Vagus Nerve Stimulation Procedure
Overview
Vagus nerve stimulation (VNS) uses technology to send small electrical signals to the vagus nerve, a key cranial nerve in the body. The vagus nerve plays a large role in the autonomic nervous system and helps control functions like digestion, breathing, and heart rate. This nerve also helps balance the parasympathetic and sympathetic nervous systems, influencing the body’s rest, digest, and fight-or-flight responses.
How VNS Works
A vagus nerve stimulator includes a pulse generator and electrodes. The implantable version is similar to a pacemaker, and surgeons usually place it under the skin in the chest. The generator connects by a wire to the left vagus nerve in the neck.
Surgeons select the left side because the right vagus nerve is more involved in regulating the heart and could affect heart function if stimulated. Once in place, the device sends regular electrical impulses up the nerve to the brainstem and then to different brain areas.
Uses for Vagus Nerve Stimulation
- Epilepsy: VNS can help reduce how often seizures happen in some people.
- Depression: For those who do not get better with other treatments, VNS may offer relief by changing certain areas of brain activity related to mood.
- Recovery After Stroke: Some people who struggle to move their arm or hand after a stroke use VNS to support brain pathways during rehabilitation exercises.
- Cluster Headache and Migraine: A noninvasive vagus nerve stimulator is placed on the skin of the neck to block pain signals.
VNS triggers several effects in the brain and body, including changes to serotonin levels and heart rate variability. These devices come in both implantable and noninvasive forms. Researchers are also exploring if VNS may help with other conditions like rheumatoid arthritis, inflammatory bowel disease, bipolar disorder, obesity, and Alzheimer’s disease.
| Component | Purpose |
|---|---|
| Pulse generator | Sends electrical impulses |
| Electrodes | Deliver signals to the vagus nerve |
| Left vagus nerve | Main target for stimulation |
| Noninvasive stimulator | Placed on neck, avoids surgery |
Reasons for Use
Seizure Disorders
Doctors use vagus nerve stimulation for people who have seizures that are not fully controlled by medication, especially those with focal epilepsy. It is an option for individuals aged 4 and older when standard treatments have not worked well. Some people with generalized epilepsy may also benefit.
Vagus nerve stimulation may help reduce sudden unexpected death in epilepsy and has shown value for drug-resistant epilepsy and certain syndromes like Lennox-Gastaut syndrome. Doctors sometimes consider this treatment for people with headaches, such as cluster headaches and migraines, especially when other options do not work.
Key Benefits
- Helps manage seizures in drug-resistant epilepsy.
- Can be used with other seizure treatments.
- Reduces frequency and severity of seizures.
Hard-to-Treat Depression
For adults experiencing treatment-resistant depression, vagus nerve stimulation may be helpful when other methods, such as several types of medication and psychological therapies, have not provided relief.
The device is used together with ongoing depression treatments. It may also assist some individuals with anxiety, bipolar disorder, or psychiatric disorders, although these uses are less common.
Checklist
- Used when at least four medicines and therapies have not improved depression.
- Supports ongoing depression management strategies.
Neurological Recovery After Stroke
Therapists sometimes add vagus nerve stimulation to rehabilitation programs after an ischemic stroke, the most common type of stroke caused by blocked blood flow in the brain.
When combined with rehabilitation exercises, it can improve movement and strength in hands and arms. Some research is exploring its effects on recovery in other brain conditions like Alzheimer’s disease.
In Rehabilitation
- Supports motor recovery after stroke.
- Can improve hand and arm use with therapy.
- May also affect symptoms linked to other neurological conditions.
| Condition | Main Use for VNS | Notable Effects |
|---|---|---|
| Epilepsy | Drug-resistant seizures | Fewer, milder seizures |
| Depression | Treatment-resistant depression | Mood improvement |
| Stroke rehabilitation | Post-stroke motor recovery | Better hand and arm function |
Dangers Connected to Vagus Nerve Stimulator Implants
Problems Linked to the Operation
Surgeons make small cuts to place the device and its wires, so certain risks come with the procedure. Common issues include:
- Pain or discomfort where the surgeon made the cuts
- Possible infection around the incision area
- Difficulty swallowing
- Vocal cord weakness or temporary paralysis
In some cases, the wires (leads) placed during surgery can become misplaced or damaged, which might need extra treatment. Although these complications do not happen often, patients should be aware. General anesthesia also has risks, such as nausea or low blood pressure during surgery.
| Risk Type | Possible Event |
|---|---|
| Infection | Redness, swelling, fever |
| Pain | Pain at incision, inflammation |
| Vocal cord problem | Hoarse voice, paralysis |
Reactions That May Happen After Surgery
After the device is implanted and activated, individuals may notice:
- Changes in voice quality or a hoarse throat
- Pain or a prickly sensation in the neck or skin
- Coughing
- Trouble breathing or shortness of breath
- Problems with sleep, including sleep apnea
- Difficulty swallowing
Some people also report headaches, tingling, or feeling irritable. Most side effects lessen as the body gets used to the device, but some may continue. If they become unmanageable, a healthcare professional can change the device’s settings or switch the device off.
