Mathematical models of human middle ear in chronic otitis media

Biomechanics of the tympanic membrane

“…In Le and Huynh (2008) the TM displacement distribution, the maximum value, and the displacement value at the umbo are reported: ranging from 0.2 to 0:4 mm and equal to about 0:050 mm at approximately 120 and 80 dB, respectively. Most authors (Abel and Lord, 2001;Ferrazzini, 2003;Ferris and Prendergast, 2000;Gan et al, 2004;Kelly et al, 2003;Lee et al, 2010;Liu et al, 2009) report experimental and model-derived frequency response curves (umbo displacement or velocity vs. frequency, sometimes normalized by the input sound pressure value) as a crucial output of analysis.…”

“…The geometry of the TM can be based on: a simplified parametric geometry (e.g. 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.…”

“…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).…”

“…Therefore an homogeneous isotropic material is commonly assumed for the PF. In the reviewed literature isotropic material models for both the PT and the PF (with equal or different Young's modulus values) have been proposed in Elkhouri et al (2006), Funnell (2001, Funnell et al (1999), Funnell and Laszlo (1978), Gan and Sun (2002), Gentil et al (2005), Koike et al (2001Koike et al ( , 2002Koike et al ( , 2005, Ladak et al (2006), Le and Huynh (2008), Lesser and Williams (1988), Liu et al (2009), andMikhael et al (2004). While they both are considered orthotropic in Abel and Lord (2001), many studies assume an orthotropic PT and an isotropic PF, respectively (Funnell, 2001;Funnell and Laszlo, 1978;Gan, 2006;Gan et al, 2004Gan et al, , 2006Lee et al, 2006aLee et al, ,b, 2010Sun et al, 2002;Wen et al, 2006;Zhao et al, 2009).…”

“…In the reviewed works, there is a general agreement on setting a 0.3 value for the human and animal TM Poisson's ratio (Funnell, 2001;Laszlo, 1978, 1982;Gan, 2006;Gan et al, 2004Gan et al, , 2006Gan et al, , 2007Gentil et al, 2005;Koike et al, 2001Koike et al, , 2002Koike et al, , 2005Kuypers et al, 2005;Ladak and Funnell, 1995;Ladak et al, 2006;Le and Huynh, 2008;Lee et al, 2006aLee et al, ,b, 2007aLee et al, ,b, 2010Liu et al, 2009;Mikhael et al, 2004;Sun et al, 2002;Wen et al, 2006;Zhao et al, 2009) as for the isotropic case and on the lack of relevant experimental data, even if motivation of this choice represents a controversial issue: some authors consider its influence negligible on simulation results (Decraemer and Funnell, 2008;Laszlo, 1978, 1982;Le and Huynh, 2008;Mikhael et al, 2004;Sun et al, 2002;Zhao et al, 2009) while other authors point out the necessity of further investigation on the influence of varying this parameter in biological material modeling, proposing other values as zero value (Funnell, 2001;Funnell and Laszlo, 1978) or values closer to 0.5 Daphalapurkar et al, 2009;Elkhouri et al, 2006;Huang et al, 2008;Lesser and Williams, 1988;Tuck-Lee et al, 2008) since a 0.5 value (Fay et al, 2005) (i.e. incompressibility) can cause computational problems.…”