Parkinson's disease

Surgery for Parkinson’s disease: Deep Brain Stimulation and lesioning

When we refer to ‘surgery’ in Parkinson’s disease it usually refers to Deep Brain Stimulation (DBS).

Deep Brain Stimulation involves placing a wire with electrodes at its tip into one of three target sites in the brain - the thalamus, the globus pallidus or the subthalamic nucleus. A few days after they are connected to an implantable pulse generator (IPG). This small unit is inserted under the skin on the chest wall. When the IPG is turned on the electric pulses stimulate the target area and produce a change in the Parkinsonian symptoms.. 

Before DBS was introduced in the 1980’s the only operation available for Parkinson’s disease involved selectively damaging certain cells in the thalamus and the gobus pallidus called 'lesioning'. While this sometimes relieved symptoms the damage was irreversible and the operation was risky. With DBS the insertion of the electrodes can be checked to confirm that they have been sited correctly and there are further opportunities for ‘fine tuning’ through the IPG. The technical advances which have made this operation possible have been the development of CT and MRI scanning which allow the surgeon to locate the target site with great accuracy. While it is not essential, it is usual for the electrodes to be inserted with the patient awake so that they can provide evidence that the target has been reached.

For several of the people we interviewed who had not had the operation, the possibility of being awake while their brain was being manipulated was enough reason for them to dismiss the very idea of undergoing it.

As Humphrey said, “One does see things in the paper sometimes about an operation involving electrodes in the brain, which requires open-head surgery without anaesthetic. So I don’t want to have that very much, thank you very much. I’d rather have Parkinson’s frankly.” 

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Others however had looked into it and were willing to consider it as a future option, especially if it offered the chance of regaining some of their lost quality of life. Many people's attitude was coloured by having met someone who had had the operation, mostly people who had benefited from it, but in one case someone who was definitely no better if not worse. The operation was known to be very expensive and some people thought that even if they were judged to be suitable for it they might find that there was no NHS funding available where they lived. Alan had actually taken out private health insurance to cover the operation should he need it.
 
Elisabet, who had her operation through Norway’s National Insurance System when she was 65, realised that she was lucky to have been accepted as she knew that they had to make choices and that she would not have been considered if she had been over 70.
We interviewed 6 people who had had DBS. For them the threat of being awake during the operation was more than compensated for by the offer of improvement in their symptoms. In each case they and/or their physicians felt that they had come to the end of the line with drug treatments. Either they had been tried on every possible drug available for Parkinson’s disease and none of them had produced significant improvement or had caused intolerable side effects. Or they had had the disease for many years and had reached a stage when they were experiencing increasingly disabling dyskinesia from the high doses of dopaminergic drugs they were having to take.
So despite the warnings that they would be awake, that it would take all day, that there was a risk that they would not survive the operation, and that they could suffer brain damage, these people agreed to accept the DBS operation. Only Neil who had had a previous operation as part of a trial of a drug known as GDNF was asleep for both operations. All the others found that to their surprise the experience of being awake was not terrible; they remember with interest things that happened in the operation.
A few days after the electrodes had been inserted a second operation, this time under anaesthetic, was carried out to join the wires emerging to the pulse generator which was implanted into the chest wall.
 
In the days following the operation both the patients and their friends and family were amazed and delighted.
Not all signs of their Parkinson’s disease had disappeared. For Stephen what has been important has been the improvement in his quality of life allowing him to remain relatively independent and to be able as a single parent to continue to care for his teenage children. An unexpected and gratifying side effect of Stephen’s DBS is the disappearance of the urinary incontinence which had bothered him before the operation.
Some people have difficulties with their speech following the operation, a symptom which some did not have before DBS. As John described it, “I’ve lost my ability to throw my voice. I found when I’m in company I can’t talk to anybody, nobody hears me. If I’ve got two people I’m out of it.” Neil lost his hearing which he was told was probably the consequence of a sensitive area getting touched during the positioning of the electrode. Elisabet has found that since the DBS she is sometimes totally unable to find a word she wants, but has otherwise had no untoward effects.
One important change which has affected all the people who had DBS was being able, as Elisabet did, to cut down on the amount of medication they have had to take to control their symptoms. In doing this they have mostly succeeded in avoiding the dyskinesia which had troubled them before the operation (also see Other medications for Parkinson's disease and how to manage medication).
 
For Khadim the situation though much improved is not perfect, “They’ve cut it down to half, then they cut it down to another half and that wasn’t enough, I had to go back on to first half, you know, if I go on the full amount then I getting the chorea back in my leg, you know, and the leg starts wobbling about, you know, they go all over the place.”
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In the years following DBS regular hospital follow-up appointments were required to ‘fine tune’ the pulse generator.
Khadim had been given a remote control device which allowed him to turn off his pulse generator at night thus lengthening the life of the battery, which he thought is normally about two years. He also described a system of lights to allow you to recognise when the battery was beginning to run down.
None of the people who had had DBS regretted it, but they realised that they might have to face further deterioration in the future.
Research into treatments for Parkinson’s disease
When Fred was asked what he hoped for in the future he said without much conviction ‘a miracle cure’. In fact on a later occasion he admitted, ‘I would love a miracle cure. But it’s unlikely to happen.’

For most people with Parkinson’s disease the hopes of a breakthrough in treatment looks towards advances in stem cell research. No-one had any idea how this would apply to Parkinson’s disease, but they knew that it is often mentioned when stem cell research is discussed in the media. Most people realised that offers of miracle cures tend to be over optimistic but admit that references to them in the media tended to attract their attention. Jean said that if her professor was to offer it she would be down there immediately as she really trusts him.
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No-one we interviewed raised any of the commonly aired objections to stem cell research.
Neil had been involved in a research project in which he was one of 10 people who were given an operation involving the drug GDNF, made in America. This was in some ways similar to Deep Brain Stimulation but instead of electric pulses the target area was flooded with the drug. The trial was stopped after two years of treatment because of side effects and failure to prove that the positive results were greater than those of the control group of patients. Neil was at first allowed to continue on the medication but eventually his treatment was stopped. He later went on to have DBS which was reasonably successful though he feels no way near so much so as GDNF.
Deep brain stimulation and lesioning are the most common types of surgery for Parkinson's, but researchers are continuing to look into other techniques. Information about other surgical treatments and current research can be found on the Parkinson’s UK website.

Last reviewed May 2017.
Last updated May 2017.

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