What is essential tremor?
Essential tremor is the most common type of tremor that is not related to Parkinson's disease.

Essential tremor causes difficult-to-control shaking of the hands (one or both), particularly when performing everyday tasks. It can also involve the head and neck, voice, and sometimes the legs.

Essential tremor occurs mainly in the elderly, but may occur in young people. In many cases it may be inherited.

Essential tremor is particularly amenable to surgery.

How is it treated?
Essential tremor is treated in the first instance with medications, such as beta-blockers. These are frequently effective. Unfortunately, the effectiveness of such medications may decrease over a number of years.

When medications are no longer providing adequate benefit, surgery may be of value. The two types of operations most commonly used to treat Essential tremor are deep brain stimulation (DBS) and thalamotomy. Both operations are done under local anaesthetic, and the patient is kept awake so that changes in their tremor during surgery can be used to guide the neurosurgeon to the best target.

Who may benefit from surgery?
Surgery can significantly improve the quality of life for patients with Essential tremor who have failed optimal medical therapy. 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.

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 ET are deep brain stimulation (DBS) and thalamotomy.

What are the alternatives to surgery?
At present, the only alternatives to surgery are medications. You should check with your 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 all of 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 a specific portion of the thalamus (Vim or ventralis intermedius). This is known as thalamic DBS or ‘Vim stim’. The thalamus is a major relay station deep within the brain. DBS works by reducing the activity of this area that generates the tremor.

  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 or reduce tremor. Medication reduction is another frequently seen benefit.

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 the same area within the thalamus by controlled heating.

  More information on thalamotomy for movement disorders

How is thalamotomy 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 75 degrees for 60 seconds). Once this is done, we will sew up 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.

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 (much less than 1 in 100). Over 95% of patients come through surgery without significant complications.

What are the benefits of surgery?
Surgery for Essential tremor frequently results in a reduction in the severity of the tremor. Over two-thirds of Essential tremor pts will experience complete or near complete tremor resolution at up to 8 years following surgery, using either technique.

How long will the benefits last?
This will vary from patient to patient. Typically, patients obtain a benefit for 6-8 years or longer. The procedure can often be repeated if the tremor recurs.

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.