What is deep brain stimulation (DBS)?
Deep brain stimulation (DBS) is a surgical option for patients with Parkinson's disease (PD), essential tremor (ET) and dystonia. Future applications for DBS include treatment for epilepsy and severe depression.
During DBS surgery, electrodes are implanted within the brain to deliver electrical impulses. The stimulation offers patients relief from many symptoms of PD including tremor, rigidity, slowness of movement and stiffness. It also offers relief from the tremor associated with ET (also called familial tremor) as well as the often painful muscle contractions associated with dystonia. The stimulation can be adjusted as a patient's condition changes over time.
DBS is a new and improved alternative to two surgeries often-performed previously, a thalomotomy and a pallidotomy. These surgeries involved destroying small parts of the brain within structures called the thalamus and the globus pallidus (GPi). The surgeries are still being done, but much less often, as DBS no longer makes it necessary to destroy even small parts of the brain.
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How does DBS work?
During DBS surgery, small electrodes are implanted in the brain. The electrodes emit pulses of energy to block the abnormal activity in the brain which causes the symptoms. The amount of stimulation delivered by the electrode is controlled by a pacemaker-like device placed under the skin, usually in your upper chest. The success of DBS surgery is directly related to:
- Choosing the right candidates for the surgery
- Finding the specific area in the brain for stimulation
- Finding the right settings on the stimulator after surgery
- Choosing a center with an experienced DBS team and a history of successful outcomes
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Who is a candidate for DBS surgery?
Candidates for DBS surgery are patients:
- With PD symptoms that are causing a decline in quality of life
- Who have had an adequate and reasonable trial of medications (includes ET, dystonia and PD)
- Who still respond to medications but are bothered by side effects
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How is DBS surgery done?
It is important to note that surgical techniques can vary among centers and surgeons. The surgical method described here is just one way to perform the procedure.
DBS involves implanting a thin wire, or lead, containing four electrode contacts into a specific target area in the brain. Different areas of the brain are targeted for different diseases. The lead extends through a small opening in the skull and is connected to an extension wire. The extension wire is connected to a pulse generator or “pacemaker” that is implanted under the skin in the chest. This generator, also called a neurostimulator, is programmable from the outside of the body after the procedure is completed.
Computerized brain-mapping technology aids the surgeon in finding the precise location in the brain where nerve signals generate the tremors and other symptoms. Highly sophisticated imaging and recording equipment are used to map both the physical structure and the functioning of the brain.
To allow the surgical team to assess brain functions, patients need to be awake during surgery. A local anesthesia is used to numb the scalp while the surgeon makes the small opening in the skull Due to the unique nature of the human brain and its inability to generate pain signals, patients experience no pain while the electrodes are being placed in the brain.
Surgery to implant the electrodes requires most patients to stay in the hospital for two or three days. At a later date, usually within a week, the neurostimulator is implanted in the patient’s chest below the collarbone during a same-day surgery procedure. General anesthesia is used for this procedure. Within a week or two, the patient will return and the neurostimulators will be turned on for the first time.
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What happens after DBS surgery?
Over the next weeks or months after the neurostimulator is first activated, a series of adjustments in the electrical pulse will be made. For this reason patients need to be able to travel to a location where the stimulation of their implanted devices can be adjusted. The first few follow-up visits should be to the place at the facility where the surgery was performed. After that, electrical programming can take place at another medical facility if a specialist with the knowledge and equipment is there.
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How effective is DBS?
While results vary from patient to patient, DBS is remarkably safe and effective in properly selected patients. The beneficial effects of symptom control have been demonstrated to last for several years. Patients with ET may experience an 80 percent to 100 percent reduction in their tremors.
Consider the following findings:
- Patients with essential tremor may experience an 80 to 100 percent reduction in their tremors.
- Patients with PD who initially responded well to medications but over time have developed side effects may experience a 60 to 80 percent improvement in symptoms such as tremor and slowness of movement.
- On average, patients report a 50 percent improvement in their walking and balance.• Patients with involuntary movements (dyskinesia) due to their medications experience a greater than 80 percent reduction in their involuntary movements.
- Most patients are able to significantly reduce their medications following deep brain stimulation.
- On average, DBS doubles the amount of "on-time" without dyskinesia. An important indicator of the effectiveness of any treatment for people with PD, in particular, is the duration of "on-time" without dyskinesia. This means the patient is mobile and can perform everyday tasks without experiencing the involuntary movements.
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What risks are associated with DBS?
As with any surgery, the procedure is not risk free. There is about a 1 percent to 3 percent chance of brain hemorrhage that may be of no significance or may cause paralysis, stroke, speech impairment or other major problems. This means that for every 100 patients who undergo surgery, one to three will experience a permanent or severe complication. However, this also means that most patients will have no serious complications.
There is a 15 percent chance of a minor or temporary problem that resolves quickly or over a short period of time. Rarely, infections can occur. While treatment of infection may require removal of the electrode, the infections themselves have not caused lasting damage. The device can be implanted again after the infection clears.
The electrode that is implanted in the brain and the electrical systems that provide stimulation are generally very well accepted by the brain with no significant changes in brain tissue around the electrodes. The neurostimulators implanted in the chest that produce the stimulation have a limited life span and will require future surgery to replace them.
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Who can be evaluated for DBS?
Possible candidates for DBS are patients with Parkinson's disease, essential tremor and dystonia who experience movement-related symptoms that cannot be controlled by medications. Patients who experience intolerable side effects from medication may also be candidates. New uses for DBS are being investigated, including symptom control for patients with epilepsy, Tourette’s syndrome, depression and chronic pain syndromes.
DBS has been successful in treating patients as young as 13 years old. In general, surgery is performed on patients under 75 years old, but this is not a firm guideline. Each patient must be assessed individually in regard to his or her stamina and overall health.
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Has DBS been approved by the Food and Drug Administration?
Yes. DBS was approved for the treatment of essential tremor in 1997, and in January 2002, the FDA approved deep brain stimulation for the treatment of Parkinson's disease.
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Does Medicare cover DBS?
This procedure is covered by Medicare for the treatment of Parkinson’s disease and essential tremor. In Wisconsin, Medicare also covers DBS for dystonia. Outside of Medicare, most insurance companies are also covering the costs of DBS surgery. To determine if your insurance policy covers all or a portion of the cost, you need to contact your benefit representative directly. If you need help with this, please contact us.
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How do I contact Froedtert & The Medical College of Wisconsin for more information?
To speak to someone about our program, or to make an appointment for an initial evaluation with a movement disorders neurologist, please call 414-805-3666 or 800-272-3666.
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