Pallidotomy is a procedure where a tiny electrical probe is placed in the globus pallidus

Globus pallidus

The globus pallidus also known as paleostriatum, is a sub-cortical structure of the brain. Topographically, it is part of the telencephalon, but retains close functional ties with the subthalamus - both of which are part of the extrapyramidal motor system...

 (one of the basal ganglia

Basal ganglia

The basal ganglia are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit. They are situated at the base of the forebrain and are strongly connected with the cerebral cortex, thalamus and other brain areas...

 of the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

), which is then heated to 80 degrees celsius for 60 seconds, to destroy a small area of brain cells. Pallidotomy is used to treat dyskinesia

Dyskinesia

Dyskinesia is a movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements, similar to tics or choreia. Dyskinesia can be anything from a slight tremor of the hands to uncontrollable movement of, most commonly, the upper body but...

s in patients with Parkinson's disease

Parkinson's disease

Parkinson's disease is a degenerative disorder of the central nervous system...

.

Technique

In a pallidotomy, the surgeon destroys a tiny part of the globus pallidus by creating a scar. This reduces the brain activity in that area, which may help relieve movement symptoms such as tremor and rigidity.

Before surgery, detailed brain scans using MRI are done to identify the precise location for treatment.

The patient 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. Liquid nitrogen

Liquid nitrogen

Liquid nitrogen is nitrogen in a liquid state at a very low temperature. It is produced industrially by fractional distillation of liquid air. Liquid nitrogen is a colourless clear liquid with density of 0.807 g/mL at its boiling point and a dielectric constant of 1.4...

 is then circulated inside the probe. The cold probe destroys the targeted brain tissue. The probe is then removed, and the wound is closed.

The surgery usually requires a 2-day hospital stay. Most people recover completely within about 6 weeks.

Parkinsonism

Pallidotomy may be considered when a patient with advanced Parkinson's disease has:

• Developed severe motor fluctuations, such as dyskinesias and on-off responses, as a result of long-term levodopa treatment.
• Severe or disabling tremor, stiffness (rigidity), or slow movement (bradykinesia) that medication can no longer control.
• Pallidotomy is not a good choice for treatment when a person has not responded to levodopa. Some studies suggest that people with parkinsonian symptoms who do not improve with levodopa therapy do not gain much benefit from pallidotomy.

The most striking effect of pallidotomy is a reduction in dyskinesias that are caused by long-term levodopa therapy. This improvement can be seen almost immediately. By reducing these side effects, pallidotomy enables some patients to adjust their levodopa dosage, allowing for better symptom control.

Pallidotomy may reduce tremor, muscle rigidity, bradykinesis, and other motor symptoms. Balance and speech may also be improved.

It is not known how long the effects of pallidotomy can be expected to last. Benefits may fade over time in some people.

Reduction in use

Doctors rarely perform pallidotomy anymore. Instead, doctors use deep brain stimulation

Deep brain stimulation

Deep brain stimulation is a surgical treatment involving the implantation of a medical device called a brain pacemaker, which sends electrical impulses to specific parts of the brain...

, a procedure that does not destroy brain tissue and has fewer risks than pallidotomy.

This type of brain surgery has less risk today than 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 not common, although less serious side effects are.

Complications

Complications of pallidotomy can include a stroke

Stroke

A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

caused by bleeding in the brain.

Many people who have a stroke recover fully and benefit from pallidotomy. Pallidotomy has caused problems with thought and memory (cognitive impairment) in some people.http://www.ncbi.nlm.nih.gov/pubmed/9233412

Other risks include:

• Infection.
• Seizures.