Vagus Nerve Stimulation (VNS) for epilepsy

What is VNS?

Vagus nerve stimulation (VNS) is a surgical treatment that can be used to treat epilepsy. The aim of VNS is to reduce the number of seizures you have and make them less severe.

In the UK, the VNS Therapy system for epilepsy is manufactured and supported  by a company called LivaNova.

How does VNS work?

The VNS Therapy system is made up of 3 parts:

• A small device which generates the electrical impulses. This is called a generator. There are different types of generator available. The type of generator used will depend on your individual needs.
• A thin flexible wire, called a lead
• A hand-held magnet. This can be used to manually stimulate the VNS device

The generator device is implanted under your skin. This is usually on the left side of your chest. The lead then connects the device to the vagus nerve in your neck under your skin. The device electrically stimulates the nerve at regular intervals. The nerve then carries these electrical stimulations to the brain. Regular stimulation can help to reduce the number of seizures you have. It can also make them less severe.

The exact way VNS can help to reduce seizures is not yet fully understood. Research suggests that VNS may help the brain in different ways:

• By increasing levels of a type of brain chemical called  a ‘neurotransmitter’. These chemicals help to carry messages in the brain
• By increasing blood flow to certain parts of the brain
• By changing patterns of electrical activity in the brain during a seizure

These factors work together to help regulate connections in the brain that are involved in causing seizures.

What are the benefits of VNS for epilepsy?

VNS for epilepsy can help some people have:

• Fewer seizures
• Less severe seizures
• Shorter seizures

VNS can help to reduce the number of seizures you have. Some people who have VNS report a large decrease, while others report a small decrease or no decrease.

How well VNS might work for you depends on several things. This includes the type of epilepsy and types of seizures that you have. Different studies have looked at how well VNS can reduce seizures for people with drug-resistant epilepsy.

In general, around 5 or 6 out of 10 people (50-60%) who have VNS fitted will find the number of seizures they have is drastically reduced – by at least half.

People also report other benefits:

• Shorter recovery time after seizures
• Some people experience better seizure control using the magnet
• Improved quality of life. For example, better mood, or improved memory and thinking skills
• Some people may be able to gradually reduce their epilepsy medicines, including rescue medicines, with support from their epilepsy nurse or doctor. However, this is not suitable for everyone

What are the risks of VNS therapy?

VNS is not a cure for epilepsy and it does not work for everyone

While many people will have an excellent or good response with VNS, a smaller number of people will unfortunately have no real response.

VNS can have some side effects

Many VNS side effects are mild and manageable. They usually only happen during stimulation periods, and you may notice side effects less over time. If you find the side effects uncomfortable, talk to your epilepsy doctor or nurse. They may be able to help by adjusting settings.

The most common side effects are related to the neck or throat. This is because the electrical stimulations from the VNS device can cause brief muscle twitches or nerve activation in this area. This might cause things like:

• Hoarseness or a change in voice
• Sore throat
• Shortness of breath
• Prickling or tingling feeling in the skin
• Coughing
• Increase in saliva production for some people

Some people also report changes to heart rate, or signs of stomach discomfort like indigestion (acid reflux).

You can find a longer list of possible side effects in the VNS Patient Manual and on the LivaNova website.

What does VNS surgery involve?

You will need an operation to have VNS treatment for epilepsy. Surgery to implant the VNS system is usually carried out under general anaesthetic. This means you will be asleep for the operation.

Key steps in VNS surgery

Step 1: The surgeon makes 2 small incisions (cuts), one in a natural crease on your neck, and one on the side of your chest

Step 2: The generator is implanted under the skin and above the ribs in your chest. It is usually placed on the left side of your chest. Sometimes it is placed on the right side

Step 3: A lead is then inserted under the skin to connect the generator to the left or right vagus nerve in your neck

The surgery will take between 1 and 2 hours and you can usually go home the same day, or the next day.

What are the risks of VNS surgery?

Your surgeon will discuss any possible risks with you before you have the operation. As with any operation, there is a slight risk of reaction to the anaesthetic during surgery. There is also a small risk of bleeding and infection.

Between 2 and 6 in 100 people (2 – 6%) who have VNS implanted experience infection after surgery. This means that most people do not experience infection after surgery. Minor infections can be treated with antibiotics. But for more serious infection, you may have to have further surgery to remove the VNS device.

You might have some pain for a while from the area of the implant after VNS surgery. This is usually managed with paracetamol.

You can find out more about what to expect during VNS surgery on the LivaNova website.

When will my VNS start working?

Research shows that the benefits of VNS for epilepsy tend to build over time. You might find that your seizure control may not improve right away, but will slowly improve over the first year or two of VNS treatment.

What happens after VNS surgery?

The VNS device is usually kept switched off for a period after surgery. After around two weeks it is switched on. This is done by a specialist nurse or doctor at a follow up appointment in a clinic. Sometimes it can be switched on sooner than this.

The team will then work with you to adjust the device settings to the right level. The level of stimulation is started on a low level and gradually increased over time at follow-up appointments.

The aim is to find a level that is both effective and comfortable for you. For example, the VNS device might be programmed to send a stimulation for 30 seconds every 5 minutes throughout the day and night. Or it might be programmed at a higher or lower level.

You will have regular check-ups to make sure the device is working well, and to make any adjustments needed. You can also contact your doctor or nurse at any time outside of these check-ups if you have any problems.

“I have had a VNS in situ for 20+ years with a very positive outcome reducing seizure severity and frequency. This has enabled me to hold down a full-time career as a healthcare professional in the NHS, giving back to the NHS which I have relied upon for nearly 50-years due to my epilepsy.”

