Federal Laboratory for Materials Testing and Research
Dübendorf, St. Gallen und Thun, 28.11.2022 – People with hearing loss whose auditory nerve is still intact can often be helped by a cochlear implant. But inserting the implant into the inner ear is not without risks, as it can damage the facial nerves. Empa researchers have developed a new type of “smart” drill that minimizes this risk by automatically shutting off near nerves.
“Advanced manufacturing” methods can also lead to remarkable advances in surgery. A group of researchers led by Stefan Weber from the “ARTORG Center for Biomedical Engineering Research” at the University of Bern has developed a robot capable of placing cochlear implants more gently than a surgeon. “When a surgeon performs the operation, he has to remove relatively large areas of the skull,” Stefan Weber explained in an NZZ article. It is only when he sees where the nerves are that he puts the drill in place. The robot, meanwhile, only drills a channel 1.8 millimeters in diameter, the route of which is determined using a scanner made beforehand.
But surgeons cannot drill at random, because the hole for the cochlear implant must be exactly between the taste nerve and the facial nerve. These nerves are only 3 millimeters apart and must not be damaged in any way. Until now, surgeons helped themselves like this: They stopped the drill just before the narrowing and irritated the facial nerve with an electric tip. If the twitch of the patient’s face is not too strong, it is possible to continue drilling carefully.
Drill and stimulator in one
The doctors at the ARTOG center approached Empa with the following question: Could a drill not be developed which at the same time electrically stimulates the facial nerve, a drill which would therefore indicate its position in the patient’s skull? Kerstin Thorwarth from Empa’s “Surface Science & Coating Technologies” lab got to work. Together with a colleague, she developed a drill bit with a conductive tip as part of a master’s thesis and an Innosuisse project. The conductive and insulating hard layers of titanium nitride (TiN) and silicon nitride (Si3N4) were applied to the drill head by magnetron sputtering. To do this, the various turns of the wick had to be covered with special masks.
Not yet certified for medicine
The drill with the special surface developed at Empa finally had the right electrical properties and also successfully passed the laboratory tests for drilling into bone material. The partners in Bern were in any case satisfied. “The smart-drill for cochlear surgery could, for example, also be used for spinal surgery,” says project manager Stefan Weber optimistically.
The Empa research team and the surgeons in Bern are now looking for an industrial partner who can manufacture the smart-drill in accordance with the legal requirements for medical devices. “This will require further significant development efforts,” explains Stefan Weber. And that still requires adequate funding.
Address for sending questions
Dr. Kerstin Thorwarth
Surface Science & Coating Technologies
Such. +41 58 765 4547
[email protected]
Writing / Media contact
Rainer Klose
Communication
Such. +41 58 765 4733
[email protected]
Auteur
Federal Laboratory for Materials Testing and Research
http://www.empa.ch