‘Awake DBS’ is the gold standard for precise location of electrode
By Karen Hales, Neurology Solutions contributing writer
Neurology Solutions Medical Director Dr. Robert Izor has participated in more than 200 Medtronic deep brain stimulation procedures since 2004 with St. David’s Medical Center Neurosurgeon Anant Patel. Using high resolution advanced imaging technology, Dr. Izor and Dr. Patel have been able to precisely target specific areas of the brain signaling motor symptoms, allowing for excellent DBS response and no side effects. This article will lay out the most common risks and results of deep brain stimulation surgery as well as explain why “awake DBS” is the gold standard for optimal precision.
A movement disorder specialist undergoes a minimum of two to three years of additional training specifically in movement disorders over a general neurologist. Dr. Izor completed a fellowship with a focus on movement disorders that covered the selection of patients for deep brain stimulation surgery, intraoperative mapping, and post-operative programming. One of the region’s most experienced specialists in the treatment of movement disorders using DBS therapy, Dr. Izor is sought out to consult on the latest research, training and procedural education on movement disorders by other healthcare providers in the region.
Nationally, just seven out of 10 DBS implant surgeries are performed with the benefit of a neurologist in the room, according to Erin Doherty, a specialist with DBS device manufacturer Medtronic.
“The neurologist plays a critical role in optimizing lead placement, because he’s the one who is going to manage the patient following the DBS implant,” she said.
In addition to pre-surgery scans and intraoperative CT scanning, patients undergoing DBS surgery at St. David’s will benefit from the testing that is only able to be performed if the patient is awake during surgery, which Doherty describes as “the gold standard in DBS.”
The area of the brain that is being targeted is just 7 millimeters long, approximately the size of an almond. Intraoperative testing allows the surgical team to ensure the patient has little or no side effects and the most benefit before the permanent lead is implanted into the brain, which may be the difference of just a millimeter or half a millimeter.
“Dr. Izor and Dr. Patel take that time during the procedure to customize the surgery to that patient,” Doherty added. “Every single patient gets a very custom lead placement, based on what his or her doctors are able to test in the operating room,” she said.
DBS surgery involves a three-stage process. Although no surgery is without risk, Dr. Izor says precise imaging of the brain prior to surgery helps the team identify areas of tissue damaged due to disease, increased vascularity and other brain structures to plan the optimal trajectory. This precision reduces the risk of undergoing an already minimally risky procedure (less than 1% risk of hemorrhaging during surgery).
“The majority of complications in DBS surgeries involve repeated passes through the brain before targeting the correct location in the brain that produces limited side effects and optimal therapeutic effects to manage symptoms,” Dr. Izor said. “With more precisely mapped trajectory, within 1 mm of the targeted area of the brain, we are able to reduce the number of passes to a minimum. In fact, 80% of the time we don’t have to make a second pass before placing the permanent lead.”
What are risks of Medtronic deep brain stimulation surgery?
No surgery is without risk. General complications of any surgery include bleeding, infection, blood clots, and reactions to anesthesia. The major risks of DBS are a 1% risk of stroke causing a permanent deficit due to bleeding in the brain and a 2-5% chance of infection. Seizures occur in approximately 2% of patients.
Reasons for which you might need additional surgery include breakage of the extension wire in the neck; parts that may wear through the skin; and removal of the device due to infection or mechanical failure.
DBS may also cause worsening of some symptoms such as speech and balance impairments. In some patients with Parkinson’s, DBS may cause or worsen depression. If you develop any side effects from a stimulation adjustment, return to your neurologist’s office for further programming.
What are the results of DBS?
Patients considering deep brain stimulation should have realistic expectations for results. Medtronic deep brain stimulation therapy is not a cure, but it can successfully treat symptoms by disrupting the abnormal patterns of brain activity that become prominent in these diseases. It also can allow for a significant reduction in medications needed to treat your condition, reducing the side effects associated with certain drugs. It may take your neurologist up to six months of adjustments after surgery to achieve optimal results.
In the right candidates, DBS can significantly impact the patients’ quality of life, improving motor function and non-motor features of their disease. DBS often eliminates dyskinesia, a motor complication from drug therapy, and provides patients good tremor control.
- More than 70 percent of patients with Parkinson’s disease experience improved motor function as a result of DBS. DBS also can increase “on-time”—the period when a patient’s symptoms are best under control—by as much as six hours. In fact with most patients with well-placed leads, “off-times” aren’t noticed at all, and the patients are generally on a lower dose of medication than they had been prior to the beginning of DBS therapy, and have better on-state motor control than they did before the DBS surgery on their best medication therapy.
- When DBS is used for essential tremor, patients tend to have continued benefit for many years independent of medication. Often, these patents can stop medications for control of movement and postural tremor, and the condition does not tend to progress for these patients over a significant period of time (10-12 years). However DBS patients with ET must continue to modulate the stimulation delivered to maintain their state of wellness.
- Results can be dramatic in patients with dystonia. Some improvement occurs in 50 to 70 percent of patients.
Recently, researchers at the University of Alabama at Birmingham (UAB) were awarded a five-year $7.3 million grant by the National Institutes of Health (NIH) to evaluate new technology to potentially improve outcomes from DBS in Parkinson’s disease patients.
Following Your DBS Surgery
Once you have received your implant, you will be seen at regular intervals by your neurologist or movement disorder specialist to monitor and adjust your stimulator for the best control of symptoms. This may take several sessions as the brain is still healing. You may have your medications reduced. Follow-up programming visits are typically 30 to 45 minutes long. Initial programming visits are scheduled for one hour.
You will be asked to come back yearly at least to ensure you are getting the most benefit from your DBS system and to test whether your symptoms have progressed, requiring adjustments to your stimulator programming.
Neurology Solutions is accepting new patients seeking a specialist in managing Parkinson’s disease, dystonia, essential tremor and age-related movement disorders. If you are seeking another opinion on managing your symptoms from Parkinson’s disease, dystonia, essential tremor or an age-related movement disorder, call 512-865-6310 to make an appointment.
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Medtronic Deep Brain Stimulation Therapy: Precision, Risks and Results