steerable needle removes blood clots
August 9, 2013

Steerable Needle Lets Neurosurgeons Remove Brain Clots

[ Watch the Video: Vanderbilt Scientists Employ Robotics to Fight Brain Clots ]

Brett Smith for - Your Universe Online

When a vein or artery in the brain bursts, the resulting blood leak causes an intracerebral hemorrhage. The pressure on the brain from the hemorrhage can cause severe damage and even death in 40 percent of cases.

In an effort to reduce the damage caused by an intracerebral hemorrhage, a team of researchers from Vanderbilt University has developed a new ‘steerable needle’ that could be used to remove blood from within the brain, according to a new report in the journal IEEE Transactions on Biomedical Engineering.

Current operational procedures for intracerebral hemorrhages are not popular among neurosurgeons because any benefit from such a procedure can be minimized or reversed by damage caused while trying to access the clot. Doctors typically take a wait-and-see approach after administering drugs intended to decrease the swelling around the clot and pressure on the brain.

“When I was in college, my dad had a brain hemorrhage,” said Robert J. Webster III, a mechanical engineering professor who worked on the new system.

Webster said his father’s doctors decided against using an operational procedure to remove the blood clot.

“Fortunately, he was one of the lucky few who survived and recovered fully,” he said. “I’m glad I didn’t know how high his odds of death or severe brain damage were at the time, or else I would have been even more scared than I already was.”

Webster’s interdisciplinary team had been working on a steerable needle system over the past four years. The system was originally intended for operations to remove tumors in the pituitary gland or at the base of the skull. While attending a conference last summer, Webster heard University of Maryland neurosurgeon Marc Simard describe something on his “wish list”: a needle-sized robotic arm that is able to remove dangerous blood clots from the brain.

Having already been working on just such a system, Webster refined his design into a series of nested tubes that allow an operator to navigate a path through the body by extending, rotating or retracting various tubes.

After using a CT scan to determine the location of a clot, surgeons position the robotic arm outside the skull for optimum access. The surgeons then insert the outermost tube into the brain until it reaches the interior of the blood clot, using the CT scan as a guide. A pump draws blood out of the brain like a small vacuum cleaner as the surgeons rotate the tube in an effort to remove as much blood as possible.

According to the study’s simulations, the system is able to successfully remove about 92 percent of a blood clot.

“The trickiest part of the operation comes after you have removed a substantial amount of the clot. External pressure can cause the edges of the clot to partially collapse making it difficult to keep track of the clot’s boundaries,” said Webster.

The Vanderbilt team said they still need to perform additional work on the system and would like to add ultrasound imaging capabilities to the system, which would increase efficiency and safety.