3D printing has been hailed as a revolutionary technology in the medical world. Although research is ongoing, it is now possible to print certain types of organs, including skin and bladders. Made-to-measure metal bone implants are now possible, as well as prosthetic hands in new and exciting designs - like this one, based on Iron Man.
Recently, researchers have found a way of using 3D printing to combat hearing loss. Read on to find out more about this unlikely pairing.
Custom-made prosthetic replacement
A major cause of inadequate hearing is damage to three tiny bones in your ear, known as ossicles. They work to transmit sound, and damage to these bones can lead to severe hearing loss. Ossicular conductive hearing loss is treated using prostheses made from ceramic cups and stainless steel struts through surgical reconstruction. However, the failure rate of the surgery is high.
Professor Hirsch explains why the surgery is so unsuccessful:
“The ossicles are very small structures, and one reason the surgery has a high failure rate is thought to be due to incorrect sizing of the prostheses,” He added: “If you could custom-design a prosthesis with a more exact fit, then the procedure should have a higher rate of success.”
In response, researchers have created custom-made prosthetic replacements for damaged ossicles, and can situate them in the middle ear using CT scans. The new procedure was introduced at the Radiological Society of North America by study lead Jeffrey D Hirsch, MD, assistant professor of radiology at the University of Maryland School of Medicine (UMSOM) in Baltimore and his team of researchers.
Professor Hirsch and his team of researchers imaged the middle-linking bone in the ossicular chain from three human cadavers using a CT scan. After they had scanned the bones, they crafted replacement prostheses from resin using a 3D printer. The process aimed to restore continuity for each of the middle ears.
The new prosthetics were then tested by a team of four surgeons, who inserted them into the middle ear of patients. The custom-made resins were designed to exactly fit the dimensions of the bones in each individual's ear. The surgeons found that the prosthetics perfectly matched their intended temporal bones. Impressively, Dr Hirsch notes, this is so unlikely that the chances of it occurring randomly is only 1 in 1,296. Dr Hirsch says that printing the new prosthetics almost allowed for a “snap fit”.
The results show that CT scanners can pick up on notable abnormalities in human middle ear ossicles, and that these differences can be tackled using 3D printing technology. The approach allows for precision, but also significantly reduces the amount of time it takes to design and fit the prosthetics within the ear.
Allowing for Impressive advancements in the field
The custom-made prosthetic replacements highlight a new advancement in the field, made possible through the use of 3D printing technology. The precision that 3D printers offer has again proven impressive in the field of medical technology.