Peter Berkelman is designing a new, radically different generation of automated operating room assistants
Surgical robots are becoming common in technologically advanced medical facilities. These systems, with extremely sensitive control interfaces, can enhance the ability of physicians to perform complex procedures. Robots have steadier arms than humans, resulting in more accurate motion and more precise surgical procedures. These machines, in particular those made by Intuitive Surgical Corp., have allowed for new procedures that surgeons physically could not perform before. By reducing physician discomfort, the surgical robots have made lengthy operations less physically exhausting.
The basic platform for the prototype robot is an advanced endoscope manipulator Berkelman helped to develop at the University of Grenoble in France, where he pursued post-graduate work. That tool was designed to accurately position a rigid endoscope – a specialized video camera attached to a long, thin rod inserted into the human body to display images of internal tissues on an external video monitor during surgery. The robotic tool allows the physician easily to manipulate and control the endoscope with various hands-free command interfaces such as voice recognition, eliminating the need for an additional surgical assistant to hold the endoscope. The Grenoble system will likely enter clinical testing on human patients within the next year.
To the simple Grenoble endoscope manipulator design Berkelman added motors and fixtures that guide minimally-invasive surgical instruments such as tiny clamps, scalpels and suction tubes. These motors and fixtures can be attached to the endoscope manipulator and operating table by a simple system of metal clamps. The motorized mechanism can rotate and move surgical instruments inside the body cavity with precision and responsiveness more than sufficient for many typical surgical procedures. Data and power cables connected to the motors plug into an electronic control console, which is linked to a standard desktop computer.
A physician can operate the surgical instruments using a simple two-joystick system, and view the procedure via the camera mounted on the endoscope. Graduate student Ji Ma wrote a small, 10,000 line software program that connects the joysticks to the instrument manipulators via the computer. Over the past year, Berkelman and Ma have reduced the robot’s response-time latency to 20 milliseconds. That’s fast enough for surgical procedures such as gall bladder removal or hernia repair. Unlike most complicated precision instruments, Berkelman’s robot requires no calibration or time-consuming initialization procedures.
The robot remains several years away from actual tests on human subjects. Berkelman plans to patent the software and novel parts of his instrument-manipulator design. The market for such products could potentially range into the billions of dollars each year as minimally invasive surgical procedures continue to replace traditional surgeries. The system could also hold great potential for both humanitarian and military organizations, due to its transportability, low cost and ease of use. “It’s cheap enough that you could put one in every operating room,” says Berkelman. Surgeons say more affordable robots are desperately needed. Kenric Murayama, Director of Minimally Invasive surgery at the Queen’s Medical Center in Honolulu, has tested Berkelman’s robot. Says Murayama, “The technology is very good. For certain procedures it increases the ability to do more technically challenging things. It’s a good concept and it’s cheap. It’s really quite promising.”
Peter Berkelman is an assistant professor in the Department of Mechanical Engineering at UH Mānoa. His research interests include haptic interfaces, magnetic levitation, and medical robotics.
Photo: Peter Berkelman, Department of Mechanical Engineering