Vagus Nerve Stimulator

What is VNS Therapy?
This therapy is designed to prevent seizures by sending regular small electrical pulses to the brain via the vagus nerve, a large nerve in the neck.. Vagus means "wanderer" in Latin. The vagus nerve is appropriately named considering that it averages 22 inches in length in adults and wanders throughout the upper body. The vagus nerve is one of the primary communication lines from the major organs of the body to the brain. The vagus nerve has proven to be a good way to communicate with the brain because:

• There are few if any pain fibers in the vagus nerve.
• Over 80% of the electrical signals applied to the vagus nerve in the neck are sent upwards to the brain.
• The surgical procedure to attach the lead to the vagus nerve does not involve the brain.

The VNS Therapy System delivers VNS Therapy in two ways:
First, your neurologist programs a 24-hour a day, 7-day a week "dose" of periodic stimulation. One such dose frequently used by physicians is 30 seconds of stimulation followed by a five-minute period of no stimulation. The stimulation is automatically delivered (the patient doesn't have to "take" anything) until the physician reprograms the generator or the battery runs out.

The second way VNS Therapy is delivered is when a patient, a family member or a caregiver senses a seizure coming on and passes the magnet over the area in the chest where the generator is implanted to activate an extra, on-demand stimulation. The VNS Therapy magnets are easily carried on the body for fast and effortless accessibility.

Frequently Asked Questions

How do most people respond to VNS Therapy System treatment?
In clinical studies, most patients had a reduction in seizure frequency, although some had no change. Some patients do not start having a noticeable reduction until after many months of therapy.

Can I know before being implanted with the VNS Therapy System whether the device will help me?
There is no way to predict what your response will be.

What are the results of the VNS Therapy System clinical trials?
A study published in Neurology by Dr. G.L. Morris and colleagues reports the results of long-term follow-up of 440 patients treated with VNS Therapy in the controlled trials. According to the data, 23% of patients reported a 50% or greater improvement in seizure control after 3 months of VNS Therapy. The one-year and two-year seizure reductions data were 37% and 43%, respectively. In addition to decreasing the frequency of seizures, many patients experience a decrease in their medication requirements after implantation.

What is the implantation surgery like?
The VNS Therapy device is implanted in your chest. It sits under the skin just below the collarbone or close to the armpit. Two tiny wires from the device wrap around the vagus nerve on the left side of your neck. While this may sound serious, the procedure involves two small incisions, takes about an hour, and is often done on an outpatient basis. Your physician can provide additional information about the procedure.

Are there risks associated with the surgery?
Any surgical procedure carries some type of risk. It is important that you discuss this question with your surgeon.

Will the scars be noticeable? Every person has different healing and scarring results, and you should expect some scarring from surgery. Most people, however, do not consider the scarring after implantation to be a major concern. If this is a special concern for you, discuss it with your surgeon.

The black lines represent the incisions

Will people be able to see the implanted device through my skin?
The implantable Pulse Generator is shaped like a circular disk. The Model 101 is 5.4 centimeters in diameter and 1 centimeter (.4 inch) thick; it weighs about 38 grams (1.34 ounces). The Model 102 is thinner at 5.5 centimeters in diameter and 7 millimeters (.275 inch) thick; it weighs about 25 grams (.88 ounce). If you have a small frame or are very thin, the device may be visible as a slight bulge below your left collarbone.

After surgery:

At the time of surgery I will test the VNS device, but it will not be turned on. Once implanted in your body, the battery-powered device can be programmed from outside your body. Your neurologist will manage the VNS device after surgery. He/She will program your treatment schedule into your VNS Therapy System at 1-2 weeks after placement.

VNS Therapy usually does NOT stop all seizure activity. It is Not a cure for epilepsy, and does not work for everyone. The surgery carries with it the more basic risks of surgery,

• infections
• development of a blood clot
• hemorrhage

and, the risks more specific to this procedure,

• trauma or damage to the carotid artery, or other major vessels of the neck
• damage to the vagus nerve
• trauma to the muscles of the neck
• inability to implant the device
• failure of the device
• neck pain (usually transient)

Intended Use/Indications
The VNS Therapy™ System is indicated for use as an adjunctive therapy in reducing the frequency of seizures in adults and adolescents over 12 years of age with partial onset seizures, which are refractory to antiepileptic medications.

Contraindications
The VNS Therapy System cannot be used in patients after a bilateral or left cervical vagotomy. Do not use short-wave diathermy, microwave diathermy, or therapeutic ultrasound diathermy on patients implanted with the VNS Therapy System, during physical therapy. Diagnostic ultrasound is not included in this contraindication.

Warnings
Physicians should inform patients about all potential risks and adverse events discussed in the VNS Therapy System Physician's Manual including information that VNS Therapy may not be a cure for epilepsy. Since seizures may occur unexpectedly, patients should consult with a physician before engaging in unsupervised activities, such as driving, swimming, and bathing, or in strenuous sports that could harm them or others. Patients who have pre-existing swallowing, cardiac, or respiratory difficulties (including, but not limited to, obstructive sleep apnea and chronic pulmonary disease) should discuss with their physicians whether VNS Therapy is appropriate for them since there is the possibility that stimulation might worsen their condition. The VNS Therapy System may affect other medical devices and other medical devices may affect the VNS Therapy System. MRI can be safely performed, however, special equipment must be used.

Adverse Events
The most common reported side effects from stimulation include hoarseness, paresthesia (prickling feeling in the skin), dyspnea (shortness of breath) and increased coughing. The most common reported side effects from implant surgery is infection. Note: The information contained in this Summary represents partial excerpts of important prescribing information taken from the product labeling. The information is not intended to serve as a substitute for a complete and thorough understanding of VNS Therapy System nor does this information represent full disclosure of all pertinent information concerning the use of this product.

Links

Patient's manual for VNS

Epilepsy Foundation