U of C surgeons utilize ultrasound in study into less invasive approach to brain surgery

Scalpel-free brain surgery Researchers at the University of Calgary’s Cumming School of Medicine are testing the use of focused ultrasound. Brad MacLeod reports.

Researchers at the Hotchkiss Brain Institute at the University of Calgary’s Cumming School of Medicine are exploring the potential of a new technology that allows surgeons to conduct brain surgery without physically entering a patient’s skull.

Magnetic resonance guided focus ultrasound permits technicians and surgeons to heat and destroy tissue within the brain from outside the patient’s head.

“Like a magnifying glass in the sun, right at the focal point it can get very hot,” said Bruce Pike PhD, Cumming School of Medicine professor. “At the focal point inside of the brain then we can use that as a tool to heat and destroy brain tissue at a very small scale deep inside of the brain without having to open the skull at all.”

As part of the study, surgeons have been conducting thalamotomies on patients with a common movement disorder.

“We’ve been doing a procedure called a thalamotomy. Essentially that means we’re burning a hole in that part of the brain, a very small, rice-sized piece of brain that propagates tremor through various pathways,” explained Zelma Kiss, professor of neurosurgery at the Cumming School of Medicine. “It’s an old procedure in the sense that the surgery’s been around for 50 years but we would do it through a burr hole.”

“The new thing here is it’s an MRI. There’s no cutting of skin, there’s no making any risk of going through the brain to get down there. We literally just apply a high intensity ultrasound in an MRI scanner where we can monitor the temperature. We raise the temperature in that very small area to the appropriate 50 to 60 degrees and that will make a small hole in the brain that then eliminates the propagation of the tremor and his tremor gets better.”

Elias Pharaon, who will celebrate his 86^th birthday in January, is one of seven patients to have participated in the study to date. The senior, who resides in Vernon, B.C., had developed essential tremor and specialists in his home province had prescribed a medication for dementia patients that would likely take his memory.

“If I lose my memory, I’m not going to get it back again,” said Pharaon. “It means I’m with two things now; my hands are shaking and I have no memory.”

The 85-year-old’s condition was so severe that he has been unable to legibly sign his name in nearly five years.

Pharaon asked his family physician for an alternative option and he was referred to the U of C study. After undergoing testing that began in April, Pharaon was selected as a candidate.

“They told me all about the operation procedure,” said Pharaon. “Dr. Kiss told me you’re one of the first ones. She didn’t need to say guinea pig but I knew it, I am a guinea pig.”

After securing his wife’s approval, Pharaon was placed into the MRI tunnel where 1,024 ultrasound transducers were focused on a single spot inside his head.

The patient says the procedure was a resounding success. “I can do anything now. Anything! You name it and I can do it. Anything!,” laughed Pharaon. “I’ve got the shake a little bit but that doesn’t bother me.”

Pharaon says he has started enjoying soup again after a hiatus caused by the fear that his tremors could result in hot liquid landing far from his mouth.

Dr. Kiss says the patients have been monitored closely pre-surgery and post-surgery with an emphasis on neuropsychology assessments, tests of balance and tremor reviews.

The neurosurgeon says magnetic resonance guided focused ultrasound has been approved for treatment of essential tremors but the technology carries the potential for treatment of additional conditions.

“If we can user lower intensity ultrasound to modulate brain activity, monitoring temperature, monitoring a patient awake - doing things, what do they feel? -, that’s very interesting,” said Dr. Kiss. “That potentially has applicability for things like epilepsy, for Parkinson’s, for dementia, for brain tumours. There’s a number of different things that might be amenable to that.”

With files from CTV's Brad MacLeod