Computer Aided Three-Dimensional Reconstruction and Modeling of Middle Ear Biomechanics by High-Resolution Computed Tomography and Finite Element Analysis

Abstract

In order to present a systematic and practical approach that uses high-resolution computed tomography (HRCT) to derive models of the middle ear for finite element analysis (FEA). This prospective study included 31 subjects with normal hearing and no previous otological disorders. Temporal bone images obtained from 15 right ears and 16 left ears were used for evaluation and reconstruction. High-resolution computed tomography of temporal bone was performed using simultaneous acquisition of 16 sections with a collimated slice thickness of 0.625 mm. All images were transferred to an Amira visualization system for 3D reconstruction. The created 3-D model was translated into two commercial modeling packages, Patran and ANSYS, for finite element analysis. The characteristic dimensions of the model were measured and compared with previous published histological section data. This result confirms that the geometric model created by the proposed method is accurate except the tympanic membrane is thicker than that of histological section method. No obvious difference in the geometrical dimension between right and left ossicles was found (p > 0.05). The 3D model created by finite element method and predicted umbo and stapes displacements are close to the bounds of the experimental curves of Nishihara's, Huber's, and Gan's data across the frequency range of 100-8000 Hz. The model includes a description of the geometry of the middle ear components, and dynamic equations of vibration. The proposed method is quick, practical, low cost and most importantly, non-invasive as compared with histological section methods.

Biomechanics of the tympanic membrane

“…Although there is a general agreement in considering a non-homogeneous distribution of thickness in different locations of the TM, a uniform thickness value, ranging from 30 to 150 mm for the human TM is usually adopted (Daphalapurkar et al, 2009;Decraemer and Funnell, 2008;Funnell and Laszlo, 1982;Gaihede et al, 2007;Liu et al, 2009). In Abel and Lord (2001), Le and Huynh (2008), Lee et al (2006a,b, 2010), Wen et al (2006 a 100 mm value is assumed, while in other works a different thickness between PT and PF (Kelly et al, 2003;Mikhael et al, 2004) is considered. Most authors agree to adopt an average value around 74 mm Ferrazzini, 2003;Funnell and Laszlo, 1982;Gan et al, 2004;Huang et al, 2008;Luo et al, 2009a,b;Zhao et al, 2009).…”

“…in terms of a conventionally defined radius of curvature) (Abel and Lord, 2001;Funnell and Laszlo, 1978;Ladak and Funnell, 1995;Le and Huynh, 2008); previously published anatomic measurement data (Ferris and Prendergast, 2000;Gentil et al, 2005;Kelly, 2001;Koike et al, 2001Koike et al, , 2002Koike et al, , 2005Lesser and Williams, 1988); a 3D reconstruction from serial histological sections Funnell, 1996a;Gan, 2006;Gan et al, 2004Gan et al, , 2006Gan et al, , 2007Gan and Sun, 2002;Sun et al, 2002;Wang et al, 2007); interferometric techniques (i.e. phase-shift Moiré shape measurement) Buytaert et al, 2009;Elkhouri et al, 2006;Fay et al, 2006;Funnell, 2001;Funnell et al, 1999;Ladak et al, 2006;Martinez-Celorio et al, 2008); nuclear magnetic resonance (NMR) spectroscopy (Kelly et al, 2003;Vard et al, 2008); micro-computed tomography (CT) (Ferrazzini, 2003;Mikhael et al, 2004;Tuck-Lee et al, 2008); spiral CT or high-resolution computed tomography (HRCT) (Lee et al, 2006a(Lee et al, ,b, 2007a(Lee et al, ,b, 2010Liu et al, 2009;Wen et al, 2006) of living human temporal bones. …”

Mechanical properties of human tympanic membrane in the quasi-static regime from in situ point indentation measurements

“…The technique allows the complex shape and boundary conditions of the middle ear structure to be taken into account. Examples of acoustic middle ear models are Zhao et al (2009);Sun et al (2002); Tuck- Lee et al (2008); Lee et al (2006); Elkhouri et al (2006); examples of models in the quasi-static regime are Ladak et al (2004); Wang et al (2007); an example of a model investigating prosthesis behavior is Ferris and Prendergast (2000). The response of middle ear finite element models is very sensitive to tympanic membrane mechanical properties (Koike et al, 2001;Elkhouri et al, 2006).…”

Elasticity modulus of rabbit middle ear ossicles determined by a novel micro-indentation technique

“…Finite element (FE) models have been widely used recently to investigate biomechanical systems (Elkhouri et al, 2006;Koike et al, 2002;Lee et al, 2006;Mikhael et al, 2004;Prendergast et al, 1999;Sun et al, 2002). Such models need geometric data, boundary conditions and material properties.…”