Vagal nerve stimulation





Definition

Vagal nerve stimulation is a treatment for epilepsy in which an electrode is implanted in the neck to deliver electrical impulses to the vagus nerve.


Purpose

Vagal nerve stimulation is an alternative to medication or surgical removal of brain tissue in controlling epileptic seizures. The seizures of epilepsy are caused by uncontrolled electrical discharges spreading through the brain. Anti-seizure drugs interrupt this process by reducing the sensitivity of individual brain cells to stimulation. Brain surgery for epilepsy either removes the portion of the brain where seizures originate, or cuts nerve fibers to prevent the nerve impulses that occur during a seizure from spreading to other parts of the brain. Vagal nerve stimulation uses a different approach; it provides intermittent electrical stimulation to a nerve outside the brain—the vagus, or tenth cranial nerve, which influences certain patterns of brain activity.

The vagus nerve is a major connection between the brain and the rest of the body. It carries sensory information from the body to the brain, and motor commands from the brain to the body. The vagus is involved in complex control loops between these destinations; its precise pathways and mechanisms are still not fully understood. It is also not known how stimulation of the vagus nerve works to reduce seizure activity—it may stimulate inhibitory pathways that prevent the brain's electrical activity from getting out of control, interrupt some feedback loops that worsen seizures, or act in some other fashion.

Vagal nerve stimulation has been effective in reducing seizure frequency in patients whose seizures are not controlled by drugs, and who are either not candidates for other types of brain surgery or who have chosen not to undergo these procedures.

Demographics

Epilepsy affects about 1% of people in the general worldwide population. Approximately 40% of patients do not respond well to medications, however, and so may be candidates for surgical treatment. Vagus nerve stimulation was first performed in the United States in 1988 and received final approval by the United States Food and Drug Administration (FDA) in July 1997. Approximately 10,000 people worldwide have had stimulators implanted as of 2003; about a fifth of these patients are children 12 years old and younger.


Description

The vagal nerve stimulator has two parts: an electrode that wraps around the left vagus nerve in the neck; and a pulse generator, which is implanted under the skin below the collarbone. The two parts are connected by a wire. Stimulation is performed only on the left vagal nerve, as the right vagal nerve helps control the heartbeat.

Surgery to implant a VNS device takes about two hours. A neurosurgeon implants the electrode and generator while the patient is under general anesthesia. A vertical incision is made in the left side of the neck, and the helical electrode is attached to the nerve itself. A second incision is made on the left side of the chest below the collarbone, and the pulse generator (a disc about 2 in [5 cm] in diameter) is implanted under the skin. The connecting wire is threaded around the muscles and bones to join the electrode and generator. The generator makes a small bulge under the skin but is hidden by clothing after the operation.

Before the neurosurgeon closes the incisions, he or she tests the VNS device to make sure it is working, and programs it to deliver the lowest amount of stimulation. The device is usually timed to stimulate the vagus nerve for 30 seconds every five minutes.


Diagnosis/Preparation

A candidate for vagal nerve stimulation will have had many tests already to determine the focal point of seizure activity. Preoperative tests include neuroimaging as well as psychological tests to determine the patient's cognitive (thinking) strengths and weaknesses.

The patient must be fully informed about VNS—how it works, its advantages and disadvantages, what will happen during surgery—before the operation is scheduled. A video as well as written material about VNS is available to view and discuss with the doctor.


Aftercare

Implantation of the stimulator in an adult may be performed as either an outpatient or inpatient procedure. In the latter case, the patient will remain in the hospital overnight for monitoring of heart function and other vital signs . Children who are receiving a VNS are usually scheduled for an overnight stay. Pain medication is given as needed.

The stimulation parameters are adjustable, and the neurologist may require several visits to find the right settings. Settings are adjusted with a magnetic wand that delivers commands to the stimulator's computer chip. The patient may be taught how to use a magnet to temporarily increase stimulation, to prevent a seizure, or to abort it once it begins.

The VNS generator is powered by a battery that lasts several years. It is replaced during an outpatient procedure under local anesthesia.


