What is Parkinson’s disease?
Parkinson's disease is a condition which results from the loss of a substance called dopamine in the substantia nigra of the brain stem.

Parkinson’s Disease affects 1% of people aged over 50 years, and sometimes affects younger people. In most cases the cause is unknown.

The three main problems in Parkinson's disease are usually tremor, stiffness (rigidity), and slowness of movement (akinesia). Patients frequently develop medication-related side-effects such as dyskinesias (‘wriggles’), and may fluctuate wildly from being almost ‘frozen’ to very dyskinetic (‘motor fluctuations’). Walking problems (‘gait disturbance’) are very common.

How is it treated?
Parkinson's disease is treated in the first instance with medications, such as levadopa (Sinemet®). Unfortunately, the effectiveness of such medications may decrease over a number of years, and they may also cause other abnormal involuntary movements (dyskinesias).

What are the reasons for surgery?
When medications are no longer working well, or their side effects are to severe, surgery may be of value. The procedures most commonly used to treat Parkinson's disease are deep brain stimulation (DBS), thalamotomy, and pallidotomy.

Clinical studies and experience suggest that surgery should be considered early rather than late, due to the high likelihood of developing severe medication side-effects with long-term treatment, better outcomes with earlier surgery, and a higher chance of avoiding, delaying or minimising the economic and social side-effects associated with advanced Parkinson’s disease.

What are the alternatives to surgery?
At present, the only alternatives to surgery are medications. You should check with a movement disorder neurologist to ensure that you have tried all of the appropriate medications before seriously considering surgery.

What happens before surgery?
Several weeks before surgery you will undergo an MRI scan of your brain. This will be used to plan and execute your operation. You will also be seen by a neuropsychologist, clinical psychologist, and movement disorder surgery neurologist. We will arrange this for you.

What do you need to tell the doctor before surgery?
It is important that you tell your surgeon if you:

• Have blood clotting or bleeding problems
• Are taking aspirin, warfarin, or anything else (even some herbal supplements) that might thin your blood
• Have high blood pressure
• Have any allergies
• Have any other health problems

What is deep brain stimulation?
Deep brain stimulation works by implanting fine wires (electrodes) into one of three sites in the brain that are important in Parkinson's disease. These are the subthalamic nucleus (STN), the thalamus, and the pallidum. The STN is the most common structure targeted.

DBS works by reducing the activity of these tiny areas that are overactive in Parkinson's disease. DBS helps to slow these parts of the brain down because the electrical pulse inhibits the activity in the brain surrounding the wire.

  More information on deep brain stimulation (DBS) for movement disorders

What are the benefits of deep brain stimulation?
The aim of DBS is to relieve some of the problems caused by Parkinson's disease, such as tremor, stiffness, slowness, and uncontrolled movements (dyskinesias). It tends to reduce motor fluctuations and increases the amount of time spent "on". It also allows most patients to reduce their medications, often by a substantial amount.

Who may benefit from surgery?
Surgery can significantly improve the quality of life for patients with Parkinson’s disease. However these operations are not suitable for all patients and thorough assessments must be carried out to ensure that the likely benefits of surgery outweigh the risks.
A suitable patient for consideration for surgery may be as follows:

• Parkinson’s disease without unusual features that has responded to dopamine medication at some stage
• Failed optimum medical therapy
• Disabling drug-induced dyskinesias

How is deep brain stimulation performed?
The first operation (Stage 1) involves placement of special wires (electrodes) in specific regions of the brain. Before surgery you will have a special frame attached to your head. This is usually done with local anaesthetic and is not too bothersome. Then you will have a CT scan before being taken to the operating theatre. Some more local anaesthetic and some light sedation will be given before one or two small holes are shaved in your skull. This does not hurt, and is usually much less uncomfortable than going to the dentist!

The electrode is then slowly inserted and the electrical activity will be monitored to guide its final placement. Once we are confident that we are in the correct position, we will stimulate through the tip of the electrode to see whether this helps and too look for side effects. We then secure the electrode in place. A CT brain is performed immediately after surgery to confirm satisfactory electrode placement.

