San Diego Dr. Kenneth Ott, a neurosurgeon with Scripps, fights to contain a smile while talking. He has good reason to smile: his successes can be measured in human lives transformed. Ott's specialty is performing deep-brain stimulation surgery on those suffering from Parkinson's disease, and the results are dramatic.
Taber's Cyclopedic Medical Dictionary defines Parkinson's disease as "a chronic nervous disease characterized by a fine, slowly spreading tremor, muscular weakness and rigidity, and a peculiar gate." It is named for British physician Dr. James Parkinson (1755-1828) whose "Essay on the Shaking Palsy" clarified and defined the symptoms of the disease for other doctors.
"I always tell people that Parkinson's is a disease of the whole family, because it devastates and disables the whole family. There are about a million people in America who have Parkinson's disease, and the number is going up each year as our population ages. It's about half a percent of our population. And it's a very complicated, difficult disease to treat because there are so many drugs and the side effects are so complicated. It's one of the most difficult things a neurologist can deal with. Most neurosurgeons just do spinal surgery."
The treatment for Parkinson's disease has changed because of the limitations of traditional therapies. "It's a degenerative disease of the central nervous system for which there is no cure. Part of the cause is a depletion of a drug called dopa within the depths of the brain, and in the '60s they began treating patients by giving them dopa. It is highly useful in treating the symptoms, and there are three main symptoms: Tremor, which everyone knows about; bradykinesia, which means slowness of movement; and the third and very disabling symptom is rigidity. Muscles become rigid, and the patient feels like a prisoner in his own body. The tremor is more of a cosmetic problem. Dopamine is still the most important medication given. In the late '40s, there was a treatment developed called stereotactic surgery when a neurosurgeon discovered that certain areas of the brain, when destroyed, alleviated the symptoms of Parkinson's disease. One of the areas of the basal ganglea, when heated up, destroys a little group of cells, and the symptoms will go away. The surgery is done with an external frame affixed to the head, using internal landmarks of the brain to guide the needle to make the little lesion. It was quite effective, but when dopamine came in the '60s, why operate and risk injuring patients?
"Dopamine had widespread use, but after a long period of time it became evident that the effects of dopamine gradually wore off as the disease progressed. So patients would require higher and higher doses with less and less effect. And the higher doses of dopamine created a movement disorder called dystonia, with jerky, almost writhing movements of the arms and legs. After many years of treatment, patients would reach a very disabled state as they waxed and waned from being 'on' on the medications, and when they'd wear off, they'd freeze, and this would happen several times a day. In the past 15 to 20 years, stereotactic surgery has undergone a revival because imaging of the brain is so much better, and we can see the structures better. The operation is much safer because of two new technologies that allow us not to destroy the brain: One, we can put an electrode in the brain and stimulate these areas without destroying them -- making it reversible. It's placed in the sensitive area of the brain and let out under the skin to a little stimulator much like a pacemaker. The other technology has been the gamma knife, which has very focused radiation that can destroy an area noninvasively without heating up an area with an electrode." The gamma knife is a laser device that allows surgeons to use radiation in treating what were once considered inoperable brain tumors without even making an incision.
The use of stimulators or deep-brain stimulation was first tried by French neurologist A.L. Benabid in 1991. "It's like Newton said, 'If I've seen farther than others, it's because I've stood on the shoulders of giants' -- you've heard that aphorism. That's the way it is with surgical innovations. [Benabid] didn't just invent this. The fact is, part of the operation to destroy an area of the brain with a heating current is to stimulate it first to be sure you were in the right spot. Benabid thought, 'Let's just leave the electrode in there and hook it up to a stimulator.' By then, the technology for pacemakers had been invented, so we had the stimulators. The electrode is placed through a small hole in the head and a wire is let underneath the skin so you can't see it, and the stimulator is placed in the chest wall below the collar bone."
The most important thing about the surgery for Dr. Ott is that it works. "For tremor, it's about 80 to 90 percent successful improvement. There are scales of measuring rigidity and movement, a unified Parkinson's disease ratings scale. It rates activities of living, motor function, rigidity, tremor, and other side effects of Parkinson's. It's a semi-qualitative assessment. The FDA did a scientific study with control groups with the stimulator off and on -- people assessed how well it worked who did not have a vested interest in it -- neurologists who were blinded as to whether the stimulators were off or on. They found a significant improvement in the rating scales."
Ott has been performing deep-brain stimulation surgery for about four years. "The battery just wore out on my first patient yesterday, and I had to replace her stimulator, which is easy to do." One other hospital in San Diego, UCSD, also offers the procedure, but Ott believes it is about to become more available -- even to younger patients such as actor Michael J. Fox, who has battled the disease since 1991. "The results of the stimulators are so good now, that they are considering liberalizing the indications to people who are younger and not yet disabled. Why put up with the expense and problems of dopamine when it can be repaired this way? There's also some theoretical advantages to stimulation -- this is controversial -- that there may be some protection against continuing degeneration of these people. But that needs to be proven.