Risks

The most common adverse effects from vagal nerve stimulation are a hoarse voice, cough, headache, and ear pain. These side effects can be reduced by adjusting the stimulation settings, and may subside on their own over time. Infection and device malfunction are possible though rare.

Patients who have had a VNS implanted must avoid strong magnets, which may affect the stimulator settings. Areas with warning signs posted regarding pacemakers should be avoided. The patient should consult with the neurologist and the neurosurgeon about other hazards.


Normal results

Approximately half of all patients who have received vagal nerve stimulation experience about a 50% reduction in seizures. Another 9% of patients obtain complete relief from seizures. Most patients who continue to take antiseizure medications can reduce their dosage, however, which offers some relief from the side effects of these drugs.


Morbidity and mortality rates

Vagal nerve stimulation is a relatively safe procedure, with no deaths attributed to the stimulation as of 2003. Pilot studies of 300 patients that were done prior to FDA approval of VNS reported the following complication rates: hoarseness, 37% of patients; coughing, 14%; voice alteration, 13%; chest pain, 12%; and nausea, 2%.


Alternatives

Some candidates for vagal nerve stimulation are also likely to be candidates for a corpus callosotomy , temporal lobectomy, or other surgical procedures.

See also Hemispherectomy .


Resources

BOOKS

Devinsky, O. A Guide to Understanding and Living with Epilepsy. Philadelphia: E. A. Davis, 1994.

"Seizure Disorders." Section 14, Chapter 172 in The Merck Manual of Diagnosis and Therapy , edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

PERIODICALS

Rielo, Diego, MD, and Selim R. Benbadis, MD. "Vagus Nerve Stimulation." eMedicine , April 12, 2002 [June 10, 2003]. http://www.emedicine.com/neuro/topic559.htm .

ORGANIZATIONS

American Association of Neurological Surgeons (AANS). 5550 Meadowbrook Drive, Rolling Meadows, IL 60008. (847) 378-0500. http://www.neurosurgery.org .

Epilepsy Foundation. 4351 Garden City Drive, Landover, MD 20785-7223. (800) 332-1000. http://www.epilepsyfoundation.org .


Richard Robinson

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?



The implanting of a VNS device is performed by a neurosurgeon in a hospital, in consultation with a neurologist.

QUESTIONS TO ASK THE DOCTOR



  • What will the procedure cost? Will my insurance cover the cost?
  • How often will I need to return to have the stimulator adjusted?
  • Will my medication dosages be reduced after this procedure?
  • How long will the procedure take?
  • How many VNS devices have you implanted? What is your success rate?

User Contributions:

