The patient, who is from Mexico, was born with microtia, a rare birth defect that causes the auricle, or external part of the ear, to be small and malformed (it also can affect hearing in the ear). With more research, company executives said, the technology could be used to make many other replacement body parts, including spinal discs, noses, knee menisci, rotator cuffs and reconstructive tissue for lumpectomies. Further down the road, they said, 3-D printing could even produce far more complex vital organs, like livers, kidneys and pancreases.

“This is so exciting, sometimes I have to temper myself a little bit,” said Dr. Arturo Bonilla, a pediatric ear reconstructive surgeon in San Antonio who performed the woman’s implant surgery. The trial was funded by 3DBio Therapeutics, but Dr. Bonilla does not have any financial stake in the company. “If everything goes as planned, this will revolutionize the way this is done,” he said.

James Iatridis, who heads a spine bioengineering laboratory at Mount Sinai’s Icahn School of Medicine, said that other 3-D printed tissue implants were in the pipeline, but that he was unaware of any other products being tested in a clinical trial.

“The 3-D ear implant is then a proof of concept to evaluate biocompatibility, and shape matching and shape retention, in living people,” Dr. Iatridis said.

Still, the external part of the ear is a relatively simple appendage that is more cosmetic than functional, said Dr. Feinberg of Carnegie Mellon. He cautioned that the path toward solid organs — like livers, kidneys, hearts and lungs — was still a long one. “Just going from an ear to a spinal disc is a pretty big jump, but it’s more realistic if you’ve got the ear,” he said.

The 3-D printing manufacturing process creates a solid, three-dimensional object from a digital model. The technology generally involves a computer-controlled printer depositing material in thin layers to create the precise shape of the object.