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Vagus Nerve Blocking Therapy for Treatment of Obesity

Policy Number: MP-598

Latest Review Date: March 2024

Category: Surgery                                                           


Intra-abdominal vagus nerve blocking therapy in all situations, including but not limited to the treatment of obesity is considered investigational.


Vagus nerve blocking therapy for obesity consists of an implantable device that delivers electrical stimulation to branches of the vagus nerve on the anterior abdominal wall. The intent is to cause intermittent blocking of signals to the intra-abdominal vagus nerve to disrupt hunger sensations and induce feelings of satiety.


Obesity is a common condition in the United States. A large nationally representative survey conducted in 2009 to 2010 found that 36% of American adults age 20 and older were obese, defined as body mass index (BMI) of 30 kg/m2 or more. Fifteen percent of adults had a BMI of 35 kg/m2 or more and 6% had a BMI of 40 kg/m2 or more. Among children age 2 to 19 years, 17% were obese, defined in the population as being at or above the 95% percentile in sex-specific BMI for corresponding age (based on the U.S. Centers for Disease Control and Prevention age growth charts).

Obesity is a major cause of premature death and is linked to serious illnesses including heart disease, Type 2 diabetes, sleep apnea, osteoarthritis, and certain types of cancer. In a 2013 systematic review, being obese has been associated with higher all-cause mortality and death from cardiovascular disease. In that same year, the American Medical Association officially recognized obesity itself as a disease.

Management and Treatment

Lifestyle interventions, specifically changes to diet and exercise, are the first-line treatment of obesity. These interventions can be enhanced by participation in a structured weight loss program. There are also prescription weight loss medications available, but they have limited evidence of efficacy and there are adverse effects (e.g., oily stool, nausea, dizziness) associated with their use.

Weight loss (bariatric) surgery is a potential option for obese patients who have failed conservative treatments. Common procedures include gastric bypass surgery (open or laparoscopic approaches), sleeve gastrectomy, and laparoscopic adjustable gastric banding. Certain types of bariatric surgery have been found to improve outcomes in selected patients who choose that treatment. (Refer to medical policy #053 Surgical Management of Morbid Obesity for additional information.)

Vagus nerve blocking therapy is another potential treatment option for obese patients. The vagus nerve consists of two long cranial nerves that extend from the brain stem to the viscera. The term vagus is Latin for wandering and the vagus nerve winds through the abdomen and has branches that come in contact with the heart, lung, stomach and other body parts. The vagus nerve plays a major role in autonomic and sympathetic nervous system functioning, including regulation of heartbeat and breathing. It is also involved in regulation of the digestive system, although its exact role in controlling appetite and feelings of satiety is unknown. Vagus nerve blocking therapy involves intermittent blocking of signals to the intra-abdominal vagus nerve, with the intent disrupting hunger sensations and inducing feelings of satiety.

In January 2015, FDA approved a medical device specifically designed to provide vagal nerve blocking therapy for weight regulation in obese patients. This device, the Maestro® Rechargeable System, includes a neuro-blocking pulse generator that is implanted subcutaneously on the thoracic sidewall, and flexible leads approximately 47 cm in length that are placed on the abdominal anterior and posterior vagal nerve trunks. External components include a mobile charger, a transmit coil, a programmable microprocessor and customized software. The system delivers high-frequency pulses of electrical current to vagal nerve trunks; therapy parameters and the treatment schedule can be customized by a clinician. Like other surgical interventions, there is the potential for adverse effects. In addition, there may be other unintended consequences of disrupting signals to a particular portion of the vagus nerve.

Stimulation of the vagus nerve via a device implanted within the carotid artery sheath has also been evaluated as a treatment for obesity. Refer to medical policy #260 Vagus Nerve Stimulation for additional information. Vagus nerve stimulation is FDA-approved to treat epilepsy and depression, not for obesity treatment.


To assess obesity treatments, a double-blind randomized controlled trial is optimal because these interventions require changes to patient behavior (i.e., diet, exercise) that are subject to the placebo effect. Health outcomes such as mortality, cardiovascular events, and rates of type 2 diabetes would be optimal, but are difficult to use as study end points due to the need for a large sample size and long follow-up period. Cardiovascular risk factors, such as changes in blood pressure, glucose, and lipid levels, are good intermediate measures because they have been linked with these health outcomes, and would require smaller sample sizes. Weight loss outcomes, reported as absolute change in weight or BMI, or as percent excess weight loss or percent BMI are acceptable intermediate outcome measures and are commonly used in obesity studies. Weight loss has been linked to improvements in cardiovascular risk factors. While no generally accepted threshold of percent excess weight loss is considered clinically significant, bariatric surgery trials generally define clinical success as at least 50% excess weight loss. The amount of weight loss is expected to be lower for other, less dramatic weight loss interventions.