Getting Ready
What to Know About Food and Medication
Doctors may ask patients to stop eating or drinking several hours before the procedure. Some medicines may also need to be paused. A doctor or nurse will give specific instructions about which medicines to avoid and when to take them. Patients should give the healthcare team a list of all current prescriptions and over-the-counter drugs. Use the table below to track changes:
| Medicine Name | Usual Dose | Stop Date | Notes |
|---|---|---|---|
What You Can Expect
Before having the vagus nerve stimulator placed, most people have a health exam. This helps ensure they are ready for surgery. Sometimes, the healthcare team gives antibiotics before the operation to lower the chance of infection.
Patients may be told to stop eating or drinking a few hours before the procedure. A nurse or healthcare worker will review what will happen and answer questions. This period is a good time for patients to talk about any worries, like sleep, stress response, and recovery steps.
What Happens During Surgery
Doctors usually perform the device implantation as an outpatient procedure, so patients can go home the same day. The patient will get general anesthesia, which means they will be asleep and not feel pain. A neurosurgeon or trained surgeon makes two small cuts—one in the chest or armpit and another on the left side of the neck.
The surgeon places a small device, about the size of a stopwatch, called a pulse generator, under the skin on the upper left chest. This device runs on batteries. Then, the surgeon attaches a thin wire and guides it under the skin to the left side of the neck, where it connects to the vagus nerve. This process does not involve the brain itself.
The device sends mild electrical impulses to the vagus nerve, which helps send signals to areas of the brain that control mood, stress response, and motor functions. The device works in cycles to support normal body rhythms.
Table: Device Placement Steps
| Step | Description |
|---|---|
| Anesthesia given | Patient is put to sleep for comfort and safety. |
| Chest/neck incisions | Surgeon makes two small cuts. |
| Device inserted | Pulse generator placed under the skin. |
| Wire attached | Lead goes from chest to the left vagus nerve. |
| Device tested | Surgeon checks device before closing the cuts. |
What to Know After Surgery
The first few weeks after implantation are for healing. The device is not usually turned on right away. Instead, patients visit their healthcare provider after a few weeks for the first programming session.
During this visit, the team sets how often and how strong the device delivers mild electrical impulses. The settings can be adjusted over time, depending on symptoms and any side effects.
People may notice mild effects, like tingling or light discomfort in the neck when the device is active. Some notice a hoarse voice during stimulation, or it may cause a mild cough. These effects are often temporary and happen only when the device delivers stimulation.
Aftercare Steps
- Go to follow-up appointments.
- Notify your healthcare team if you feel pain or the device seems out of place.
- Ask before scheduling tests like MRI scans, because the device may be affected.
- Use a magnet as instructed by your healthcare team to control the device if needed.
- Rest and avoid strenuous activities as you heal.
Some patients find that activities such as meditation, humming, or mindful breathing may complement recovery and help with the body’s natural relaxation response.
Study Findings
Vagus nerve stimulation (VNS) has shown benefits for some people with epilepsy and depression, but it is not a cure. Many individuals still experience seizures and usually continue taking their epilepsy medications.
However, up to half of the patients may notice a drop in how often seizures occur. Often, the seizures also become less severe. The table below highlights reported changes in seizure-related outcomes after VNS:
| Metric | Observed Change |
|---|---|
| Seizure Frequency | Up to 50% reduction |
| Seizure Intensity | Often less severe |
| Recovery After Seizure | Shorter duration |
| Quality of Life | Improved for some |
Improvements in both seizure control and the time it takes to recover after seizures can take several months or longer to develop. Some patients also report a better mood and more positive outlook, which adds to improved quality of life.
In the case of depression, VNS may help reduce symptoms, but the process is usually slow and may take months before noticeable results appear. VNS treatment does not work for everyone with depression and is used alongside other therapies.
There is some evidence that people who had strokes and used VNS during rehabilitation can see better physical function and may benefit in thinking and swallowing abilities.
Results for other conditions—like Alzheimer’s disease and heart issues—are uncertain, with more research needed. Insurance coverage for VNS varies, and it may not be available to everyone due to cost.
