The Department of Energy's massive environmental cleanup operations have something in common with delicate eye surgery. Both will benefit from computer software that can control robots. DOE's Sandia National Laboratory developed SMART software Sequential Modular Architecture for Robotics and Teleoperation. This software is used to control mechanical robot arms that can be used for cleanup functions inside underground storage tanks containing radiological material and hazardous chemicals. The copyrighted software receives information from sensors attached to the robot arm and can scan to create maps of the storage tank. Since humans cannot go inside the tanks, the sensors are essential for helping robot operators avoid collisions as they control a robot's movements within a storage tank.
Steve Charles, a vitreoretinal surgeon, mechanical engineer, and founder of MicroDexterity Systems, already knew the potential that robots, which are excellent with precision motion, held for microsurgery. So when he learned about Sandia's robotics expertise and SMART technology for detecting objects in underground storage tanks, Charles realized the system could be modified to detect delicate areas of the eyes, ears, and brain during surgery. Now, MicroDexterity Systems has a CRADA—Cooperative Research and Development Agreement—with Sandia so they can work together on the computer technology and mechanical devices necessary for performing microsurgery. The CRADA gives Charles the short cut he needs to avoid having to start building his robotics microsurgery technology from scratch, but at the same time, DOE will benefit from what Sandia learns during the course of the project that can be applied to environmental remedation.
Using current microsurgery methods, a surgeon views the patient's eye through a microscope and uses tiny probes, cutting tools, and other surgical instruments. The surgeon's challenge is in manipulating the instruments to carry out precise maneuvers in a confined space. Even small inadvertent movements by the surgeon or patient can seriously complicate a procedure. As Alan Morimoto, a mechanical designer with Sandia working on the project points out, "When you're holding a pencil, you may not see a lot of movement, but under a microscope you would." It's the same in microsurgery. Surgeons have steady hands, but they cannot stop all unwanted hand movement or prevent patients from shifting even under anesthesia.
Sandia and MicroDexterity hope to develop a surgeon-controlled micropositioner that could filter out extraneous movements and extend a surgeon's sensory and perceptual capabilities. Using joystick-like controls and the SMART software, the surgeon could control the robot while looking at an enlarged image of the eye on a computer screen. The surgeon's hand movements would result in corresponding movements of surgical instruments held by the micropositioner, only to a much smaller degree. For example, a one centimeter movement of the joystick by a surgeon may shift a probe inside a patient's eye less than one millimeter. Specific movement ratios could be programmed into the system. Through sensors in the micropositioner, signals would be sent to the joystick to allow the surgeon to feel extremely small degrees of resistance from the eye while controlling the robot's movements. Artificial barriers could be created in the software to override unwanted hand movements that could damage eye structures.
The system would also open up a new realm in teaching surgical procedures. Since all the motions and actions directed by the surgeon would first go through a computer, they could be recorded. By pairing the computer playback with video footage of the procedure, it would be possible to create a virtual reality environment that would allow a student to repeat the operation, follow the same motions, and feel the same forces the surgeon experienced during the actual operation. The system also could be used to monitor and evaluate medical students' dexterity to help identify which students are potential microsurgeons.
