A Better Way to Connect Arteries How Coulter’s Newest Licensed Product Is Making Its Way from the Classroom to the Clinic

February 27, 2018

Everter team members (from left): Jeffrey Plott, Adeyiza Momoh, Paul Cederna, Hakam Tiba, Brandon Cummings Brendan McCracken, Jon Zwier. Credit: Brandon Baier

When reconstructive surgeons repair a breast after mastectomy or a severely injured leg after a car accident, they often move tissue harvested from one part of the body to another using microsurgical techniques. A new device developed at U-M and supported by the Coulter Translational Research Partnership Program will make it possible to connect arteries in the transferred tissue to those at the repair site in just minutes with a few easy steps. The device, called the arterial everter, looks like a thin silicone pen with a flexible steel spine. It was developed as an accessory for the market’s leading product for connecting vessels, the GEM Microvascular Anastomotic Coupler from Synovis Micro Companies Alliance, enabling it to work as well on arteries as it currently does on veins.
The Arterial Everter & Synovis Coupler
The arterial everter was developed at U-M to allow Synovis’ GEM coupler to connect arteries as easily as it connects veins. To use the coupler, a surgeon slides two cut vessels through a pair of plastic rings, secures each vessel’s end to a series of metal pins, and then clips the rings together. The everter allows surgeons to spread the more muscular arterial walls over the rings and push them securely onto the pins. Credit: Jeffrey Plott

This enhanced usability has long been on many mircosurgeons’ wish lists because of the coupler’s speed, ease of use, and effectiveness in re-establishing venous blood flow from transplanted tissue. However, arteries’ more muscular walls have made them hard to maneuver on the coupler (see image above). This typically requires them to be meticulously hand-sewn and adds significant time to surgery.

Overcoming this barrier, say the everter’s developers, was made possible by the rich ecosystem of biomedical innovation at U-M – one that has taken the device down a carefully crafted pathway, from classroom challenge to Coulter project to industry license.

Bringing Your Problems to Class

This innovation began as an increasing number have in recent years – as a classroom project. U-M’s Plastic Surgery Section Chair Paul Cederna, MD, has long been familiar with the time-consuming and technically demanding nature of hand-sewing tiny, 1 to 3 millimeter arteries in complex tissue transfers. But he’s also a professor of biomedical engineering and knew this was an ideal problem for U-M’s engineering design students.

So, Cederna brought the problem to ENG 490/ME 450, a multidisciplinary design and manufacturing course co-taught by Mechanical Engineering Professor Albert Shih, PhD, to see what solutions might emerge. Cederna further upped the odds of success by convening a crack support team: Jeffrey Plott, then a PhD student in Shih’s lab, to serve as a product-development mentor, plus two fellow U-M plastic surgeons, Associate Professors Adeyiza Momoh, MD, and Jeffrey Kozlow, MD, for clinical guidance, prototype testing and feedback.

The team presented the problem, advised the students and was soon rewarded with a number of potential solutions. By the course’s end, the leading contender could successfully evert artery walls over Synovis’ existing coupler.

Though a breakthrough in function, the design developed in class involved more moving parts than was ideal in the operating room. But, in it, the team saw the seeds of a winning device. With input from the surgeons and students, Plott continued streamlining the concept. When he arrived at a pen-like tool that could spread the cut end of an artery and affix it to the coupler, the team knew they were onto something.


Developing the Everter
The challenge with using the coupler on arteries is that their muscular walls are hard to spread over the device’s rings, often popping off one anchoring pin as the next is attached.
In the class design, a catheter balloon stabilized the artery while a plunger-type tool (yellow) pushed its ends onto the coupler pins all at once. Credit: ENG 490 student team The next version was a rigid plastic tool with a telescoping dilation mechanism and channels that could accept the coupler’s pins with a single push. Though streamlined, it required precise surgical alignment to avoid bending the pins. Credit: Jeffrey Plott The latest design is a flexible tool with a tapered silicone tip that can spread the artery onto the coupler’s pins from almost any angle. The pins pierce through the artery and into the silicone without bending, and the tool’s shaft can be angled as needed. Credit: Carolyn McCarthy

Tapping Coulter, Engaging Industry

Cederna approached his contacts at Synovis to gauge their interest in a product with the potential to enhance the coupler’s usability and – since it would now be ideal for both types of vessels – boost its sales. With their interest piqued, his next call was to Coulter.

