(CNN) Mia Gonzalez spent the first 3½ years of her life missing out. She had to skip day care and dance classes because she constantly had colds and pneumonia. When Mia could go out and play, she was easily winded and took multiple asthma medications to try to help her breathing.

After about 10 hospital stays, doctors realized that Mia had a malformation in her aorta, the vessel that pumps blood from the heart. The 4-year-old would need an operation to close off the part of her aorta that was putting pressure on her windpipe and making it hard to breathe, swallow and get rid of phlegm when she got a cold.

“We freaked out to go from thinking she had asthma to being told she needed to have open heart surgery,” said Katherine Gonzalez, Mia’s mom. But Mia’s malformation was complicated. The surgeons at Nicklaus Children’s Hospital in Miami, where Mia was treated, might have been apprehensive about the procedure were it not for a new technology: the 3-D printer.

No longer ‘inoperable’

Earlier this year, the hospital got a 3-D printer that makes exact replicas of organs that doctors can use to plan surgery, and even do practice operations. The printer uses images from patients’ MRI or CT scan images as a template and lays down layers of rubber or plastic.

Dr. Redmond Burke, director of pediatric cardiovascular surgery at Nicklaus Children’s Hospital, meditated on the model of Mia’s heart for a couple of weeks. He showed it to colleagues for their input and even carried it around in his gym bag for quick reference.

By Carina Storrs, Special to CNN