Differences between human septal and alar cartilage with respect to biomechanical features and biochemical composition.

Cartilage grafts have become popular in facial plastic surgery to reconstruct defects or to improve aesthetic outcomes in various applications. But there is a considerable rate of graft failure like resorption or deformation. To improve graft survival and function, accurate understanding of the properties of the recipient site is indispensable. Therefore 10 noses of human cadavers were meticulously dissected and specimens of alar and septal cartilage subjected to confined compression and tensile tests. Furthermore, cell number, glycosaminoglycan and hydroxyproline content were measured. RESULTS: showed a significant difference (p < 0.05) of alar and septal cartilage regarding Equilibrium Modulus, cell number and glycosaminoglycan but not hydroxyproline content. Tensile tests showed a significant difference (p < 0.001) between alar and septal cartilage (vertical vector of force) for E-modulus, maximal force and maximal strain but not for horizontal vector of force. There was a significant difference (p < 0.05) within septal cartilage samples depending on vector of force (vertical vs. horizontal). Finally multifactorial linear regression allowed an estimation of Equilibrium Modulus depending on compression, glycosaminoglycan content and cell number with statistical significance (p < 0.05). In conclusion, nasal cartilage differs in function and composition depending on anatomical location and the prevalent forces. Therefore further research will be necessary to evaluate if graft failure depends on a mismatch of functional properties and if grafts can be adapted to the recipient site.