Octopus arm inspires robotic surgical tool

Inspired by the octopus arms, scientists have developed a robotic device for surgical operations that can enable surgeons to easily access remote, confined regions of the body.
The device can bend, stretch and squeeze through cluttered environments and can manipulate soft organs without damaging them.
It could reduce the number of instruments, and thus entry incisions, necessary in surgical operations, with part of the arm being used to manipulate organs whilst another part of the arm operates, researchers said.
The device holds a key advantage over traditional surgical tools due to its ability to quickly transform from a bending, flexible instrument into a stiff and rigid instrument.

It has been inspired by the eight highly flexible arms of the octopus which have no rigid skeletal support and can thus easily adapt to the surrounding environment by twisting, changing their length or bending in any direction at any point along the arm.
The octopus can vary the stiffness of its arms, temporarily transforming the flexible limbs into stiffened segments to allow the octopus to move and interact with objects.

To achieve the same effect in the robotic arm, the researchers, from the Sant'Anna School of Advanced Studies in Italy, constructed a device that was made from two interconnecting identical modules.

Each module could be made to move by the inflation of three cylindrical chambers that were equally spaced inside the module.
By alternating and combining the inflation of the three chambers, the module could be made to bend and stretch in various directions.
The stiffness of the two modules could also be controlled by exploiting a 'granular jamming phenomenon' in which a flexible membrane inside the module is filled with a granular media. When a vacuum is applied to the membrane, its density increases and the whole membrane becomes rigid.
"The human body represents a highly challenging and non-structured environment, where the capabilities of the octopus can provide several advantages with respect to traditional surgical tools," lead author of the study Dr Tommaso Ranzani said.

Researchers performed a number of characterisation tests on the robotic device, showing that it could bend to angles of up to 255 degree and stretch to up to 62 per cent of its initial length. The stiffening mechanism was able to provide stiffness increases from 60 per cent up to 200 per cent.
The ability of the robotic arm to manipulate organs while surgical tasks are performed was successfully demonstrated in simulated scenarios where organs were represented by water-filled balloons.
The research was published in the journal Bioinspiration and Biomimetics.