Surgery enters virtual world

Hip replacement outcomes could become far more predictable thanks to a revolutionary virtual surgery system developed by European researchers.

The IST-funded MULTISENSE project combined virtual reality, force-feedback systems, tissue profiling and stereoscopic vision to create virtual patients that mimic the tissue of real patients. Surgeons can now perform a hip-replacement operation on a virtual copy of their real patient.

More importantly, after the virtual surgery doctors can get a read-out indicating the likely success of the operation. This is a major step forward for prosthetic orthopaedics.

“Right now, many implants fail, but for some of them we’ve no definite idea about why they fail,” says MULTISENSE scientific coordinator Cinzia Zannoni, a researcher at CINECA. “The really unique aspect of MULTISENSE is that it will give an indication of if an implant in a particular patient will fail.” Surgeons can then test another implant to determine if that has a better chance of success.

The key to the MULTISENSE system is the Muscular Modelling tool. This is a semi-automatic modelling function that takes data from CT scans to make a virtual reconstruction of an individual patients’ muscle tissue.

“We have to customise the system to model the tissue of the individual patient to get an accurate indication of the probable outcome before each virtual surgery,” says Zannoni.

It’s a very advanced application of virtual reality. Up to now, most medical systems simply replicated specific conditions, like appendicitis, for educational uses. The MULTISENSE system is tailored to specific patients.

The Muscle Modelling system is tied to a haptic, or force-feedback, system. Medical haptics are a vast advance on the feedback system used in the joysticks of games consoles. These devices create the force and resistance of real tissue, so when surgeons make a cut they feel the sensation of real surgery.

Add to that a stereoscopic viewing system and doctors can see, and feel, the surgery during the planning stage.

The haptic and virtual reality systems can also be voice controlled using simple commands. “A doctor would say ’I’m cutting the skin’ or, ’I’m lifting the muscle’, and the haptic system will adjust the force and pressure to suit that stage of the operation,” says Zannoni. It means the operation is as close to reality as is possible with current systems.

The system could prove very cost effective if it reduces the number of implant failures, particularly since predictions indicate that hip implants will grow with Europe’s ageing population.

In the future, MULTISENSE could also be adapted to work in Computer-Aided Surgery. “We designed our system to work at every stage of the operation, from planning to actual surgery. Right now it will be used only for planning the surgery, but if there is a need it could help doctors to perform operations, too.”

This is a growing are in medical science, with doctors increasingly taking advantage of the precision of robotic arms, for example.

The system could also be used for other surgeries, though MULTISENSE currently has no plans to develop them. Currently surgeons are evaluating the prototype. Once that’s completed, Italian company SCS-B3C will commercialise the software and the system. The haptic research will be exploited by a British company,” says Zannoni.