Vagus nerve stimulation (VNS, Liva Nova Inc, formerly Cyberonics) is a way of treating seizures that are not controlled by medication. It is a pacemaker-like device that gives electrical pulses on and off to the left vagus nerve, which is a nerve in the neck that leads directly to the brain. These electrical pulses modify brain activity and reduce seizures in many people. We do not understand fully how it works. It does create changes in blood flow and activity in certain regions involved in seizures, as well as changes in normal chemical levels in the brain. The effects take time to kick in but are long lasting.
VNS is FDA approved for patients 16 and over with partial (focal) epilepsy. There have been many studies including our own showing it works well in generalized epilepsies and children.
The surgery takes about 1 hour, under general anesthesia, and you go home the same day.
There is a 1 inch incision on the left side of the neck, and a 2 inch incision in the left armpit. Our surgeon is very careful to make the scars as small, mild and out of the way as possible. There are bandages on the incisions which can come off in about a week on their own. There are no stitches or staples to come out afterward.
The VNS is turned on at a low setting in the operating room, and then adjusted at office visits using a radio transmitter wand held over the chest attached to a hand held computer. There are many different settings, and it may take time to find the right combination.
Usually the treatment starts with a cycle of the VNS being on for 30 seconds at a time, then off for 5 minutes between pulses. When it is off there are no side effects. When it is on, there may be some hoarseness to the voice or a tickle in the throat or cough. Pain is rare. All these side effects are the most severe right after the settings are changed in the office, so the doctor can see them and change the settings immediately if they are uncomfortable. No one leaves our office uncomfortable. Over time the side effects go away and the settings can be increased.
Usually we have office visits 2 weeks after surgery, then every month for several months. It can take over a month to see the effects of any setting changes on seizures. Once things are stable, visits every 6 months or so are recommended. At each visit the VNS is checked to be sure it is functioning properly.
You are given a strong magnet to wear on a wrist band or carry with you. If a seizure occurs, you or someone with you can swipe the magnet over the VNS in the left chest to turn it on for 30 to 60 seconds, which often reduces or stops the seizure. If there are any possible side effects of stimulation, you can tape the magnet down on the chest over the pacemaker to temporarily shut it off until you can get to the doctor’s office.
The Model 106 VNS can detect the heart rate and deliver automatic increased therapy (like an automatic magnet). This can be useful for people who get rapid heartbeats during seizures.
Overall there are no activity limitations with the VNS. There are some medical procedures which cannot be done, and your doctor can discuss that with you. It is safe to go through airport security or be near a microwave oven.
Risks of bleeding or infection are very low. In many ways the VNS is safer than medication, since it is delivering therapy directly to the brain, unlike medications which can affect any organ. VNS does not cause drowsiness, dizziness, upset stomach, liver damage, blood cell problems or skin rashes. VNS does not interact or interfere with any medications.
Roughly 50-60% of people with VNS will cut their seizures in half or more. About 5-10% may stop having seizures almost completely. Some people may be able to reduce medication doses without seizures getting worse, which can be an improvement in quality of life.
Authored by: Eric B. Geller, MD