Thursday, August 30, 2018, marks the 100th Sunnybrook patient being treated using MRI-guided focused ultrasound for essential tremor. It is a procedure that Sunnybrook brain scientists pioneered in 2012.
Essential tremor causes debilitating tremors in a person’s arms and hands.
MRI-guided focused ultrasound targets a thousand beams of ultrasound energy on a precise location of the brain using a specialized helmet. These beams generate heat and cause a lesion, which disrupts a pathway in the brain associated with a particular condition, in this case, essential tremor. It is a non-invasive procedure that does not require cutting into the brain to treat areas deep inside it.
In 2016, Health Canada and the Food and Drug Administration in the United States provided approval for the scalpel-free procedure for essential tremor.
Dr. Michael Schwartz was the principal investigator in this world first study. Since the first patient six years ago, he says there have been interesting discoveries along the way that are helping to pave the way for more precise care in the future.
How do you feel about reaching this milestone?
It’s very exciting. Sunnybrook treats one of the larger number of these patients in the world and since Kuellervo Hynynen, who developed and pioneered this procedure, is here, it’s good to be part of the excellent team that we have. It’s a testament to the great work and collaboration that happens here.
Sunnybrook’s unit was one of a very few in 2012 and now, there are 200 centres in the world doing this. One of the things that has changed over time, is that focused ultrasound is becoming the standard method of treating essential tremor.
How can focused ultrasound help patients with essential tremor?
It can be very dramatic. There are people who can’t feed themselves, who can’t even brush their teeth, drink from a glass, everyday things like that. And immediately after the procedure, many patients can do all of those things.
Does this treatment work for everyone?
Over the past six years, we have learned a great deal. It doesn’t work for every patient, but we’ve had excellent results in about half of the people.
About 10 per cent of those with essential tremor whom we treat with focused ultrasound will lose the treatment effect over the first three months. It may be that improvements need to be made in targeting exactly the right place to make the lesion. At the time of doing the procedure, we are likely creating enough of a disturbance that it shuts off some neurons which then survive to produce the tremor as soon as they function again.
The other 40 per cent will lose some of the treatment effect but end up better than they were when they started
One of the things we’re working on is how to choose the target better, so that we can get the lesion in the right place more often.
What are some of the things that the team has learned since the first patient?
We’ve gotten better at it. Me, specifically, I know how to search for the target better than when we started. We’ve become more confident about making larger lesions, so that when we get it in the right place, the effect is more likely to be permanent than it was when we first started.. The software has improved somewhat, and we are still doing investigations ourselves, to determine what can be done to enhance patient outcomes.
How does being a part of this make you feel on a professional and personal level?
Professionally, it’s a chance to be on the cutting edge of a new advance in medicine. On a personal level, it’s really exciting each time to see how we are often able to make a person dramatically better. In some cases, it is difficult to achieve a really good effect, but when it happens it’s exciting for me – every time.
One of the first patients with essential tremor to participate in the original trial sketched a portrait of Dr. Schwartz which was showcased in the spring 2018 Sunnybrook Magazine. It was one of the first she had attempted in nearly 30 years. Dr. Schwartz says, “I was very touched. It was very kind of her to do that. She created a wonderful portrait. It makes me feel very good that she chose to do that.”
Check out this FAQ page on focused ultrasound for essential tremor to learn more about this procedure.
Photos from this exciting milestone
Click images below to expand and view captions