Pallidothalamic Tractotomy (PTT) for Parkinson symptoms

This page was written by the Unit of Functional Neurosurgery at the National Hospital for Neurology and Neurosurgery, Queen Square, London, with help from people who suffer from Parkinson Disease (PD).

Many people with Parkinson disease eventually find that their movement symptoms - such as tremor, stiffness, or slowness - no longer respond well enough to medication. We offer several types of functional neurosurgery to help with these symptoms, including deep brain stimulation (DBS) and radiofrequency (RF) lesion of brain areas such as the ventral intermediate nucleus of the thalamus (VIM) or the internal globus pallidus (GPi). However, these options are not suitable for everyone, especially for patients with other specific health conditions, balance problems, or concerns about memory and thinking.

Radiofrequency pallidothalamic tract lesion (RF-PTT) is a safe, focused, alternative treatment. It involves temporarily inserting a thin probe into the brain and heating the tip to create a very small, precisely targeted lesion. This interrupts specific nerve pathways that contribute to Parkinson movement symptoms.

Expected benefits may include:

• Reduced tremor and dystonia
• Improvement in stiffness (rigidity), slowness (bradykinesia), and involuntary movements (dyskinesia)
• Lower medication requirements, which can reduce medication-related side effects
• Better day-to-day functioning and overall quality of life

Overall, RF-PTT is an important treatment option for people with Parkinson disease who may not be good candidates for DBS or other traditional RF procedures. Although this technique is already used in specialist centres around the world (including by UCL neurosurgeons operating abroad), it is a new addition to the treatments offered at UCLH.

This booklet is designed to help patients with Parkinson disease understand this procedure and decide whether it may be suitable for them. It is not meant to replace a conversation with your consultant.

If you have any questions about RF-PTT or would like more information, please contact a member of our team. We are here to help and are happy to talk through any concerns you may have.

For most people with Parkinson disease, lesion surgery is done while they are awake. This allows the surgical team to see immediately how the treatment is working. In some cases, the procedure can be done under general anaesthetic (“asleep”), and your neurosurgeon and DBS team will discuss which option is best for you.

You may be asked not to take your Parkinson’s medications on the morning of surgery. This helps the team clearly see your symptoms and understand the effect of the procedure. Our DBS specialist nurses will give you detailed instructions about how to manage your medications beforehand.

The first step of the procedure involves attaching a special frame to your head using local anaesthetic. An MRI scan is then performed. The highly accurate, 3-dimensional MR images help guide the surgeon to the exact target in the brain. Your hair will not be shaved, but it will be cleaned with antiseptic solution, and you will receive antibiotics during surgery to reduce the risk of infection.

The surgery itself uncomfortable but not painful because the area is fully numbed with local anaesthetic. The surgeon makes a small incision and creates a small opening in the skull, around the size of a £1 coin usually hidden behind the hairline when possible. There can be a lot of vibration and noise for under 1 minute while the hole is being made, but there is no pain. A very thin probe – about 1.5 mm wide – is then gently guided to the precise treatment area. This technique is extremely accurate, within 1 to 1.5 millimetre of the intended plan.

When the probe is in place, the team passes a small electric current through the area to check how this affects your movement and to make sure there are no unwanted side effects. When they are confident the probe is in the correct position, the lesion is created – this typically requires two short treatments lasting about 50 seconds each.

Once the treatment is finished, the probe is removed and the hole in the skull is covered with a small Titanium plate. The incision is then closed with stitches and small metal clips. A final MRI scan is performed to document placement of the lesion and ensure there are no complications. The entire procedure, including all scans, usually takes about 2–3 hours.

This treatment works by placing a very small, carefully targeted lesion in an area of the brain that sends overly active signals through between brain structures involved in controlling movement. By gently interrupting these signals, RF-PTT can help improve movement and reduce symptoms, while avoiding important nearby areas of the brain.

Because of the site of the lesion, this procedure has an excellent safety record and a very low risk of complications. Unlike many of the other targets, there are minimal to no reports of worsening balance, memory, or thinking. RF-PTT is usually done on only one side of the brain, opposite the side of the body that has the most symptoms.

All treatments and procedures have risks, and the functional neurosurgery team will talk to you about the risks of lesion surgery in detail during your consultation and again before the procedure.

Problems that may happen straight away

Complications from this surgery are very rare when it is performed in experienced, well-established centres. Although serious complications are uncommon, it is important to understand them. Most complications, if they do occur, are mild, reversible, and easy to treat. They do not usually lead to long-term problems.

