Feature | August 21, 2013

Robot Treats Brain Clots with Steerable Needles

For the last four years, a team at Vanderbilt University has been developing a steerable needle system for “transnasal” surgery

August 21, 2013 — The idea that surgery to relieve the pressure caused by hemorrhaging in the brain is a perfect job for a robotic system is the basic premise of a new image-guided surgical system under development at Vanderbilt University. It employs steerable needles about the size of those used for biopsies to penetrate the brain with minimal damage and suction away the blood clot that has formed.

The system is described in an article accepted for publication in the journal IEEE Transactions on Biomedical Engineering. It is the product of an ongoing collaboration between a team of engineers and physicians headed by Robert J. Webster III, assistant professor, and Kyle Weaver, assistant professor of neurological surgery.

For the last four years, Webster’s team has been developing a steerable needle system for “transnasal” surgery: operations to remove tumors in the pituitary gland and at the skull base that traditionally involve cutting large openings in a patient’s skull and/or face. Studies have shown that using an endoscope to go through the nasal cavity is less traumatic, but the procedure is so difficult that only a handful of surgeons have mastered it.

Webster’s design, which he calls an active cannula, consists of a series of thin, nested tubes. Each tube has a different intrinsic curvature. By precisely rotating, extending and retracting these tubes, an operator can steer the tip in different directions, allowing it to follow a curving path through the body. The single needle system required for removing brain clots was actually much simpler than the multi-needle transnasal system.

The brain-clot system only needs two tubes: a straight outer tube and a curved inner tube. Both are less than 1/20th  of an inch in diameter. When a computed tomography (CT) scan has determined the location of the blood clot, the surgeon determines the best point on the skull and the proper insertion angle for the probe. The angle is dialed into a fixture, called a trajectory stem, which is attached to the skull immediately above a small hole that has been drilled to enable the needle to pass into the patient’s brain.

The surgeon positions the robot so it can insert the straight outer tube through the trajectory stem and into the brain. He also selects the small inner tube with the curvature that best matches the size and shape of the clot, attaches a suction pump to its external end and places it in the outer tube.

Guided by the CT scan, the robot inserts the outer tube into the brain until it reaches the outer surface of the clot. Then it extends the curved, inner tube into the clot’s interior. The pump is turned on and the tube begins acting like a tiny vacuum cleaner, sucking out the material. The robot moves the tip around the interior of the clot, controlling its motion by rotating, extending and retracting the tubes. According to the feasibility studies the researchers have performed, the robot can remove up to 92 percent of simulated blood clots.

“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 goal of a future project is to add ultrasound imaging combined with a computer model of how brain tissue deforms to ensure that all of the desired clot material can be removed safely and effectively.

For more information: www.vanderbilt.edu

Related Content

Arto System Shows Promise as Less-Invasive Therapy for Heart Failure Patients
News | Heart Failure| May 26, 2017
Recent outcomes from the MAVERIC clinical trial confirm earlier positive findings that MVRx’s Arto System safely and...
Edwards Lifesciences Centera self expanding transcatheter (TAVR) valve
News | Heart Valve Technology| May 24, 2017
May 24, 2017 — Late-breaking data presented at EuroPCR 2017 demonstrating excellent clinical outcomes for...
Shockwave Medical Announces CE Mark for Coronary Lithoplasty System and Activities at EuroPCR 2017
News | Cath Lab| May 23, 2017
Shockwave Medical announced last week CE Mark for the company’s Coronary Lithoplasty System for the treatment of...
Abbott recalls its NC Balloon catheters
News | Balloon Catheter| May 22, 2017
May 22, 2017 — Abbott Vascular has initiated a voluntary recall of specific lots of three catheters due to 19 reports
Contego Medical Receives CE Mark for Vanguard IEP Peripheral Balloon Angioplasty System
News | Peripheral Arterial Disease (PAD)| May 17, 2017
Contego Medical LLC announced recently that it has received CE Marking of its Vanguard IEP Peripheral Balloon...
Early Treatment for NSTEMI Patients Shows Greater Rate of Survival
News | Cath Lab| May 16, 2017
An analysis of non ST-elevation myocardial infarction (NSTEMI) patients who undergo coronary revascularization within...
Large Multicenter Study Shows High Success Rate for Robotic PCI Procedures, SCAI, Corindus CorPath 200
News | Robotic Systems| May 16, 2017
The largest real-world study of robotic percutaneous coronary intervention (PCI) demonstrated clinical and technical...
Adept Medical Launches IR Platform, interventional radiology
Technology | Cath Lab| May 16, 2017
Adept Medical announced the launch of the IR Platform, designed as an over-patient work surface for vascular and...
Overlay Init