Sham controls are useful for establishing the efficacy of an intervention beyond the placebo effect and for controlling for other nonspecific effects of interventions including disease natural history and regression to the mean. Because there are so many existing treatment options for weight loss, if sham-controlled weight loss intervention studies are positive, trials using an active comparator, such as medication or other types of surgery, are desirable.


The most recent literature review was updated through March 6, 2024.

Summary of Evidence

For individuals with obesity who receive vagus nerve blocking therapy, the evidence includes 2 sham-controlled randomized controlled trials (RCTs). Relevant outcomes are change in disease status, morbid events, quality of life and treatment-related morbidity. The primary efficacy outcome, at least a 10% difference between groups at 12 months, was not met for either trial. In the first trial (EMPOWER), the observed difference in EWL between groups at 12 months was 1%. In the more recent trial (ReCharge), the observed difference in EWL between groups at 12 months was 8.5%. In a post hoc analysis, the 8.5% EWL was statistically significant, but this magnitude of change may not be clinically significant according to the investigators’ original trial design decisions. Post hoc analyses of longer-term data have been published and are subject to various biases including missing data and unblinding at 12 months. The evidence is insufficient to determine the effects of the technology on health outcomes.

Practice Guidelines and Position Statements

American Society for Metabolic and Bariatric Surgery

A position statement published in 2016 by the American Society for Metabolic and Bariatric Surgery includes the following conclusions and recommendations on vagus nerve blocking therapy for treatment of obesity:

“1. Reversible vagal nerve blockade has been shown to result in statistically significant EWL at 1 year compared with a control group in one of 2 prospective randomized trials.

2. Reversible vagal nerve blockage has been shown to have a reasonable safety profile with a low incidence of severe adverse events and a low revisional rate in the short term. More studies are needed to determine long-term reoperation and explantation rates.

3. The prospective collection of VBLOC outcomes as part of the national center of excellence databases is encouraged to establish the long-term efficacy of this new technology.”

U.S. Preventive Services Task Force Recommendations

In 2018, the U.S. Preventive Services Task Force updated recommendations for screening and management of obesity in adults. The Task Force recommended screening all adults for obesity and referring those with a body mass index of 30 kg/m2 or higher to intensive, multicomponent behavioral interventions. Vagus nerve blocking therapy and other surgical interventions were not addressed in the recommendations or literature review.


Vagus nerve blocking therapy, VBLOC® vagal blocking therapy, Maestro, obesity, neurostimulator, Neuromodulation Weight Loss Device, Maestro® Rechargeable System


FDA approved the Maestro Rechargeable System, (Enteromedics, St. Paul, MN) through the premarket approval process on January 14, 2015. The device is indicated for use in adults age 18 years and older who have a BMI of 40 to 45 kg/m2 or a BMI of 35 to 39.9 kg/m2 with one or more obesity-related conditions such as high blood pressure or high cholesterol and have failed at least one supervised weight management program within the past five years. Implantable components are incompatible with magnetic resonance imaging (MRI). Additional contraindications to use of the device include conditions such as cirrhosis of the liver, portal hypertension and clinically significant hiatal hernia, and the presence of a previously implanted medical device.

The commercial availability of the Maestro® System is unclear. On the FDA's Weight-Loss and Weight-Management Devices webpage (content noted as current as of 09/05/2019), the Maestro® Rechargeable System is described as "no longer marketed as of September 2018". Additionally, on the ReShape LifesciencesTM website (previously EnteroMedics), the Maestro® Rechargeable System, is not listed among their current portfolio of medical devices to treat obesity and metabolic disease. However, updates to the Maestro® Rechargeable System were noted in the FDA Premarket Approval database (P130019) subsequent to September 2018, including updates to the circuit assembly and application firmware of the mobile charger (01/25/2019) and approval of modifications to the follow-up schedule for the post-approval study protocol.


Coverage is subject to member’s specific benefits. Group-specific policy will supersede this policy when applicable.

ITS: Home Policy provisions apply.

FEP: Special benefit consideration may apply. Refer to member’s benefit plan.


