New tool to help surgeons 'feel' what they can't touch

 Scientists have designed a small vibrating device that can be attached to surgical tools to help surgeons 'feel' different shapes and textures in a patient's body that cannot be physically touched.

During minimally invasive surgeries, doctors rely on long, thin, metal tools to explore their patients' bodies.

Such laparoscopic surgeries benefit patients by reducing the size of surgical cuts and minimising scarring, but surgeons can no longer use their fingers to directly touch patients to sense essential information about their organs.

"Typical medical tools obtain information about the patient's condition. There are very few devices that aim to enhance the doctor's skill," said study lead author Yuichi Kurita, associate professor at Hiroshima University in Japan.

The vibrator, called PZT Actuator, attaches to a surgical tool and vibrates in the surgeon's palm at a constant rate. The vibrations are so subtle they cannot be sensed.

However, this constant, uniform vibration enhances the surgeon's sensitivity to other, irregular sensations.

The natural variations of touching different tissues with a metal tool may normally be too subtle for the surgeon to detect, but the constant vibrations supplied by the PZT Actuator boost the sensation to a noticeable level.

Volunteers were blindfolded and asked to use surgical forceps with the PZT Actuator attached to the handle to identify different textures of sandpaper and find a small Styrofoam ball inside a cup filled with silicone.

These tests mimic detecting tissue texture and identifying a solid tumour.
The results of these tests and other analysis showed that there is a range of vibration intensity that significantly improves anyone's sensitivity.

The tool does not need to be fine-tuned to each user's unique sense of touch, meaning the PZT Actuator should be robust and simple to use.

The PZT Actuator remains safe for patients because the device is only on the handles of the surgeon's tools, not inside the patient's body.

The vibrations are so subtle that they do not shake the tool. The electrical power supply is also safe for doctors and patients.

"Our next set of experiments will confirm the usefulness of the PZT Actuator in surgical situations. Before we can give this tool to surgeons, we must also develop a method to maintain good hygiene of the device so it is always safe for patients," said Kurita.