Future Directions in Robotic Neurosurgery

In this paper, we highlight promising technologies in each phase of a robotic neurosurgery operation, and identify key factors affecting how quickly these technologies will mature into products in the operating room. We focus on specific technology trends in image-guided cranial and spinal procedures, including advances in imaging, machine learning, robotics, and novel interfaces. For each technology, we discuss the required effort to overcome safety or implementation challenges, as well as identifying example regulatory approved products in related fields for comparison. The goal is to provide a roadmap for clinicians as to which robotic and automation technologies are in the developmental pipeline, and which ones are likely to impact their practice sooner, rather than later.

An intuitive surgical handle design for robotic neurosurgery

Purpose The expanded endoscopic endonasal approach, a representative example of keyhole brain surgery, allows access to the pituitary gland and surrounding areas through the nasal and sphenoid cavities. Manipulating rigid instruments through these constrained spaces makes this approach technically challenging, and thus, a handheld robotic instrument could expand the surgeon’s capabilities. In this study, we present an intuitive handle prototype for such a robotic instrument. Methods We have designed and fabricated a surgical instrument handle prototype that maps the surgeon’s wrist directly to the robot joints. To alleviate the surgeon’s wrist of any excessive strain and fatigue, the tool is mounted on the surgeon’s forearm, making it parallel with the instrument’s shaft. To evaluate the handle’s performance and limitations, we constructed a surgical task simulator and compared our novel handle with a standard neurosurgical tool, with the tasks being performed by a consultant neurosurgeon. Results While using the proposed handle, the surgeon’s average success rate was $$80\%$$ 80 % , compared to $$41\%$$ 41 % when using a conventional tool. Additionally, the surgeon’s body posture while using the suggested prototype was deemed acceptable by the Rapid Upper Limb Assessment ergonomic survey, while early results indicate the absence of a learning curve. Conclusions Based on these preliminary results, the proposed handle prototype could offer an improvement over current neurosurgical tools and procedural ergonomics. By redirecting forces applied during the procedure to the forearm of the surgeon, and allowing for intuitive surgeon wrist to robot-joints movement mapping without compromising the robotic end effector’s expanded workspace, we believe that this handle could prove a substantial step toward improved neurosurgical instrumentation.

Outcome-thinking

I was invited in 2017 to speak about the future to a gathering of some 2,000 neurosurgeons. My opening statement was that patients do not really want neurosurgeons. What they want, I said, is health. For a particular type of health problem, I acknowledged that neurosurgeons are undoubtedly the best solution we have today. But I went on to say that this might not always be so, because fifty years from now, give or take, we will probably look back and think it primitive that we used to cut people’s heads open. I wanted to challenge those present who felt that the future lay only in robotic neurosurgery, because, I said, surgery will surely not be with us in the long run—the health troubles to which neurosurgeons currently devote their energies will in due course be sorted by non-invasive techniques.

Nonlinear Force Feedback Enhancement for Cooperative Robotic Neurosurgery Enforces Virtual Boundaries on Cortex Surface

Surgeons can benefit from the cooperation with a robotic assistant during the repetitive execution of precise targeting tasks on soft tissues, such as brain cortex stimulation procedures in open-skull neurosurgery. Position-based force-to-motion control schemes may not be satisfactory solution to provide the manipulator with the high compliance desirable during guidance along wide trajectories. A new torque controller with nonlinear force feedback enhancement (FFE) is presented to provide augmented haptic perception to the operator from instrument-tissue interaction. Simulation tests were performed to evaluate the system stability according to different nonlinear force modulation functions (power, sigmoidal and arc tangent). The FFE controller with power modulation was experimentally validated with a pool of nonexpert users using brain-mimicking gelatin phantoms (8–16% concentration). Besides providing hand tremor rejection for a stable holding of the tool, the FFE controller was proven to allow for a safer tissue contact with respect to both robotic assistance without force feedback and freehand executions (50% and 75% reduction of the indentation depth, respectively). Future work will address the evaluation of the safety features of the FFE controller with expert surgeons on a realistic brain phantom, also accounting for unpredictable tissue motions as during seizures due to cortex stimulation.