Sue Theisen
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Feb 18, 2006 @ 9:09 am
Is the stimulator ever removed if it is not successful?
Is there long term effects of this procedure-such as vagal nerve damage?
If it helps control the seizures does it continue to help seizures indefinitely or does the effect diminish with time as medications have?
Martha Collignon de Gómez
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May 26, 2006 @ 11:23 pm
I have been suffering from chronic migraines and depression for almost 20 years now. I have tried Lexapro, Vivactil and Prozac to treat the depression. Antiinflamatories ibuprofen, Aleve, Excedrin and profenid.
Imitrex (which I take almost every other day), do takes care of the pain.
The only medicine that helped diminish the frequency of my migraines was Topamax, but one of the side effects, (really spaced out), was unbearable.
If an antiepileptic drug considerably helpes me reduce the migraines and at the same time I suffer from chronic depression wouldn´t the VNS be an option for me?
I am willing to try it regardless the lack of evidence or trials proving it´s effectiveness on migraines.
Thank you very much.
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Apr 20, 2010 @ 5:17 pm
I have had severe chronic nerve pain in my r inner ear that radiates up and inside the R side of my head. The symptoms are severe: constant burning, extreme tingling and electric shock sensations that start in the auricle of the r inner ear and go up and inside the r side of my head. I have had this pain for over 6 years. I was an RN but have been unable to work for over 2 years. Of course, I am on narcotics for this pain. sometimes they work and sometimes they don't. I just got approved for disability. would a nerve stimulator be appropriate for me, and where would it be placed. What is the cost and the general success rate? The pain is so bad that I have lost over 35 pounds because I can not eat when the pain is so intense; I am underweight and only weigh 118 pounds and am 5ft 8inches tall. Also I am on medicare now and wonder if they will pay for it. This pain basically ruined my life and I lost everything : my career, car and my own place to live. It is horrible. I had worked for 33 years of my life fulltime and raised a daughter totally by myself so I am not just a wimp. When I say I am in pain it definitely is the truth. Can you respond to this.
balinder chahal,
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Sep 27, 2010 @ 12:12 pm
WHAT IS THE PROCEDURE AND THE RISK INVOLVED WITH HAVING VNS REMOVED?
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Jul 11, 2011 @ 5:05 am
My 19 yr old son was hit by a car nearly 2 yrs ago sustaining a severe traumatic brain injury. 10 months after the accident he began to have grand mal seizures due to sudden onset seizure disorder related to his TBI. He's been on 7 different anit-seizure meds & each have caused horrible reactions, none have properly controlled the seizures. We are seriously considering the VNS & need to know the detailed risk factors as he seems to experience all the one-in-a-million things in the fine print! Do most patients with a VNS stop their anti-seizure meds? What ratio of VNS patients are TBI/SOSD patients rather than epileptic? We're seeing his neurologist on July 13th & planning on discussing the matter at length. Any additional input would be greatly appreciated.
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Aug 27, 2011 @ 9:21 pm
u may want to read this dad.. its some good information i found on my surgery
Unknowngender92
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Sep 4, 2011 @ 6:18 pm
I got this stupid implant when I was 8 and it didn't do a damn thing! I've been doing som research and most surgeons are afraid to take this piece of shit out! My seizures got worse after a few weeks of having it in. Just last year I had a temporal lobectomy (aka a surgery that actually does help! [that is if it is in your temporal lobe. {mine was left temporal lobe, but right temporal lobectomies have some higher risks.}]). After the temporal lobectomy I've been slowly getting off my medications and as of this past august I'm 2 years with no seizures.
P.S. Does anyone here know of a surgeon that is willing to remove the whole VNS???
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Sep 18, 2011 @ 6:18 pm
I have had a VNS for about 4 years. Everything is doing great till this afternoon. I was using 120 volt electric grinder. It seems like my VNS started going off. Could it be the grinder making this happen or could the battery be going out.
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Nov 10, 2011 @ 1:13 pm
i started having seizures when i was 15. and now im 38. ive been on all kinds of meds. some worked,some didnt. what started my seizures was gentic. they say seizures aint gentic, but i dont agree, 2- of my sisters,my oldest son,his dad and his uncle has seizures.my oldest son got it from my side and his dad's side.ive had 2- v.n.s. done.my first one didnt work that well, they say after 10 years the battery aint no good. so, i had to go for another one.. after about a few years later my dr. wanted to check it,and i told him no i dont want you to check it, just leave it alone.. every time that thing is being checked i end up having a seizure. so, ive turned it off.since ive had it off im doing pretty good.i got my drivers license back.and it feels good to be independent again..i can live my life " normal " again. so, if i had the choice to do it again, I WOULDNT DO IT AT ALL!!! IF YOU HAVE ANY QUESTIONS PLEASE CONTACT ME...
