UW News

November 19, 1997

New simulator technology to give surgeons ‘feel’ of really operating

Surgical students soon will be able hone their skills with simulators that for the first time present a realistic feel of performing surgery thanks to a research project under way at the University of Washington. The project also could improve patient care by leading to the development of instruments that enhance surgeons’ sense of touch.

A team of engineers and surgeons at the UW has been awarded a $500,000 grant from the Defense Advance Research Projects Agency to develop technology for precisely measuring the forces and torques involved in performing various surgical procedures. These measurements will be programmed into training simulators with force-feedback technology so that surgeons and medical students can learn exactly how it feels to execute a procedure correctly before they perform it on live patients.

“These enhanced surgical simulators have the potential to drastically reduce the time and cost involved in training surgeons and to improve performance,” says Dr. Mika Sinanan, associate professor of surgery, who is co-directing the project along with Blake Hannaford, associate professor of electrical engineering.

More than 90 percent of surgical skills training currently is done in the operating room. Resident surgeons learn procedures by assisting in hundreds of operations under the supervision of teaching doctors. This form of training is expensive (costing up to $24 per minute), time-consuming and creates inefficiencies in the provision of surgical care.

It would be beneficial, Sinanan says, if resident surgeons could hone their skills before they set foot in the operating room much like pilots learn to fly in simulators before taking to the air. But unlike flight simulators, existing surgical simulators don’t come close to replicating the feel of performing an operation and consequently are of limited value.

One of the problems, according to Hannaford, is that nobody has accurately measured the forces involved in doing surgery. As a result, simulators have relied on subjective impressions from surgeons rather than objective data in attempting to recreate forces such as the amount of pressure that should be applied to surgical instruments for a given procedure or the different levels of resistance offered by healthy and diseased tissue.

“Practicing surgeons know from experience what these forces feel like, but they have never been quantified,” says Hannaford, an expert in force-feedback technology.

To get those measurements, post-doctoral fellows Mark MacFarlane and Jacob Rosen have attached specialized sensors to surgical instruments such as scalpels, graspers and cauterizing tools. In laboratory experiments, the sensors will measure the pressure and torque applied by surgeons to the handles of the instruments as well as the forces acting on the working end of the tools. The experiments also will quantify the force tolerance levels of various tissues in order to establish performance standards.

These measurements eventually will be used to program small motors and sensors to recreate the prescribed forces and performance parameters in surgical simulators. The measurements also could be programmed into ‘smart’ surgical instruments to enhance surgeons’ sense of touch or prevent them from causing injury by exceeding normal tissue tolerances.

The demand for more sophisticated training simulators and ‘smart’ instruments has grown over the past decade with the rise of videoendoscopic surgery. This minimally invasive technique allows surgeons to perform procedures such as gall bladder surgeries and hernia repairs using specialized instruments fitted with tiny cameras that are inserted through small incisions in the body. Videoendoscopic procedures result in smaller scars and faster healing, according to Sinanan, but they require a new set of surgical skills.

“Surgeons used to reach in and feel the tissue or organs with their own hands, but now they’re wearing two pairs of latex gloves and using endoscopic tools that really distort their sense of touch,” Hannaford says. “What we’re trying to do is give that force- feedback information back to the surgeon.”


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