Robot helps hip operations

A pilot study by Imperial College London has shown that a new surgical robot makes medical undergraduates three times more accurate during practice hip operations.

Imperial researchers will address the British Society for Computer Aided Orthopaedic Surgery Conference, reporting results from a pilot study that saw graduates 95 per cent more confident using this robotic technique than when using conventional surgical methods in training.

The pilot study tested whether planning before an operation, combined with robotic navigation equipment could increase the success rates of students practising hip resurfacing arthroplasty procedures - a method for correcting painful hip bone deformities by coating the femoral head with a cast of chrome alloy.

The Navigation Wayfinder, a navigation tool being used for the first time in the UK, works in a similar way to a GPS tracking system. It helps the user to navigate during surgery by plotting correct surgical incisions. It also calculates the correct angles for inserting chrome alloy parts needed to repair hip bones.

It has twin digital arms protruding from a console. One senses the movement of surgical tools as they slice through a patient's hip area. The other takes detailed images of the bones. This information is fed into software which generates a virtual model of a patient's hip as it is being operated on.

Students used model replicas of deformed hip bones for the trial, scanned by the Wayfinder's digital arm. This information was used to create a 3D virtual model of the bone area.

The Wayfinder's computer programme developed an operation plan, setting out the actions required for undergraduates to correct the hip deformity.

Students were asked to carry out a virtual operation on the 3D model of the hip. Using the tool tracking arm, they practised techniques for fastening chrome alloy on virtual deformed hip bones. This built up their confidence, technique and skill.

They then were asked to perform surgery on model casts of real hip bones. By using the Wayfinder to help them navigate, undergraduates were able to attach a post to the centre of the femoral head and thread it, via a guide wire, to the femur.

The second method required students to operate using an optical navigation device. A camera and pinpoint lights were used to create an image of the hip on a computer screen. This was used by undergraduates for visual navigation during the procedure.

Clinical trials using the Wayfinder are currently being carried out at Warwick Hospital, Bath Hospital, Truro Hospital and the London Clinic.