Thalamotomy, Pallidotomy and Subthalamotomy

Lesioning surgery is a procedure that involves purposefully damaging select areas of the brain, to help in the management of a health condition, such as Parkinson’s disease.  There are several types of lesioning surgery, including thalamotomy, pallidotomy and subthalamotomy, according to the area of the brain that is targeted.

Surgical Procedure

Prior to the surgical procedure, the target site must be accurately established with a brain scan. Magnetic resonance imaging (MRI) or computed tomography (CT) scan may be used to visualize the areas of the brain and identify target areas.

The procedure involves the insertion of an electrode into the target region, as identified by the brain scans, which delivers an electric current to the cells in the target area.

The area of the brain affects the symptoms that may be relieved by the procedure, in addition to the possible adverse effects that may present. As the lesion is irreversible, the effects of the procedures are permanent.

Thalamotomy

A thalamotomy involves the lesion being created in the thalamus of the brain. This is the least common type of lesioning surgery that is only used rarely in current practice.

This type of lesioning surgery is not commonly used in practice, as it is only effective for the relief of tremor. Addition, there is a significant risk of complications associated with a thalamotomy, which accounts for the fact that thalamotomy is usually conducted only on one side in most cases, as bilateral surgery is considered to be significantly more dangerous.

Pallidotomy

Pallidotomy is a type of lesioning surgery that involves targeting to the region of the brain known as the globus pallidus internus.

This is the most common type of lesioning surgery and is most widely indicated for the relief of symptoms related to Parkinson’s disease, due to its wide action and effective improvement of symptoms. It can lead to relief of:

• Tremor
• Rigidity
• Bradykinesia
• Motor fluctuations
• Dyskinesia
• Uncoordination

Efficacy of a pallidotomy procedure can be estimated by the patient response to the pharmaceutical treatment for Parkinson’s disease, levodopa. All symptoms (except tremor and dyskinesia) will only notice an improvement if the patient noted a slight response to the oral medication. The efficacy of the procedure also depends on the precise placement of the lesion in the target area.

Pallidotomy has many benefits in comparison to other management techniques, such as deep brain stimulation. There is no need to implant wires of batteries, which reduces the risk of associated infections. It is often a more cost-effective solution and is widely available, even when travelling in a foreign country.

This type of surgery should be conducted bilaterally for the best effect, although this can increase the risk of certain side effects. This includes difficulty speaking and swallowing, in addition to cognitive problems.

Subthalamotomy

Subthalamotomy is a type of lesioning surgery that targets the region in the subthalamic nucleus of the brain. Subtalamotomy has a wide range of benefits and can effectively improve several symptoms associated with PD.

However, this is not a common technique in most developed nations but is a viable option in regions of the world where deep brain stimulation is not available for use in the treatment of Parkinson’s disease.

References

• http://www.parkinsons.org.uk/content/lesioning-techniques
• http://www.parkinson.org/sites/default/files/Guide_to_DBS_Stimulation_Therapy.pdf
• http://www.ncbi.nlm.nih.gov/pubmed/15077235

Further Reading

• All Parkinson's Disease Content
• What is Parkinson’s Disease?
• Parkinson’s Disease Pathophysiology
• Parkinson’s Disease Diagnosis
• Parkinson’s Disease Treatment

Written by

Yolanda Smith

Yolanda graduated with a Bachelor of Pharmacy at the University of South Australia and has experience working in both Australia and Italy. She is passionate about how medicine, diet and lifestyle affect our health and enjoys helping people understand this. In her spare time she loves to explore the world and learn about new cultures and languages.