Like other printers, it jams
The machine at Children’s looks unremarkable, not much different than an industrial copier. It hums and whirs like a home printer. Peer through the printer’s glass surface while it’s running and you can see a bloblike model taking shape.
Depending on how complex a job is, it can take anywhere from a few hours to an entire day to produce a model. Instead of ink, the printer uses liquid plastics, which cost about 40 cents a gram. The tiniest heart might use about $30 of material; the plastic for a larger heart could run closer to $100. The models are built from bottom to top, each layer a thin plastic shaving on top of the one before.
“You have UV lights on both sides of the printer head,” Krieger said. “While it’s printing, it cures the level that is below. So it really builds it up stack by stack and cures it, so it solidifies and becomes hard.”
(And, no, printer jams aren’t just limited to the machines that spit out paper. “Absolutely, that happens with this printer,” Krieger said.)
Because of the high temperature during the process, models are surrounded with a soft filler material so that they don’t collapse on themselves as they’re being printed. This means that when a job is complete, the finished product looks at first like a warm, gelatinous blob.
“A solid mass, you wouldn’t recognize it at all,” said Kevin Cleary, technical director of the institute’s bioengineering initiative. “It’s like a diamond before you polish it up. Then you put it in a bath or in a power-washing machine to scrub it out.”
After the cleaning process, the model is complete.
The team at Children’s is making models in all colors, sizes and textures. The beige model of an infant’s heart is walnut-size and hard as a clamshell, while a much larger heart model — representing a 24-year-old patient — is jet-black and rubbery. Sometimes doctors choose different colors and textures so they can better examine distinct anatomic qualities. In other cases, the choices are purely aesthetic.
“You can print with different colors, different materials,” said Kim. “Some of them are transparent and see-through. You can use different materials from hard to soft to silicon.”
Though the possibilities of 3-D printing are enormous, the technology is still new, and it’s expensive. The printer at Children’s cost about $250,000. A high-end ultrasound machine can cost about $270,000, and a portable CT unit is about $550,000, according to Laurie Hogan, the director of radiology services at Children’s.
Making 3-D models is also time-consuming. Just prepping ultrasound images for the printer can take many hours.
“The very first one I did was not even recognizable as a heart, and it probably took me like 25 hours to do,” Olivieri said.
Although Johns Hopkins Hospital uses 3-D printing to make models of skull plates to prep for reconstructive surgeries, it doesn’t have a printer on-site, instead partnering with medical modeling companies. Other area hospitals, such as MedStar Georgetown University Hospital and George Washington University Hospital, don’t use 3-D printing at all.
But doctors at Children’s believe the investment — in time and money — is worth it.
“Complex congenital heart disease, thank goodness, is fairly rare,” Olivieri said. But “this is something that’s going to really help us take care of them.”
For Olivieri, there’s also the thrill of being on the cutting edge.
“Not that long ago, people with congenital heart disease didn’t even survive,” she said. With new surgical techniques, and now 3-D printing, “I don’t even think we now realize what it’s going to be, what impact that will have.”
LaFrance is a writer based in Washington and New York. Her husband is a pediatric cardiology fellow at Children’s, but he is not involved in the 3-D printing project.