Research Could Prevent Accidents in Minimally Invasive Surgery

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This research focusing on the use of magnetorheological (MR) fluids to provide tactile feedback, funded by the National Science Foundation, appeals to surgeons performing minimally invasive surgeries—and it will make their patients much happier as well.

Greg Washington, associate dean for research at the College of Engineering and professor in the Department of Mechanical Engineering, is conducting this research along with mechanical engineering professor, Stephen Bechtel.

Minimally invasive surgery (MIS) is done through small incisions. Using specialized techniques, miniature cameras with microscopes, tiny fiber-optic flashlights and high definition monitors, surgeons in many specialties can perform surgery through an incision that requires only a stitch or two to close.

This alternative telerobotic surgery interfaces a computer between the surgeon’s hands, controlling a manipulator or joystick, and the instruments on the remote robot. The robot reproduces the surgeon’s movements in real-time. MIS is a preferred surgery when compared to, for example, open-heart surgery, a procedure where the surgeon would saw through the breastbone, pry open a rib cage and physically stop the heart from beating in order to repair valves.

For patients, MIS means less trauma to the body, less blood loss, smaller surgical scars and quicker recoveries. However, MIS can take an unintended turn during the course of a surgery, when doctors do not have the proper feedback from the robotic device.

Washington and Bechtel learned that one of the leading concerns expressed by surgeons who perform this procedure was that their main source of feedback is visual and it comes from scope cameras during the surgery. This feedback has limitations in that it does not notify a surgeon by way of force feedback when tissue or bone is in unintentional contact during the surgery.

Washington’s research is currently investigating the use of MR fluid-based systems as a source of force feedback during MIS. MR fluids are a special class of “smart” materials that produce a resistance force with an applied magnetic field.

“Bones have been broken because the surgeons cannot see them during the procedure,” says Washington. “And there have been lawsuits filed for this reason in the past.”

“During the procedure, when a surgeon would come in contact with a bone or muscle,” says Washington, “this system would send a current producing the appropriate magnetic field to the MR device in the surgeon’s manipulator—the device will then replicate the resistance encountered by the robot at that time.”

For example, if the robot inadvertently comes in contact with bone, the mechanical joints in the surgeon’s manipulator will stiffen and not allow the surgeon to continue with movement until the situation is examined and contact with bone is no longer an issue.

Washington notes that the most common use of MIS, specifically on Ohio State’s campus, is for prostate surgeries because the surgery is done with minor incisions there’s the possibility of less loss of sexual function. One could only imagine the seriousness of a case where unintended tissue could be destroyed during such a surgery.

[ibimage==101==standard_medium==none==self==ibimage_Right]“We want to be able to give tactile feedback to the surgeons to eliminate this sort of “accident” from happening,” says Washington.

MR fluids have been used previously in gaming systems, to mimic force contacted during battle in the video games. Honda and GM have used these fluids as well, for stability control as well as smoothing out the ride on the rough terrain and firming up on smooth surfaces for spirited driving.“

These MR fluid applications could be used in all sorts of other areas as well,” says Washington. “If a team needs to remove contaminants from a nuclear power plant with a robotic system, they may want to have that tactile feeling as well.”

The MR fluid systems, when added to the robot controllers, will not significantly increase the cost of the procedure and Washington notes that patients will be happier in the long run, because eliminating chances of an accident occurring during surgery will guarantee a short-term recovery.