Experimental measurement and modeling analysis on mechanical properties of incudostapedial joint

Abstract

The incudostapedial (IS) joint between the incus and stapes is a synovial joint consisting of joint capsule, cartilage, and synovial fluid. The mechanical properties of the IS joint directly affect the middle ear transfer function for sound transmission. However, due to the complexity and small size of the joint, the mechanical properties of the IS joint have not been reported in the literature. In this paper, we report our current study on mechanical properties of human IS joint using both experimental measurement and finite element (FE) modeling analysis. Eight IS joint samples with the incus and stapes attached were harvested from human cadaver temporal bones. Tension, compression, stress relaxation and failure tests were performed on those samples in a micro-material testing system. An analytical approach with the hyperelastic Ogden model and a 3D FE model of the IS joint including the cartilage, joint capsule, and synovial fluid were employed to derive mechanical parameters of the IS joint. The comparison of measurements and modeling results reveals the relationship between the mechanical properties and structure of the IS joint.

Model-oriented review and multi-body simulation of the ossicular chain of the human middle ear

“…In particular for the ISJ, a portion of elastic ligamentous tissue is usually interposed between the two adjacent ossicles, whose characteristics, in terms of density and Young's modulus, are 1.2 × 10 3 kg/m 3 and 0.6 MPa respectively [4,46]. However, recently two studies on the ISJ modeling were presented, one on a sub-structured FE model of the cat joint [51], the other one on an experimentally calibrated FE model with hyperelastic tissue characterization [52].…”

Modeling microstructure of incudostapedial joint and the effect on cochlear input

“…1 show details of the ISJ from longitudinal (axis from incus to stapes) and transvers views of configurations of the articular cartilage, meniscus, synovial fluid, and joint capsule that connects the lenticular process and stapes head. The dimensions of all components are listed in Table 1 based on the data reported in the literature [9,11]. In the FE model of ISJ, the cartilage and meniscus were assigned as linear elastic Solid 45 elements in ANSYS.…”

“…To identify the mechanical properties of joint components and determine the effects of components on vibration transduction through the middle ear ossicular chain, we created 6 cases of different mechanical properties for joint capsule, cartilage, meniscus, and synovial fluid. Case 1 was a baseline case in which the capsule was assumed as viscoelastic material using the standard linear viscoelastic model with 3 material parameters: E 0 , E 1 , and τ 1 [11,12]. The articular cartilage and meniscus were assumed as elastic material with the Young's modulus E and Poisson's ratio .…”

“…As the first step toward the investigation of biomechanics of ISJ, we published the first ever study on mechanical properties of the human ISJ using both experimental measurement and FE modeling analysis [11]. The results demonstrated that the ISJ is a viscoelastic structure with nonlinear stress-strain relationship and sustains higher force with less deformation in compression than in tension.…”

Human ossicular-joint flexibility transforms the peak amplitude and width of impulsive acoustic stimuli

“…Contemporary work has supported the idea that the IMJ is mobile at frequencies above 2 kHz (Gerig et al , 2015), as well as under quasi-static loading conditions (Ihrle et al , 2016). The ISJ has received relatively less scrutiny than the IMJ, though a number of studies have demonstrated that it is functionally mobile at hearing frequencies (Nakajima et al , 2005; Zhang and Gan, 2011) and that fixing it causes changes in sound transmission (Hato et al , 2003; Alian et al , 2013). …”