Medical Policy: 07.01.62 

Original Effective Date: January 2014 

Reviewed: October 2017 

Revised: October 2017 


Benefit Application:

Benefit determinations are based on the applicable contract language in effect at the time the services were rendered. Exclusions, limitations or exceptions may apply. Benefits may vary based on contract, and individual member benefits must be verified. Wellmark determines medical necessity only if the benefit exists and no contract exclusions are applicable. This medical policy may not apply to FEP. Benefits are determined by the Federal Employee Program.


This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.



Gastric electrical stimulation (GES) is performed using an implantable device designed to treat chronic, refractorynausea and vomiting secondary to gastroparesis of diabetic, idiopathic, or postsurgical etiology.  Gastric electrical stimulation has also been investigated as a treatment of obesity. The device may also be referred to as a gastric pacemaker or gastric pacing.


Gastric electrical stimulation has been investigated primarily as a treatment for gastroparesis that helps control the chronic nausea and vomiting associated with gastroparesis by stimulating the smooth muscles of the lower stomach. Currently available devices consist of a pulse generator, which can be programmed to provide electrical stimulation at different frequencies connected to intramuscular stomach leads that are implanted during laparoscopy or open laparotomy. 


Gastroparesis is a chronic disorder of gastric motility characterized by delayed gastric emptying of solids in the absence of mechanical obstruction. It can frequently result from longstanding diabetes mellitus and vagal nerve injury, or can be idiopathic in nature. Gastroparesis leads to postprandial nausea and vomiting, bloating, early satiety and discomfort. In severe cases, nausea and vomiting may cause weight loss, dehydration, electrolyte disturbances and malnutrition due to inadequate caloric and fluid intake. 

  • Idiopathic – idiopathic gastroparesis may be the most common form of gastroparesis. It is estimated that no detectable underlying abnormality is found in approximately one-half of patients with delayed gastric emptying.

  • Diabetes Mellitus – Diabetes mellitus (DM) is the most frequently recognized systemic disease associated with gastroparesis. Gastrointestinal complications of diabetes typically occur in patients who have had the disorder for more than five years.  Patients with diabetes mellitus have abnormalities at several levels in the process of gastric emptying, including abnormal postprandial proximal gastric accommodation and contraction, and difficulties with antral motor function. These abnormalities are primarily due to autonomic dysfunction or abnormal intrinsic nervous system.

Hyperglycemia (blood glucose > 200 mg/dL) may also contribute to delayed gastric emptying.

  • Post-Surgical – previous gastric and thoracic surgery can result in gastric stasis due to intended or accidental injury to the vagus nerve.

The evaluation of gastroparesis is to exclude mechanical obstruction and establish the diagnosis of gastroparesis by an assessment of gastric motility. If there is no evidence of mechanical obstruction on imaging or upper endoscopy, scintigraphy is typically performed to document the presence of delayed gastric emptying. Scintigraphy measures the motor function of the stomach by quantifying the emptying of a physiologic caloric meal. The technique involves incorporating a radioisotope tracer into a standard meal and tracking its passage through the stomach using a gamma camera. Images are typically gathered at 1, 2, 3, and 4 hours.

Delayed gastric emptying is defined as gastric retention of  > 10 percent at 4 hours and/or > 60 percent at two hours when using a standard low fat diet. Although the severity of symptoms do not always correlate with the rate of gastric emptying, delayed gastric emptying has been classified based on the extent of gastric retention on scintigraphy at four hours into the following:

  • Mild 10 to 15 percent
  • Moderate 15 to 35 percent
  • Severe > 35 percent

Primary medical management for gastroparesis includes dietary modification and pharmacologic therapy with prokinetic agents such as metoclopramide, macrolide antibiotics such as erythromycin and antiemetic agents such as granisetron or ondansetron. Patients refractory to treatment are difficult to manage. Treatment may involve changing or combining medications; placement of gastrostomy or jejunostomy tube for enteral feedings, or in severe cases, total parenteral nutrition (TPN) for brief periods. Some patients, however, remain refractory to gastroparesis treatment.