“I’d worked with Coulter in the past and knew our team would benefit from their expertise in translating products to the clinical arena,” says Cederna. “I also knew we’d need funding for animal studies to confirm the device could do what we thought it could do.”

Recognizing the everter’s potential, Coulter took the unusual step of submitting the project for approval outside its traditional funding cycle. “This project was unique in a number of ways,” says Managing Director of U-M’s Coulter Program Thomas Marten. “It offered a simple, elegant solution to a clear clinical need. It was an accessory to an existing, market-leading device. And it promised to improve patient care, reduce time under anesthesia and decrease surgical costs. With all this and an industry partner engaged, we were eager to maintain the team’s momentum.”

Coulter approved the project, and its funding allowed Plott and the team to further refine their prototype, generating a device that was easy to both use and manufacture. They knew they’d nailed it when the team connected model arteries in minutes.

Coulter also helped the team engage with Synovis and its parent company, Baxter, to design a pilot animal study to provide the safety and efficacy data the company would need to consider licensing the everter.

The resulting Coulter-funded trial involved plastic surgeons Adeyiza Momoh and Ian Sando, MD, in cutting and reconnecting the femoral arteries in a large-animal model, one side using the everter-coupler combination and the other using traditional hand-suturing. After the initial cases showed that the everter-coupler technique attached the vessels securely without damaging their walls, maintained unobstructed blood flow, and reduced procedure time from more than 20 minutes to just five, Coulter invited representatives from Synovis and Baxter to see the results.

“That was a big day for us,” says Synovis President Michael Campbell. “It’s one thing when you see an idea on the blackboard; it’s another to see that it works. We were excited.”

So much so, that with support from the U-M Office of Technology Transfer, Synovis has just licensed the everter and plans to continue developing it for market.

Product of an “Innovation Ecosystem”

The everter is a great example of how multiple aspects of the U-M environment can come together to support biomedical innovation, says Bryce Pilz, director of licensing for the Office of Technology Transfer. “Projects at U-M benefit from schools that are top in their respective areas, have great researchers, and have also invested heavily in commercializing research, with programs like Fast Forward Medical Innovation at the Medical School, the Center for Entrepreneurship at the College of Engineering, and the Coulter Program that spans both.” Along with Tech Transfer, these programs are part of a rich support system that educates faculty about commercialization and helps develop projects to the point that they’re ready for industry.

Coulter is a critical component of U-M’s biomedical innovation ecosystem that helps educate faculty about commercialization and develop projects to the point that they’re ready for industry.

Coulter’s role in this ecosystem is offering financial resources, connections and expertise in product development and regulatory planning to help investigators evaluate their technology’s market potential and develop a product that will be attractive to investors.

“With the everter,” says Pilz, “Coulter helped the team engage Synovis in preclinical research to de-risk the technology to the point that the company was prepared to license it and invest its own resources in getting the product cleared by the FDA and into the marketplace.”

Such support is essential, says Paul Cederna, in bridging the vast but underappreciated gap between an idea or device developed in the academic world and one that is teed up for industry. “Programs like Coulter are essential in helping us span the ‘valley of death,’ where you’ve created something that works beautifully in the lab but dies while you’re trying to get it into the clinic,” he says. “They not only fund experiments, but things like market analyses and business plan development – activities that granting agencies just don’t invest in.”

It’s this kind of support, he says, that combines with U-M’s extensive collaborations across medicine and engineering to make biomedical innovations like the everter possible.

Results from the everter study were recently published in the Journal of Reconstructive Microsurgery. In addition, the device has won national recognition in the Create the Future Design Contest and with a Baxter Young Investigator Award.


Funding for the arterial everter was provided by the Coulter Translational Research Partnership Program. The program provides funding, expertise, and comprehensive support to accelerate the development of U-M technologies into new products that improve health care. Details at: coulter.bme.umich.edu.