Inner Ear Active Hearing Device in Non-Otosclerotic, Severe, Mixed Hearing Loss

OBJECTIVE: To verify the efficacy of a powerful active hearing device in a patient different from far-advanced otosclerosis, specifically when the stapes footplate is mobile. PATIENT: A patient with severe-to-profound mixed hearing loss, who was not benefiting from the use of a conventional hearing aid, was selected for an inner ear active implant. This was justified by a bone conductive threshold above 60 dB, which had discouraged any other rehabilitative solutions such as a bone conductive implant, or an active middle ear implant (AMEI). INTERVENTION: The hearing device was surgically applied using a combined transmastoid/transcanal approach. During surgery, a mobile stapes were found and was perforated for the insertion of a piston prosthesis, crimped on the new-incus of the device. MAIN OUTCOME MEASURE: The bone conduction threshold was assessed postoperatively to identify any possible surgery-related hearing deterioration. Pure tone audiometry was conducted in a sound field, and a speech reception threshold test was performed with the contralateral ear masked. The hearing outcome was assessed soon after the implant activation (6 weeks after surgery), and 6 months after surgery. RESULTS: Upon activation of the device, a PTA of 45 dB was obtained (at 0.5, 1, 2 and 4 kHz). At 6 months after surgery, the speech discrimination score reached 90% at 80 dB SPL. CONCLUSION: The application of the Codacs device has shown to be compatible with a mobile stapes footplate, as demonstrated in this report. The footplate perforation did not cause any further hearing deterioration, and has allowed to achieve a favorable auditory outcome

Usefulness of image guidance in the surgical treatment of petrous apex cholesterol granuloma

The petrous apex is a pyramid-shaped structure, located medial to the inner ear and the intrapetrous segment of the internal carotid artery. Lesions of the petrous apex can be surgically treated through different surgical routes. Because of the important neurovascular structures located inside the temporal bone, anatomical 3D knowledge is paramount. For this reason, image-guided surgery could represent a useful tool. We report the case of a young woman who came to our observation for a trigeminal neuralgia due to a petrous apex cholesterol granuloma. The lesion was treated through the placement of a drainage tube via an infracochlear approach, with the aid of neuronavigation and intraoperative MRI. Preoperative CT scan images and intraoperative MRI images were fused for surgical planning. The accuracy of the neuronavigation system has proved to be good, and the safety of the procedure was enhanced. Therefore, neuronavigation and intraoperative MRI, though not available in all neurootological centres, should be considered useful tools in these challenging procedures

Examining the assumption of homogeneous horizontal layers within seismic site response analysis

One-dimensional analyses can be conducted to estimate the impact of superficial soil layers on earthquake ground motions. Such analyses are based on the assumption that all boundaries are horizontal and that the response of a soil deposit is predominantly caused by horizontal shear waves propagating vertically from the underlying bedrock. This assumption is made even for sites with a relative large surface area, e.g. the footprint of large infrastructure such as power plants. An important step then is to create a model of the near subsurface that is representative of the overall area under analysis. This means it is essential to evaluate geomechanical characteristics of the soil at certain locations and extend these measurements over the whole site. As a consequence of this, it is assumed that the soil characteristics, which include stratigraphy, geometry and geotechnical properties, are homogeneous. Recent observations, however, have clearly demonstrated that even over a small area (~1km2) ground conditions can vary greatly. The purpose of this study is to examine the impact of relaxing the assumption of infinite horizontal layers by undertaking a parametric study of the variability in amplification across areas with gently dipping subsurface layers. Starting from a 1D approach the influence of dipping layers is evaluated through simplified but geometrically representative models. Randomization of shear-wave velocity profiles using the Toro (1995) method, as implemented in STRATA, is used to compute the variability in site amplification that would be captured by a standard 1D technique. This provides a baseline for comparison with the variability introduced by the dipping layers. Subsequently, two-dimensional simulations are conducted for the same sites with dipping layers to estimate the error made through the assumption of 1D response. The goal of this study is to understand when the 1D assumption can be used in the presence of dipping layers

Mechanical Performance of Fiber Reinforced Cement Composites Including Fully-Recycled Plastic Fibers

The use of virgin and recycled plastic macro fibers as reinforcing elements in construction materials has recently gained increasing attention from researchers. Specifically, recycled fibers have become more attractive owing to their large-scale availability, negligible cost, and low environmental footprint. In this work, we investigate the benefits related to the use of fully-recycled synthetic fibers as dispersed reinforcement in Fiber Reinforced Cement Composites (FRCCs). In light of the reference performance of FRCCs including virgin polypropylene (PP) fibers only, the mechanical response of composites reinforced with polyolefin filaments treated with a sol-gel silica coating and polyethylene terephthalate (PET)/polyethylene (PE) cylindrical draw-wire fibers is here assessed through three-point bending tests. Remarkably, recycled polyolefins lead to a notable enhancement in terms of peak strength and post-crack energy dissipation capability. This improvement is ascribed to both the flattened shape of fibers and the surface coating, which turns out to be very effective at strengthening the fiber-to-matrix bond. On the other hand, PET/PE fibrous reinforcement generally leads to a lower toughness, if compared to the virgin fibers. However, no reduction in terms of peak stress is evidenced. Balancing the significance of mechanical performance and environmental sustainability in the framework of a circular economy approach, both fully-recycled fibers at hand can be regarded as promising candidates for innovative structural application

Cone beam computed tomography after round window vibroplasty. do the radiological findings match the auditory outcome?

