Tissue Engineering Auricular Cartilage: A Review of Auricular Cartilage Characteristics and Current Techniques for Auricular Reconstruction

Microtia and anotia are congenital auricular anomalies that negatively impact the psychosocial development of those affected. Because auricular cartilage is a type of elastic cartilage that lacks regenerative capacity, any notable defect in its structure requires a surgical approach to reconstructing the auricle. While there are several reconstructive options available between alloplastic and prosthetic implants, autologous rib cartilage grafts remain the most commonly used treatment modality. Still, this widely used technique is accompanied by significant patient discomfort in a young child and carries additional risks secondary to the traumatic process of rib cartilage extraction, such as pneumothorax and chest wall deformities, and the final esthetic results may not be ideal. To circumvent these limitations, tissue engineering approaches have been used to create a realistic-looking ear that mirrors the complex anatomy of the normal ear. This article reviews the biochemical and biomechanical properties of human auricular cartilage as they relate to design criteria. In addition, a variety of cell sources, biocompatible scaffolds, scaffold-free techniques, and mechanical and biological stimuli are discussed. This review aims to identify knowledge gaps in the literature related to auricular cartilage characteristics and make recommendations to drive the field of auricular tissue engineering.