Determination of strength and deformation behavior of human cartilage for the definition of significant parameters

Abstract

In reconstructive surgery, an artificial supporting scaffold made from autogenous cartilage from the rib, the ear concha, or the nasal septum is used as a substitute for the destroyed endogenous tissue in the ear concha, the nose, the trachea, and in parts of the facial skeleton. For the successful use of polymer materials in reconstructive surgery, an exact knowledge of the material properties of the natural tissues is required. The applicability of conventional material test methods was examined with regard to the suitability of the test methodology. Materials properties are to be assessed for different specimen sizes and geometries. Human cartilage specimens from the septum, rib, and ear were subsected to the following test methods: (1) tension, (2) bending, (3) compression, and (4) micro-hardness measuring. Specimen geometry was evaluated for each experimental method by taking into account the dimensions of samples used in plastics testing as well as the appropriate model of miniaturization. Elastic properties determined using test methods (1), (2), and (3) are Et-sep=(7.2+/-3.4) MPa, Ef-rib=(8.8+/-2.9) MPa, and Ec-rib=(103+/-30) MPa. The micro-hardness values hpl fluctuate for septum from 1 to 4 N/mm2 and for the rib from 0.5 to 1.3 N/mm2. The experiments have shown that, beside the sex- and age-specific values recorded, the standard values and their variation are particularly influenced by preparation technique and by the conditions of storage. As a result of these first investigations, characteristic values for strength and deformation were determined under quasistatic and dynamic load conditions. The aim of this study was not the determination of statistically firmed properties, but the examination of the applicability of mechanical test methods of the polymer testing for these materials.

Conventional and complex modal analyses of a finite element model of human head and neck

“…By performing modal analysis on the 3D FE head -neck system using the Willinger et al (1999). c Grellmann et al (2006). d Al-Bsharat (2000).…”

Biomechanical Characterisation of the Human Auricular Cartilages; Implications for Tissue Engineering

“…In comparison, in this study the concha was found to demonstrate a greater Young’s Elastic Modulus in compression to the helix. Grellmann et al designed a study to test nasal, costal and auricular cartilage using the following tests: micro-hardness, tension test, compression test, bending test 4. However, deeming the auricular cartilage too difficult to test, the authors did not calculate any numerical values for the auricular cartilages 4.…”

Model to Estimate Threshold Mechanical Stability of Lower Lateral Cartilage

“…Currently, estimates of elastic moduli for nasal cartilage presented in the literature vary greatly among studies and testing methods. Values for the elastic modulus of human septal cartilage presented in previous studies 11,12 have ranged from approximately 0.5 to greater than 30 MPa. Similarly, values for the elastic modulus of human LLC have ranged from 2 to 25 MPa.…”

“…The set of phantoms was created to have elastic moduli that spanned a range of values consistent with elastic moduli values for nasal cartilage calculated in previous studies (Table). 11–15 The elastic modulus for the medial and lateral ends of all phantoms was 30.6 MPa.…”

“…Furthermore, previous attempts to quantify the mechanical properties of nasal cartilage have used a variety of different techniques and subsequently yielded a wide range of results, giving an imprecise estimate of how stiff nasal cartilage is or should be. 11–15 Most studies 11,12,14,15 confuse intrinsic material properties of the tissue with the integrated response of a structure to deformation that also depends just as much on the object form factor (shape). This study presents a novel method of quantifying the stiffness of nasal cartilage based on the experience and expertise of surgeons and aims to identify the minimally adequate level of stiffness required for lower lateral cartilage (LLC) to maintain proper form and function in a human nose.…”