Serious but very rare risks

There is a very small risk of bleeding in the brain during or in the days after surgery. This could lead to complications such as stroke, weakness or paralysis, or even death. These outcomes are extremely rare and have never happened in our centre in patients who have normal blood clotting. The overall risk of bleeding that could cause serious disability is reported to be less than 1% (1 in 100 patients).

There is also a small risk of seizures (less than 1%). If seizures occur, they usually happen immediately after surgery, but we have never seen them lead to long-term epilepsy.

A small collection of blood (a haematoma) may form under the skin near the surgical site. This is usually harmless and settles on its own.

Other possible problems after surgery

Infection is also rare (less than 1%). Keeping the area clean and dry is very important to help keep this risk low.

Wound care advice

To reduce the chance of infection:

• Before surgery, all patients are swabbed for Methicillin Resistant Staphylococcus Aureus (MRSA). All patients are advised to strictly follow a MRSA treatment regimen for 5 days before surgery. After surgery, avoid touching the wound area and wash your hands regularly.
• Keep the wound clean and dry at all times.
• The dressing will be checked every day and should be changed every 3 days. This can be done by one of your family members after discharge.
• Do not wash your hair until the stitches are removed.
• Stitches are usually removed around 7 days after surgery.

Possible side effects

Some side effects may occur due to temporary brain swelling, especially during the first 2–3 days after the procedure. These are usually short-lived.

Short-term side effects may include:

• Speech problems, such as slurred speech - usually temporary

Longer-lasting side effects that have been reported (though still uncommon) include:

• Eyelid apraxia (difficulty opening the eyelids) – less than 1%
• A small increase in Parkinson’s medication needs – about 2.5%

Although long-term balance problems or thinking and memory difficulties have not been reported with RF-PTT for Parkinson’s disease, it is still possible – though very rare that these types of complications could occur.

Who to contact

While you are in the hospital, please report any side effects or concerns to the ward staff or directly to our team. After you go home, you can contact our DBS nurses during working hours (details are provided at the end of this booklet). There is also a 24-hour neurosurgery on-call team available through the hospital switchboard if you need urgent advice (020 3456 7890).

Some medical conditions may affect whether this treatment is suitable for you. These will be carefully assessed by our team before any decisions are made.

• Memory and thinking problems:
  If you already have significant difficulties with memory or thinking, this treatment may not be suitable. However, patients with mild-to-moderate changes can still be considered. Our neuropsychology team will assess this before your MDT clinic appointment.
• Falls and balance problems:
  A history of frequent falls or major balance issues may affect suitability. However, patients with moderate balance problems may still be eligible. This will be assessed during your MDT clinic visit.
• Speech and swallowing difficulties:
  If you already have severe problems with speech or swallowing, you will need an assessment by a speech and language therapist to make sure the treatment is safe for you.
• Changes seen on MRI scans:
  Significant structural changes in the brain – such as marked shrinkage – may mean the treatment is not recommended.
• Other medical conditions:
  Conditions such as heart disease, kidney problems, breathing issues, bleeding disorders, or the use of blood-thinning medication do not automatically rule out the procedure. However, they may increase the risks from surgery, so the team will review these carefully.

For people with Parkinson’s disease, we review all the possible treatment options that may help with symptoms. These can include deep-brain stimulation (DBS) of the subthalamic nucleus (STN) and DBS or radiofrequency treatment (RF) of the VIM or GPi. Each option has its own balance of benefits and risks, and our aim is to help choose the treatment that best fits your symptoms and overall situation.

If none of these treatments are suitable for you, we will refer you back to your GP or neurologist so you can explore other therapies or management options together.

If you decide not to go ahead with surgery, we will refer you back to your referring consultant so you can discuss other treatment options together.

If you are recommended for surgery, our DBS coordinator will contact you as soon as a surgery date becomes available. The waiting time for lesion surgery is usually around 3 to 6 months.

About six weeks before your operation, you will attend a pre-surgery assessment clinic. This visit includes blood tests, MRSA swabs, and any other tests you may need. All patients must complete MRSA eradication treatment before surgery - this will be explained in detail during your pre-assessment appointment.

Around two weeks before surgery, the DBS nurses will call you to review your current medications and guide you on how to take them in the days leading up to your operation.

Important medication information:

• You must stop taking any medicines that contain aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) – such as Ibuprofen (Nurofen), Naproxen, or Diclofenac (Voltarol) – for two weeks before and two weeks after surgery. This is essential to reduce the risk of bleeding in the brain during the procedure.
• If you need pain relief, Paracetamol or Co-codamol are safe options.
• Please speak to the specialist nurses if you take any of the above medicines, contraceptives, or herbal/homeopathic products.

