Developing micro-robots for the future of neurosurgery

A research team is working to develop micro-robots with unique dexterity capabilities. Controlled by magnetic fields, this technology is a departure from the rigid, wired designs of most micro-surgical tools, and could one day be used to perform minimally invasive brain surgery.

The research team is co-led by Dr. James Drake, Surgeon in Chief, Chief of Perioperative Services at The Hospital for Sick Children (SickKids) and Eric Diller, Engineering Professor, University of Toronto (U of T).

“Advancing surgery through an endoscope in the paediatric brain requires miniaturized versatile tools which can be precisely controlled,” explains Drake, who is also a Professor, Department of Surgery, U of T. “This novel concept of using tiny, magnetized tools, controlled by robotic external magnets shows great promise in addressing this need for both paediatric and adult patients.”

Over 700,000 patients in North America are living with brain tumours.  These tumours are the most common form of solid cancer in children, and surgery to remove the tumour is often the first recommended course of treatment. The surgeries can be highly invasive with a long recovery process. Less invasive endoscopic surgery isn’t always possible, primarily because standard endoscopic tools are not versatile enough to remove the tumours while controlling any bleeding.

Building on work by Drake and his team at The Wilfred and Joyce Posluns Centre for Image Guided Innovation & Therapeutic Intervention (PCIGITI), Drake and Diller developed this novel concept of externally magnetically controlled miniaturized neurosurgical tools.

The research team has been developing a prototype with tiny grippers mounted on the end of a flexible wire ‘wrist’ and controlled by external magnetic fields. The tool features magnets on both the gripping forceps and the flexible wrist. As magnetic fields are applied, the tool will either open and close the grippers or move the wrist.

In tests performed on a life-like 3D printed model of the brain with a simulated tumour, the gripper was able to successfully enter the ventricles of the brain and remove the tumour, controlled completely by external magnetic fields.

The researchers are now working on a second prototype of the gripping tool that features a simpler design to allow for more control over the forceps. Compared to traditional surgical robot tools, which are about five millimetres across, these prototype magnetic tools are being developed to be half the size, while maintaining the same dexterity.

“Developing new technology for paediatric minimally invasive surgery, in this case neurosurgery, takes a collaborative team of engineers and surgeons. Our team from PCIGITI at SickKids and the Department of Mechanical and Industrial Engineering at U of T has been very successful in this regard,” says Drake. 

There are still several steps to be taken before these micro-robots are seen in the operating room. The team plans to create more tools, including micro-scissors. They also need to determine the best way to generate magnetic fields in the operating room.

“Our next step will be to join our colleagues at SickKids for a simulation in vivo, which will provide the opportunity to see how these micro-robots will function in the operating room, and to try different ways of setting up the magnetic coils,” says Diller.

The research team’s work, "Design and Comparison of Magnetically-Actuated Dexterous Forceps Instruments for Neuroendoscopy", was published in the Journal, IEEE Transactions on Biomedical Engineering.

This research is supported by the Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Research Council of Canada (NSERC) and SickKids Foundation.