Vagus nerve stimulation therapy (VNS)

Vagus nerve stimulation (VNS) is a treatment for epilepsy where a small generator is implanted under the skin below the left collar bone. This is connected to a lead with three coils at one end. These coils are wrapped around the vagus nerve in the left side of the neck in a small operation. The VNS stimulates the vagus nerve at intervals to reduce the frequency and intensity of seizures.

How does it work?

The generator sends impulses from the vagus nerve in the neck to the brain and delivers therapy in two ways:

1. A doctor programmes a 24-hour a day, seven-day a week "dose" of intermittent stimulation. One such dose frequently used is 30 seconds of stimulation followed by a five-minute period of no stimulation. The stimulation is automatically delivered.

2. When a patient, a family member or a caregiver senses a seizure coming on, they can pass a magnet over the area in the chest where the generator is implanted. This activates an extra, on-demand stimulation.

What does the operation involve?

The generator and lead are implanted into the chest and left neck area, in a procedure that involves:

• an operation, which lasts approximately one to two hours
• an incision on the left side of the neck for the lead
• an incision on the left upper chest or armpit for the generator
• a stay in hospital of around one or two days

Two small scars will be evident after surgery. The scar in the left upper chest area is for the generator and the one in the skin creases in the neck is for the lead. These are usually not noticeable or fade with time. There may also be a small bulge on the left upper chest where the generator is positioned.

How is the generator programmed?

During routine outpatient visits, the doctor can read and adjust stimulation settings using the programming computer and the programming wand. This is painless and can be done through the clothes. The doctor places the programming wand over the area where the generator is and programmes this with the computer.

Who would benefit from this procedure?

Vagus nerve stimulation is suitable for people with any type of epilepsy that has proven difficult to control.

Around 43,000 people worldwide have been implanted with vagus nerve stimulators. These people are of all ages, with a variety of seizure types and epilepsy syndromes.

What are the risks?

As the operation is carried out under general anaesthetic, it carries a slight risk of reaction to the anaesthetic. There is also a small risk of bleeding or infection. There may be some pain from the site of the operation. This can be relieved with mild painkillers.

The doctor who carries out the operation will talk to the person in more detail about the risks involved, before the operation takes place.

What are the side effects?

Certain side effects are associated with VNS. The most commonly reported side effects are:

• temporary hoarseness/change in voice tone
• sore/tickling throat
• shortness of breath
• coughing

These problems usually happen during the ‘on’ time, which is usually about 30 seconds every five minutes. Most people who experience hoarseness tolerate it well and notice it less as time goes on.

Other discomforts such as breathing difficulties can happen if the generator setting is too high initially or is increased too rapidly. If this happens, the doctor can re-programme the stimulation settings.

Will the VNS stop the seizures?

Studies show that most people with a VNS have a reduction in seizure frequency, although some have no change. It can take from a couple of months to two years to see a noticeable reduction.

Due to experiencing fewer and less severe seizures, some people have reported a better quality of life.

Will anti-epileptic medication be discontinued?

Medication will continue as normal while receiving stimulation, for at least the first three months after implantation. After three months, the doctor will review the person’s medication and advise them if they need to make any changes.

Will the generator need to be replaced?

Yes, but only after some years. The latest generators need to be replaced around every six to eleven years. The higher the frequency and output of the stimulation, the faster the battery will run down. A doctor or nurse can tell when the battery is running down by reading the VNS therapy device. They will then arrange for a new generator to be implanted. This involves a small operation, which takes less than an hour and does not usually require an overnight stay.

Is VNS available to NHS patients?

It is available to both NHS and private patients.
Details of implant centres and programming can be obtained on the Vagus Nerve Therapy website, or from your GP and specialist.

Support organisation

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305 Glossop Road
Sheffield
S10 2HL
Telephone 0114 2755335
Freephone Advice Line 0800 521629
E-mail fable@btconnect.com
Website www.fable.org.uk