At this moment, there are two types of microsurgery operating at the
limits of their dexterity: ophthalmic surgery in retinal procedures and
some surgical procedures in the middle and inner ear.
Peripheral nerve procedures and some neurosurgeries are close to their limits
as well. A fair number of surgical errors result from these surgeries, Goldfarb
says, since surgeons' motor skills are not accurate enough to do these surgeries
reliably. Telerobotics can enhance surgical dexterity through the employment
of macro-micro robots.
Working on a pentagraph principle, a micro surgeon, attached by wires to
a macro or "master" robot, observes an image of the surgery site
(which could be in the same room or millions of miles away) through stereomicroscopes.
The surgeon grabs a scalpel and moves it around, creating electrical signals
which are then transmitted through the macro-robot to activate the micro
or "slave" robot, which does the actual cutting of tissue.
Once cutting has begun, the micro-robot processes, through computer information
received from actuators and sensors, and "reports" back to the
macro-robot. The surgeon then begins to "feel" the force reflection
of the tissue incision. The actual force felt by the macro-robot could not
be felt by a human; it must be amplified through the computer.
As a preliminary study of this technology Goldfarb has developed a one degree
of freedom macro-micro gripper pair. The micro gripper is a tiny force-reflective
gripper, or hand, designed to enhance microscopic procedures, especially
medical ones.
"You can put this gripper around a little capillary and feel the pulse
and grab different things and see what they feel like. This robot is an
intelligent tool with a computer to control it, not a large sort of autonomous
robot that walks around," he says.
The gripper (micro) robot will have sensors to move it around, and the macro
part of the robot will have an arm, similar to a human arm only shorter
and smaller, through which it will play back the forces the micro-robot
senses.
NASA, which is funding Goldfarb's research, has a special interest in tele-operated
microsurgery.
When the space station goes up and stays for an extended time, a limited
number of crew members will go with it, including a limited number of medical
personnel. If a certain type of surgery is needed in the station, the appropriate
specialist on earth can perform surgery through micro-macro robots.
Goldfarb thinks that his work will interface with an emerging engineering
field, Microelectromechanical Machine Systems (MEMS), the making of tiny
mechanical parts.
"Presently we can make these parts, but we can't put them together
because they are too small. What I'm doing is a way of interfacing with
MEMS.
"Some people think that getting into microrobotics now is like getting
into computers was 20 years ago; there definitely is momentum in this field."
Michael Goldfarb
Assistant Professor of Mechanical Engineering
"Development of a Telemicrorobot for Telemanipulation of a Microscopic
Environment," NASA
-Photo by Billy Kingsley