The second operation (Stage 2) involves giving you a general anaesthetic and running the wires under your skin from your head to your chest. They are connected to a battery placed under the skin just below your collarbone (sometimes this is placed in your abdomen or flank). You will be discharged from hospital one or two days later. Your neurologist will adjust your stimulation settings and medications progressively over a number of months.

What is thalamotomy?
Thalamotomy involves inactivating part of the brain, known as the thalamus, by controlled heating. This is less commonly performed than DBS. Thalamotomy is successful in alleviating tremor in 90% of patients and rigidity in some patients. It is not effective for dyskinesias or slowness of movements, however.

  More information on thalamotomy

What is pallidotomy?
Pallidotomy is similar to thalamotomy, but targets the pallidum rather than the thalamus. Pallidotomy is very effective for the relief of dyskinesias and rigidity. In some people it can improve the slowness and tremor.

How are thalamotomy and pallidotomy performed?
This surgery is performed in one stage only. Before surgery you will have a special frame attached to your head. This is usually done with local anaesthetic and is not too bothersome. Then you will have a brain scan before being taken to the operating theatre. Some more local anaesthetic and some light sedation will be given before one or two small holes are shaved in your skull. This does not hurt, and is usually much less uncomfortable than going to the dentist! The electrode (wire) is then slowly inserted and the electrical activity will be monitored to guide its final placement. Once we are confident that we are in the right position, we will stimulate through the tip of the electrode to see whether this helps and too look for side effects. If you are happy with the result, we will go ahead and heat the tip up (to around 70-80 degrees for 60-70 seconds). Once this is done, we will close the incision and take the frame off. You will have an MRI scan a day or two later and will be discharged after that. Your neurologist will adjust your medications over a few months after surgery.

Who may benefit from surgery?
Surgery can significantly improve the quality of life of many patients with Parkinson's disease. These operations, however, are not suitable for all patients and thorough assessments must be carried out to ensure that the likely benefits of surgery outweigh the risks.

A suitable patient for consideration for surgery may be as follows:

• Parkinson's disease without unusual features that has responded to dopamine medication at some stage
• Failed optimum medical therapy
• Disabling drug-induced dyskinesias

What are the risks of surgery?
There is a very small risk of infection, haemorrhage (bleeding), stroke, and seizures (epilepsy). The risk that the surgery could cause death is extremely small (less than 1 in 100). Over 95% of patients come through surgery without significant complications.

How successful is surgery?
Surgery for Parkinson's disease frequently results in a reduction in the symptoms and signs of this condition, and an improvement in quality of life. Some patients are able to return to their previous occupation following successful treatment. Surgery does not return you to "normal" however, and it is important that you understand this before going ahead. Overall, of the patients selected for surgery, around 80-90% will significantly benefit.

How long will the benefits last?
This will vary from patient to patient. Typically, patients obtain a benefit for 5-8 years or longer. The benefit gradually decreases with time (due to progression of the underlying disease). A small proportion of patients may benefit from repeat surgery if the benefits drop off.

What happens when you go home?
You will need to take it easy for 6 weeks. You should do an hour of gentle exercise such as walking, every day or two.

Your GP should check your wounds 4 days after discharge. You should not sign or witness any legal documents until you have been seen by your GP. You will be given instructions about when the staples need to be removed (either by your GP or by the Precision Neurosurgery Practice Nurse).

You will be reviewed after several weeks by your neurologist and neurosurgeon. You should not drive a motor vehicle or operate heavy machinery until they give you the go ahead.

If you have had deep brain stimulation you will also be given some detailed information about things you must avoid, such as metal detectors at airports. It is critical that you read such information thoroughly.

What should you notify your doctor of after surgery?

• Increasing headache
• Fever
• Swelling or infection of the wounds
• Leakage of fluid from the wound
• Fitting (seizures)
• Abnormal sensations or movements in your face, arms or legs
• Weakness or numbness
• Drowsiness
• Any other concerns

The consent process
You will be asked to sign a consent form before surgery. This form confirms that you understand all of the treatment options, as well as the risks and potential benefits of surgery. You should also understand the costs involved with surgery before going ahead, and should discuss this with your surgeon. If you are unsure, you should ask for further information and only sign the form when you are completely satisfied.