A team from Hiroshima University have developed a vibrating device to attach to hand-held surgical tools that has the possibility to improve surgeons’ sensitivity to the various shapes and textures within the body of a patient.

During keyhole surgery, surgeons are reliant on long, thin, metal tools that allow for the reduction of patient scarring and reduce the size of surgical cuts but leave surgeons without the use of their fingers to directly touch patients in order to feel what is happening within the body.

The new device, called the PZT Actuator, attaches to the surgical tool and then vibrates in the surgeon’s palm at a constant rate. The vibrations are far too subtle to be detected but the constant, uniform vibration increases the surgeon’s sensitivity to any other, irregular sensations.

While variations are present while using a metal tool, they are for all intent and purpose undetectable; the actuator’s vibrations however, raise the surgeons’ sensitivity to a point where the varying sensations of the tool touching different tissues will be noticeable.

“We started this work six years ago, trying to enhance human fingertip sensitivity, but in 2012 I had the idea that increased sensitivity could be valuable during minimally invasive surgeries,” said Dr Yuichi Kurita, lead author of the study and associate [rofessor at Hiroshima University.

“ Typical medical tools obtain information about the patient’s condition. There are very few devices that aim to enhance the doctor’s skill.”

In order to test the device, the team blindfolded volunteers and had them use forceps with the actuator attached to identify different textures of sandpaper and find a small styrofoam ball inside a cup filled with silicone. The test was designed to mimic the detection of tissue textures and identifying a solid tumour.

These tests, alongside further analysis, showed that sensitivity is drastically improved within a certain range of vibration intensity. Importantly, this improvement is consistent across users, meaning that the actuator does not need to be refined to each surgeon’s particular sense of touch but, is instead simple to use by anyone.

The safety of the device is also a huge boon; the fact that it remains outside of the patient’s body at all times means that there is no risk to those going through the surgery. Its power supply and the subtlety of the vibrations are further guaranteed as safe for both surgeon and patient.

“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.

The Hiroshima team who put the device together are a combination of medical and mathematical engineers, who originally tested the actuator through mathematical modelling using calculations of four types of neurons and their response to different levels of mechanical stimulation.