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Vagus Nerve Block

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Updated on August 9, 2022
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Before learning what a vagus nerve block is, what is a vagus nerve and it’s functions?
The Vagus nerve is the 10th cranial nerve in the body. Among the cranial nerves, the vagus is the longest, traveling through the esophagus, lungs, and heart that carries a considerable amount of indicators from the organs to connect the abdomen to the brain.

It majorly constitutes the parasympathetic nervous system regulating involuntary processes like digestion, saliva and mucus production, immune response, orgasm, mood control, heart rate, and muscle sensations. The vagus nerve has the sensory fiber that sends real-time situations in the liver, pancreas, gut, and gallbladder based on the metabolites. It senses the state of insulin resistance and stimulates B cell proliferation.

As one of its functions, the vagus nerve communicates hunger signals from the stomach to the brain. It helps the stomach produce acid to break down food so that it can be emptied from the stomach and also helps the pancreas produce enzymes that are necessary to produce food. The theory of the vagus nerve block reduces the function of the nerve by taking away some of those critically important factors that influence the digestion of food.

Vagal nerve blocking therapy was developed as a less invasive alternative to conventional therapy (bariatric surgery), for the treatment of obesity. The treatment option is given to patients who find the pharmacological approach and behavioral therapies ineffective, and do not want to undergo current bariatric surgical options.

Upon evaluation, Approximately one-third of adults in the United States are obese with about 8.8% of adults having a BMI of 35 to 39.9 (class 2 obesity). About 6% had a BMI of 40 or greater(class 3 obesity), also known as severe obesity. (3)

Obesity is a crucial health issue that results in an increased risk of numerous diseases like type 2 diabetes, certain types of cancer, stroke, heart diseases, coronary artery diseases, and increased economic cost and mortality rate(4)

Before we conclude on why vagus nerve blocking is a preferred option over bariatric surgery for the treatment of obesity, let us learn what bariatric surgery is.

Bariatric surgeries work in several ways, either by reducing the quantity of food a stomach can hold, restricting the body’s ability to absorb nutrients, or both. It is a weight loss treatment option that involves the surgical reduction of the size of the stomach.
It can be done either by;

  • Sleeve Gastrectomy involves the removal of about 80% of the stomach. A tube-shaped pouch is left. This enables the stomach to hold a smaller quantity of food and reduces ghrelin, a hormone that regulates appetite.
  • Gastric band: This involves placing an inflatable band around the upper part of the stomach creating a smaller pouch at the top. This way, a smaller quantity of food is stored and patients get filled faster.

Although Bariatric surgery has shown effectiveness in the treatment of morbid obesity, research suggests that only a small number of qualified patients eventually take up the surgery. This is due to the high economic cost burden and mortality rate over time.
Due to these disadvantages, a better therapy was found. This option is called intermittent Vagal blocking, developed as a less invasive option to standard bariatric surgery which involves implantation of electrodes through laparoscopic surgery.
It is designed to work for up to 8 years. This disc is lodged just under the skin and is connected to nerves in the stomach by two small leads.

How does it work?

This therapy uses a specific sporadic vagal nerve blocking method to reduce communication signals transmitted between the brain and stomach that affects the awareness of hunger and fullness. The Maestro System works best when optimally used in combination with portion control diets, and where possible, increasing the amount of exercise you do. The surgery takes about 90 minutes to complete under general anesthesia. You charge the device once or twice every week to keep it functional (hence “rechargeable system”). The device itself is meant to last a lifetime, but the half-life of the rechargeable battery has a shelf life of only eight years which will need to be replaced.
During waking hours, the device acts like a pacemaker that uses electrodes to stop neural signal transmission to the vagus nerve known to play an important role in reducing sensations of hunger and food metabolism. The system works by delivering an electrical pulse 5 minutes on and 5 minutes off to the vagus nerve while awake, and should be turned off while you sleep. (5)

The VBLOC Rechargeable device delivers high frequency, minute energy, and sporadic electrical impulses to the intra-abdominal vagal trunks for a specific number of hours every day. The result of this blockage results in fewer hunger pangs, which assists the patient in regulating their food intake. With a simple doctor’s visit, the device can be recharged and adjusted. The external components include a mobile charger and transmit coil.

