1462.
  7. Cigaina V, Hirschberg AL. Plasma ghrelin and gastric pacing in morbidly obese patients. Metabolism. 2007;56(8):1017-1021.
  8. Cigaina V. Long-term follow-up of gastric stimulation for obesity: The Mestre 8-year experience. Obes Surg. 2004;14 Suppl 1:S14-S22.
  9. Cigaina V. Gastric pacing as therapy for morbid obesity: Preliminary results. Obes Surg. 2002;12 Suppl 1:12S-16S.
  10. Deitel M, Shikora SA. Introduction. Gastric pacing for obesity. Obes Surg. 2002;12 Suppl 1:2S.
  11. Greenstein RJ, Belachew M. Implantable gastric stimulation (IGS) as therapy for human morbid obesity: Report from the 2001 IFSO symposium in Crete. Obes Surg. 2002;12 Suppl 1:3S-5S.
  12. Hasler WL. Methods of gastric electrical stimulation and pacing: A review of their benefits and mechanisms of action in gastroparesis and obesity. Neurogastroenterol Motil. 2009;21(3):229-243.
  13. Jensen MD. Potential role of new therapies in modifying cardiovascular risk in overweight patients with metabolic risk factors. Obesity (Silver Spring). 2006;14 Suppl 3:143S-149S.
  14. Liu S, Hou X, Chen JD. Et al. Therapeutic potential of duodenal electrical stimulation for obesity: Acute effects on gastric emptying and water intake. Am J Gastroenterol. 2005;100(4):792-796.
  15. Ma J, Rayner CK, Jones KL, Horowitz M. Diabetic gastroparesis: Diagnosis and management. Drugs. 2009;69(8):971-986.
  16. Maisiyiti A, Chen JD. Systematic review on gastric electrical stimulation in obesity treatment. Expert Rev Med Devices. 2019;16(10):855-861.
  17. McCallum RW, Snape W, Brody F, et al. Gastric electrical stimulation with Enterra therapy improves symptoms from diabetic gastroparesis in a prospective study. Clin Gastroenterol Hepatol. 2010;8(11):947-954.
  18. McNatt SS, Longhi JJ, Goldman CD, McFadden DW. Surgery for obesity: A review of the current state of the art and future directions. J Gastrointest Surg. 2007;11(3):377-397.
  19. Mintchev MP. Gastric electrical stimulation for the treatment of obesity: From entrainment to bezoars-a functional review. ISRN Gastroenterol. 2013;2013:434706.
  20. Mizrahi M, Ben Ya'acov A, Ilan Y. Gastric stimulation for weight loss. World J Gastroenterol. 2012;18(19):2309-2319.
  21. Morales-Conde S, Alarcon Del Agua I, Busetto L, et al. Implanted closed-loop gastric electrical stimulation (CLGES) system with sensor-based feedback safely limits weight regain at 24 months. Obes Surg. 2018;28(6):1766-1774.
  22. Ouyang H, Yin J, Chen JD. Therapeutic potential of gastric electrical stimulation for obesity and its possible mechanisms: A preliminary canine study. Dig Dis Sci. 2003;48(4):698-705.
  23. Paulus GF, van Avesaat M, van Rijn S, et al. Multicenter, phase 1, open prospective trial of gastric electrical stimulation for the treatment of obesity: First-in-human results with a novel implantable system. Obes Surg. 2020;30(5):1952-1960.
  24. Policker S, Haddad W, Yaniv I. Treatment of type 2 diabetes using meal-triggered gastric electrical stimulation. Isr Med Assoc J. 2009;11(4):206-208.
  25. Salvi PF, Brescia A, Cosenza UM, et al. Gastric pacing to treat morbid obesity: Two years experience in four patients. Ann Ital Chir. 2009;80(1):25-28.
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Gastric Pacing and Gastric Electrical Stimulation for Gastro-Intestinal Dysmotility

  1. Sallam HS, McNearney TA, Chen JD. Acupuncture-based modalities: Novel alternative approaches in the treatment of gastrointestinal dysmotility in patients with systemic sclerosis. Explore (NY). 2014;10(1):44-52.

Gastric Pacing and Gastric Electrical Stimulation for Cyclic Vomiting Syndrome and Selected Indications

  1. Grover I, Kim R, Spree DC, et al. Gastric electrical stimulation is an option for patients with refractory cyclic vomiting syndrome. J Neurogastroenterol Motil. 2016;22(4):643-649.
  2. Lee S, Abd-Elsayed A. Some non-FDA approved uses for neuromodulation in treating autonomic nervous system disorders: A discussion of the preliminary support. Neuromodulation. 2016;19(8):791-803.

