How burning a hole in the brain eliminates a patient’s shaking

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Toronto neurosurgeon Andres Lozano offers his patient, Tony Lightfoot, a foam cup of water and asks him to take a sip.

Lightfoot looks at him uncertainly. "Have you got a raincoat?" he jokes.

He lifts both hands and reaches toward the cup, but his arms do not obey. They shake uncontrollably, and, failing to even grab hold of the cup, he shakes his head. "I can't. I can't do it."

Lightfoot, 68, says holding an open cup of liquid has been "impossible" for long time. He developed essential tremor 15 years ago, and his condition has gradually worsened to the point where he is unable to fasten the top buttons of his shirt, to drink coffee without a straw and even to write his own signature.

But this was before Lozano, of Toronto Western Hospital, and a team of doctors and technicians at the Sunnybrook Health Sciences Centre eliminated Lightfoot's tremor with a groundbreaking procedure that is so far used only in a handful of facilities around the world.

The treatment, conducted on Tuesday as part of a collaborative research trial at Sunnybrook, is a first in Canada, and it promises to profoundly change Lightfoot's life by burning a hole in his brain, destroying the dysfunctional neurons responsible for his shaking.

Essential tremor, the cause of which is unknown, is a common condition that affects as much as 5 per cent of the population. However, only a small number of individuals are affected so severely that they are debilitated by it.

People who do not respond to medication are commonly treated with deep brain stimulation, an invasive procedure that involves drilling into the patient's skull and implanting an electrode that interrupts the tremor-producing neural pathway.

But with the new "scalpel-free surgery," doctors use more than 1,000 concentrated beams of ultrasound to create a permanent hole, about three to four millimetres wide, in the malfunctioning ventral intermediate nucleus, located deep in the central part of the brain. This procedure does not require puncturing the skull, thus eliminating the risk of infection. And since patients are not put under general anesthetic, they are able to offer immediate feedback to let doctors know that they are targeting the right spot.

In a ground-floor room of Sunnybrook, neurosurgery resident Nir Lipsman shaves Lightfoot's head with a plastic razor to prepare him for the procedure. Lipsman and Michael Schwartz, Sunnybrook's head of neurosurgery and the principal investigator of the study, then fit a metal frame over Lightfoot's head, bolting it to his skull.

They walk Lightfoot into a magnetic resonance imaging (MRI) room and lay him down on the brain-imaging machine. Then, they affix the frame on his head to a helmet, which contains ultrasound emitters and a circulating water bath that will prevent his skull from overheating.

In an adjoining room, the research team reassembles around two computer screens. The MRI machine produces loud, angry "grr ... grrr" noises, as it thoroughly maps Lightfoot's brain.

Once the doctors home in on what they believe is the right area, they gently raise the temperature of the ultrasound beams to about 40 degrees Celsius, just three degrees above normal body temperature, and periodically check with Lightfoot to see how he feels. Any tingling sensations or muscle weakness mean that they are off target, and they need to adjust their focal point. By starting at a low temperature, they are able to test whether they are on mark without permanently damaging any brain tissue. Once they are certain they have hit the right spot, they can crank up the temperature to as high as 63 degrees to destroy the neurons.

The doctors proceed with great caution. Burning a hole in the wrong area of the brain could produce disastrous results. And since treating both sides of the brain could have unexpected side effects, such as speech problems, they limit the procedure to only one side of the brain, affecting the dominant side of the body. But so far, having successfully treated four previous patients since the summer, the doctors are encouraged about the safety and efficacy of the procedure.

"This is the start," says Kullervo Hynynen, Sunnybrook's director of physical sciences, who developed the procedure. "This will revolutionize how the brain will be treated in the future."

Beyond treating essential tremor, Hynynen says, the MRI-guided focused ultrasound may be used to treat patients suffering from Parkinson's disease and chronic pain and to eradicate tumours. In the future, he believes that it can be widely used to treat a broad range of ailments.

Frank Winnacott, 78, was the third patient to undergo the new procedure at Sunnybrook. For the first time in close to 40 years, it allowed him to drink from a teacup without spilling. Such a task may seem minor, but being able to do it was nothing short of "pleasure," says Winnacott, who now has full control of his dominant hand. "It was something I was looking forward to."

In the MRI room, Lightfoot is gradually showing signs of improvement. Each time Lipsman checks in on him, his right hand is steadier and steadier. About three hours later, the doctors are satisfied that they have eliminated his tremor almost completely.

Lozano turns to Schwartz. "What do you think? Are we done?" he asks.

"We're done," Schwartz says, grinning.

The two men shake hands in celebration.

The real test, however, comes when Lightfoot steps out of the MRI room and is again asked to pick up the foam cup of water and take a drink.

"I'm still scared," he says. But, miraculously, he picks it up and brings it to his lips without spilling a drop.

"I never, never thought it would happen," Lightfoot says. "This is marvellous."