Histomorphological Findings of Cartilage and Surrounding Tissues According to Thickness and Manipulations in Rabbits.

[BACKGROUND] Costal cartilage is commonly employed as a dorsal implant in Asian rhinoplasty. To achieve better outcomes, it is important to know which types of costal cartilage are most appropriate for dorsal augmentation.

[OBJECTIVES] The authors investigated how various forms of costal cartilage affect the surrounding tissues and their resorption over time, as well as their clinical appearance, using histomorphological analysis.

[METHODS] Cartilage samples were collected from the anterior chest wall of 10 rabbits. Four forms of cartilage-2-mm solid block, 1-mm solid block, diced, and crushed-were prepared and inserted into the subcutaneous tissue pockets of the nasal dorsum of each rabbit. The animals were killed 3 and 6 months later, and graft specimens were examined.

[RESULTS] Histomorphological analysis revealed important findings of the cartilage and surrounding tissues. The thickness of thick cartilage significantly decreased over time, but the thickness of thin cartilage did not significantly change (P = 0.038). Additionally, the thick cartilages showed a lower degree of vascularization than the thin cartilages (P < 0.001). A comparison of the cartilage forms revealed that the diced cartilages had better chondrocyte survival than the solid block cartilages (P < 0.001). Fat tissues were prominently observed surrounding the diced cartilages at 3 months (P = 0.01), and fibrosis was more prominently observed in the crushed cartilage than in the other types of cartilages (P = 0.04 and P = 0.005 at 3 and 6 months, respectively).

[CONCLUSIONS] This study revealed differences in resorption depending on the thickness of the costal cartilage in rabbits. Among the various forms of costal cartilages, diced and thin solid-block cartilage were the best option for dorsal augmentation when considering long-term graft survival.