Amir H. Faraji, M.D., Ph.D.
Functional & Restorative Neurosurgery
Deep Brain Stimulation (DBS) for Movement Disorders
DBS has been approved for the treatment of movement disorders since the 1990's and early 2000's. Numerous studies have proven this technique's superiority to medical therapy alone. The time to consider DBS surgery is when the patient's quality of life is no longer acceptable on optimal medical therapy as administered by a movement disorders specialist. DBS surgery is safe with a low complication rate and recent advancements in device technology and surgical accuracy have improved patient outcomes as well.
DBS surgery offers significant relief in patients with moderate disability from Parkinson's disease. DBS therapy improves the motor symptoms of Parkinson's, including tremor (shaking), rigidity (stiffness), and bradykinesia (slowness). In short, DBS improves the symptoms that medications (typically levodopa) improves, but DBS offers smoother therapy throughout the day that reduces fluctuations between "off" and "on" periods. DBS is likely to improve tremor even if the tremor does not respond to medication. Also, it's a common misconception that DBS is only a treatment for Parkinson's tremors, but even patient's without tremor may see improvement in their other motor symptoms with DBS. DBS can reduce involuntary movements called dyskinesias, and patient's may be able to reduce their medication doses after surgery, although surgery often will not replace medication entirely.
DBS surgery is a highly effective therapy for patients with essential tremor, often resulting in tremor reduction of 80% of more. DBS works well to reduce the tremor of the hands, but also may improve tremors in other parts of the body such as the head, voice, and legs. Patients with essential (familial) tremor that have not had an adequate response to at least one or two medications, and whose tremor impacts their quality of life, are likely to be good candidates for DBS. Patients with tremor secondary to stroke, traumatic brain injury, or multiple sclerosis are less likely to benefit; however, DBS may be considered if expectations are realistic.
DBS surgery decreases the abnormal movements and postures of dystonia, especially in the generalized, primary, and inherited forms of the disorder. The degree of benefit appears to vary with both the type of dystonia and the duration of the symptoms. DBS may help patients with other forms of dystonia if medications fail, but the response may be less.
Common Questions About DBS
Please review the accompanied video for a discussion about movement disorders, DBS, and new horizons for this therapy in a discussion with Dr. Amir Faraji, Dr. William Ondo, and Dr. Mark Richardson.
Who should get DBS?
This is a common question with a surprisingly simple answer: anyone who would be expected to get significant benefit from the treatment and who can undergo the operation with minimal risk. It is not necessary to suffer for years after a diagnosis or trying every known combination of medicine before DBS can be considered. DBS is a proven surgical option that is known to improve the quality of life for patients impacted by movement disorders. When the quality of life is dramatically affected by the disease or medication side effects, it's time to consider DBS!
What is DBS?
DBS surgery involves placing a thin electrode (about the diameter of a piece of spaghetti) into one of several possible brain targets on one or both sides of the brain. The electrode is connected to a battery, which is implanted under the skin in the chest just bellow the collarbone. All parts of the stimulator system are internal with no wires coming out through the skin. A programming computer is used during routine office visits to adjust the settings for optimal symptom control. Unlike lesioning procedures, such as gamma knife or high focused ultrasound, DBS does not permanently destroy brain tissue. Instead, it reversibly alters the function of the brain tissue in the region of the stimulating electrodes. It is important to note that DBS therapy may require considerable time and patience with programming sessions before the effects are optimized.
How does DBS work?
DBS surgery is not a cure for movement disorders, but it can successfully treat symptoms by disrupting abnormal patterns of brain activity that become prominent in these diseases. DBS is often referred to as a brain "pacemaker" because constant pulses of electrical current are delivered at settings that are thought to restore normal brain rhythms allowing the restoration of more normal movements. The exact mechanisms of this neuromodulation are still being understood.
How is DBS surgery performed?
