Removing tumors from the inner ear canbe a tricky business, with surgeons often having to remove a largeamount of bone to safely complete procedures. Researchers atGermany's Fraunhofer Institute have created a new tool, likened to arobotic worm, that is designed to revolutionize the process, while loweringthe physical impact of the surgery on the patient.
Modern technology is continuing to expand the number of tools surgeons have at their disposal. In fact, the FraunhoferInstitute itself has been responsible for some ingenious inventions oflate, recently unveiling a robotic device designed to act as a third arm for doctors during procedures.
Its latest work is the NiLiBoRo – aGerman acronym which standards for Non-linear Drilling Robot. The prototype tool is designed to allow surgeons to perform tumor removals from the innerear through a small tunnel, where current methods usually require theremoval of the entire mastoid bone in order for the procedure to becompleted safely.
While devices exist to allow doctors toaccurately drill through bone, the NiLiBoRo is the first tool that'sable to alter its orientation, quite literally turning corners insidethe patient's head. For inner ear surgery, a hole bored by a straightline tool could be no wider than 2 mm (0.08 in) – any wider and therewould be a risk of damaging nerve tissue. Unfortunately, that's toosmall a gap through which to perform the procedure.
The NiLiBoRo's ability to turn cornersallows it to drill a hole 5 mm (0.2 in) wide, which is a spaciousenough tunnel through which to perform surgery. The secret to the design of thelittle robot lies in a series of hydraulic lines that allow it tocrawl forward in a motion similar to that of a real worm.
The device consists of "head" and"tail" sections, similar to a dual carriage articulated bus. Thetwo sections are connected by an expandable, bellows mechanism, andthere are numerous hydraulic lines running from the top of the tool where the drill bit is located, back out to the operating theaterfrom where it's controlled.
Hydraulic fluid is pumped into the rearsection of the device, causing it to expand and lock into placeagainst the surrounding bone. The bellows section is then expanded,pushing the drill-carrying head of the tool further into the bone.Finally, the front section is filled with fluid to hold it in placeagainst its surroundings, at which time the tail section deflates andis pulled forward by the head. The direction of the tool iscontrolled by filling different bladders in the head section withliquid.
"We can alter the robot's directionof travel by adjusting the bladders in the front section." saidproject scientist Lennart Karstensen. "For instance, if we wantedto move left then we fill the left bladder with less fluid than theright, which will cause the robot to veer to the left."
While the NiLiRoBo makes its wayforward, its progress is monitored by the surgeon via anelectromagnetic tracking system that intermittently captures stillimages of the robot using computer tomography. This tracking system, known asEMT, was designed by researchers at the Technical University ofDarmstadt.
The NoLiRoBo is an ambitious, butpotentially highly effective tool. There's a little way to go beforeit'll be ready for use, though, with the current prototype version being fivetimes the size of the planned final version. The team plans tocontinue developing the device, perfecting the technologies involvedas it moves towards a smaller device that is expected to be ready fortesting in two years time.
The research was completed incollaboration with the University of Aachen and the DusseldorfUniversity Clinic. The NiLiBoRo robot is being shown at the Compamedexhibition in Dusseldorf, Germany this week.
Source: Fraunhofer Institute