– Epilepsy Action supporter

How long before my VNS needs replacing?

Your VNS will need replacing when the VNS generator battery runs low. The length of time that the VNS battery lasts can vary. Epilepsy specialist nurses who regularly work with VNS tell us that it will generally last between 2 and 6 years. The battery life could be longer or shorter than this, depending on the model and settings used.

Your epilepsy specialist can tell when the battery is running down during your follow up appointments. Or, you may notice the pulses from your VNS device becoming weaker.

Your specialist can then arrange for a new generator to be fitted. This involves a small operation under general anaesthetic. It usually lasts less than an hour.

Do I still need to take epilepsy medicines with VNS?

VNS is designed as an add-on (or adjunctive) treatment to work alongside epilepsy medicines. This means that most people still need to keep taking epilepsy medicine after they have had a VNS system implanted.

Some people are able to reduce the amount of epilepsy medicine they take over time. This can include sometimes reducing the amount of rescue medicines you use. Very occasionally, some people may be able to eventually come off epilepsy medications altogether. But only with help from an epilepsy specialist.

It can be dangerous to suddenly reduce or stop taking epilepsy medicines. Always talk to your epilepsy specialist first if you are considering making any changes to your medicines.

What is the magnet for in VNS?

If you have VNS you will also be given 2 hand-held magnets. One magnet comes with a clip that can be attached onto your belt for easy carrying. You will also be given a velcro strap holder that you can wear like a wrist band.

You can use these magnets to make the generator device send a longer, stronger stimulation, or an extra stimulation to the vagus nerve. It works when you swipe a magnet over the generator. You or someone else can do this if you have an aura or feel a seizure starting, or when you are having a seizure.

Some people say that using the magnet can help to:

• Stop a seizure happening
• Shorten the seizure
• Make the seizure less severe
• Decrease the time it takes to recover after a seizure

Other people say the magnet has little or no effect.

You can find out more about the VNS magnets and how to use them in the VNS Therapy Patient Guide. It is available to download in different languages from the LivaNova website.

Can I have VNS for my epilepsy?

In the UK, VNS is only available for people who are not seizure free despite trying different epilepsy medicines. This means they have drug-resistant epilepsy.

The National Institute for Health and Care (NICE) guidelines say that VNS may be an option for you alongside epilepsy medicines if:

• You have drug-resistant epilepsy. This means you have tried 2 or more epilepsy medicines and are still having seizures, and,
• Epilepsy brain surgery is not a suitable option for you

If you think VNS might help you, talk to your epilepsy specialist. They can refer you for assessment for VNS.

Find out more about epilepsy surgery and other treatments for epilepsy.

Can my child have VNS for epilepsy?

Yes, there is no upper or lower age limit for VNS.

NICE supports the use of VNS in children with epilepsy. Similar to adults, VNS is only recommended for children if:

• They have drug-resistant epilepsy (tried at least 2 epilepsy medicines and they have not worked), and
• They are not eligible for brain surgery

Ask your child’s doctor whether VNS could be an effective therapy for your child.

All children in England, and Wales, and Northern Ireland will go through the Children’s Epilepsy Surgery Service (CESS) pathway to have a VNS implanted. Find out more about this on our pages for CESS and epilepsy surgery for children.

LivaNova also have information on their children’s VNS website. It includes videos you can watch with your child.

What precautions might I need to take with a VNS?

Some common devices can generate a strong magnetic field or electromagnetic interference. This can potentially affect your VNS implant if you get very close to them. This will not directly harm you or damage the VNS implant. But it could interfere with your doses of stimulation.

It can help to keep any devices that may interfere with your VNS stimulation at least 20 cm or 8 inches away from your chest. If something does activate your VNS implant, moving away will prevent it.

Here are some common things that may interfere with your VNS stimulation if you get too close:

• Induction hobs – only if your implant is very close. Normal cooking with induction hobs is usually fine
• Magnetic tag deactivators that are used to remove anti-theft clothing tags in shops. These may affect VNS stimulation if you are very close. These are not the same as the anti-theft system alarms located at shop exits. Your VNS will not usually be affected by these, or activate the alarms as you exit the shop
• Any equipment which carries a pacemaker warning sign.  These might also affect your VNS stimulation

You can find a full list of VNS system precautions in the VNS Patient Manual. Ask your doctor or epilepsy specialist nurse if you are worried whether something could affect your VNS implant.

Can I have an MRI scan with a VNS?

You can have certain types of magnetic resonance imaging (MRI) scan with a VNS, but not others.

If an MRI scan is recommended for you, it must be done under specific conditions. Talk to your doctor about this before you have the scan and make sure that everyone who is involved in doing the scan knows about your VNS device.

Find out more about having an MRI scan with a VNS device in the VNS Patient Manual.

Can I travel abroad with a VNS implant?

Yes, you can travel abroad with VNS. Here are a few tips for travelling with your VNS device:

Remember to keep your VNS  magnet with you

Keep it away from credit cards and mobile phones, as it could damage them

Walk through airport scanners at a steady pace

Airport security scanners and metal detectors should not cause a problem with your VNS. However, the makers of VNS say that to be safe, you should aim to:

• Walk through airport scanners at a steady pace
• Do not linger close to the scanners
• Try to stay at least 40 centimetres or 16 inches away from the equipment

If this is not possible, you could tell the security staff about your VNS and ask for a pat down check instead.

Use your VNS card to let others know

When you first have your VNS implanted you will be given a VNS card along with your magnets. You can use this card to explain to staff about your VNS. Some families also report that it helps to explain that VNS can be treated a bit like a pacemaker.

Find out more about travelling abroad with epilepsy.

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