As a cardiothoracic surgeon at the Royal Brompton Hospital in London, Richard Trimlett knows a few things about the heart. He and his colleagues in the UK perform 35,000 heart surgeries every year on average.
Trimlett typically begins an open-heart surgery by stabilizing the heart with a suction device. But a minimally invasive procedure called keyhole heart surgery is even more delicate. “The heart is beating during the surgery, but we need to hold this very small area that we’re working on still,” Trimlett says. “We need tools with very small parts that we can pass in and out.”
Trimlett was looking for a new way of doing this when he ran into Alex Berry, the CEO of Sutrue, a design development center that specializes in developing medical instruments used in cardiology. “I asked Alex if he could make something that comes apart in pieces and passes through a very small incision that we could use to hold the heart stable,” Trimlett says. Ideally, he wanted a tool that was customizable by shape and size and also disposable.
Previously, such a combination would have been very expensive, but Berry had a plan. For the past two years, Sutrue has been using a 3D printer called the Mlab cusing, which prints medical instruments from a bed of stainless steel powder, layer by layer. (Last fall, GE acquired a majority stake in Concept Laser, the company which makes Mlab.)
The first tool Sutrue developed was a 3D-printed suture device that would allow doctors to automatically stitch up wounds. The prototype is addressing an important need: Some 240,000 medical professionals suffer needlestick injuries while stitching each year.
Sutrue 3D printed a miniature gear mechanism that lets the curved stitching needle rotate smoothly as fast as three rotations per second. The device can stitch faster than a human and wastes fewer needles. It’s still undergoing trials and is not on the market.
Still, that suturing device impressed Trimlett, and he and Berry soon started printing prototypes of his heart stabilizer. Each version took only about four hours to make, compared with months using standard methods. The tool took just three months to finish, an uncommon feat considering that a new medical tool can take as many as 10 years to develop. “The solution cost an estimated £15,000 to develop,” Berry says. “Comparable developments used to cost upwards of a million pounds.” Like the automatic suture device, the stabilizer still needs to pass tests and approvals.
Next, Trimlett is planning to work with Berry on something even more advanced: a 3D-printed mechanical heart. Previous models were essentially mechanical pumps that perform the function of the heart. But with additive manufacturing, the pumps could be made smaller and could even come complete with electromagnetic functions. “Additive manufacturing always fascinated me, but it is still underestimated today,” Berry says. “It could lead to new thinking in this area, inspiring the experts with the freedom of geometry, miniaturization, short development times, and other benefits that can be exploited even more widely.”
Says Berry: “In principle, any conventional component can be reconceived. Redesign will probably be our consistent theme in the future.”