Design Optimization of Cartilage Myringoplasty using Finite Element Analysis

Objective: The purpose of this study was to determine the acoustic transfer characteristics of cartilage for optimal cartilage myringoplasty. Material and Methods: We developed a cartilage plate-tympanic membrane coupled finite element model to investigate the transfer characteristics of cartilage myringoplasty. Cartilage specimens of the tragus were obtained from fresh human cadavers and were investigated by means of a tympanic membrane model. The parameters of tragus were determined by curve fitting and cross calibration. The cartilage plate was reconstructed based on an ear drum perforation using our 3-dimensional middle ear biomechanical model. The optimal thickness of cartilage myringoplasty was calculated using finite element analysis. Result: Reducing cartilage thickness leads to an improvement into acoustic transfer qualities. From an acoustic point of view, 0.1-0.2 mm thick cartilage plate seems to give the best results in term of tympanic membrane vibration. Conclusion: Tragal cartilage is useful for reconstruction of tympanic membrane from the perspective of acoustic properties. The acoustic transfer loss by the cartilage can be reduced by decreasing its thickness. A thickness of 0.2 mm at lower frequency and 0.1mm at higher frequency are regarded as a good compromise between sufficient mechanical stability and low acoustic transfer loss.