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

Abstract

Microtia and anotia are congenital auricular anomalies that negatively impact the psychosocial development of those affected. Because the auricular cartilage is a type of elastic cartilage that lacks regenerative capacity, any notable defect in its structure requires a surgical approach to reconstruct 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 it carries additional risks secondary to the traumatic process of rib cartilage extraction, such as pneumothorax, chest wall deformities, and the final aesthetic results may not be ideal. To circumvent these limitations, tissue-engineering approaches have been employed to create a realistic-looking ear that mirrors the complex anatomy of the normal ear. This article provides an overall description of the ear’s anatomy and reviews the traditional management options for auricular reconstruction. The biochemical and biomechanical properties of human auricular cartilage are detailed as they relate to design criteria. In addition, a variety of cell sources, biocompatible scaffolds, scaffold-free techniques, mechanical and biological stimuli have been 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.