Application of finite element model of middle ear in the study of the middle ear biomechanics in normal and diseased states

Aim: The aim of this study was to create a three-dimensional model of the middle ear by finite element (FE) analysis, using measurements performed on human and cadaveric high-resolution computed tomography (HRCT) temporal bone, and to study the biomechanics in diseased conditions. Materials and Methods: This observational, cross-sectional study was conducted in Acharya Vinoba Bhave Rural Hospital, Sawangi, Meghe, Maharashtra, in the Department of Otorhinolaryngology. The first step of FE modeling approach comprised computer-aided geometric model incorporating the static dimensions from human and cadaveric temporal bones and dynamic dimensions from prepublished data. HRCT Scans of both sets of temporal bones were performed with 0.5 mm cuts, and measurements of the ossicles, middle ear, and tympanic membrane were taken. The cadaveric temporal bones were drilled, the ossicles dissected out and measured using HRCT as well as vernier calipers. This was followed by construction of the working FE model and application of this FE model for studying middle ear biomechanics in normal and diseased states. Results: The mean measurements of ossicles were calculated, and the movement of tympanic membrane was maximum at the site of umbo and stapes footplate, whereas minimum movement was within the ossicles. Larger peak-to-peak displacement was seen at 1000 Hz to 3000 Hz frequency. Our results suggest that FE model can prove beneficial in the study of middle ear biomechanics. Conclusion: The changes in the tympanic membrane movement in diseased state have been compared to normal ear and can be applied to reconstructed ears. FE analysis can be used to study the effect of material properties of various graft materials used in tympanomastoidectomy.