How a 3D-printed graft could speed healing of ruptured eardrums

In the weeks that followed the 2013 Boston Marathon bombing, doctors saw a flood of patients with a common injury: a ruptured eardrum.

Ruptured eardrums aren’t rare — patients with chronic ear infections or some traumatic injury often develop them. But the influx of cases made it clear to otolaryngologist Aaron Remenschneider, at the time a resident at specialty hospital Massachusetts Eye and Ear, that the standard surgical technique of using a graft to patch up the injury could use an upgrade.

“The techniques used to repair a hole in the eardrum really originated in the 1950s and the materials that are commonly used are taken from the patient,” said Remenschneider, now a physician at UMass Memorial Health.

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In 2014, Remenschneider and a colleague reached out to Wyss Institute biomedical engineer Nicole Black and her mentor Jennifer Lewis to develop a 3D-printed tool that could improve on tympanoplasties, the surgery to fix ruptured eardrums. Together, the group launched a startup called Beacon Bio to advance the technology that came out of their brainstorming sessions: a tiny, synthetic device called the PhonoGraft, which was acquired earlier this month by 3D-printing company Desktop Health as it looks to grow its footprint in health care.

“It was really a very fitting and really perfect relationship between surgeons and engineers to try to address this question from multiple different angles,” said Elliott Kozin, an otolaryngologist and the colleague of Remenschneider’s who helped develop the PhonoGraft.

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Historically, the tympanoplasty was done with a microscope in an operating room, though Kozin said endoscopes have allowed for less invasive procedures for more than a decade. And while the current procedure is reasonably successful, no tissue can conduct sound in the eardrum quite like the eardrum tissue itself. Black and her team researched and tested various biomaterials and designs to try to make that possible.

The PhonoGraft, made of a synthetic biomaterial able to conduct sound like the eardrum, also acts as a medium for the patient’s own eardrum tissue to grow over and repair itself. After the eardrum has repaired itself, the PhonoGraft breaks down within the patient’s body, leaving behind a healed eardrum that ideally works as well as it did before it ruptured.

The PhonoGraft is designed to take the procedure from one requiring general anesthesia to one using local anesthesia, and it could shorten current tympanoplasty procedures from around 150 minutes to 20 minutes of a surgeon’s time, along with eight hours of outpatient care to a single hour.

“We designed PhonoGraft with this accessible aspect in mind, because ultimately, if you can change this procedure from an operating-room-based procedure to a clinic-based procedure you save thousands of dollars on overhead costs to the hospital,” said Black. That would be especially beneficial to uninsured patients or those in rural areas, she added.

Black noted how because of the pandemic, elective procedures such as the tympanoplasty had been canceled to make room in hospitals, only for a flood of patients to start seeking them just as hospitals start to find their footing. In the meantime, the patients that had a perforated eardrum had impaired hearing and were more susceptible to infections in their ear.

And because the PhonoGraft is made from a completely synthetic material, it could be relatively cheap to produce and easier to transport than a device that uses  biological materials like proteins or cells.

“We can think about transporting these devices to other areas of the world relatively easily,” said Black, adding that could “really open up new markets as well with increased transport and shelf stability.”

Black said Desktop Health’s acquisition of Beacon Bio will help the company accomplish her goal from the start: get the PhonoGraft to patients.

“We’re going to have a lot of resources to push this forward — a lot of expertise that we’re going to benefit from, particularly on the marketing and sales side from within Desktop Health,” said Black, who has become vice president of biomaterials and innovation at Desktop Health.

Michael Jafar, president and CEO of Desktop Health, said the company’s investment at such a critical product development juncture will provide Beacon Bio with valuable expertise and infrastructure that could help the PhonoGraft eventually get to market.

The company’s printing capabilities will also allow the PhonoGraft to be manufactured internally, rather than having to outsource production.

Jafar said he’s also hopeful Desktop Health can use the license for the PhonoGraft to not only revolutionize the tympanoplasty space, but to adapt the technologies for other biological purposes.

“I immediately thought of at least five — we know that would potentially be 10 — use cases beyond just the eardrum … that synthetic material and the way it was tooling was very interesting to me,” said Jafar. “I’ll bet we’ll learn a lot about what this property can do in … the body beyond just the eardrum.”

Source: STAT