Currently, only one gastric electrical stimulator has received approval from the U.S. Food and Drug Administration (FDA), the Enterra™ Therapy System, manufactured by Medtronic and it was cleared by the FDA as a humanitarian use device. This system delivers a high frequency (12 cycles per minute), low energy stimulation to the stomach.  The FDA labeling for Enterra™ Therapy System indicates the use of this system for the treatment of chronic, intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology.


Humanitarian Device Exemption (HDE)

In rare instances, certain medical devices intended to be used for humanitarian purposes are evaluated by the US Food and Drug Administration (FDA) through the Humanitarian Device Exemption (HDE) process. The FDA’s humanitarian use device (HUD) designation permits the use of certain medical devices when there is no comparable device available to treat or diagnose a disease or condition affecting fewer than 4,000 individuals annually. Since clinical investigation demonstrating the device's efficacy is not feasible (given the low prevalence of the disease in the population), an HDE grants manufacturers an exemption to the usual premarket approval process and allows marketing of the device only for the FDA-labeled HDE indication(s).

Under FDA requirements, an HUD may only be used after institutional review board (IRB) approval has been obtained for the use of the device in accordance with the FDA-labeled indication(s) under the HDE.


The evidence from a few randomized controlled trials and a number of case series in the published peer reviewed medical literature indicates that gastric electrical stimulation (GES) may be a safe and effective option for those patients with chronic, intractable nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology who have failed all other treatments. The Enterra Therapy System (Medtronic, Inc., Minneapolis, MN) is a gastric electrical stimulation device which received FDA marketing approval as a Class III medical device under the Humanitarian Device  Exemption (HDE), it is indicated for the treatment of chronic intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology. The evidence is sufficient to determine the effects of this technology on net health outcomes for the treatment of chronic intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic and idiopathic etiology.


Gastric Electrical Stimulation for the Treatment of Obesity

Gastric electrical stimulation (GES) is currently under investigation for the treatment of obesity as a technique to increase a feeling of satiety by delaying gastric emptying with subsequent reduced food intake and weight loss. The exact mechanisms of action is unclear. Proposed possibilities include: a local enteric nervous system effect, an effect mediated by the autonomic nervous system, possible central nervous system changes and neurohormonal changes. Optimal stimulation patterns are unknown, as is the importance of the number of leads and the location of the electrodes. Optimal screening of patients for gastric electrical stimulation (GES) for obesity has not yet been determined. Also, the best combination of behavioral, drug, device and surgical therapy has not been determined.  Currently there are no GES devices approved by the U.S. Food and Drug Administration for the treatment of obesity. Based on review of the medical literature which includes 1 published randomized study (SHAPE trial), this trial did not show any improvement in weight loss with GES compared with sham stimulation.    


The use of gastric electrical stimulation (GES) for the treatment of other conditions such as obesity remains unproven.  Optimal patient selection criteria, electrode position, lead number and stimulation patterns have not yet been determined. Additional well designed studies are needed to demonstrate the safety and effectiveness of GES for the treatment of obesity.  Based on the 1 published randomized trial (SHAPE trial), this trial did not show significant improvement in weight loss with GES compared to sham stimulation. The evidence is insufficient to determine the effects of this technology on net health outcomes. 


Practice Guidelines and Position Statements

American College of Gastroenterology

In 2013, the American College of Gastroenterology published a clinical practice guideline  on the management of gastroparesis. The recommendations for these guidelines were based on review of the evidence base through 2011. The evidence on GES consisted of 2 randomized crossover trials and the case series. The recommendation for GES was that “Gastric electrical stimulation may be considered for compassionate treatment in patients with refractory symptoms, particularly nausea and vomiting. Symptom severity and gastric emptying have been shown to improve in patients with diabetic gastroparesis (DG), but not in patients with idiopathic gastroparesis (IG) or postsurgical gastroparesis (PSG). (Conditional recommendation (there is uncertainty about trade-offs), moderate level of evidence (further research would be likely to have an impact on the confidence in the estimate of effect)


National Institute for Health and Care Excellence (NICE

In 2014, the National Institute for Health and Care Excellence issued guidelines on    gastroelectrical stimulation for gastroparesis that made the following recommendation:

  • Current evidence on the efficacy and safety of gastric electrical stimulation for gastroparesis is adequate to support the use of this procedure with normal arrangements for clinical governance, consent and audit.
  • During the consent process, clinicians should inform patients considering gastric electrical stimulation for gastroparesis that some patients do not get any benefit from it. They should also give patients detailed written information about the risk of complications, which can be serious, including the need to remove the device.
  • Patient selection and follow up should be done in specialist gastroenterology units with expertise in gastrointestinal motility disorders, and the procedure should only be performed by surgeons working in these units.
  • Further publications providing data about the effects of the procedure on symptoms in the long term and on device durability would be useful. 