There are no specific CPT codes for this procedure. This would likely be reported with an unlisted procedure code.

CPT Codes:

64999 Unlisted procedure, nervous system



Vagus nerve blocking therapy (morbid obesity); laparoscopic implantation of neurostimulator electrode array, anterior and posterior vagal trunks adjacent to esophagogastric junction (EGJ), with implantation of pulse generator, includes programming (Deleted 12/31/22)


laparoscopic revision or replacement of vagal trunk neurostimulator electrode array, including connection to existing pulse generator (Deleted 12/31/22)


laparoscopic removal of vagal trunk neurostimulator electrode array and pulse generator (Deleted 12/31/22)


removal of pulse generator (Deleted 12/31/22)


replacement of pulse generator (Deleted 12/31/22)


neurostimulator pulse generator electronic analysis, includes reprogramming when performed (Deleted 12/31/22)


  1. Apovian CM, Shah SN, Wolfe BM, et al. Two-year outcomes of vagal nerve blocking (vBloc) for the treatment of obesity in the ReCharge trial. Obes Surg. 2017 Jan;27(1): 169-176.
  2. Curry SJ, Krist AH, Owens DK, et al. Behavioral Weight Loss Interventions to Prevent Obesity-Related Morbidity and Mortality in Adults: US Preventive Services Task Force Recommendation Statement. Jama. Sep 18 2018;320(11):1163-1171.
  3. Flegal KM, Kit BK, Orpana H, et al. Association of all-cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta-analysis. JAMA. Jan 2 2013; 309(1):71-82.
  4. Hwang SS, Takata MC, Fujioka K, Fuller W. Update on bariatric surgical procedures and an introduction to the implantable weight loss device: the Maestro Rechargeable System. Med Devices (Auckl). 2016 Aug 17;9:291-9.
  5. Ikramuddin S, Blackstone RP, Brancatisano A, et al. Effect of reversible intermittent intra-abdominal vagal nerve blockade on morbid obesity: the ReCharge randomized clinical trial. JAMA. Sep 3 2014; 312(9):915-922.
  6. IOM (Institute of Medicine). 2011. Clinical Practice Guidelines We Can Trust. Washington, DC: The National Academies Press.
  7. Johannessen H, Revesz D, Kodama Y, et al. Vagal Blocking for Obesity Control: a Possible Mechanism-Of-Action. Obes Surg. 2017 Jan;27(1):177-185.
  8. Morton JM, Shah SN, Wolfe BM, Apovian CM, Miller CJ, Tweden KS, Billington CJ, Shikora SA. Effect of Vagal Nerve Blockade on Moderate Obesity with an Obesity-Related Comorbid Condition: the ReCharge Study. Obes Surg. 2016 May;26(5):983-9.
  9. Ogden CL, Carroll MD, Kit BK, et al. Prevalence of childhood and adult obesity in the United States, 2011-2012. JAMA. Feb 26 2014; 311(8):806-814.
  10. Papasavas P, El Chaar M, Kothari SN, et al. American Society for Metabolic and Bariatric Surgery position statement on vagal blocking therapy for obesity. Surg Obes Relat Dis. Mar-Apr 2016; 12(3):460-461.
  11. ReShape LifesciencesTM. Summary of Transformative Technologies for the Treatment Continuum. 2020.
  12. Sarr MG, Billington CJ, Brancatisano R, et al. The EMPOWER study: randomized, prospective, double-blind, multicenter trial of vagal blockade to induce weight loss in morbid obesity. Obes Surg. Nov 2012; 22(11):1771-1782.
  13. Shikora SA, Wolfe BM, Apovian CM, et al. Sustained weight loss with vagal nerve blockade but not with sham: 18-month results of the ReCharge trial. J Obes. 2015; 2015:365604.
  14. U.S. Food and Drug Administration. Premarket Approval (PMA) Database: Maestro Rechargeable System (P130019). 2020.
  15. U.S. Food and Drug Administration. Summary of Safety and Effectiveness Data (SSED): Maestro Rechargeable System.
  16. U.S. Food and Drug Administration. Summary of Safety and Effectiveness Data (SSED): Maestro Rechargeable System. 2015; 
  17. U.S. Food and Drug Administration. Weight-Loss and Weight-Management Devices. 2019; 
  18. U.S. Preventive Services Task Force. Weight Loss to Prevent Obesity-Related Morbidity and Mortality in Adults: Behavioral Interventions. 2018;
  19. U.S. Preventive Services Task Force. Obesity in Adults: Screening and Management. 2012; 
  20. Worrest TC, Wolfe BM, Mattar SG, Gilbert EW. Laparoscopic vagal nerve blocking device explantation: case series and report of operative technique. Surg Endosc. 2019 Nov;33(11):3600-3604. doi: 10.1007/s00464-018-06643-4. Epub 2019 Jan 10. 