Gastric Per-Oral Endoscopic Myotomy

  1. Aghaie Meybodi M, Qumseya BJ, Shakoor D, et al. Efficacy and feasibility of G-POEM in management of patients with refractory gastroparesis: A systematic review and meta-analysis. Endosc Int Open. 2019;7(3):E322-E329.
  2. Camilleri M. Treatment of gastroparesis. UpToDate [online serial]. Waltham, MA: UpToDate; reviewed April 2019.
  3. Gonzalez JM, Benezech A, Vitton V, et al. G-POEM with antro-pyloromyotomy for the treatment of refractory gastroparesis: Mid-term follow-up and factors predicting outcome. Aliment Pharmacol Ther. 2017;46(3):364-370.
  4. Huang Z, Cui Y, Li Y, et al. Peroral endoscopic myotomy for achalasia patients with prior Heller myotomy: A systematic review and meta-analysis. Gastrointest Endosc. 2020 Jun 6 [Online ahead of print]
  5. Kahaleh M, Gonzalez JM, Xu MM, et al. Gastric peroral endoscopic myotomy for the treatment of refractory gastroparesis: A multicenter international experience. Endoscopy. 2018;50(11):1053-1058.
  6. Khashab MA. Peroral endoscopic myotomy (POEM). UpToDate [online serial], Waltham, MA: UpToDate; reviewed April 2019.
  7. Khoury T, Mizrahi M, Mahamid M, et al. State of the art review with literature summary on gastric peroral endoscopic pyloromyotomy for gastroparesis. J Gastroenterol Hepatol. 2018;33(11):1829-1833.
  8. Kozlov Y, Kovalkov K, Smirnov A. Gastric peroral endoscopic myotomy for treatment of congenital pyloric stenosis -- First clinical experience. J Laparoendosc Adv Surg Tech A. 2019;29(6):860-864.
  9. Kristensen HO, Bjerregaard NC, Rask P, et al. Peroral endoscopic myotomy (POEM) for nutcracker esophagus. Three cases with 12 months follow-up. Scand J Gastroenterol. 2014;49(11):1285-1289.
  10. Malik Z, Kataria R, Modayil R, et al. Gastric per oral endoscopic myotomy (G-POEM) for the treatment of refractory gastroparesis: Early experience. Dig Dis Sci. 2018;63(9):2405-2412.
  11. Mekaroonkamol P, Li LY, Dacha S, et al. Gastric peroral endoscopic pyloromyotomy (G-POEM) as a salvage therapy for refractory gastroparesis: A case series of different subtypes. Neurogastroenterol Motil. 2016;28(8):1272-1277.
  12. Mekaroonkamol P, Patel V, Shah R, et al. Association between duration or etiology of gastroparesis and clinical response after gastric per-oral endoscopic pyloromyotomy. Gastrointest Endosc. 2019;89(5):969-976.
  13. Myint AS, Rieders B, Tashkandi M, et al. Current and emerging therapeutic options for gastroparesis. Gastroenterol Hepatol (N Y). 2018;14(11):639-645.
  14. Shen S, Luo H, Vachaparambil C, et al. Gastric peroral endoscopic pyloromyotomy versus gastric electrical stimulation in the treatment of refractory gastroparesis: A propensity score-matched analysis of long term outcomes. Endoscopy. 2020;52(5):349-358.
  15. Tao J, Patel V, Mekaroonkamol P, et al. Technical aspects of peroral endoscopic pyloromyotomy. Gastrointest Endosc Clin N Am. 2019;29(1):117-126.
  16. Xu J, Chen T, Elkholy S, et al. Gastric peroral endoscopic myotomy (G-POEM) as a treatment for refractory gastroparesis: Long-term outcomes. Can J Gastroenterol Hepatol. 2018;2018:6409698.

Diverticular Peroral Endoscopic Myotomy (D-POEM)

  1. Maydeo A, Patil GK, Dalal A. Operative technical tricks and 12-month outcomes of diverticular peroral endoscopic myotomy (D-POEM) in patients with symptomatic esophageal diverticula. Endoscopy. 2019;51(12):1136-1140.
  2. Sato H, Takeuchi M, Hashimoto S, et al. Esophageal diverticulum: New perspectives in the era of minimally invasive endoscopic treatment. World J Gastroenterol. 2019 8;25(12):1457-1464.
  3. Yang J, Zeng X, Yuan X, et al. An international study on the use of peroral endoscopic myotomy (POEM) in the management of esophageal diverticula: The first multicenter D-POEM experience. Endoscopy. 2019;51(4):346-349.
  4. Zeng X, Bai S, Zhang Y, et al. Peroral endoscopic myotomy for the treatment of esophageal diverticulum: An experience in China. Surg Endosc. 2020 Apr 28 [Online ahead of print].