Pallidotomy

Pallidotomy is a neurosurgical procedure in which a small section of the brain called called globus pallidus interna is destroyed using liquid nitrogen. The procedure is usually done for the management of Parkinson’s disease (PD).

Parkinson’s disease is a neurodegenerative disorder that primarily affects a part of the brain called substantia niagra. This part is responsible for the production of the hormone dopamine, a chemical messenger that transmits signals between neurons (cells of the brain and the spinal cord) to trigger movements. Thus, by reducing the production of dopamine, Parkinson’s disease affects movements in the body. Decreased production of dopamine in the substantia nigra results in its hyperactivity in another part of the brain called globus pallidus interna that further affects the ability of the brain to control movements. Although there is no cure available for PD, the condition is not considered fatal since it is possible to control the symptoms of the disease for years using the available treatments.

Destruction of the hyperactive globus pallidus interna helps to provide relief from symptoms of PD such as hand tremors and difficulty swallowing. It also helps in providing relief from the side effects of certain PD medications, such as stiffness and involuntary body movements.

Pallidotomy is recommended in individuals with advanced Parkinson’s disease who experience symptoms such as slow movement, severe tremors, and rigidity that can no longer be controlled by medications.

It is also done to provide relief from severe symptoms caused due to long-term use of a PD medication, specifically levodopa. Long-term use of levodopa results in uncontrolled jerky movements and on-off periods. On-off periods are caused due to fluctuating dopamine levels. It results in intermittent off -periods, wherein the person freezes for a few seconds or minutes, and on-periods that causes uncontrollable body movements.

The surgeon may not perform this surgery in individuals who do not respond to treatment with levodopa as such people may not benefit from pallidotomy either.

In addition, pallidotomy may not be recommended in individuals with the following conditions:

• Dementia
• Striatonigral degeneration (A neurological conditon that occurs due to break down of connection between two areas of the brain)
• Supranuclear palsy (a neurodegenerative disorder that leads to problems in vision, movement, balance and speech)
• Life-threatening medical conditions

Prior to the procedure, the surgeon will ask you to visit the hospital multiple times for various preoperative examinations and to assess your symptoms of PD. Some of these tests include:

• Blood tests
• Video recordings to study your symptoms while performing various activities
• Magnetic resonance imaging (MRI) to look at the area in the brain to be operated
• Neuropsychological assessment to study your mood, memory, and thinking process

The surgeon will discuss all the risks and benefits associated with the surgery. Based on the information, you can decide whether to undergo surgery or not. If you understand the procedure and agree to it, the hospital staff will ask you to sign a consent form.

In the days leading to the surgery, the surgeon will ask you to discontinue the following medications two weeks before the surgery:

• Warfarin, aspirin, clopidogrel, and other medicines that thin the blood
• Diclofenac, ibuprofen, and some other painkillers

After you arrive at the hospital for the surgery, the hospital staff will ask you to wear a hospital gown. They will also provide you with special stockings to prevent blood clot formation in your legs during your stay at the hospital. You will be awake throughout the procedure. The surgery usually involves the following steps: 

• An anesthetist will inject local anaesthesia, a numbing medicine, at four sites in your scalp.
• After the skin turns numb, the surgeon will insert four pins at these sites in the skull. The pins are inserted a few millimetres deep into the skull.
• A special frame called stereotactic head frame will then be fitted on top of the pins. The frame will hold your head in a fixed position during the surgery.
• If you feel any discomfort during the procedure, the doctor will give you a mild sedative (a medicine to make you feel relax).
• A computer tomography (CT) scan will be performed to identify the target location in your brain with respect to your head frame.
• You will again be given local anaesthesia.
• Next, the surgeon will drill a small hole on one side of your skull (above the area that needs to be operated on) to insert a hollow probe (a blunt-end surgical tool used to expose the part of the body) in the direction of the globus pallidus interna.
• He/she will administer liquid nitrogen, an extremely cold substance, through the probe to destroy the area.
• Once the area is destroyed, the surgeon will close the wound and remove the head frame and pins.

The surgery usually takes about two hours for completion. After the procedure, the hospital staff will wheel you to the recovery room. You will need to stay in the hospital for about two to three days after surgery or until the surgeon feels you can look after yourself. You can expect the following during your hospitalisation period:

• The medical team will perform an MRI procedure on the day after the surgery to confirm the success of the procedure.
• You will be given medicines and liquids through an intravenous drip in your hand.
• Your wound and vital signs, such as blood pressure and pulse, will be closely monitored.
• The surgeon will advise you to change your bed position frequently to avoid stress on a particular part of the body.
• If you experience pain or sickness, talk to the hospital staff. They will provide you with appropriate medications for the same.

The surgeon will give you the following instructions to look after yourself post surgery:

• You should not drive for at least six months following surgery.
• Ask a family member, a friend, or a responsible adult to assist you with household chores for the initial few days after discharge. You can resume work four to six weeks after the surgery.

A majority of the individuals who undergo this surgery recover completely within six weeks of the procedure. 

When to see the doctor?

You should immediately inform the surgeon if you experience symptoms such as:

• High temperature/fever
• Confusion
• Sensitivity to light (severe)
• Memory problems
• Problems with vision
• Increasing drowsiness
• Weakness of the facial muslces
• Serious headache
• Stiff neck
• Swelling, pain, or redness in the thigh or calf
• Jerking or twitching movements
• Tingling or numbness in any body part
• Difficulty walking
• Blurred vision or double vision

Some risks and complications associated with the surgery include:

• Stroke (bleeding in the brain that results in impaired eyesight, speech difficulty, and weakness in one side of the body)
• Infection (small risk)
• Seizures (small risk)
• Slurred speech or weakness (permanent)
• Lack of improvement in symptoms
• Cognitive impairment (problems with memory and thoughts)

Before you leave the hospital, your surgeon will share a schedule for follow-up appointments. Your stitches will be removed during the follow up in five to seven days post surgery.

In addition, you will need to visit the hospital approximately six weeks after the procedure wherein your doctor will examine the operated part of your brain. You may have another in-clinic appointment about three months after the operation.

Disclaimer: The above information is provided purely from an educational point of view and is in no way a substitute for medical advice by a qualified doctor.