If you take blood-thinning medication for heart or clotting conditions, we will discuss with you in the MDT when to stop then. In more complex cases, you might be referred back to your treating doctor for advice on how and when to pause these medicines safely.

If you have questions or worries at any point, the specialist nurses and the rest of the team are here to support you.

We want you to feel fully involved in every decision about your care. If you choose to go ahead with treatment, we are required by law to ask for your written consent. A member of staff will explain the procedure, including the risks, benefits, and alternatives, before asking you to sign the consent form.

If anything is unclear or you feel unsure at any stage, please talk to a senior member of the team – we are always happy to explain things again.

Most patients are admitted 1–2 days before surgery. During this time, you will have a clinical assessment (including some video recordings), and sometimes a detailed MRI scan.

After the operation, you will usually stay in hospital for 1–3 days. Please bring your regular medications with you when you come in.

You can go home once your condition is stable and there are no concerning complications.

You will have a follow-up appointment 2 weeks after discharge with the specialist nurses. At this visit, they will check your wound, remove any clips or stitches, review your recovery, and assess whether early improvements have been maintained.

Further follow-up depends on your individual response to surgery. Most patients are contacted again between 6 months and 1 year after the operation. You can reach the specialist nurses at any time by phone or email if you need advice or to arrange a clinic appointment.

We advise patients not to drive for the first week after surgery or until they are fully recovered (whichever is longer). If you feel well and have no side-effects, there are no legal restrictions, but please discuss any concerns with the team.

For urgent medical concerns, please contact the Unit’s coordinator or secretaries, who will notify your specialist nurse or doctor. We will support you over the phone or arrange an urgent appointment if needed.

During weekends or bank holidays, you can call the UCLH switchboard and ask for the on-call doctor at the National Hospital for Neurology and Neurosurgery (020 3456 7890). They will advise you and, if necessary, arrange for you to be seen in hospital or recommend attending your nearest A&E.

During your hospital stay, you may be invited to take part in a research study. This is completely voluntary. Choosing not to take part – or deciding to withdraw later – will not affect your care in any way.

If you do take part in future research, please remember to inform the research team that you have had lesion surgery.

1. Horisawa S, Kim R, Sakaguchi T, Kawamata T, Taira T. Unilateral pallidothalamic tractotomy for akinetic-rigid Parkinson’s disease: a prospective open-label study. J Neurosurg. 2021;135(3):799-806. doi:10.3171/2020.9.JNS202909.

2. Gallay MN, Moser D, Jeanmonod D. MRgFUS pallidothalamic tractotomy for chronic therapy-resistant Parkinson’s disease in 51 consecutive patients: single center experience. Front Surg. 2019;6:76. doi:10.3389/fsurg.2019.00076.

3. Ikezawa J, Tanaka M, Yamamoto K, et al. Bilateral effects of unilateral pallidothalamic tractotomy using focused ultrasound in Parkinson’s disease. Mov Disord. 2025;40(5):1123–1132. doi:10.1002/mds.30281.

Haris Charalambous
Multi-disciplinary team (MDT) Coordinator
Telephone: 0203 448 8730 (first point of contact)
Email: haris.charalambous@nhs.net

Secretaries:
0203 448 8726
0203 448 8740
0203 448 8737
0203 448 8719

DBS Nurse Specialists:
Joseph Candelario-McKeown
Catherine Hartigan
Maricel Salazar
John Esperida
Email: uclh.enquiry.dbsnurses@nhs.net

UCLH switchboard telephone number: 020 3456 7890

Travelling to National Hospital for Neurology and Neurosurgery

By Rail
Euston, King’s Cross and St Pancras are all only about 15 minutes walk from the station to the hospital.

By Bus
Southampton Row – Numbers 59, 68, 91, 168, 188, 501
Theobalds Road – Numbers 19, 38, 55, 243
High Holborn / New Oxford Street – Numbers 8, 25, 242, 501, 521

Please note: You can travel on buses and trams using an Oyster or contactless payment card with pay as you go credit, or you can add a Travelcard or Bus & Tram pass to your Oyster card. You are no longer able to use cash to pay for your bus fare.

By Tube
Russell Square (Piccadilly Line) and Holborn (Central and Piccadilly Lines)
Both stations are within walking distance.

Nearest Airport 
London City Airport – via DLR from London City Airport to Bank station, transfer to Central Line to Holborn station Heathrow Airport – via Piccadilly line about 45 minutes to Russell Square tube station.

Gatwick Airport – via Gatwick Trains to London Victoria Station then take Victoria
Line to Green Park station then transfer to Piccadilly line to Russel Square station.