Bariatric Surgery Alternative: What Is vBloc?

What Is the Vagus Nerve and Can It Boost Weight Loss?

vagus nerve stimulation for weight loss
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There is a bariatric surgery alternative that is not as well known as the lap band, stomach pump or gastric balloon. It's called vBloc and it works by blocking the vagus nerve. What is the vagus nerve? It's a pathway in your body that plays a role in your sensation of hunger. And it may hold the key to long term weight loss. But many experts are still cautious about recommending the treatment.

What Is the Vagus Nerve?

Also known as cranial nerve X, the vagus nerve is the tenth and longest of your cranial nerves.

The vagus nerve is sometimes called the wandering nerve. It extends from part of your brain stem (the medulla oblongata) throughout organs in the neck and chest and finally into your abdomen and digestive tract.

The vagus nerve sends important information to your brain about your body's physical and emotional state. In doing so, it helps to regulate several parasympathetic (or involuntary) functions. Vagus nerve stimulation (VNS) is sometimes used to treat people with certain conditions including epilepsy, migraines, or depression. Although results of these treatments have been mixed.

So what does the vagus nerve have to do with weight loss? The vagus nerve runs down into the stomach and helps communicate to your brain about your state of satiety. That means that the nerve sends signals to your brain about hunger and fullness. Based on these signals, hormones are secreted that either encourage or inhibit eating.

What Is vBloc Therapy?

Some researchers believe that if you block certain signals sent by the vagus nerve, you can change the urge the eat. The vagus nerve stimulation system has become one of four bariatric surgery alternatives for people who struggle with their weight.

A company called EnteroMedics recieved FDA approval for a device called the Maestro Rechargeable System that uses neurometabolic therapy (or vBloc therapy) for weight loss.

As part of the therapy, the device changes hunger signals sent to your brain and may help a patient eat less.

Patients who undergo vBloc therapy have a small device implanted near the stomach. The device also attaches to the vagus nerve. As a result of stimulation from the device, the stomach expands less and contracts less often during food digestion. This helps the patient feel full sooner so that they are less inclined to overeat.  Stimulation is ongoing for twelve hours throughout the day.

Bariatric surgery alternatives like vBloc are popular because they don't require you to undergo major surgery and because they don't involve any surgical change to the stomach. The vBloc system is implanted using a minimally invasive laparoscope, usually as part of a 60 to 90 minute outpatient procedure. It can be removed or deactivated at any time.

While using the vagus nerve stimulation system, patients also receive lifestyle coaching. They are encouraged to connect with a registered dietitian for remote one-on-one counseling and are also provided with tracking tools and access to other online tools like videos and instructional materials.

One drawback of the system, however, is that FDA approval limits the type of patient who can get vBloc.

Only people with a BMI (body mass index) between 40 and 45 are eligible for the system. If you are a patient with a BMI of 35 to 39.9 and also have a weight-related condition such as type 2 diabetes or hypertension you may also be eligible for vBloc. Patients also need to demonstrate that they have tried a supervised, traditional weight loss program without success to be eligible for the system.

How Much Does Vagus Nerve Block Therapy Cost?

Even though this is one of the least invasive surgery alternatives, it is not the cheapest. Estimates put the cost of vBloc at approximately $18,500. Your total cost to get electronic nerve stimulation for weight loss will depend on the hospital and surgeon you choose and other variables.

Because the treatment is relatively new, insurance may not cover your procedure. So, by comparison, this may be one of the more expensive weight loss surgery alternatives. Options like the gastric balloon and even the AspireAssist stomach pump are less costly. But EnteroMedics provides counseling to patients who are interested to help navigate their insurance policy for potential coverage.

How Effective Is vBloc?

Can vBloc really help you slim down? The jury is still out on whether or not vagus nerve stimulation is an effective treatment for weight loss. According to the American Society for Metabolic and Bariatric Surgery (ASMBS), the long-term weight loss effects of the procedure are not yet known.

According to ASMBS, published studies on the weight loss method have provided mixed results. One trial included nearly 300 subjects. All patients had the device implanted but only two-thirds had it activated. The device in the other third remained deactivated. After twelve months the amount of excess weight lost by the activated group and the deactivated group was about the same.

In another study, patients who had an activated device showed greater weight loss than those whose device was not activated. But the weight loss was not as impressive as researchers had hoped. The activated implant group (treatment group) lost 24.4 percent of their excess weight while the the deactivated group (sham group) lost 15.9 percent of their excess weight.

When researchers revisited this study group after 18 months, they did, however, see more promising results. Patients in the treatment group lost 23.5 percent of their excess weight or 8.8 percent of their total weight. Patients in the sham group lost 10.2 percent of their excess weight or 3.8 of their total weight.

vBloc Risks and Side Effects

When the Food and Drug Administration approved the Maestro Rechargeable System or vBloc device they identified potential downsides to using the method for weight loss. According to the FDA Device Approval information, certain patients do not make good candidates for the weight loss method. They include patients with

  • Cirrhosis of the liver
  • Increased pressure in hepatic veins
  • Dilated veins in the esophagus
  • Hiatal hernias that are clinically significant and cannot be corrected by surgery

According to additional information provided by the FDA, problems that arose during clinical trials of the Maestro Rechargeable System included nausea, vomiting, surgical complications, pain (including chest pain), heartburn, problems swallowing, and belching.

As a result of their evaluation of the vBloc system, the ASMBS concludes that "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." In short, the organization sees promise with the device but is holding out to see what happens with patients over the long-term.

Sources:

Chae, MD, CF, FACS F. VBloc therapy - all you need to know - Bariatric surgery source. https://www.bariatric-surgery-source.com/vbloc-therapy.html.

Klarer M, Arnold M, et al. Gut Vagal Afferents Differentially modulate innate anxiety and learned fear. The Journal of NeuroScience. 2014;34(21):7067–7076. doi:10.1523/JNEUROSCI.0252-14.2014. http://www.jneurosci.org/content/34/21/7067. 

Moore SK. The Vagus nerve: A back door for brain hacking. Institute of Electronic and Electrical Engineers (IEEE). http://spectrum.ieee.org/biomedical/devices/the-vagus-nerve-a-back-door-for-brain-hacking

Papasavas, M.D. P, El Chaar, M.D. M, et al. Vagal blocking therapy for obesity - American society for metabolic and Bariatric surgery. American Society for Metabolic and Bariatric Surgery. https://asmbs.org/resources/vagal-blocking-therapy-for-obesity. 

Tewfik, MD TL. Vagus nerve anatomy: Gross anatomy, microscopic anatomy, natural variants. Medscape. August 2015. http://emedicine.medscape.com/article/1875813-overview

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