Neurovascular team performs novel brain aneurysm procedure

By Elizabeth Benner

In May, the Neurovascular team at St. Michael’s Hospital of Unity Health Toronto performed the first surgery in North America using a novel stent that may simplify surgical treatments for complex aneurysms and decrease procedural risks for the patient.

Dr. Vitor Pereira, a neurosurgeon at St. Michael’s Hospital who specializes in minimally-invasive procedures of brain and spinal cord blood vessels, led the team which included, technologists, nurses, physicians and researchers.


“The challenge of treating complex aneurysms is to have a device that is large and long enough to reconstruct the artery,” says Dr. Pereira. “With previous generations of the stent, we might need multiple devices to treat the same case, which increases the complexity and risk of the procedure. This device has also a coating system that decreases the stroke risk for the patient as well.”

Throughout our bodies, a branching network of vessels distributes blood to keep us alive. A compromised arterial wall can lead to a ballooning of a vessel which swells with blood, called an aneurysm. Aneurysms can be dangerous, especially in the brain, as they can lead to a stroke if ruptured. A brain aneurysm on a large, irregularly-shaped section of artery is often called a Complex Intracranial Aneurysm.

One of the treatments for this condition is to insert an endoluminal stent, a small tube of braided wire often only a few millimeters in diameter, to redirect blood flow out of the aneurysm and allow it to decrease in size. This is done by making a small incision in the artery in the groin and navigating through the blood vessels to the brain using wires and catheters.

For more than two years leading up to the surgical procedure, Dr. Vitor Pereira and his research team at the RADIS lab – short for Robotics, Artificial Intelligence, Dynamic Flow, (Advanced) Imaging, and Simulation – performed numerous experiments that helped inform device engineers  on how to increase the stent’s efficiency.

The stent, ‘Pipeline Vantage’, was manufactured and designed by the medical device company, Medtronic, and went through various improvements such as decreasing the circumference of the wires, improving the deployment system of the stent and incorporating a new surface coating. These changes resulted in an 80 per cent overall improvement compared to the initial prototype.

The RADIS Lab is located at the Li Ka Shing Knowledge Institute at Unity Health Toronto. As the name describes, this team of surgeons and scientists specialize in using advanced technology to develop novel treatments in the neurovascular field. They are building a repertoire of groundbreaking accomplishments, including performing the world’s first robotic-assisted brain aneurysm repair in 2019.

“Translating advanced technologies from bench to bedside is what we do best. Before taking any new technology to the procedure room, we perform numerous experiments in the lab to ensure its safety for patients,” says Nicole Cancelliere, Research Program Manager and Radiographer at the RADIS lab. “We are committed to driving innovation to continuously improve the care we can offer our patients. It’s rewarding to see this new stent technology that we helped develop in the lab being used in the clinical space to treat patients and improve outcomes.”

This fourth generation stent is not yet approved in the U.S., nor are any other North American neurosurgeons trained in it. The first 50 cases treated with the stent are being performed at locations in Europe and Australia, and St. Michael’s Hospital is the only North American unit that has been given permission by the developer and Health Canada to use the product.

“The patient who received the stent had a brain aneurysm which was sending clots to the brain and causing strokes. We admitted him in an emergency setting and we used the novel stent to reconstruct his complex aneurysm. It was a good application for this new technology.” Dr. Pereira says about the first North American patient to receive the stent. “The MRI that we performed after the surgery showed that the stent was well-positioned and the patient was discharged two days later. We are now waiting for the next follow-up which will be in six months.”

A second procedure using the new stent took place in late June and Dr. Pereira will perform a study to compare previous generations of the stent to the most recent version.

Once the initial 50 cases have been performed, a training program is aimed to commence this year for physicians looking to learn the new technique. Dr. Pereira says that training can increase the success rate of the procedure and reduce complications. “It’s a pretty rewarding experience being part of the training of physicians and a new technology like this one. I’m passionate about education and training,” he says.

Elizabeth Benner is a communications intern at Unity Health Toronto