Regulatory Status

Currently, only the Gastric Electrical Stimulator (GES) system (now called Enterra™ Therapy System; Medtronic, Minneapolis, MN) has been approved by the U.S. Food and Drug Administration (FDA; see note below). The GES system consists of 4 components: the implanted pulse generator, 2 unipolar intramuscular stomach leads, the stimulator programmer, and the memory cartridge. With the exception of the intramuscular leads, all other components have been used in other implantable neurologic stimulators, such as spinal cord or sacral nerve stimulation. The intramuscular stomach leads are implanted either laparoscopically or during a laparotomy and are connected to the pulse generator, which is implanted in a subcutaneous pocket. The programmer sets the stimulation parameters, which are typically set at an “on” time of 0.1 second alternating with an “off” time of 5.0 second.

Note: In March 2000, the GES system was approved by FDA through a humanitarian device exemption (HDE Approval H990014). This regulatory category was established in 1996 and only applies to devices intended to benefit fewer than 4000 patients. The approval process is similar to that of a premarket approval application (PMA) but is exempt from the effectiveness requirements of a PMA. Thus the application is not required to include results of scientifically valid clinical investigations but must contain sufficient information for FDA to determine that the device does not pose unreasonable or significant risk of illness or injury. A humanitarian use device may only be used in facilities that have an institutional review board to supervise clinical testing of the device.

Currently, no GES devices have been approved by the FDA for the treatment of obesity. The Transcend (Transneuronix; acquired by Medtronic in 2005), an implantable gastric stimulation device, is available in Europe for the treatment of obesity.


Prior Approval:

Not applicable.




See also Humanitarian Use Devices medical policy 10.01.14

See also Vagus Nerve Stimulation (VNS) medical policy 07.01.60


Gastric electrical stimulation (eg, Enterra™ Therapy) may be considered medically necessary for the humanitarian device exemption (HDE) indication granted by the US Food and Drug Administration (FDA) for the treatment of chronic intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology when the following criteria are met:

  • Diagnosis confirmed by gastric emptying scintigraphy and/or radiopaque markers testing; and
  • Individual is refractory, intolerant or has contraindications to the use of prokinetic and antiemetic medications 

An institutional review board (IRB) must approve the use of gastric electrical stimulation for the treatment of gastroparesis to ensure that it will be used in accordance with the HDE indication(s) granted by the FDA.  Documentation of IRB approval may be requested to ensure compliance with such indications.


See FDA-labeled HDE indication(s) External Site


Replacement of gastric electrical stimulation (GES) may be considered medically necessary for an individual that meets the above medical necessity criteria and the existing stimulator is no longer under warranty and cannot be repaired.

Gastric electrical stimulation and gastric pacing would be considered investigational for all other indications, including but not limited to the following because the safety and effectiveness of this service cannot be established by review of the available published medical literature:

  • As an initial treatment for gastroparesis
  • For treatment of diabetes mellitus in persons without gastroparesis
  • For the treatment of gastrointestinal dysmotility disorders other than gastroparesis as indicated above
  • For the treatment of obesity


Procedure Codes and Billing Guidelines:

To report provider services, use appropriate CPT* codes, Alpha Numeric (HCPCS level 2) codes, Revenue codes, and/or diagnosis codes.

