Scary surgery gives relief to Parkinson's victim
July 21, 2000 Web posted at: 10:13 AM EDT (1413 GMT)
CHICAGO (Reuters) -- Parkinson’s disease patient Gary Prazak said the worst part of his brain surgery was being awake while surgeons drilled into his skull to implant electrodes.
Since the surgery 14 months ago, during which he responded to surgeons’ commands to ensure the electrodes were properly placed, tiny electric pulses have calmed the disease’s tremors and released his body from its grip.
“It’s like a modern-day miracle,” said Prazak, who has begun ballroom dancing lessons and returned to playing the piano. “I was awake for the entire 10-hour procedure. The drilling was the only part I wasn’t prepared for. It was very loud.”
Prazak, 63, is one of a small group of Parkinson’s patients in the United States participating in a study of “deep brain stimulation,” a procedure that has won preliminary approval from the Food and Drug Administration to treat Parkinson’s.
Scientists say brain stimulation may prove to be the answer to controlling the seizures of severe epileptics and treat some types of depression, obsessive compulsive disorder, tinnitus, even obesity. The roots of those disorders, like Parkinson’s, may lie deep inside the brain where its circuitry goes haywire.
It works by delivering tiny electrical pulses to targeted brain cells within the thalamus, two walnut-sized masses of nerve tissue that influence motor control. The pulses block brain signals that cause the tremors, stiffness, slowness, lack of movement and poor balance common to Parkinson’s sufferers.
Parkinson’s is caused by a degeneration of the bundles of brain cells called basal ganglia and a resulting lack of dopamine, a neurotransmitter that smoothes out bodily movements. There are 650,000 victims in the United States alone.
“The patient is part of the surgical team for mapping the brain and responding to stimulation,” said chief of neurosurgery Kim Burchiel at Oregon Health Sciences University in Portland.
The procedure, which has been available in Canada, Europe and Australia since 1998, is performed only when medication for Parkinson’s does not work or is badly tolerated.
“Using our increased understanding of how these conditions come about, we can identify parts of the brain that are active, abnormally active or not active at all,” said Cleveland Clinic neurosurgeon Ali Rezai. “The technology allows us to go into the areas that are functioning abnormally and control them.”
Prazak, for whom drugs caused uncomfortable side effects, was plagued by involuntary movements, periods of freezing up, slurred speech and nearly paralyzed facial muscles.
“Parkinson’s kept me from doing a lot of things I had done before, like walking, biking and playing the piano. I can do all of that now. I got my smile back, I’m taking ballroom dancing with my wife and I can do things around the house,” he said.
The procedure treats certain symptoms of Parkinson’s disease, mainly tremors, but does not alter the supply of dopamine in the brain or cure for the disease.
There is still a lot to learn about the therapy, Burchiel said. For example, the long-term effects of the surgery are still unknown, as is the durability of the outcome.
“My experience with this technique is that it works, it’s dramatic,” Burchiel said. “It’s very exciting and it’s the best thing we’ve got right now, but we’re still playing catch-up a bit in terms of the evidence.”
The technology used for deep brain stimulation, developed by Minneapolis-based Medtronic Inc., the world’s biggest medical device manufacturer, grew out of the same technology used in cardiac pacemakers.
Those advances include better magnetic resonance imaging (MRI) techniques, making it easier for doctors to navigate inside the brain, more sophisticated surgeons’ tools and improved understanding of brain structure and chemistry.
Electrodes have been used for more than 30 years to treat chronic pain by interfering with pain signals traveling through the spinal cord to the brain. The FDA has approved their use to treat essential tremor, one of the neurological conditions grouped together as “movement disorders.”
Among the benefits of brain stimulation is that it can be turned off or fine-tuned to suit the individual patient. A programmer can change the frequency or strength of the impulses by using a remote device that resembles a laptop computer, and the patient can wave a hand-held magnet over his chest to switch the stimulator on or off.
Risks associated with the surgery are serious, including intracranial hemorrhage, infection and seizures. In addition, the device implanted in the upper chest can cause infection, or the wire attached to the electrodes can split.
A common surgical approach to treating Parkinson’s tremors when medication does not work is a thalamotomy, which involves destroying brain tissue in the thalamus, an important relay center for sensory information flowing into the brain. Actor Michael J. Fox underwent this procedure in 1998.
The problem with it, or with any procedure where lesions are made on the brain, is that doctors cannot treat both sides of the brain safely because there is the risk of impairing speech and other functions.
“That’s why stimulation has a lot of appeal, because you can treat both sides of the brain, but you don’t end up with irreversible side effects and it’s tunable,” Burchiel said.