Objective To evaluate the diagnosis value of temporal Done high-resolution computed tornography (HRCT) in cholesteatoma. Methods There were 30 causes that had received the mastoid surgery because of cholesteatoma. Each patient’s mastoid plain films (Schuller’s and Mayer’s ) and HRCT had been taken and compared with each other and surgical findings and evaluated with health economic evaluation methods. Results The sensitivity rate in diagnosing cholesteatoma with HRCF was much higher than that with mastoid film (Plt;0.005). The more important benefit with HRCT was that it can afford the detail information in ear such as the ossicular chain, facial nerve canal, tympanic sinus, etc. which were basis for otologist in surgery to remove the focus thoroughly and reconstruct the middle ear function at the same time. In the view of health economic evaluation, HRCT is also much better than mastoid X-ray film. Conclusion HRCT should replace masloid Schuller’s and Mayer’s film in diagnosis cholesteatoma and HRCT should use as ordinary examination in chronic otitis media.
To investigate the influence of the preload and supporting stiffness on the hearing compensation performance of round window stimulation, a coupling finite model composed of a human ear, an actuator and a support was established. This model was constructed based on a complete set of micro-computed tomography (Micro-CT) images of a healthy adult’s right ear by reverse engineering technology. The validity of the model was verified by comparing the model’s calculated results with experimental data. Based on this model, we applied different amplitude preloads on the actuator, and changed the support’s stiffness. Then, the influences of the actuator’s preload and the support’s stiffness were analyzed by comparing the corresponding displacements of the basilar membrane. The results show that after applying a preload on the actuator, its hearing compensation performance was increased at the middle and high frequencies, but was deteriorated at low frequencies; besides, compared with using the fascia as the actuator’s support in clinical practice, utilizing the titanium alloy to fabricate the support would enhance the hearing compensation performance of the round window stimulation in the whole frequency range.
In order to study the effect of middle ear malformations on energy absorbance, we constructed a mechanical model that can simulate the energy absorbance of the human ear based on our previous human ear finite element model. The validation of this model was confirmed by two sets of experimental data. Based on this model, three common types of middle ear malformations, i.e. incudostapedial joint defect, incus fixation and malleus fixation, and stapes fixation, were simulated by changing the structure and material properties of the corresponding tissue. Then, the effect of these three common types of middle ear malformations on energy absorbance was investigated by comparing the corresponding energy absorbance. The results showed that the incudostapedial joint defect significantly increased the energy absorbance near 1 000 Hz. The incus fixation and malleus fixation dramatically reduced the energy absorbance in the low frequency, which made the energy absorbance less than 10% at frequencies lower than 1 000 Hz. At the same time, the peak of energy absorbance shifted to the higher frequency. These two kinds of middle ear malformations had obvious characteristics in the wideband acoustic immittance test. In contrast, the stapes fixation only reduced the energy absorbance in the low frequency and increased energy absorbance in the middle frequency slightly, which had no obvious characteristic in the wideband acoustic immittance test. These results provide a theoretical reference for the wideband acoustic immittance diagnosis of middle ear malformations in clinic.