Modelling of Components of the Human Middle Ear and Simulation of Their Dynamic Behaviour

Beer, H.-J.; Bornitz, Matthias; Hardtke, H.‐J.; Schmidt, Rolf; Hofmann, G.; Vogel, Uwe; Zahnert, Thomas; Hüttenbrink, Karl-Bernd

doi:10.1159/000013835

Cited by 69 publications

(36 citation statements)

References 6 publications

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“…Many mathematical middle-ear models have used simply supported, fully clamped, or a combination for the boundary conditions of the TM (Funnell 1975;Funnell and Laszlo 1978;Funnell et al 1987Funnell et al , 1992Funnell and Decraemer 1996;Rabbitt & Holmes 1986;Ladak & Funnell 1996;Beer et al 1996Beer et al , 1999Fay et al 2006;Elkhouri et al 2006;Eiber et al (2000); Ladak et al 2006;Qi et al 2008). Changing a model from simply supported to fully clamped boundary conditions may cause differences in response that, depending on the characteristics of the model and the magnitude of the applied load, may be more or less important.…”

Section: Boundary Conditions In Mathematical Modelsmentioning

confidence: 99%

Tympanic Membrane Boundary Deformations Derived from Static Displacements Observed with Computerized Tomography in Human and Gerbil

Gea

Decraemer

Funnell

et al. 2009

JARO

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The middle ear is too complex a system for its function to be fully understood with simple descriptive models. Realistic mathematical models must be used in which structural elements are represented by geometrically correct three-dimensional (3D) models with correct physical parameters and boundary conditions. In the past, the choice of boundary conditions could not be based on experimental evidence as no clear-cut data were available. We have, therefore, studied the deformation of the tympanic membrane (TM) at its boundaries using X-ray microscopic computed tomography in human and gerbil while static pressure was applied to the ear canal. The 3D models of the TM and its bony attachments were carefully made and used to measure the deformation of the TM with focus on the periphery and the manubrium attachment. For the pars flaccida of the gerbil, the boundary condition can, for the most part, be described as simply supported. For the human pars flaccida, the situation is more complicated: superiorly, the membrane contacts the underlying bone more and more when pushed further inward, and it gradually detaches from the wall when sucked outward. In gerbil, the attachment of the TM to the manubrium can be described as simply supported. In human, the manubrium is attached underneath the TM via the plica mallearis and the contact of the TM with the bone is indirect. For both human and gerbil, a simple boundary condition for the peripheral edge of the pars tensa is not appropriate due to the intricate structure at the edge: the TM thickens rapidly before continuing into the annulus fibrosis which finally makes contact with the bone.

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Section: Boundary Conditions In Mathematical Modelsmentioning

confidence: 99%

Tympanic Membrane Boundary Deformations Derived from Static Displacements Observed with Computerized Tomography in Human and Gerbil

Gea

Decraemer

Funnell

et al. 2009

JARO

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“…The anatomical features include the morphometry of the middle-ear bones as well as the morphometry of the soft tissues. Inertial properties of the middle-ear bones for human (Kirikae 1960;Beer et al 1999;Weistenhö fer and Hudde 1999;Puria et al 2007a;Sim et al 2007) and for cat, guinea pig, and chinchilla (Puria et al 2007a) have been reported previously. However, detailed morphometry of the soft tissues such as their dimensions and relative positions mostly remains unknown.…”

Section: Introductionmentioning

confidence: 71%

Soft Tissue Morphometry of the Malleus–Incus Complex from Micro-CT Imaging

Sim

Puria

2008

JARO

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The malleus-incus complex (MIC) is unique to mammalian hearing. To develop a comprehensive biomechanical MIC model for the human middle ear, measurements regarding its anatomical features are a necessity. Micro-scale X-ray computed tomography (micro-CT) imaging, which is known to be a suitable method for imaging high-density tissue such as middle-ear ossicles and surrounding bones, is used in this study to determine the three-dimensional (3-D) morphometry of the soft tissue attachments of the MIC. The MIC morphometry is based on their 3-D reconstruction from micro-CT image slices with resolutions ranging from 10 to 20 mm. The suspensory ligament and tendon attachments of the malleus and the incus as well as the incudomalleal joint (IMJ), are quantified in terms of dimensions, positions, and orientations for four human cadaver temporal bones. The malleus principal frame, the incus principal frame, and the MIC principle frame are calculated and the morphometry is reported in relation to each of these frames for the first time. The resulting values show significant variation across ear samples, suggesting that models of the MIC should be based on individual anatomy. The IMJ morphometry dimensions appear to be proportional to the ossicular mass. The micro-CT imaging modality is a nondestructive and relatively fast method for obtaining soft tissue morphometry and provides accurate anatomical features in relation to the principal axes of bones.

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“…A number of groups have since used the finiteelement method to study the mechanics of the eardrum and ossicles in humans (Wada et al 1992;Beer et al 1999;Bornitz et al 1999;Prendergast et al 1999;Koike et al 2002;Sun et al 2002) and in cats (Funnell and Laszlo 1978;Funnell et al 1987;Ladak and Funnell 1996;Funnell et al 2005). The geometries have generally been oversimplified and material properties have often been based on curve fitting.…”

Section: Introductionmentioning

confidence: 99%

Low-Frequency Finite-Element Modeling of the Gerbil Middle Ear

Elkhouri

Liu

Funnell

2006

JARO

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The gerbil is a popular species for experimental middle-ear research. The goal of this study is to develop a 3D finite-element model to quantify the mechanics of the gerbil middle ear at low frequencies (up to about 1 kHz). The 3D reconstruction is based on a magnetic resonance imaging dataset with a voxel size of about 45 mm, and an x-ray micro-CT dataset with a voxel size of about 5.5 mm, supplemented by histological images. The eardrum model is based on moiré shape measurements. Each individual structure in the model was assumed to be homogeneous with isotropic, linear, and elastic material properties derived from a priori estimates in the literature. The behavior of the finite-element model in response to a uniform acoustic pressure on the eardrum of 1 Pa is analyzed. Sensitivity tests are done to evaluate the significance of the various parameters in the finiteelement model. The Young_s modulus and the thickness of the pars tensa have the most significant effect on the load transfer between the eardrum and the ossicles and, along with the Young_s modulus of the pedicle and stapedial annular ligament, on the displacements of the stapes. Overall, the model demonstrates good agreement with low-frequency experimental data. For example, (1) the maximum footplate displacement is about 35 nm; (2) the umbo/stapes displacement ratio is found to be about 3.5; (3) the motion of the stapes is predominantly piston-like; and (4) the displacement pattern of the eardrum shows two points of maximum displacement, one in the posterior region and one in the anterior region. The effects of removing or stiffening the ligaments are comparable to those observed experimentally.

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Modelling of Components of the Human Middle Ear and Simulation of Their Dynamic Behaviour

Cited by 69 publications

References 6 publications

Tympanic Membrane Boundary Deformations Derived from Static Displacements Observed with Computerized Tomography in Human and Gerbil

Tympanic Membrane Boundary Deformations Derived from Static Displacements Observed with Computerized Tomography in Human and Gerbil

Soft Tissue Morphometry of the Malleus–Incus Complex from Micro-CT Imaging

Low-Frequency Finite-Element Modeling of the Gerbil Middle Ear

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