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The present study aims to compare spinal stability after two different minimally invasive techniques, the lateral lumbar interbody fusion (LLIF) and the transforaminal lumbar interbody fusion (TLIF) approaches. Two nonlinear three-dimensional finite element (FE) models of the L4–L5 functional spinal unit (FSU) were subjected to the loads that usually act on the lumbar spine. Findings show that the LLIF approach yields better results for torsion load case, due to the larger surface area of the implant. For extension, flexion and lateral bending loads, the TLIF approach presents smaller displacements probably due to the anterior placement of the cage and to the smaller damaged area of the annulus fibrosus. [ABSTRACT FROM AUTHOR]

This paper presents a finite element analysis to investigate the biomechanical changes caused by transforaminal (TLIF) and anterior lumbar interbody fusion (ALIF) at the L5-S1 level, applying two different implants: T_PAL (TLIF) and SynFix (ALIF). The main objective is to determine which one is more stable for patients. Numerical simulations of segmental motion show that, in the early postoperative phase, displacements and rotation angles obtained in ALIF are greater than the corresponding ones obtained in TLIF, as well as the principal stress values on the ligaments. So, TLIF performed with T_PAL is more stable than ALIF, especially during the recovery phase. [ABSTRACT FROM AUTHOR]

A numerical approach to simulate the delamination effect occurring in metal foam composites is being presented in this work. It is shown that in order to create reliable numerical models to simulate general components produced with aluminum metal foam sandwiches, the delamination effect of the aluminum skins from the metal foam must be considered. Delamination occurs within the polyurethane adhesive layer, causing the loss of the structural integrity of the structure. Foam is not a continuum medium, nevertheless, when simulating foam structures, foam is commonly assumed as a continuum, with homogeneous properties. This approach requires the calibration of the mechanical properties of the polyurethane adhesive layer, in order to compensate the effect of the foam’s discontinuous structure. The finite element method was used to numerically simulate a three-points bending test and an unconstrained bending test. The cohesive behavior was modelled by using a traction separation law. For the damage initiation criteria, a maximum-stress-based criterion was used, whereas for the damage evolution, a displacement-based damage evolution law was adopted. The experimental data were obtained from the group’s previous work, including a compression test, a tension test, a three-points bending test, and an unconstrained bending test. [ABSTRACT FROM AUTHOR]

Otitis media is a group of inflammatory diseases of themiddle ear. Acute otitis media and otitis media with effusion (OME) are its two main types of manifestation. Otitis media is common in children and can result in structural alterations in the middle ear which will lead to hearing losses. This work studies the effects of an OME on the sound transmission from the external auditory meatus to the inner ear. The finite elementmethod was applied on the present biomechanical study. The numerical model used in thiswork was built based on the geometrical information obtained from The visible ear project. The present work explains the mechanisms by which the presence of fluid in the middle ear affects hearing by calculating the magnitude, phase and reduction of the normalized umbo velocity and also the magnitude and phase of the normalized stapes velocity. A sound pressure level of 90 dB SPL was applied at the tympanicmembrane. The harmonic analysis was performedwith the auditory frequency varying from 100 Hz to 10 kHz. A decrease in the response of the normalized umbo and stapes velocity as the tympanic cavity was filled with fluid was obtained. The decrease was more accentuated at the umbo. [ABSTRACT FROM AUTHOR]