Thalamotomy and pallidotomy for treatment of essential tremor and Parkinson’s disease

The aim of this leaflet s to give information and guidance to patients who have been diagnosed with Parkinson’s disease or essential tremor and who may be considering thalamotomy and pallidotomy treatment. Family and carers may also find it helpful.

What are thalamotomy and pallidotomy treatments?

Thalamotomy and pallidotomy are surgical procedures used to treat movement problems. due to Parkinson’s disease or essential tremor. Both procedures involve temporarily inserting a thin probe into a specific area in the brain which is then heated to remove a small amount of tissue in a precisely targeted brain region to create a ‘lesion’. This lesion blocks those abnormal brain signals that are responsible for the symptom (such as tremor or uncontrolled involuntary movements known as dyskinesia). These procedures are usually done only on one side of the brain – on the side opposite to the most affected body part.

Thalamotomy – in the brain the ventrointermedial nucleus of the thalamus (or Vim) provides sensory information in relation to movement. A thalamotomy procedure involves creating a lesion in the Vim areas and this can help with tremor symptoms due to Parkinson’s disease or to essential tremor among disorders.

Pallidotomy – the function of the Globus Pallidus interna (or GPi) in the brain is to control conscious and proprioceptive movements. A pallidotomy involves creating a lesion in this region of the brain. It can help with excessive movement or dyskinesia due to Parkinson’s or other conditions.

Pre-assessment and medications

Before carrying out the procedure(s), we will invite you to a pre-assessment appointment.

During this appointment we will advise you about which medications you will need to temporarily stop taking and which you can continue taking. Please contact us as soon as you receive your appointment letter if you are taking:

• aspirin
• warfarin (if you are taking warfarin, we may need to admit you before the day of your procedure, so that we can make sure your blood is clotting properly)
• clopidogrel
• any other drugs which thin the blood (including some types of painkillers, such as ibuprofen and diclofenac)

The DBS (deep brain stimulation) nurses will advise on how to take medications prior to surgery. For example patients may be advised to withhold tremor medications on the morning of the surgery.

Your hospital stay

You are typically admitted to the hospital on the morning of your surgery. Then following your surgery you would typically be in hospital for one to three days. You are advised to bring your own prescribed medications when you come to the hospital. For some patients, the tremor or dyskinesia may settle immediately after the surgery, however, this is not the case for all patients It is important to remember that the aim of the surgery is for long-term benefit rather than focusing on the immediate effect which will vary from patient to patient.

What is involved in the procedures?

Thalamotomy is usually performed while you are awake. This allows us ongoing assessment of the effect the probe stimulation is having on the targeted brain region before proceeding to the final lesion. The procedure takes two to three hours. The steps in the surgery are as follows:

1. A frame will be attached to your head so that we can precisely locate the target areas within the brain; we use local anaesthetic to numb the area where the pins attach to your head.
2. You will then be transferred to the radiology department for a scan of your head with the frame in place. This scan enables the surgeon to precisely target the problem. You then return to the operating theatre for the full procedure.
3. Using a local anaesthetic we will make an incision and drill a small hole in the skull, behind the hairline if possible. Based on the information (frame coordinates) generated by your scan, we will insert a probe and then stimulate with an electric current to ensure the target is correct. Finally, we will generate the lesion.
4. The probe is removed and the surgical wound is carefully closed using surgical staple clips or stitches.

For pallidotomy or thalamotomy surgery, in specific cases the procedure can be performed under general anaesthetic or ‘asleep’. We would discuss this with you in advance. Advice will be given by the deep brain stimulation (DBS) nurses regarding how to take your medications prior to surgery – for example, you may be advised to withhold tremor medications on the morning of the surgery.

Please note:

• We may need to shave a small patch of your hair before surgery.
• We will administer antibiotics during your surgery.

Who is not suitable for thalamotomy and pallidotomy surgery?

This surgery is not suitable for patients with:

• Pre-existing significant cognitive (thought process) decline (such as short-term memory problems).
• Pre-existing speech and swallowing problems; these patients will require assessment by the speech therapist.
• Pre-existing significant brain structural changes according to the MRI (for example shrunken brain).
• History of falls and balance problem.
• Other medical conditions that may have an increased risk from this surgery such as heart surgery, kidney problems, problems with breathing, prolonged bleeding problems, patients on blood thinning medication.

Risks of surgery

Major complications from this surgery are rare. There is a small risk of bleeding in the brain during the surgery, which often causes no symptoms. However, larger brain bleeds can result in serious complications such as a stroke, paralysis or death. The chance of suffering a major complication like this is less than 1% (less than one in a hundred).

Infection may occur from one week onwards after surgery from the surgical wounds on the head. Keeping your surgical wounds clean and dry is very important. This is also a rare risk (<1%, that is less than one in a hundred).

Neurological symptoms as a permanent side effect of the lesion, or more commonly due to transient brain swelling, can include:

• balance problems
• speech problem such as slurred speech
• sensory symptoms (buzzing, tingling sensation, numbness or change in taste)

Wound care advice following surgery

• Before surgery, you are swabbed for bugs that do not respond to antibiotic treatment such as methicillin-resistant staphylococcus aureus (MRSA). However, the common cause of infection are bugs that are commonly found in the skin. You are advised to strictly follow the advised treatment regime with a special wash lotion (Octenisan) for five days prior to surgery. You will be given clear instructions with the lotion.
• After surgery, you are advised to avoid touching the wound area.
• Regular handwashing is important.
• Always keep the wound area clean and dry.
• You may remove the wound dressing on the third day following your surgery and after this you may shower; do use the Octenisan lotion you used prior to your surgery.
• Stitches are taken out seven to 10 days after the surgery. You will be reminded to make an appointment at your GP practice for this.

Driving

You do not need to contact the DVLA to let them know that you have had this operation. Providing there are no complications from surgery, you may drive after we have confirmed your recovery at your follow-up appointment.

Additional information

Additional information about these two operations and lesioning is available from the following websites:

• National Tremor Foundation (opens in a new tab)
• International Parkinson’s and Movement Disorder Society, Essential tremor: essential facts for patients (opens in a new tab)
• International Essential Tremor Foundation (opens in a new tab)

Please be cautious in searching about lesioning on the Internet. Some information may not be accurate and not appropriate for your condition. We advise that you contact the DBS nurses to discuss any further information you may need.

Contacts

DBS Specialist Nurse, Claire Rudwick: Telephone 01223 217471, Email Claire Rudwick

MyChart

If you have not already done so, we would encourage you to sign up for MyChart. This is the electronic patient portal at Cambridge University Hospitals which allows patients to securely access parts of their health record held within the hospitals’ electronic patient record system (Epic). It is available via your home computer or smart phone.

If you are interested in this please let us know and we can provide information, or look on our website: MyChart.