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Nov 17, 2011 @ 12:12 pm
I got the first V.N.S. in my state (minnesota) about 14 years ago. I have had a second replacement 8 years later and hopefully will have it changed again next year. The V.N.S. has helped me control my seizures 100 percent. I had brain surgery, been on the ketogenic diet and can't tell you how many different med changes. The VNS has helped improve my life 100 percent. The only side effect I get from it is, when the implosives are going off my voice does get horse for 30 seconds. My friends can still understand me and I am okay with that. I didn't have any other side effects from it. The first one I had they made me stay over night at the hospital, since I was the first one getting it. The next time I got it, I was only in recovery room for two hours and then went home. I never lost any energy. I know it's getting close to getting a new one now, because I only have about 7 months before I need a new one. From the VNS I got to throw away my last helmet. I wore a helmet 15 years before that. My VNS last twice as long also, because I don't use the magnet. My seizures are so short, the time you get the magnet out, it's over. I only use the magnet if I am doing public speaking to schools, so they can understand me.
Karilyn
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Jan 31, 2012 @ 5:17 pm
I have had the VNS since April 2011...My voice still changes and now i get a painful sharp burning sensation right around the vns..anybody out there that knows whats going on with me please help
Marla Scott
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May 17, 2012 @ 5:17 pm
great web site..lots of answers for ppl out there that may consider this VNS..check out the mayo clinic site for VNS..I am 46 and considering this surgery..not only was i diagnosed in 08 with ASD(adult seizure disorder)..I have tried every medicine it there but my body doesn't take to drugs very well..I refuse electrode shock, no thank you!!I have had very severe head trauma, and most of my pain is on the left side of my head..I have migraines for days..took topamax for awhile, loved the weight loss side affect, but after some time it just didnt work. This is my 7th medication, and 3rd neurologists. I pray this one figures something out.
Dion Ryan
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Jun 2, 2012 @ 10:10 am
I have had 2 VGN Stimulators done.Neither time worked. I have grandma seizures ,So I opted for the neuro-cranial brain surgery. Problem is when the Doctor took out the VGN Stimulator,the wire was left in my neck.Does anyone know the side effects. Other than severe migraines and my face goes numb. What site can I visit reguarding this problem. Neurologist are keeping my in the dark.
Nicole
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Jun 26, 2012 @ 8:08 am
My daughter is on her third vns. We have seen mixed results in seizure control. However, her vns is now sending out an IFI code. Does anyone have information on this code? I know it means Immediate Follow Up is needed but haven't been able to find much more than that.
Ralph
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Sep 19, 2012 @ 8:08 am
My son is going in for his pre-op in Oct. I was just reading up on this VNS. I'm concerned, because he is an athlete. He plays basketball, I haven't seen any responces of athletes who have had this procedure done. He is on medications now, he is aloud to play sports! But he doesn't like to take his meds! They make him drousy, along with some of the other side effects. Can I get an athletes take on this procedure please? Thanks.
kara
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Sep 25, 2012 @ 1:13 pm
My son who is now 7 years old, had a stroke when he was just an infant. He suffers from a seizure disorder called Lennox Gastaut Syndrome. He has 3-4 different types of seizures, which are not controlled with any medication. we are going to talk to a surgeon about a possible VNS placement. I am just curious of side affects? Will it work for my son? Has anyone had a oung child get a VNS before?
Shane
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Oct 23, 2012 @ 4:04 am
I've had my vns for 6 1/2 years. I have been to my neurologist 3x this year because the vns cannot hold its programmed setting. Can anyone tell me if it is time for me to consider a battery replacement. (listen to me...I sound like the energizer bunny.) Thanks
Margaret Curry
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Oct 25, 2012 @ 7:19 pm
My daughter has had the VNS for several years. It is not working now probably needing a new battery. She is having problems & I would like for her to have a MRI which is not possible with this implanted. Is there a possibility for removal of this device (leaders also) so she can get the MRI. Thanks for any information you can give me. Blessings, Margaret
Shane
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Oct 27, 2012 @ 7:07 am
Margaret,

