DEAR DOCTOR K: It seems like the latest “hot” new electronics technology is 3-D printers. Do they have any role in medicine?

DEAR READER: 3-D printers already are starting to be used in medicine, and I think we’ll be seeing a lot more of them. These printers are directed by computers to build three-dimensional structures. Designs for the structures are entered into a computer. The computer communicates the shape of the structure to the 3-D printer. Then the printer sprays liquid plastic (which later hardens) in the shape of the structure directed by the computer.

How could this be useful in medicine? In 2014, a hospital in Utrecht, Netherlands, was treating a 22-year-old woman with a rare bone disease. The disease made her skull keep growing thicker. As it grew, it was pressing down on the brain below it, causing severe headaches and reducing her eyesight. If nothing were done, the consequences would be far worse.

Clearly, the thickened areas of her skull had to be removed. That was not a technical challenge. Brain surgeons cut into skull bones as part of doing brain surgery. The challenge was: What do you replace the skull with? You have to replace it; the brain is as soft as jelly. If you take away the bony cap, you’ve got to replace it with something hard and that fits. From pictures of the woman’s skull and brain, the doctors used a 3-D printer to make a hard plastic skull that was shaped just right. They performed the delicate surgery, removing the thickened bone and replacing it with a much thinner and very strong plastic skull. The patient’s headaches went away and her vision returned to normal.

Here’s another example. Some children, because of birth defects or terrible injuries, don’t have functioning hands. Conventional technologies can create artificial hands that the children can learn to control, but they are very expensive. Moreover, children grow – and keep outgrowing their artificial hands.

Already, 3-D printers are being used to create such artificial hands, at much less expense. One example was reported in the Wilmington, Delaware, News Journal in 2015. Colin Consavage, a 10-year-old boy, was born with a shrunken hand, locked in a fist. He couldn’t use it.

Colin heard about 3-D printers and found a website for a global community dedicated to using 3-D printers to create artificial hands, called e-NABLE. Colin now has a hand. The first thing he did with it was pick up a can of potato chips – something he had never been able to do before. He even recently won an arm wrestling contest with it.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115