Robots on the brainCALGARY - When Harvey Cushing and William Bovie introduced electrocautery (which uses a high-frequency current to seal blood vessels or make incisions) in 1926, their innovation transformed neurosurgery. Given the precision required to operate on an organ as delicate as the brain, the convergence of mechanical technologies with the art of surgery catalyzed progress in the field.
Neurosurgical advances always pursue minimalism. As in any other surgical field, the less the procedure interferes with the body, the less likely it is to affect the patient’s quality of life adversely, and the sooner the patient will be able to return to normal activity.
This imperative is even more pronounced when it comes to sensitive neurological procedures. Tasks like maneuvering small blood vessels that are one-to-two millimeters in diameter, or removing a brain tumor without damaging the surrounding tissue, require technologies, such as the operating microscope and multimodal imaging tools that complement surgeons’ skills and augment their abilities.
A step further would be to allow a human-controlled robot to enter the brain. Robots are capable of performing repetitive tasks with a higher degree of precision and accuracy than are humans without muscle fatigue. And they can also be upgraded periodically to integrate new features seamlessly.
What robots lack is the human brain’s executive capacity. Given that comprehending - and reacting appropriately to - the immense number of variables that can arise during surgery would require enormous computing power, surgical robots aim to integrate human experience and decision-making ability with mechanized accuracy.
One example of this convergence is neuroArm, developed by my research team at the University of Calgary in conjunction with engineers at MacDonald, Dettwiler and Associates. The neuroArm actually has two arms, which can hold various surgical tools while the surgeon maneuvers them from a remote workstation.
The workstation provides a multitude of data - including magnetic resonance imaging (MRI), a three-dimensional image of the surgical field, sonic information, and quantifiable haptic (or tactile) feedback from tool-tissue interaction - that enable the surgeon to experience the surgery through sight, sound, and touch. Because the human brain makes decisions based on sensory input - and, of course, experience - such data are essential for the surgeon to make the most informed choices possible during surgery.
Technologies like MRI can help in surgical planning, resection control, and quality assurance. Magnetic-resonance-compatible robotics allow for real-time imaging, providing information about anatomical structures and changes in the brain relative to surgical pathology while operating, thereby minimizing risk.
Given that the robot receives the MRIs and provides haptic feedback, electronic highways or surgical corridors can be established before the procedure, as can “no-go” zones. Tool manipulation can thus occur only within the predetermined corridor, preventing unintended injury to the brain.
Furthermore, robotic surgery has the potential to progress beyond the scope of unaided human capability. Motion scaling - which allows the robotic arms to mimic the exact movements of the surgeon’s hands but on a much smaller scale - will enable surgeons to manipulate tissue that is too small for the naked eye to detect. With the development of smaller microsurgical tools and high-performance cameras and monitors, operating at the cellular level will be possible.
A related area with important implications for neurosurgery is virtual reality. Building on simulation technology, virtual reality will allow surgeons to rehearse procedures, including with surgical robots, in a digital environment. The ability to map out complex cases and practice rare procedures before performing them on a patient will undoubtedly lead to better surgical performance and improved medical outcomes.
Virtual reality will also enhance surgical training by providing students with a wider range of experience and enabling quantification of their performance. Surgeons operating manually know how much force they exert only by the way it feels; a surgical simulator, by contrast, could measure that force and indicate when a trainee is applying excessive or insufficient pressure.
Moreover, instructors will be able to program controlled scenarios to assess how a trainee copes in challenging circumstances. The ability to reset and retry surgeries without any risk or additional cost will enhance neurosurgical training significantly. After all, practice makes perfect.
To be sure, virtual reality remains a relatively young technology. Given that realistic neurosurgical simulations, which must account for a large number of variables and potential outcomes, are particularly difficult to develop, virtual reality is not yet being used widely in the field. But surgical-simulation technology is advancing rapidly, bolstered by developments in parallel computing. As these simulations become more realistic, their training value will increase.
The merging of human surgical experience with machines and computerized technologies is driving neurosurgical advancement, with robotic surgery serving as an important model of the benefits of the human-machine interface. Add virtual reality to the equation and the future of neurosurgery takes shape; a future in which the discipline is elevated to new levels of excellence.
Copyright: Project Syndicate, 2013.
* The author is a professor of neurosurgery in the Department of Clinical Neurosciences at the University of Calgary, Canada.
by Garnette Sutherland