A custom-made cartilage ear implant that decreases complexity and operative time of facial surgeries, creating a state-of-the-art, high-precision cartilage milling process.
The ear is a critical, identifying feature of the human face, and its deformity can have profound effects on self-confidence and psychological development—as well as carrying functional problems, like the inability to wear prescription glasses. Ear anomalies can occur by either congenital causes (microtia and anotia) or acquired injury (e.g., trauma, bites, burns, or malignancy), affecting both children and adults.
Unfortunately, reconstructing the ear is particularly challenging due to its complex 3D geometry. Existing options carry significant disadvantages: the gold-standard technique involves harvesting the patient’s ribs and sculpting them into an ear, which is very technically demanding, time consuming, requires several stages, and creates considerable donor-site morbidity. The alternative is using a synthetic ear implant that is placed under the skin, which carries its own risks of exposure, severe infections, and full ear loss.
Bioengineering solutions proposed to date have not resulted in clinical translation mostly due to the lack of structural support and ultimate resorption. A better solution is needed.
Our innovation is called REPLICA: an off-the-shelf, implantable ear framework made of pre-processed human cadaveric rib cartilage, sculpted into its final ear shape using a high-precision 3D freeze-micromilling process (3DFM).
This ear reconstruction alternative combines the advantages of biologic cartilage (biocompatibility, integration, relative resistance to infection and ischemia, and structural support) and synthetic materials (customization, ease of use, and lack of donor site). The cartilage ear framework could be made patient-specific to resemble the contralateral ear using imaging or be standardized into set shapes/sizes of ears.
At the time of the operation, the surgeon would obtain the shaped cartilage ear and implant it in the standard approach used for current procedures. The human cadaveric rib cartilage (HCRC) utilized is already commercially available and proven safe for facial surgery.
Advantages to our approach would include: 1) elimination of donor site morbidity, while offering a non-synthetic alternative; 2) reduction in the number of surgeries, decreasing certain risks and cost; 3) reduction in operative time; 4) decrease in technical demand for the surgeon; 5) production of consistent, high-precision, customized shapes; 6) could grant a more widespread access to ear reconstruction procedures; 7) removes concerns of using synthetic prostheses with their associated complications.
The competitive landscape analysis below summarizes key features of this solution, and current competitors working to solve similar healthcare problems.
By the end of the funding period, we will have an improved prototype of our implantable ear made from human cadaveric cartilage using our 3D freeze-micromilling (3DFM) technology, with initial biomechanical and in-vivo data to support it. Our goal is to utilize this data to apply for further grant support (NIH, DARPA, AFIRM) for project development, as well as full patent within one year.
Later steps, after PInCh, will be to develop a strict sterilization process and appropriate manufacturing protocols. Since the cadaveric cartilage that we use as a substrate is already approved and commercialized, we anticipate simplified FDA clearance once we can demonstrate that our sculpting process does not significantly alter cartilage properties. Within the next three to five years, we would aim to create a start-up or license our product to one of the biomedical companies who already commercialize human cadaveric cartilage. Within five years, assuming successful preliminary work, we aim to try it in humans. Scientific publications and presentation of findings in academic settings will be pursued along the process.
"We restore, rebuild, and make whole those parts which nature hath given, but which fortune has taken away. Not so much that it may delight the eye, but that it might buoy up the spirit, and help the mind of the afflicted."
-Gaspare Tagliacozzi (1545 – 1599), referring to Plastic and Reconstructive Surgery
Why is facial reconstruction an important matter, including the reconstruction of ears?
Our face makes us recognizable to others; the representation of our being that allows us to transmit emotion and interact with the world. The ear is a critical, identifying feature, and its deformity can profoundly affect self-confidence and psychological development—as well as carry functional problems, like the inability to wear glasses.
Why not simply make cartilage grow in an ear shape, instead of carving it?
Although scientists have tried to create ears in the lab, none of them have successfully made it to clinical translation due to the consistent lack of structural stability. Under the pressure of the overlying skin, bioengineered or matrix-grown cartilage resorbs within weeks. However, cadaveric cartilage provides lasting structural support.
Are there additional applications for your cartilage 3D freeze-milling technique?
While our initial focus will be on the ear—chosen for its incredible complexity to manually reproduce—our novel process to fabricate customized implants by 3D-sculpting cadaveric cartilage could be used for a wide variety of applications where cartilage is missing or defective. Ears are only the beginning.
Is the human cadaveric cartilage safe? Can it be rejected or be immunogenic?
Fortunately, the main substrate (human cadaveric cartilage) of this project has already been studied in depth. Human cartilage is clinically available and in use, and research has shown no immunogenicity, good tolerance, and stability over time. Regardless, we will work hard to ensure safety and durability before clinical application.