Dr. Faraji was one of the first surgeons to pioneer the use of ROSA robotic assistance for placement of DBS electrodes. ROSA is similar to a GPS device for the brain. It provides the surgeon with a roadmap to reach the intended brain targets. Surgery is typically performed as two stages: stage 1 is the intracranial DBS electrode insertion and stage 2 is placement of the DBS battery, which is performed on average two weeks later. For stage 1 surgery, the patient is sedated for the beginning of surgery while we place a guidance frame and make small incisions in the skin and bone openings at the surgical site(s). The patient will not feel or remember this part of surgery, but once these steps are complete, he/she may be awoken for the remainder of the surgery.
We use neurophysiology recordings from very thing electrodes inserted into the brain to map activity in the intended target and confirm the best spot for the DBS electrode. It is important for the patient to be awake during this part of the surgery to obtain the best recordings possible for optimum placement of electrodes. The brain mapping is not painful and the surgical team remains present to provide reassurance and feedback the entire time.
Intra-Operative Stimulation Testing
When the best site is determined from the brain mapping, the DBS electrode is inserted and tested. We monitor the patient for improvement in their symptoms, for example tremor, and also ask him/her to report any new sensations or changes. This part of the procedure is not painful and provides valuable feedback to the surgical team.
Stage 2 Surgery
The patient will return an average of two weeks later for a second procedure under general anesthesia to place the battery and connect it to the brain electrodes. This surgery is short and is performed as an outpatient procedure.
In all, we understand that the thought of being awake for part of a brain surgery can be overwhelming and scary. We advise you to discuss your concerns with your surgical team. Accommodations, or different surgical approaches such as the Clearpoint MRI-Guided stereotaxy procedure, can be considered for patients who are unable or unwilling to participate in an awake surgery.
Types of DBS Systems
Dr. Faraji offers patients a choice of all possible DBS systems, of which there are three manufacturers. Please keep in mind that all three systems are similar in terms of effectiveness, but there are some advantages or each that may fit your lifestyle better than another. Ultimately, manufacturer selection also involves the movement disorder specialist who will often be programming the DBS system after surgery is complete.
With their first DBS product approved by the FDA in 1997, Medtronic is the longest-running manufacturer of DBS equipment. They offer both a non-rechargeable and a rechargeable battery that lasts up to 15 years. The new SenSight segmented leads allow the ability to steer the electrical activity towards a desired anatomic target to maximize the therapeutic benefit and reduce potential side effects. The Percept battery system provides the additional benefit of sensing surrounding brain activity from the DBS electrodes, which may help in programming. This is currently under investigation. Patients are given a patient programmer, which they can use to adjust their settings within a pre-set range. This system is MRI compatible with 1.5 and 3.0 T.
This DBS system also has segmented leads that allow the ability to steer the electrical activity towards a desired anatomic target to maximize the therapeutic benefit and reduce potential side effects. Multiple independent current control (MICC) provides a dedicated power source for each electrode to precisely control stimulation and refine the shape of the electric field. They offer both a non-rechargeable and a rechargeable battery that lasts up to 15 years. Patients are given a patient programmer, which they can use to adjust their settings within a pre-set range. This system is MRI compatible with 1.5 T.
Abbott (St. Jude Medical)
This DBS system also has segmented leads that allow the ability to steer the electrical activity towards a desired anatomic target to maximize the therapeutic benefit and reduce potential side effects. They offer only a non-rechargeable battery. Patients are given a patient programmer, which they can use to adjust their settings within a pre-set range. The unique Neurosphere Virtual Clinic system may allow for telemedicine programming without trips to see the neurologist as well. This system is MRI compatible with 1.5 T.
Dr. Faraji performing DBS surgery with the ROSA stereotactic robot system. The robotic arm aligns to pre-set trajectories to improve accuracy for brain mapping and for DBS electrode placement. Dr. Faraji was the primary author on the publication describing surgical technique, workflow optimization, and outcomes. ROSA DBS surgery is being adopted nationally and internationally following this publication.