This flower-shaped electrode promises minimally invasive brain surgeries

Made of gold vapors, this soft and flexible electrode can change the way neurosurgeons perform brain surgeries to treat conditions like epilepsy and dystonia.
Rupendra Brahambhatt
The foldable electrode developed by the EPFL team.
The foldable electrode developed by the EPFL team.

EPFL / Alain Herzog

Scientists at the Swiss Federal Institute of Technology Lausanne (EPFL) have revealed a tiny flexible electrode that can be deployed inside the skull without damaging the brain. It will allow doctors to perform minimally invasive surgeries on patients living with epilepsy and various other brain disorders.

The electrode array is made of gold and a transparent elastomer material and is thin enough to fit in the narrow space between the skull and the brain. In a recently published study, the EPFL team mentions that they have successfully tested the electrode in a pig. 

The main advantage of this device is that it can enter the brain through a small hole in the skull and then expand inside, enabling neurosurgeons to work on a larger surface area (more neurons and tissues) of the brain. Here is how the uncanny electrode works. 

What makes the electrode so special?

When fully deployed, the electrode has six spiral-shaped arms that require a four-centimeter diameter to fully spread. However, that doesn’t mean doctors are required to drill a large four-centimeter hole in the skull to plant the device.  

Before deployment, the rubber-like electrode is first folded and packed inside a cylindrical tube called a loader. This tube then funnels the electrode into the brain through a two-centimeter hole in the skull. Once it reaches inside the skull, the spiral-shaped arms spread fully, and the electrode regains its original shape.

Such everting action is mostly demonstrated by soft robots. “The soft robotics community has been very much interested in this eversion mechanism. The beauty of the eversion mechanism is that we can deploy an arbitrary size of an electrode with a constant and minimal compression on the brain,” said Sukho Singh, lead researcher.

The spiral shape of the electrode also has its own significance. Interestingly, the first prototype of the electrode had straight arms, but during tests, it failed to evenly distribute the electrode and covered less brain surface. 

With spiral-shaped arms, the researchers were able to overcome these limitations, and they were able to successfully deploy the electrode in a pig. The EPFL team believes that their innovation could trigger the development of more such soft and flexible neurosurgery applications that will make complex brain surgeries more accessible and less risky.

The significance of foldable flexible electrodes

This flower-shaped electrode promises minimally invasive brain surgeries
The electrode placed on a human brain model.

Electrodes are implanted inside the skull mostly to perform deep brain stimulation (DBS). During DBS, electrical currents from an external device are used to stimulate those parts of the brain which are not functioning well due to disorders ranging from epilepsy to dystonia and Parkinson’s.

Foldable soft electrodes raise hopes for millions of patients across the globe who are living with the abovementioned medical conditions. This is because, compared to conventional implants, foldable electrodes are less invasive, and they can be deployed in a safer and more convenient manner. 

Plus, their flexible structure allows them to cover more brain tissues with minimum risk to the skull and the brain during DBS. Stéphanie Lacour, senior study author and a professor at EPFL, said, “Minimally invasive neurotechnologies are essential approaches to offer efficient, patient-tailored therapies.”

Lacour and her team plan to continue their research so that soon their electrode and many other similar technologies could be available for humans.   The study is published in the journal Science Robotics.   

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