The external ear plays an important role in the way sound is captured and channelled into the inner ear. We all demonstrate this instinctively when we attempt to accentuate those properties by cupping our hands to our ears to hear better.
But those who have been born without ears or who have lost an ear through accident know only too painfully the additional aesthetic value of normal looking ears.
A four-year old boy, Kai Sherwood is one of the 1-4 children out of 10,000 born with the deformity known as Microtia. Children with this deformity are born with one ear missing and although the internal ear is usually normal the cosmetic disfigurement can lead to very real emotional and social development issues in later life. His mother observed that even at four years old Kai “is starting to notice he is different from everybody else and people are looking at him. ‘Why does his big brother’s glasses get to sit on his ears and he’s got to wear a band?’”
Fortunately, Kai has benefited from recent extraordinary developments in the use of 3D printers.
The problems with traditional prosthetic ears
Until recently the ultimate in prosthetic ear construction consisted of using cartilage from between the ribs to painstakingly recreate an ear, which was then implanted beneath the skin at the side of the head. The serious disadvantages of this procedure included:
- Difficulty finding donors
- The seriousness and painfulness of the surgery
- The extremely complex and challenging process of shaping a normal, natural looking ear
- Maintaining the health of the implanted tissue
- The discomfort of wearing the current stiff prosthetic ears
- The cost
3D Printers offer a better way
For little Kai Sherwood recent explorations in the use of 3D printer technology have meant that he now has a new ear without having to suffer the usual painful operation. Doctors at the Huntsman Cancer Institute in Salt Lake City, Utah used a 3D camera to create a highly detailed 3D image of Kai’s normal left ear and then reversed the image.
The image was then sent through a powder-based 3D printer to create a multiple layer mould of the ear. Next, the doctors used the mould to create an ear out of silicon, which was then attached to Kai’s head using surgical glue. His new silicon ear is so realistic that it is almost indistinguishable from the surrounding tissue. Unfortunately, Kai will have to have further prints, moulds and ears made for him as he grows but for now he can enjoy life without the stigma of looking abnormal. 
Scientists at Cornell University have been experimenting with taking this 3D printing process a step further. They used a collagen gel derived from animals to form the mould around the image from the 3D printer. Collagen is a structural cell protein commonly found in animal tissue including human tissue. The collagen acted as a scaffold for the 250 million cartilage cells that the scientists injected into the mould.
The mould was placed into a cell culture medium for several days allowing the cartilage cells to form a new much more life-like cartilage based ear around the mould. 
Ultimately, it is hoped that scientists will be able to use a human cell culture in the mould that will retain the ability to grow true living ear tissue thereby removing the need for repeating the implant process as the recipient grows.
Bionic ears—can we rebuild them better than before?
Researchers have also been playing with the possibilities of growing artificial ears around sophisticated electronics. The LA Times reported on experiments at Princeton University where researchers used ink consisting of calf cartilage cells, silver nano-particles, silicon, and an ordinary off the shelf 3D printer to recreate the 3D image.
The silver nano-particles formed a simple radio antenna around which the cartilage grew to produce a natural ear. In time it is hoped that scientists will be able to incorporate electronic sensors connected to the auditory nerves that would allow the full restoration of hearing. Indeed, it is entirely foreseeable that human hearing may even be improved although hopefully for a lower price than what it cost for the six million dollar man.
Come and visit us at https://www.houseofhearing.ca/ — we are always on the lookout for the best solutions for you and your loved ones.
 This story was reported at: http://3dprint.com/56087/3d-printed-ear/