Fabrication of various body parts has been in evolution for years involving tissue growth biologies and various biomaterial technologies. The latest innovation in this process is that of 3D printing, specifically creating a 3D-printed artificial ear. From the laboratories of Cornell University in New York, work has been published online of this new method of creating a bioengineered ear replacement. Such fabrications would be useful in in children born with incomplete or no ears (microtia) and in those who have lost part of all of their ear from an accident or cancer.
These bioengineered ears were made from a digital 3D image of an intact ear which was fed into a 3D printer to produce an ear-shaped mold. This mold was then injected with a gel material composed of living ear cells from a cow and collagen. Out of the mold comes an instant ear ready for implantation after the implanted cells created a cartilaginous ear in the shape of the mold. The whole process takes about three months, most of which is spent creating the cartilage in the mold after implantation in the backs of rats. Ultimately human cartilage cells must be used for this to transition into clinical plastic surgery use.
How are ears currently made or reconstructed? The options are to either use a prefabricated ear made out of a plastic material (Medpor) or to shape it out of the patient’s own ribs. The use of the patient’s ribs is almost always better long-term but does require a painful postoperative harvest site and a tedious fabrication process that takes an experienced plastic surgeon to do it.Taking the cartilaginous ribs 6, 7 8 and making an ear framework for implantation is a true work of art that takes several hours to do.
Once implanted, an autologous rib framework can create a reasonable looking ear whose final external appearance depends on the quality if the overlying skin. In somes cases, tissue expansion is done before implantation of the rib framework. In others it may be covered by a temporalis fascial flap and skin graft if not enough good skin exists over it. Either way, rib grafts can be successfully used for any type of ear reconstruction.
It is easy to see how a 3D ear created by printing a replica of the patient’s normal ear and grown to this shape after being implanted in a mold has tremendous potential. It would save hours of operative time and the harvesting of the patient’s own ribs. This is not the first time that ears have been grown in the backs of rats and has been done as long as a decade ago. But the 3D printing process and the improvements in cell growth technologies make it likely that that this method of ear reconstruction will transition to human in the near future.
Dr. Barry Eppley
Indianapolis, Indiana