Robots detect tumour tissue

Canadian researchers have developed a robotically controlled method for finding tumours inside patients’ bodies.

A team from Western Ontario University and Canadian Surgical Technologies and Advanced Robotics (CSTAR) has enabled robots to control the same minimally invasive surgery (MIS) sensing instruments used by surgeons.

The researchers claimed that their specially developed robots can detect tougher tumour tissue in half the time and with 40 per cent more accuracy than a human. The technique also minimises tissue damage.

Surgeons developed MIS techniques and instruments so that procedures that would previously have required a large incision can now be performed through a tiny 10mm cut.

These methods reduce tissue damage and infection compared with more traditional surgery and can reduce recovery times and costs.

Usually, a tumour is first discovered in a patient pre-operatively by using scanning techniques such as magnetic resonance imaging (MRI) and computed tomography (CT). While malignant tissue can be mapped out using these techniques, tissues can shift during surgery, making it hard to rely on the position identified by the scan.

Therefore, surgeons must use gentle pressure (palpation) to confirm the location of the tumour or additional tumours not picked up through scanning.

This technique is especially difficult with MIS because areas in the body are more difficult to access. The surgeon must attempt to feel for harder tissue using long, slim instruments through a very small incision.

Various handheld sensors and grasping instruments have been developed since the mid-1990s for use in surgery. The drawback with these instruments, however, is that they do not in themselves control the amount of pressure used, nor do they position themselves correctly.

Yet, under the control of robots, the researchers demonstrated that tactile MIS sensing instruments could be used with greater success.

For its demonstration, the research team used animal livers for human tissue and 10mm and 5mm blobs of glue wrapped in wire representing tumours. The researchers relied on a torque sensor to measure the force of the palpations.

The researchers claimed that robotically controlled sensing instruments used 35 per cent less force compared to a human-controlled instrument. The team also said that the accuracy of tumour detection was far greater with the robot - between 59 per cent and 90 per cent depending on the robot control method used for palpation.

If developed further, the researchers suggest that this type of instrument would be of particular benefit to surgeons performing lung tumour resection, where tissue often shifts significantly.

The researchers are now making plans to develop the prototype robot for use in real MIS. For this, they will upgrade their design to include a flexible rotating head and a remote centre of motion. They also plan to add an improved interface to help surgeons overcome any fears about using robots in this type of surgery.