Medical Policy Panel, April 2015

Medical Policy Group, May 2015 (3): New policy adopted for this procedure - already considered investigational 0312T-0317T; no change in coverage – remains investigational

Medical Policy Administration Committee, June 2015

Available for comment June 4 through July 18, 2015

Medical Policy Panel, February 2016

Medical Policy Group, February 2016 (3): 2016 Updates to Key Points & References. No change in policy statement; remains investigational.

Medical Policy Panel, February 2017

Medical Policy Group, February 2017 (3): 2017 Updates to Title, Description, Key Points & References. No change in policy statement; remains investigational. Changed “vagal” to “vagus” throughout policy; no change in intent.

Medical Policy Panel, February 2018

Medical Policy Group, March 2018 (4): Updates to Description and Key Points.  No change to policy statement.

Medical Policy Panel, February 2019

Medical Policy Group, March 2019 (4): Updates to Description, Key Points, and References.  No change to policy statement.

Medical Policy Panel, February 2020

Medical Policy Group, February 2020 (5): Updates to Key Points, Approved by Governing Bodies, U.S. Preventive Services Task Force Recommendations, Key Words, and References. No change to Policy Statement.

Medical Policy Panel, February 2021

Medical Policy Group, February 2021 (5): Updates to Key Points, and References. No change to Policy Statement.

Medical Policy Panel, March 2021

Medical Policy Group, March 2021 (5): Effective March 15, 2021: Active policy but no longer scheduled for regular literature reviews and updates. Reviewed by consensus. No new literature identified that would alter coverage statement at this time. No change to Policy Statement.

Medical Policy Group, March 2022 (5): Reviewed by consensus. No new literature identified that would alter coverage statement at this time. Updates to Key Points, and References. Policy Statement updated to remove “not medically necessary,” no change to policy intent.

Medical Policy Group, November 2022 (5): 2023 Annual Coding Update. Created Previous Coding section to include the following deleted codes: 0312T, 0313T, 0314T, 0315T, 0316T, 0317T. No change to Policy Statement.

Medical Policy Group, March 2023 (5): Reviewed by consensus. No new literature identified that would alter coverage statement at this time. Updates to Key Points and Benefit Application.

Medical Policy Group, March 2024 (11): Reviewed by consensus. No new literature identified that would alter coverage statement at this time. Updates to Key Points, Key Words, Current Coding and References.

This medical policy is not an authorization, certification, explanation of benefits, or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All medical policies are based on (i) research of current medical literature and (ii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.

This policy is intended to be used for adjudication of claims (including pre-admission certification, pre-determinations, and pre-procedure review) in Blue Cross and Blue Shield’s administration of plan contracts.

The plan does not approve or deny procedures, services, testing, or equipment for our members. Our decisions concern coverage only. The decision of whether or not to have a certain test, treatment or procedure is one made between the physician and his/her patient. The plan administers benefits based on the member’s contract and corporate medical policies. Physicians should always exercise their best medical judgment in providing the care they feel is most appropriate for their patients. Needed care should not be delayed or refused because of a coverage determination.

As a general rule, benefits are payable under health plans only in cases of medical necessity and only if services or supplies are not investigational, provided the customer group contracts have such coverage.

The following Association Technology Evaluation Criteria must be met for a service/supply to be considered for coverage:

1. The technology must have final approval from the appropriate government regulatory bodies;

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes;

3. The technology must improve the net health outcome;

4. The technology must be as beneficial as any established alternatives;

5. The improvement must be attainable outside the investigational setting.

Medical Necessity means that health care services (e.g., procedures, treatments, supplies, devices, equipment, facilities or drugs) that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury or disease or its symptoms, and that are:

1. In accordance with generally accepted standards of medical practice; and

2. Clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the patient’s illness, injury or disease; and

3. Not primarily for the convenience of the patient, physician or other health care provider; and

4. Not more costly than an alternative service or sequence of services at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of that patient’s illness, injury or disease.