  • 43647 Laparoscopy, surgical; implantation or replacement of gastric neurostimulator electrodes, antrum
  • 43648 revision or removal of gastric neurostimulator electrodes, antrum
  • 43659 Unlisted laparoscopy procedure, stomach (if used to report laparoscopic procedures related to gastric electrical stimulation electrode placement)
  • 43881 Implantation or replacement of gastric neurostimulator electrodes, antrum, open
  • 43882 Revision or removal of gastric neurostimulator electrodes, antrum, open
  • 43999Unlisted procedure, stomach (if used to report laparotomy procedure related to gastric electrical stimulation electrodes placement)
  • 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 (eg, rate, pulse amplitude and duration, configuration of wave form, battery status, electrode selectability, output modulation, cycling, impedence and patient measurements) gastric neurstimulator pulse generator/transmitter; intraoperative, with programming.
  • 95981 subsequent, without programming
  • 95982 subsequent with reprogramming
  • C1767 Generator, neurostimulator (implantable), nonrechargeable
  • C1778 Lead, neurostimulator
  • C1787 Patient programmer, neurostimulator
  • C1816 Receiver and/or transmitter neurostimulator (implantable)
  • C1820 Generator, neurostimulator (implantable), non high-frequency with rechargeable battery and charging system
  • C1822 Generator, neurostimulator (implantable), high frequency, with rechargeable battery and charging system
  • C1897 Lead neurostimulator test kit (implantable)
  • E0765 FDA approved nerve stimulator with replaceable batteries for treatment of nausea and vomiting 
  • L8679 Implantable neurostimulator, pulse generator any type
  • L8680 Implantable neurostimulator electrode, each
  • L8681 Patient programmer (external) for use with implantable programmable neurostimulator pulse generator, replacement only
  • L8682 Implantable neurostimulator radiofrequency receiver
  • L8683 Radiofrequency transmitter (external) for use with implantable neurostimulator radiofrequency receiver
  • L8685 Implantable neurostimulator pulse generator, single array, rechargeable, includes extension
  • L8686 Implantable neurostimulator pulse generator, single array, nonrechargeable, includes extension
  • L8687 Implantable neurostimulator pulse generator, dual array, rechargeable, includes extension
  • L8688 Implantable neurostimulator pulse generator, dual array, nonrechargeable, includes extension
  • L8689 External recharging system for battery, (internal) for use with implantable neurostimulator, replacement only


Selected References:

