Long before performing a DBS surgery, Dr. Davis studies the patient’s MRI images to plan the operation. “When I get to the operation, I already have a target in mind,” Dr. Davis says, adding he also has a safe entry planned into the patient’s brain to avoid blood vessels and other critical areas.
DBS surgery involves the placement of electrodes in the brain, which are connected to a small battery-operated electric pulse generator about the size of a stopwatch that is implanted in the chest.
“There’s something really special about DBS when you can change someone’s life for a prolonged period through several hours of surgery. That’s why I really enjoy doing what I do, especially deep brain stimulation.” Behrang Saminejad, MD, Movement Disorders Chief with Lehigh Valley Fleming Neuroscience Institute
In DBS surgery, patients are given an anesthetic “scalp block” that numbs the scalp while the surgeon makes the entry holes into the skull. In this stage, the patient is in what’s known as twilight, sedation similar to that used in other procedures, such as a colonoscopy.
Dr. Davis inserts electrodes into the brain to get recordings of electronic signatures of different tissues within the brain. Based on those readings, Dr. Davis knows where to position the electrodes. In Sutter’s case, electrodes were placed on both sides of her brain, though that’s not always the case with DBS surgery and is patient specific.
In this stage, patients like Sutter are fully awake. They must be awake so surgeons can determine the effect of the stimulation from the electrodes. “We turn it on and test. We’re looking for the effect of the stimulation. We want to make sure the tremor is suppressed,” Dr. Davis says. “We’re also looking for side effects. That’s really one of the big reasons we do it this way.”
Sutter says that during surgery, she spoke with Dr. Davis and his team, drew a circle, wrote her name and more. “It was the best feeling in the whole world,” she says.
“The effect is dramatic,” says Dr. Davis. “It’s part of why I chose to do this. This is a specialty that very distinctly has happy patients. The mechanics of this kind of surgery is not something that is appealing to most neurosurgeons.” DBS surgeons like Davis are relatively few compared to the overall number of neurosurgeons.
DBS patients don’t leave the hospital with their DBS system functioning. That’s because doctors must wait for brain swelling to go down and for scar tissue to encapsulate the electrodes. Patients then go to the DBS clinic, where neurologists fine-tune the settings on the pulse generator to achieve optimal results.
Sutter also has head and neck tremor and was receiving botulinum toxin treatments for many years to help quell those symptoms. DBS surgery for ET is for tremor of the extremities and typically does not have a large effect on head and neck tremor. Sutter says she’ll continue to get the botulinum toxin treatments.
“Her head tremor has not improved as much as we would have hoped for through surgery, but it was a secondary target. Fixing the hand tremor was the most important part for her, which has significantly improved,” Dr. Saminejad says.