Chinchillas Tested Fancy New Ear Devices to Solve a Centuries-Old Medical Problem
A simple design change could help treat ear infections more effectively.
A new design for an old device might revamp treatments for one of the most common childhood ailments in the United States.
Doctors have given placed metal or plastic tubes in patients’ ears to fight infections since the mid-1800s — but their design (essentially a tiny straw shape) hasn’t changed much since.
Now, a team of researchers wants to give ear tubes a makeover. With a smaller and curvier design, the scientists found that the devices may be less likely to scar eardrums — a current risk for some patients. This simple update also helped prevent bacterial cells from sticking to the tube.
What really sets them apart from their predecessors: These next-generation ear tubes can send antibiotics directly to the infected area — potentially paving the way for lower regiments of doses, according to a new study published in the journal Science Translational Medicine.
Doctors usually give patients ear tubes to stave off stubborn or recurring ear infections, and they’re inserted via a procedure known as a tympanostomy. Since children haven’t yet developed strong immune systems — especially those under 3 years old — they’re significantly more likely to develop chronic ear infections and make up the bulk of tympanostomy patients.
In the United States, around 700,000 pediatric tympanostomies are performed each year, according to the Agency for Healthcare Research and Quality. “It’s the number one surgery for children in the U.S.,” Joanna Aizenberg, a materials scientist at Harvard University and co-author of the new study, tells Inverse.
During the procedure, a doctor inserts a small metal or plastic cylinder into the eardrum to prevent the painful buildup of fluids behind the membrane.
Eventually, dead cells and pus often build up around the insertion site. While this is a relatively routine and safe surgery, the tubes can cause scarring or even hearing loss in a small percentage of patients when removed.
And ear tubes are usually used in combination with oral antibiotics, which “creates antibiotic resistance and a whole range of other issues,” Aizenberg says.
A new approach
Aizenberg and her team set out to create ear tubes that wouldn’t leave behind so much scarring and cellular debris, while also capable of delivering a small dose of antibiotics directly to the infected area. Using an algorithm, the researchers looked for simple geometric design changes that would make it easier to insert or remove ear tubes.
They found that by making the tubes smaller and more curved, they could both stave off infection and dramatically reduce scarring. Specifically, the curvature selectively filters fluids based on hydrostatic pressure.
This allows medicines like ear drops and antibiotics to pass into the ear canal while blocking discharge like pus and clumps of bacteria. “In fact, it creates conditions for bacterial cells not to adhere,” Aizenberg says, “so infection doesn’t take place and the cells do not grow on this tube.”
To test the tubes before they’re used in people, Aizenberg’s chose arguably the world’s most adorable lab rodent: chinchillas. Believe it or not, these luxuriously soft creatures have ear canals that closely resemble the size and shape of human middle ears. As a result, they’re often used in aural research. “It’s a gold standard,” Aizenberg says.
The team noticed that the new ear tubes left no sign of scar tissue in the chinchillas’ eardrums after removal. And they were able to quickly deliver antibiotics right to the middle ear, cutting back on the dose of drugs needed for treatment — an important breakthrough amid a global surge in antibiotic-resistant infections.
Going forward, the algorithm used by the researchers could help improve all sorts of medical tools: In the future, Aizenberg thinks it might assist scientists in designing more effective devices for conditions such as eye infections or hydrocephalus in the brain.
It could also help create custom devices that work best for each specific patient and their condition, she says.
For now, the team will stay focused on their ear tube research — and hopefully, one day help alleviate painful ear infections for hundreds of thousands of children.