  • National Institute of Clinical Excellence (NICE). Gastroelectrical Stimulation for Gastroparesis. December 2004.
  • Michael Camilleri, M.D., Henry P. Parkman, M.D., Mehnaz A. Shafti, M.D., Thomas L. Abell, M.D. and Laruen Gerson, M.D., MSc.  2013 Clinical Guideline: Management of Gastroparesis. AmJGastroenterol 2013; 108:18-37;doi:10.1038/ajg.2012.373.
  • ECRI. Product Brief. Enterra Therapy System (Medtronic, Inc) for Treating Gastroparesis.  Updated 1/18/2016, Published 4/7/2004.
  • Information Sheet Guidance for IRBs, Clinical Investigators, and Sponsors, Frequently Asked Questions About Medical Devices
  • HDE Approvals, Listing of CDRH Humanitarian Device Exemptions
  • Soffer Edy E. Gastric Electrical Stimulation for Gastroparesis J Neurogastroenterol Motil, Vol. 18 No. 2 April 2012
  • National Institute for Clinical Excellence (NICE). Interventional Procedures Guidance (IPG489) Published May 2014. Gastroelectrical Stimulation for Gastroparesis.
  • UpToDate. Electrical Stimulation for Gastroparesis. William L. Hasler, M.D., Topic last updated September 16, 2015.
  • UpToDate. Treatment of Gastroparesis, Michael Camilleri, M.D., Topic last updated December 21, 2015.
  • UpToDate. Malignancy Associated Gastroparesis: Pathophysiology and Management, Mehnaz A Shafi, M.D., Eiad Nasser, M.D., Milind Javle, M.D., Topic last updated August 10, 2015.
  • Abell Thomas, McCallum Richard, et. al. Gastric Electrical Stimulation for Medically Refractory Gastroparesis, Gastroenterology 2003;125:421-428
  • Lin Zhiye, Forster Jameson, et. al. Treatment of Diabetic Gastroparesis by High Frequency Gastric Electrical Stimulation, Diabetes Care Volume 27, Number 5, May 2004
  • Greenway Frank, Zheng Jolene, Electrical Stimulation as Treatment for Obesity and Diabetes, Journal of Diabetes Science and Technology, Volume 1, Issue 2 March 2007
  • Naga Venkatesh G. Jayanthi, Simon P.L. Dexter, Gastric Electrical Stimulation for Treatment of Clinically Severe Gastroparesis Journal of Minimal Access Surgery, January 2013
  • Cha Ryan, Marescaux Jacques, et. al. Updates on Gastric Electical Stimulation to Treat Obesity: Systematic Review and Future Perspectives, World Journal of Gastrointestinal Endoscopy Sept 2014; 6(9):419-431
  • Shikora SA, Bergenstal R, Bessler M, et. al. Implantable gastric stimulation for the treatment of clinically severe obesity: results of the SHAPE trial. Surg Obes Relat Dis. Jan-Feb 2009;5(1):31-37. PMID 19071066
  • Chu H, Lin Z, Zhong L, et al. Treatment of high-frequency gastric electrical stimulation for gastroparesis. J Gastroenterol Hepatol. Jun 2012;27(6):1017-1026. PMID 22128901  
  • McCallum RW, Snape W, Brody F, et al. Gastric electrical stimulation with Enterra therapy improves symptoms from diabetic gastroparesis in a prospective study. Nov 2010;8(11):947-954; quiz e116. PMID 20538073
  • Lal N, Livemore S, Dunne D, et al. Gastric Electrical Stimulation with the Enterra System: A Systematic Review. Gastroenterol Res Pract. 2015;2015:762972. PMID 26246804
  • McCallum RW, Sarosiek I, Parkman HP, et al. Gastric electrical stimulation with Enterra therapy improves symptoms of idiopathic gastroparesis. Neurogastroenterol Motil. Oct 2013;25(10):815-e636. PMID 23895180
  • Teich S, Mousa HM, Punati J, et al. Efficacy of permanent gastric electrical stimulation for the treatment of gastroparesis and functional dyspepsia in children and adolescents. J Pediatr Surg. Jan 2013;48(1):178-183. PMID 23331812
  • Brody F, Zettervall SL, Richards NG, et al. Follow-up after gastric electrical stimulation for gastroparesis. J Am Coll Surg. Jan 2015;220(1):57-63. PMID 25458798
  • McCallum RW, Lin Z, Forster J, et al. Gastric electrical stimulation improves outcomes of patients with gastroparesis for up to 10 years. Clin Gastroenterol Hepatol. Apr 2011;9(4):314-319 e311. PMID 21185396
  • Timratana P, El-Hayek K, Shimizu H, et al. Laparoscopic gastric electrical stimulation for medically refractory diabetic and idiopathic gastroparesis. J Gastrointest Surg. Mar 2013;17(3):461-470. PMID 23288718
  • Zehetner J, Ravari F, Ayazi S, et al. Minimally invasive surgical approach for the treatment of gastroparesis. Surg Endosc. Jan 2013;27(1):61-66. PMID 22752276
  • UpToDate. Approach to the Adult with Nausea and Vomiting. George F. Longstreth, M.D., Topic last updated May 12, 2016.
  • UpToDate. Gastroparesis. Etiology, Clinical Manifestations and Diagnosis. Michael Camilleri M.D., Topic last updated July 14, 2016.
  • Medtronic. Gastric Electrical Stimulation – Gastroparesis.
  • Chu H, Lin Z, Zhong L, et. al. Treatment of high frequency gastric electrical stimulation for gastroparesis. J Gastroenterol Hepatol. Jun 2012;27(6):1017-1026. PMID 22128901 
  • Levinthal DJ, Bielefeldt K. Systemic review and meta-analysis: gastric electrical stimulation for gastroporesis. Auton Neurosci Jan 2017;202:45-55. PMID 27085627


Policy History:

  • October 2017 - Annual Review, Policy Revised
  • October 2016 - Annual Review, Policy Revised
  • October 2015 - Annual Review, Policy Revised
  • February 2015 - Policy Revised
  • November 2014 - Annual Review, Policy Revised
  • January 2014 - New Policy Created

Wellmark medical policies address the complex issue of technology assessment of new and emerging treatments, devices, drugs, etc.   They are developed to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. Wellmark medical policies contain only a partial, general description of plan or program benefits and do not constitute a contract. Wellmark does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Wellmark or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. Our medical policies may be updated and therefore are subject to change without notice.


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