3-D-printed prosthetic implants could improve treatment for hearing loss

December 1, 2017, Radiological Society of North America
Size comparison between 3-D printed prosthesis implant and a penny. Credit: Radiological Society of North America

Researchers using CT scans and 3-D printing have created accurate, custom-designed prosthetic replacements for damaged parts of the middle ear, according to a study being presented today at the annual meeting of the Radiological Society of North America (RSNA). The technique has the potential to improve a surgical procedure that often fails because of incorrectly sized prosthetic implants, researchers said.

Hearing works partly through the transmission of vibrations from the ear drum to the cochlea, the sensory organ of hearing, via three tiny bones in the middle ear known as ossicles. Ossicular conductive hearing loss occurs when the ossicles are damaged, such as from trauma or infection.

Conductive hearing loss can be treated through surgical reconstruction using prostheses made from stainless steel struts and ceramic cups. The surgery, which generally involves tailoring a prosthesis for each patient in the operating room, is plagued by high failure rates.

"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," said study author Jeffrey D. Hirsch, M.D., assistant professor of radiology at the University of Maryland School of Medicine (UMSOM) in Baltimore. "If you could custom-design a prosthesis with a more exact fit, then the procedure should have a higher rate of success."

Dr. Hirsch and colleagues studied 3-D printing as a way to create customized prostheses for patients with conductive hearing loss. The technology has been used successfully to solve a number of other medical prosthesis problems, including in the areas of joint replacement and facial reconstruction surgery.

The researchers removed the middle linking bone in the ossicular chain from three human cadavers and imaged the structures with CT. They employed an inexpensive 3-D printer to create prostheses to restore continuity for each of the middle . The prostheses were made from a resin that hardens when exposed to ultraviolet laser light. Each of the prostheses had unique measurements.

3-D printed prosthesis implant. Credit: Radiological Society of North America

Four surgeons then performed insertion of each prosthesis into each middle ear, blinded to the bone from and for which each was designed. The researchers then asked the surgeons to match each prosthesis to its correct source.

All four surgeons were able to correctly match the prosthesis model to its intended temporal bone—the bone containing the middle and inner parts of the ear. The chances of this occurring randomly are 1 in 1,296, according to Dr. Hirsch.

"This study highlights the core strength of 3-D printing—the ability to very accurately reproduce anatomic relationships in space to a sub-millimeter level," Dr. Hirsch said. "With these models, it's almost a snap fit."

The results suggest that commercially available CT scanners can detect significant anatomic differences in normal human middle ear ossicles, and that these differences can be accurately represented with current 3-D printing technology. More significantly, surgeons are able to detect these differences, which should not only increase the likelihood of a proper fit, but also decrease surgical time, according to Dr. Hirsch.

The next step in the research, Dr. Hirsch said, is to create prostheses out of biocompatible materials. The researchers are also looking at a different approach that would combine the 3-D-printed with .

"Instead of making the prosthesis solid, you could perforate it to be a lattice that allows stem cells to grow onto it," Dr. Hirsch said. "The stem cells would mature into bone and become a permanent fix for patients with hearing loss."

Explore further: Bacterial biofilms identified in ocular prosthesis

Related Stories

Bacterial biofilms identified in ocular prosthesis

August 5, 2015
(HealthDay)—Bacterial biofilms are associated with ocular prostheses, according to a letter to the editor published in the August issue of Clinical & Experimental Ophthalmology.

Mechanical heart valve prosthesis superior to biological

November 12, 2015
A mechanical valve prosthesis has a better survival record than a biological valve prosthesis, according to a large registry study from Sweden's Karolinska Institutet. The finding, which is published in the European Heart ...

Development of prosthetic hands stagnated for 20 years: study

June 12, 2012
The development of body-powered prosthetic hands has stagnated for over twenty years. That is the main conclusion of a study by researchers from TU Delft and the University of Groningen into this type of prosthesis, which ...

Engineers develop a new non-invasive method to detect infections in prostheses

December 14, 2016
Engineers at the University of California San Diego have developed a new non-invasive method to detect infections in prostheses used for amputees, as well as for knee, hip and other joint replacements. The method, which is ...

Recommended for you

DNA gets away: Scientists catch the rogue molecule that can trigger autoimmunity

February 22, 2018
A research team has discovered the process - and filmed the actual moment - that can change the body's response to a dying cell. Importantly, what they call the 'Great Escape' moment may one day prove to be the crucial trigger ...

Low-calorie diet enhances intestinal regeneration after injury

February 22, 2018
Dramatic calorie restriction, diets reduced by 40 percent of a normal calorie total, have long been known to extend health span, the duration of disease-free aging, in animal studies, and even to extend life span in most ...

Fertility breakthrough: New research could extend egg health with age

February 22, 2018
Women have been told for years that if they don't have children before their mid-30s, they may not be able to. But a new study from Princeton University's Coleen Murphy has identified a drug that extends egg viability in ...

Artificial intelligence quickly and accurately diagnoses eye diseases and pneumonia

February 22, 2018
Using artificial intelligence and machine learning techniques, researchers at Shiley Eye Institute at UC San Diego Health and University of California San Diego School of Medicine, with colleagues in China, Germany and Texas, ...

Gut microbes protect against sepsis—mouse study

February 22, 2018
Sepsis occurs when the body's response to the spread of bacteria or toxins to the bloodstream damages tissues and organs. The fight against sepsis could get a helping hand from a surprising source: gut bacteria. Researchers ...

Breakthrough could lead to better drugs to tackle diabetes and obesity

February 22, 2018
Breakthrough research at Monash University has shown how different areas of major diabetes and obesity drug targets can be 'activated', guiding future drug development and better treatment of diseases.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.