I have had a VNS for 6 years. Cyberonics has come out with new information that allowed me to have an MRI. It is called "passive MRI." The MRI machine is fitted with a coil of some kind. The VNS is turned off for the duration of the scan. I had this done about 6 months ago and my neurologist got the pictures he was looking for. Make sure you have your Cyberonics rep on hand to explain exactly what needs to be done.
bobbi
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Jan 6, 2013 @ 11:23 pm
I have been fighting seizures all my life they are pretty bad i was not able to have the surgery done my Dr. wanted on the left side of my brain cause the right side was now being affected so i had the vns put in i only kept it in a little over a year cause my doctor didnt want to have it removed i finially said i had enough and made them take it out the migrains were killing me and are evern worse to this day from the vns i now have the leads in my head cause they couldnt be removed i suffer from neck pain and massive migrains daily that really affect my life did anyone have this same problem with the leads and migrains im always in so much pain
write me
shari
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Jan 15, 2013 @ 3:15 pm
I am on my second VNS. 1st one lasted four years and this one is dying out a couple weeks short of two years. Has anyone else had problems like this? The machine helps with my seizures. Ask have small seizures all day which wipe me out but I can't see having to replace it every two years.
Gigi
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Feb 18, 2013 @ 12:00 am
My daughter has seizures and I train seizure alert and response dogs. I have a new young lady who has a VNS and it has done very well for her. We are now training a dog for her. First to alert so she can handle the situation, then to bring the magnet to the chip for her if she is unresponsive. For those with the chip, how often are you actually having full seizures with the chip, and if the magnet is accidently passed over the chip twice would it cause problems? The VNS is new to me so I dont want to do anything wrong here.
Sue Baker
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Mar 1, 2013 @ 11:11 am
I had my vagus nerve stimulater removed The DR refused to remove the wire around the vagus nerve Last week I went to have a MRI for a possible blood clot in my brain I was not told this by my neurosurgen until the hospitol called him and asked if an MRI could be done Because the wire had been cut I can never have an MRI
dmot
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May 5, 2013 @ 7:19 pm
Hi Gigi
I have had a seizure dog for almost 10 years now. And before I had my VNS inplant I called the company cyberonics many times. I wanted to know if she would still be able to alert me before one happened. They told me they had never done a study on this before. Well I can tell you this she would always stay very close to me 24 hours before I had a grand mal. I debated over several months because she was my security and I did not want to lose her ability to warn me because of a machine. God only knows how these wonderful animals can OUT DO a machine. But she can and has not lost that sense even though I had a mechanical device put in. As for how many times you swipe the magnet over the device it does not matter. This is per my Neuro Surgeon and I have swiped as many as 6-7 times. I was having seizures 24-7 but they were small enough I didn't know it. It was found by a 3 day study. The grand mal's were 1-2 weekly. If I can answer any other questions for you please feel free to e-mail. God bless you for training these dogs. My next dog will be trained to swipe the magnet for me. The training school is out of Atlanta GA. I would cut the wrist band down to the size of the dogs mouth leaving just enough room for her to pick up the magnet which could be attached to the bottom of the ref so the dog would know to always run there,or I would try putting it on her collar so if the pt falls down the dog can just lay her neck right ontop of the patients chest (magnet implant)the dog will feel the two magnets connect and if the dog does not get a respond she can lay down over her chest again. The dog will not hurt her by just laying her neck ontop of the VNS by her weight. It also would work better on the collar when the patient leaves the house for outings. Believe me I would rather have a dog across my chest trying to stop a seizure then having nothing at all. God Bless you hope I have been helpful.
Cheryl
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Jun 3, 2013 @ 1:01 am
Hi Gigi
Just to be safe I would get in contact with the VNS manufacturer Cyberonics for the correct information. I have had the device for three years. When you swipe the magnet over the stimulator it raises the voltage of the "shock". I wouldn't keep repeating it unless you needed to. For one thing, if I'm a case it hurts some people. Also the VNS can affect the Heart Rate. The main use of the VNS magnet is to help interrupt the seizure. If the seizure is over it will do nothing. It does not revive a person from a seizure. Contact the experts Cyberonics.com 1-800-332-1375. I hope this helps. Cheryl
lower
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Sep 27, 2013 @ 2:14 pm
Does anyone have any experience with having a second VNS implanted after the first one was removed. My 4yr old son had one put in in August but due to an infection it had to be removed a month later. It helped him immensely so I really hope they can put another one in. He went from 8-10 seizures a week to only 3 the whole month he had it in. Thanks for any input.

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