Some of the advantages of Vagal nerve blocking therapy include;

  • it is neither digestive anatomy altering nor restricting.
  • It is a reversible procedure that significantly induces excess weight loss in a short time.
  • It has no physical reactions to food eaten.
  • There is improvement in obesity-related comorbid diseases such as heart diseases and type 2 diabetes mellitus.
  • It is easily deactivated at any time.
  • It has a low occurrence of severe adverse effects.
  • The body continues to process food as it did before
  • It does not need a lifelong nutritional supplement
  • It is a cost-effective therapy when compared to conventional therapy (bariatric) among class 2 and class 3 patients with or without diabetes.
  • It is good value for money

Whom is VBLOC Meant For?

VBLOC Therapy is indicated for use in weight reduction in the following class of patients. (5)

  • Patients 18 years and above
  • Patients who have tried more than one weight management program, in the last five years.
  • Patients with a Body Mass Index (BMI) of 35 to 39.9 (Class 2) or BMI of 40 to 45(Class 3).
  • Obese patients with additional obesity-related co-morbid conditions. One or more of either type 2 diabetes, sleep apnea, high cholesterol, or high blood pressure.

Who is VBLOC Not Meant For?

Even if a class 2 or class 3 obese patient meets all criteria, the patient with the following are not considered for vBloc weight loss therapy
1. Patients who already have an electronic medical device implanted.
2. Those who require diathermy or MRIs.
3.Patients diagnosed with Hiatal hernias, esophageal varices, cirrhosis of the liver, or portal hypertension are not approved for the procedure.

Common Side Effects Experienced Include:

Just as with any surgery, some side effects experienced with the Maestro Rechargeable System are:

  • Heartburn
  • Abdominal pain
  • Nausea
  • Belching
  • Dyspepsia
  • Incision pain
  • Dysphagia

 

Adverse reactions associated with the use of the VB Rechargeable System are:

  • Allergic responses to the implanted equipment
  • Pain at neuroregulator or lead site
  • Infections at the implant site could require surgery and device explantation.
  • Damage to vagal nerve trunks
  • Malfunction of parts of the system including loss of power, and lead to migration
  • Pain at neuroregulator or lead site

How does Vagus nerve block work?

Vagus nerve block works by reducing communication signals sent between the brain and stomach which affects the awareness of hunger and fullness. When awake, the device uses electrodes to stop neural signal transmission to the vagus nerve which is known to play an essential role in reducing hunger sensations and food metabolism. 

What is the difference between VBloc and Bariatric surgery?

Bariatric surgery is a weight loss treatment that involves the surgical reduction of stomach size while VBloc is a less invasive surgery done to reduce communication signals sent from the brain to the stomach hence affecting awareness of hunger and fullness. 

Who is a good candidate for a vagus nerve block?

⦁ Patients with a Body Mass Index (BMI) of 35 to 39.9 or a BMI of 40 to 45.
⦁ Only patients above 18yrs. 
⦁ Patients who have tried other weight loss programs with supervision, in the last five years 
⦁ Obese patients with obesity-related co-morbidities such as high cholesterol, sleep apnea, type 2 diabetes, or high blood pressure

What are the side effects of having a vBloc?

⦁ Pain at the site of incision 
⦁ Nausea 
⦁ Heartburn 
⦁ Abdominal pain
⦁ Belching
⦁ Dyspepsia
⦁ Dysphagia 

Who can not undergo a vBloc?

Patients who have a concurrent chronic pancreatic disease
Patients who require MRIs
History of blood coagulation disorders or pulmonary embolism
History of ulcerative colitis 
Patients who already have an electronic medical device implanted
Patients who have been diagnosed with portal hypertension, hiatal hernias, esophageal varices, or cirrhosis of the liver

 

References

https://www.ajmc.com/view/cost-effectiveness-analysis-of-vagal-nerve-blocking-for-morbid-obesity

https://archbold.org/what-is-bariatric-surgery

https://www.ajmc.com/view/cost-effectiveness-analysis-of-vagal-nerve-blocking-for-morbid-obesity

https://en.m.wikipedia.org/wiki/Obesity_in_the_United_States

https://www.medstarhealth.org/services/vbloc-therapy

https://www.webmd.com/diet/news/20150116/obesity-maestro-system

https://www.accessdata.fda.gov/cdrh_docs/pdf13/p130019c.pdf

https://www.webmd.com/diet/news/20150116/obesity-maestro-system

https://www.accessdata.fda.gov/cdrh_docs/pdf13/p130019c.pdf

 

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