Brain Surgery for Parkinson's Disease
Surgery will not cure Parkinson’s disease but it can control the symptoms, particularly tremors and rigidity. It’s usually a last resort after all other drug treatments have been found to be unsuccessful and the symptoms unmanageable.
It’s not suitable for everyone. Surgical treatment is appropriate for just 10% of people with Parkinson’s. However it is an option for people in the advanced stages of the disease who have in the past responded well to levodopa/carbidopa drug treatment.
Currently there are three types of surgery being used to treat Parkinson’s disease:
Deep brain stimulation (DBS)
This is relatively new but already producing promising results. The great benefit is that it doesn’t destroy any part of the brain and the side effects are less than those of pallidotomy and thalamotomy.
The procedure involves placing very small electrodes in parts of the brain such as the subthalmic nucleus (the area responsible for motor function) thalamus and globus pallidus and attaching them to a device very similar to a pacemaker placed underneath the collarbone. This device stimulates the brain and blocks or paralyses the brain signals causing symptoms.
This device can be turned on or off when a special magnet is rubbed over it. It can also alter the level of stimulation going to the brain.
Deep brain stimulation has been found to be particularly effective in the thalamus area, relieving tremors. Read more on DBS
Pallidotomy/thalamotomy ablative surgery
These procedures work by destroying a section of the brain affected by the disease.
Pallidotomy - a small hole is drilled into the skull and an electric probe inserted to reach an area called the global pallidus. This is thought to be overactive in people with Parkinson’s and is responsible for slow movement, tremors and stiffness. A small area is burnt away in the hope of reducing the symptoms. It has been particularly helpful in reducing dyskenesia (involuntary movements) caused by medication. Stroke and paralysis can be side effects.
Thalamotomy - a small number of people with tremors have benefited from this. The procedure is the same as a pallidotomy but the area of the brain treated is the thalamus, which is responsible for tremor symptoms. Similar side effects to pallidotomy.
Nowadays doctors rarely perform either procedure. This type of surgery permanently destroys a part of the brain. If brain tissue transplants became possible in the future, it would be impossible for people who had undergone these procedures to benefit.
New Treatment: Fetal transplantation
This is very much a new and experimental treatment. The procedure involves replacing the dying or dead dopamine producing cells in the substantia nigra with brain cells from human fetuses. The idea behind it is that the transplanted cells will begin to reproduce dopamine and counteract the effects of Parkinson’s disease. There is a long way to go before this sort of surgery becomes readily available and many people are still treating it with cautious optimism.
Surgeons need to know what effect any transplant would have on the progression of Parkinson’s - would it hasten it after a while, slow it down or would new symptoms emerge? And as doctors don’t know what causes the disease, would the graft be eventually affected by something they don’t know about?
These are questions that will probably be answered as the use of these techniques become more common and research becomes more advanced.