Conclusion: The CBCT imaging technique has proved to be reliable for assessing the appropriate positioning of the FMT in the round window niche. However, when considering specific imaging parameters, such as lack of bony contacts and appropriate inferior support, they would not seem essential for achieving a satisfactory functional outcome. Objectives: To evaluate the value of some imaging parameters derived from a Cone Beam Computed Tomography of the temporal bone for predicting a good functional outcome after Round Window Vibroplasty (RW-VP). Method: A CBCT imaging has been carried out at certain time after RW-VP surgery in a homogenous group of patients who presented with a mixed-type hearing loss after open tympanoplasty for a cholesteatoma. Three arbitrary radiological parameters have been considered for the purpose: the FMT/RW membrane contact; eventual FMT bony contacts; appropriatmess of inferior FMT support. The audiological assessment has taken into consideration the PTA4 (500-4000 Hertz), the PTA2 (125.250 Hertz), the WRS in quiet and in noise (SNR=+10). A comparison between the unaided and the RW-VP aided condition has been performed

Simultaneous Contralateral Vestibular Schwannoma and Middle Ear Paraganglioma Tumor

To the best of our knowledge, only 2 cases of a simultaneous contralateral vestibular schwannoma (VS) and middle ear paraganglioma (MEP) have previously been reported in literature. We report the third case observed in a 43-year-old male, who presented with an 11-year history of right-sided hearing loss and a 1-year history of left-sided pulsatile tinnitus. A magnetic resonance imaging (MRI) showed a VS on the right side and computer tomography (CT) identified a Fisch type A1 paraganglioma on the left side. The VS was treated using a translabyrinthine approach and the MEP was kept under radiological observation for 1 year. Due to the growth of the MEP (Fisch type A2), it was treated with excision via a retroauricular approach. Our case was very challenging because there was a different and important pathology on each side, both carrying a risk of deafness as a consequence of the disease and/or the treatments

Intralabyrinthine Vestibular Schwannoma Responsive to Intratympanic Gentamicin Treatment

Intralabyrinthine schwannoma (ILS) is a rare benign tumor that affects the ends of cochlear and vestibular nerves. In a majority of the cases, it occurs with unilateral progressive sensorineural hearing loss. Less frequent symptoms include tinnitus, imbalance, vertigo, or fullness. The advent of magnetic resonance imaging allows early diagnosis and enables an appropriate therapeutic protocol. This report describes a case of intravestibular schwannoma, with fluctuating hearing loss and intractable vertigo, treated with intratympanic gentamicin. The patient was a 28-year-old woman with intractable vertigo and fluctuating left-side hearing loss caused by left intravestibular schwannoma. Because surgery was temporarily rejected by the patient, a single dose of intratympanic gentamicin was administered. Following this, the patient showed a significant improvement in the symptoms. However, moderate to flat sensorineural hearing loss was also observed. Intratympanic gentamicin infiltration is a valid therapeutic option for patients with ILS, affected by intractable vertigo, when the patient refuses surgery

On the role of the incompressibility constraint in soft dielectrics

In this work we demonstrate that the incompressibility constraint customarily adopted in literature to model soft dielectric composites may lead to incorrect predictions. In fact, although in these composites each phase may individually be assumed to be incompressible, for high-phase contrast in terms of elastic moduli the volumetric deformation of the softest phase can provide a non-negligible contribution to the effective behaviour. To reach our goal, we determine the effective electric response of a two-phase Dielectric Laminated Composite (DLC) actuator, whose softest phase is described by a constitutive law admitting volumetric deformation. Our results, discussed in the light of the limit case in which the softest phase consists of void, are expected to aid the design of high-performance hierarchical DLCs

On the Effect of the Volumetric Deformation in Soft Dielectric Composites with High Phase Contrast

Towards the accurate modelling of soft dielectric composites, this investigation aims at demonstrating that the incompressibility constraint customarily adopted in the literature may lead to largely inaccurate predictions. This claim is grounded on the premise that, even though in these composites each phase may individually be assumed to be incompressible, the volumetric deformation of the softest phase can provide a significant contribution to the effective behaviour if the phase contrast is high enough. To reach our goal, we determine the actuation response of two-phase dielectric laminated composites (DLCs) where the softest phase admits volumetric deformation. Our results, discussed in the light of the limit case in which the softest phase consists of vacuum, on the one hand, challenge the hypotheses usually assumed in the modelling of soft dielectric composites and, on the other hand, are expected to provide useful information for the design of high-performance hierarchical DLCs