Thalamotomy for Parkinson's disease
Thalamotomy is the precise destruction of a tiny area of the brain called the thalamus that controls some involuntary movements. Before surgery, detailed brain scans using a CT scan or MRI are done to identify the precise location for treatment.
The person is awake during the surgery, but the scalp area where instruments are inserted is numbed with a local anesthetic. The surgeon inserts a hollow probe through a small hole drilled in the skull to the target location. An extremely cold substance, liquid nitrogen, is circulated inside the probe. The cold probe destroys the targeted brain tissue. The probe is then removed, and the wound is closed.
Surgery on one side of the brain affects the opposite side of the body. If you have tremor in your right hand, for instance, the left side of your brain will be treated. The procedure can be repeated on the other side of the brain if needed, but it greatly increases the risk of speech and cognitive problems after surgery.
What To Expect After Surgery
The surgery usually requires a 2-day hospital stay. Most people recover completely within about 6 weeks.
Why It Is Done
Thalamotomy is rarely done today. It may be used to treat severe tremor on one side of the body (most often in an arm or leg) that does not respond to medications. It does not help with slow movement (bradykinesia), speech problems, or walking difficulties.
Thalamotomy usually is reserved for people younger than 65 who have normal intellectual function and normal recent memory.
People who should not have this procedure are those who have:
- Problems swallowing.
- Unpredictable shifts in voluntary motion of their arms, legs, and torso that affect their walk and posture.
- Psychological abnormalities.
- Untreated high blood pressure.
How Well It Works
Thalamotomy can be effective in reducing some symptoms of Parkinson's disease.
- It appears to be most effective when movement problems affect the arms and legs. Relief is more frequent in the arms than in the legs.
- People with tremor on only one side of the body may have immediate, complete relief of tremor in the arms and legs, although this improvement may be lost over time.
- Occasionally there may be relief on the same side as the surgery, although this is not to be expected.
- Symptoms of poor balance, monotone voice, blank facial expression, and shuffling gait generally do not improve with this surgery.
Thalamotomy offers the most benefit to a person who is still relatively functional, especially if he or she is still able to work. Improvement after the surgery is more likely to continue if the operation is done relatively early in the course of the disease.
This type of brain surgery is less risky today than it was in the past because technology allows the surgeon to identify with great precision the area of the brain that will be treated. Serious, permanent complications are uncommon.
Complications of thalamotomy can include:
- Weakness, loss of sensation, or loss of voluntary movement (paralysis).
- Temporary confusion.
- Stroke caused by bleeding in the brain, which sometimes can lead to death.
- Temporary balance problems.
- Numbness around the mouth (leading to drooling) and in the hands.
- Temporary balance problems.
- Uncontrollable, tiny running steps when walking (festinating gait).
- Loss of muscle tone.
- Impaired speech. This is much more likely when surgery is done on both sides of the brain.
- Problems with thought and memory (cognitive impairment).
What To Think About
Thalamotomy is rarely used. The effectiveness, lower risk, and nondestructive nature of deep brain stimulation have made it the preferred surgical method for treating Parkinson's disease. Even for cases in which deep brain stimulation is not an option, thalamotomy is used less often than pallidotomy because pallidotomy can improve a broader range of symptoms. Thalamotomy can greatly reduce tremor, but it does not have a strong effect on other symptoms of the disease or on involuntary movements (dyskinesias) caused by long-term levodopa therapy.
Thalamotomy may be considered as an addition to levodopa therapy, not as a replacement for it. It does not cure Parkinson's disease and does not eliminate the need for medication. After surgery, treatment with levodopa will be continued and the dose adjusted as needed.
Thalamotomy usually is not done on both sides of the brain because it greatly increases the risk of speech and cognitive problems after surgery.