Evaluation of sound transmission performances according to existing commercial prostheses, by modeling different stabilizer bone prostheses

Hearing losses occur as a result of problems in the hammer, anvil and stirrup ossicles, which provide the transmission of sounds to the inner ear in the middle ear. Often, a prosthesis is placed in place of the stirrup. In this study, it was aimed to model different stirrup bone prostheses and evaluate their sound transmission performance compared to the healthy human middle ear model and existing commercial prostheses. In the study, prosthesis designs, models and analyzes were carried out with Solidworks and Ansys programs. Three commercially produced piston type prostheses were modeled in the study. Four different materials, three different diameters and three different lengths were determined for these prostheses, and the materials, diameters and lengths of each prosthesis were evaluated. Harmonic analyzes of the designed prosthesis models and healthy ear models were carried out. At a frequency between 100 and 10000 Hz, a pressure of 90 dB, approximately 0.632 Pa, was sent from the tympanic membrane part of the modeled ear. Analyzes were carried out under specified boundary conditions. The frequency response resulting from vibration at the base of the stirrup and the velocity distribution of sound were compared with each of the commercially modeled prostheses, and their sound transmission performances were evaluated by comparing them with the healthy ear model. Among the 108 prostheses analyzed, one of the prostheses that gave the closest results to the healthy ear model was obtained in the Commercial 3 model and a 10-fold improvement in sound transmission was observed.