Toward tissue-engineering of nasal cartilages.

Nasal cartilage pathologies are common; for example, up to 80% of people are afflicted by deviated nasal septum conditions. Because cartilage provides the supportive framework of the nose, afflicted patients suffer low quality of life. To correct pathologies, graft cartilage is often required. Grafts are currently sourced from the patient's septum, ear, or rib. However, their use yields donor site morbidity and is limited by tissue quantity and quality. Additionally, rhinoplasty revision rates exceed 15%, exacerbating the shortage of graft cartilage. Alternative grafts, such as irradiated allogeneic rib cartilage, are associated with complications. Tissue-engineered neocartilage holds promise to address the limitations of current grafts. The engineering design process may be used to create suitable graft tissues. This process begins by identifying the surgeon's needs. Second, nasal cartilages' properties must be understood to define engineering design criteria. Limited investigations have examined nasal cartilage properties; numerous additional studies need to be performed to examine topographical variations, for example. Third, tissue-engineering processes must be applied to achieve the engineering design criteria. Within the recent past, strategies have frequently utilized human septal chondrocytes. As autologous and allogeneic rib graft cartilage is used, its suitability as a cell source should also be examined. Fourth, quantitative verification of engineered neocartilage is critical to check for successful achievement of the engineering design criteria. Finally, following the FDA paradigm, engineered neocartilage must be orthotopically validated in animals. Together, these steps delineate a path to engineer functional nasal neocartilages that may, ultimately, be used to treat human patients. STATEMENT OF SIGNIFICANCE: Nasal cartilage pathologies are common and lead to greatly diminished quality of life. The ability to correct pathologies is limited by cartilage graft quality and quantity, as well as donor site morbidity and surgical complications, such as infection and resorption. Despite the significance of nasal cartilage pathologies and high rhinoplasty revision rates (15%), little characterization and tissue-engineering work has been performed compared to other cartilages, such as articular cartilage. Furthermore, most work is published in clinical journals, with little in biomedical engineering. Therefore, this review discusses what nasal cartilage properties are known, summarizes the current state of nasal cartilage tissue-engineering, and makes recommendations via the engineering design process toward engineering functional nasal neocartilage to address current limitations.