By substituting mechanical instruments for human fingers, robotic tools give surgeons a new way to perform medical procedures with great precision in small spaces. But as the surgeon directs these tools from a computer console, an important component is lost: the sense of touch.
Johns Hopkins researchers are trying to change that by adding such sensations, known as haptic feedback, to medical robotic systems. "Haptic" refers to the sense of touch.
"The surgeons have asked for this kind of feedback," says Allison Okamura, an associate professor of mechanical engineering at Johns Hopkins. "So we're using our understanding of haptic technology to try to give surgeons back the sense of touch that they lose when they use robotic medical tools."
Okamura is a leading researcher in human-machine interaction, particularly involving mechanical devices that convey touch-like sensations to a human operator. In recent years, she has focused on medical applications as a participant in the National Science Foundation Engineering Research Center for Computer-Integrated Surgical Systems and Technology, based at Johns Hopkins. With funding from the National Institutes of Health and the NSF, she has established a collaboration with Intuitive Surgical Inc., maker of the da Vinci robotic system used in many hospitals for heart and prostate operations.
In the da Vinci system, a surgeon sits at a computer console, looks through a three-dimensional video display of the surgery site and moves finger controls that direct the motion of robotic tools inside the patient. Currently, this system does not send haptic feedback to the surgeon to convey what the mechanical tool "feels" inside the body. Okamura's team seeks to add these sensations to the da Vinci and similar machines.
Through the arrangement with Intuitive Surgical, Okamura's lab has acquired da Vinci hardware and software that allow her to conduct experiments toward achieving that goal. For example, the da Vinci's tools can be directed to tie sutures, but if the operator causes the tools to pull too hard, the thread can break. The Johns Hopkins researchers want the human operator to be able to feel resistance when too much force is applied.
"The sense of touch is important to surgeons," Okamura says. "They like to feel what's happening when they're working inside the body. They feel a 'pop' when a needle pokes through tissue. They can feel for calcification. Their sense of touch helps tell them where they are within the body. In robotic procedures and other types of minimally invasive surgery, surgeons insert long tools between their hands and the patient. This approach has definite medical benefits, but for the surgeon, there's a loss of dexterity and haptic information. It's like operating with chopsticks that have grippers on the end."
To address this, Okamura's team is experimenting with several techniques that could give some of those sensations back to the surgeons. One option is to attach to the robotic tools force sensors capable of conveying to the human operator how much force the machine is applying during surgery. Another idea is to create mathematical computer models that represent the moves made by the robotic tools, and then use this data to send haptic feedback to the operator.
Both approaches have advantages and drawbacks. Force sensors may be highly accurate, but they are expensive and would have to be made of sterile, biocompatible materials in order to to be used in medical robots. Computer models could be less expensive but might not respond quickly enough. "I'm exploring both approaches to see which produces the best results," Okamura says. "The most important thing is that the haptic feedback sent to the human operator must feel right because the fingers aren't easily fooled."
While this research continues, Okamura's team has developed an interim system that instead sends "haptic" information to the eyes. When a surgeon is using a robotic tool to tie a suture, for example, a colored circle follows the image of the tool in the visual display, indicating how much force is being using. A red light may signal that too much force is being applied, and the thread is likely to break. Green and yellow lights may indicate that the right amount of force is being used or that the tool is edging toward excessive force.
Okamura's team has already published a journal article describing an early version of this visual haptic feedback project and is continuing to refine the system.
Phil Sneiderman | EurekAlert!
New dental implant with built-in reservoir reduces risk of infections
18.01.2017 | KU Leuven
Many muons: Imaging the underground with help from the cosmos
19.12.2016 | DOE/Pacific Northwest National Laboratory
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Life Sciences
20.01.2017 | Physics and Astronomy
20.01.2017 | Materials Sciences