In a study at Baltimore’s University of Maryland School of Medicine, researchers have successfully produced prosthetics of the tiny, delicate bones of the human ear using 3-D printing technology. The idea of replacing one of the three bones in the middle ear in order to repair/restore hearing loss is not a new one, but the practice has a low success rate because it is incredibly difficult to produce an exact replica of these bones.

Led by the university’s Dr. Jeffrey Hirsch, an assistant professor of radiology, the research team removed the middle link bone from three cadaver ears and then performed a CT imaging scan of the middle ear. They used the images to design a custom prothesis to fit the gap of the removed bone in each ear, and then 3-D printed it.

Lastly, they conducted a blind test to determine the accuracy of their technique. Four otologic surgeons with no prior knowledge of which prosthetic belonged to which cadaver ear were asked to match them. All four of them were successful in matching all of the prosthetics to the correct ear. “The chances of that occurring randomly are one in 1,296,” Dr. Hirsch told Digital Trends. “We felt this shows our methods to produce a 3D-printed prosthesis captured small, yet meaningful, variances in middle ear anatomy that were detectable by otologic surgeons.”

3D Printing in Medicine published a paper detailing the team’s work.