“Injectable Cartilage Micro-tissue Regenerated by Autologous Chondrocytes for Nasal Augmentation: a 5-year follow-up study”

Abstract

Background: A lack of ideal filling materials is a critical limitation in current rhinoplasty. Cartilage sheet regeneration by autologous chondrocytes is expected to provide an ideal source of material. However, the inability to perform minimally invasive transplantation of cartilage sheets has greatly limited the clinical application of this material. Here, we propose the concept of “injectable cartilage micro-tissue” (ICM) based on cartilage sheet technology, with the aim of achieving minimally invasive augmentation rhinoplasty in clinical practice. Methods: Approximately 1.0 cm 2 of posterior auricular cartilage was collected from 28 patients. Isolated chondrocytes were expanded, then used to construct autologous cartilage sheets by high-density seeding and in vitro culture in chondrogenic medium with cytokines (e.g., transforming growth factor beta-1 and insulin-like growth factor-1) for 3 weeks. Next, ICM was prepared by granulation of the cartilage sheets; it was then injected into a subcutaneous pocket for rhinoplasty. Results: ICM was successfully prepared in all patients, and its implantation efficiently raised the nasal dorsum. Magnetic resonance imaging confirmed that regenerative tissue was present at the injection site; histological examinations demonstrated mature cartilage formation with typical cartilage lacunae and abundant cartilage-specific deposition of extracellular matrix. Excellent or good postoperative patient satisfaction results were achieved in 83.3% of patients over 5 years of follow-up. Obvious absorption of grafts only occurred in two patients (8.3%). Conclusions: These results demonstrated that ICM could facilitate stable cartilage regeneration and long-term maintenance in the human body; the implantation of ICM enabled natural augmentation of the depressed nasal dorsum.