Deep Brain Stimulation
Deep brain stimulation (DBS) is a surgical procedure used to treat a variety of disabling neurological symptoms—most commonly the debilitating symptoms of Parkinson’s disease (PD), such as tremor, rigidity, stiffness, slowed movement, and walking problems. The procedure is also used to treat essential tremor, a common neurological movement disorder. At present, the procedure is used only for patients whose symptoms cannot be adequately controlled with medications.
Deep brain stimulation, or DBS, uses tiny electrodes surgically implanted into part of the brain. The electrodes are connected by a wire under the skin to a small electrical device called a pulse generator that is implanted in the chest beneath the collarbone. The pulse generator and electrodes painlessly stimulate the brain in a way that helps to stop many of the symptoms of PD. DBS is stereotactic surgery, meaning it uses a 3D coordinate mapping system to locate tiny areas in our bodies in order to perform surgery accurately.
DBS usually reduces the need for levodopa and related drugs, which in turn decreases dyskinesias. It also helps to relieve on-off fluctuation of symptoms. People who initially responded well to treatment with levodopa tend to respond well to DBS. While the benefits of DBS can be substantial, it usually does not help with speech problems, “freezing,” posture, balance, anxiety, depression, or dementia.
DBS is not a good solution for everyone. It is generally used only in people with advanced, levodopa-responsive Parkinsons Disease who have developed dyskinesias or other disabling “off” symptoms despite drug therapy.
Deep Brain Stimulation surgery may be performed on one or both sides of the brain depending on the patient and their symptoms. Sometimes the surgery is done in two parts with the first surgery done to implant the electrodes in the brain, and a second surgery to implant the neurostimulator. Because each patient is different, your surgeon will discuss the options that are best for your particular situation.
Deep Brain Stimulation surgery is performed by a Neurosurgeon under sterile conditions in an operating room with the patient initially awake but sedated. General anaesthesia is administered to finish the surgery once the electrodes have been placed in the brain.
Prior to surgery the patient is sedated and with the use of local anaesthetic, a rigid stereotactic frame is placed around the skull. A stereotactic MRI scan is taken to identify and locate the exact target within the brain where electrical nerve signals generate the PD symptoms. The target area is mapped with coordinates on a computer.
The patient is then taken to the operating room:
- A small area of the head is shaved and numbed with local anaesthetic.
- The surgeon makes an incision in your scalp behind the hairline.
- A drill is then used to create a small hole in the skull bone about the size of a nickel.
- At this point, the patient is taken off sedation medications and is awake while the surgical team “maps” the brain to ensure the precise location of electrode placement.
- The surgeon then locates the precise area of the brain that the electrodes are to be implanted and places the tip of the electrodes within this targeted area.
- Once the electrodes are placed and tested, the patient is again sedated and the scalp incision is closed with sutures and covered with sterile bandages.
- The patient is then placed under general anaesthesia for the rest of the surgery.
- The surgeon tunnels the thin wire attached to the electrode under the skin of the head, neck and shoulder.
- The neurostimulator or pulse generator is a small box that is implanted in the chest beneath the collarbone, or elsewhere depending on your surgeon’s preference.
- Your surgeon then connects the neurostimulator to the wire to enable pulses to be transmitted to the electrodes in the brain.
- The surgeon then closes the chest incision with sutures and covers the area with sterile bandages
- Once the system is in place, electrical impulses are sent from the neurostimulator up along the extension wire and the lead and into the brain. These impulses interfere with and block the electrical signals that cause PD symptoms.
After surgery your surgeon will give you guidelines to follow depending on the type of surgery performed and the surgeon’s preference.
Common Post-operative guidelines following Deep Brain Stimulation surgery include:
- You will probably stay in the hospital a few days if no complications occur.
- You will be given pain medications to keep you comfortable and antibiotics to prevent infection.
- Keep the incisions clean and dry. You may shower once the stitches and/or staples are removed unless otherwise directed by your surgeon.
- Your surgeon will give you activity restrictions to follow.
- Do not scratch the incision areas as this can lead to infection.
- If the incision areas become red, painful or draining, call your surgeon as these are signs of infection.
- If you experience headache, vomiting, visual problems, confusion, fever, or increased lethargy, call your surgeon right away.
- It is important to keep all your post-operative appointments with your surgeon to ensure a good outcome.
- Eating a healthy diet and not smoking will promote healing
Follow Up Care
Patients must return to the medical centre frequently for several months after DBS surgery in order to have the stimulation adjusted by trained doctors or other medical professionals. The pulse generator must be programmed very carefully to give the best results. Doctors also must supervise reductions in patients’ medications. After a few months, the number of medical visits usually decreases significantly, though patients may occasionally need to return to the centre to have their stimulator checked.
If you have deep brain stimulation surgery performed, you must inform your dentist or surgeon if you should need dental work or surgery in the future. You must also inform any physician who may want to order an MRI scan on your brain or body due to the hardware components placed.
Risks and Complications
Specific complications of DBS surgery are rare but can include:
- Brain damage
Other complications that can occur, although rare, involve the hardware components that are placed inside the body. Complications involving hardware will usually require another surgery to repair or replace and can include:
- Fracture or breakage of the wire or cable
- Battery failure
- Erosion of the cable or device through the skin
- Migration of the electrode in the brain due to failure of the anchor