artificial outer ear

The outer ear

Outer ear (pinna) loss can result from cancer or trauma.  Researchers believe that in addition to improving a person’s appearance, artificial (prosthetic) ears can help improve hearing and speech recognition in noisy environments.

The function of the outer ear is to collect sounds for the middle and inner ear to process.  People with outer ear loss may have difficulty hearing and understanding speech.  Researchers at Northwestern University Feinberg School of Medicine in Chicago used models to discover that artificial outer ears improved hearing and speech recognition in the presence of background noise.  The next step for investigators is to conduct similar tests on actual patients with artificial ears.

 
Growing new outer ears

Up to a thousand troops might need an ear, and prosthetics are not a great solution. A rod or other fastener is required to attach them to the head. They don't look or feel natural and they wear out every couple of years. A matching ear grown from a patient's own cells would be a huge improvement.

Using a computer model of a patient's remaining ear, a 3D digital model was created and designed with help from a facial plastic surgeon to make sure the shape and proportions were correct.The resulting model was printed and cast in polydimethylsiloxane, a special silicone compound, to create a mould which was then split along the outer contour, resulting in two pieces.

They take a snip of cartilage from inside the nose or between the ribs and seed the scaffold with these cells. This is incubated for about two weeks in a lab dish to grow more cartilage. When it's ready to implant, a skin graft is taken from the patient to cover the cartilage and the ear is stitched into place.
Scientists  have maintained lab-grown sheep ears on those animals for 20 weeks, proving it can be done successfully and last long-term. They also have grown anatomically correct human ears from cells. These have been implanted on the backs of lab rats to kee
p them nourished and allow further research. But that wouldn't happen with ears destined for patients -- they would just be grown in a lab dish until they're ready to implant.

the above diagram shows the implants wire that keeps them in shape to give them a natural look.
limitations
 A novel way of producing a biological ear scaffold has been hatched the problem will come when it needs to be inserted into the tight skin of the head. The skin on the back of the rat was baggy and so the skin covering was easy.
If the scaffold is not strong enough it would collapse when inserted.
graft rejection might also still be an achillies foot in this discovery and the plethora of drugs that ride along it.
However this issues remain tentaive as we wait for human implants to be approved.