What are the surgical treatment options for essential tremor?
The National Hospital for Neurology and Neurosurgery in Queen Square has one of the most active functional neurosurgery teams in the United Kingdom. With the recent investment made by the Queen Square Imaging Centre in focused ultrasound equipment, the team is now able to offer patients with essential tremor, the option of all three recognised forms of surgical treatment.
The most widely known therapy among people who suffer from tremor and who do not derive a benefit from medications is that of deep brain stimulation (or DBS for short), a surgical procedure that has been in use for around 30 years. Deep brain stimulation involves the implantation of electrodes within the thalamus (a part of the deep brain), which are in turn connected by means of subcutaneous wires (wires under the skin) to a type of pacemaker-like device, which instead of driving the heart is driving the brain. It’s a neural pacemaker. Although it is described as a ‘stimulator’, what actually happens is the inhibition of a circuit within the thalamus that is driving a symptom, such as tremor.
Queen Square undertakes more deep brain stimulator related surgical procedures than any other centre in the UK.
More recently, there’s been a lot of information going around online about a new form of therapy – MR-Guided focused ultrasound. This is a novel way of performing a lesion in the thalamus, by which we mean we very precisely ablate or kill a small number of cells in the part of the circuit that is causing the abnormal brain activity and driving the symptom of tremor.
To many people, creating a lesion by killing cells may seem like a radical thing to do to treat a disease and improve quality of life. However, the technique of ‘lesioning’ in the thalamus has actually been with us since the 1940s and is used regularly to treat tremor and deliver improved quality of life for patients. Lesions have been made in the thalamus for over half a century using another surgical technique called Radio Frequency Ablation. This technique involves making an incision in the scalp and then a burhole in the skull to drive a probe deep into the brain to the target. A high frequency electrical current is then passed through the brain to the tip of the electrode which heats the tissue around the tip of the probe and causes a lesion. An easy way to understand what happens is to consider how we heat an egg to cause coagulation of the protein in the egg, turning the transparent egg white into the non-transparent egg white. The amount of tissue that is destroyed or ‘ablated’ during a lesioning procedure is absolutely tiny – an area about a quarter of the size of a little fingernail. Compared to the the brain which is 1.5 kilograms in weight, it is really a tiny portion of the brain.
The evolution of MR Guided focused ultrasound has been an exciting development for patients seeking essential tremor treatment, because it takes an old and proven concept, which is that a stereotactic lesion can provide fantastic benefits, but allows us to do this in an incisionless way, with the patient awake and without the need to lift a knife to create an incision or burhole. This means that patients can now find therapeutic benefit for moderate to severe tremor, but without the associated risks (including pain, infection and bleeding) and necessary recovery time following deep brain stimulation surgery, or radio frequency ablation.
Where can I find further information about focused ultrasound treatment?
MR-guided focused ultrasound treatment for essential tremor is now available in Queen Square for private patients. If you are interested in treatment and would like to find out more, please contact our treatment coordinators at firstname.lastname@example.org.
Additional information is also available at https://queensquare.com/services/focused-ultrasound-essential-tremor-treatment/
Professor Ludvic Zrinzo
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