Vertigo Associated with Otosclerosis and Stapes Surgery-A Narrative Review.

Otosclerosis is a pathological condition affecting the temporal bone, and is characterized by remodelling of the labyrinthine bone tissue through a dynamic process of osteolysis and osteogenesis. This condition progressively leads to hearing loss, tinnitus, and vertigo. Stapedotomy, a surgical procedure involving the removal of the stapes superstructure and its replacement with a prosthesis, is the treatment of choice to improve hearing in individuals with otosclerosis. However, vestibular dysfunction is a significant complication associated with this procedure, which can occur intraoperatively or postoperatively, ranging from the immediate postoperative period to weeks, months, or even years after surgery. This paper aims to provide a comprehensive review of the most important causes of vertigo associated with otosclerosis and stapes surgery with the goal of minimizing the incidence of this complication. Understanding the underlying factors contributing to vertigo in this context is crucial for the prevention and effective management of vertigo in patients undergoing stapedotomy.

The Effect of Pluronic-Coated Gold Nanoparticles in Hearing Preservation Following Cochlear Implantation-Pilot Study.

Introduction: During cochlear implantation, electrode insertion can cause cochlear damage, inflammation, and apoptosis, which can affect the residual hearing. Nanoparticles are increasingly studied as a way to increase the availability of inner ear protective factors. We studied the effect on rats of Pluronic-coated gold nanoparticles (Plu-AuNPs) containing dexamethasone, which were applied locally in the rat's middle ear following the implant procedure. Methods: Seven rats were used in the study. The right ear served as a model for the Dex-Plu-AuNP group. Following the intracochlear dummy electrode insertion through the round window, Dex-Plu-AuNPs were placed in the round window niche. In the right ear, following the same insertion procedure, free dexamethasone (Dex) was placed in the same manner. Auditory brainstem response thresholds (click stimulus, pure tones at 8 kHz, 16 kHz, 24 kHz, and 32 kHz) were measured before and one week after the procedure. A two-tailed T-test was used for the variables. Statistical significance was set as p < 0.05. Results: In the Dex-Plu-AuNP group, the threshold shift was less than that in the free dexamethasone group, but no statistical significance was noted between the groups. When compared individually, only the 8 kHz frequency showed statistically significant, better results after one week, in favor of the Dex-Plu-AuNP group. The mean postoperative 8 kHz threshold in the Dex-Plu-AuNPs was significantly lower than that of the control group (p = 0.048, t-test). For the other frequencies, statistical analysis showed no significant differences between the mean threshold shifts of the two cohorts. Conclusions: The local application of Plu-AuNPs containing dexamethasone following cochlear implantation may better protect the residual hearing than dexamethasone alone, but a larger sample size is needed to reach a possible statistical significance. Dex-Plu-AuNPs do not seem to cause ototoxicity and may be used as a carrier for other agents. In a clinical setting, Dex-Plu-AuNPs may have the effect of protecting lower frequencies in patients with partial deafness who are candidates for electric acoustic stimulation (EAS). If we consider this tendency, Dex-Plu-AuNPs may also be beneficial for patients with Ménière's disease.

Biopolymer Lipid Hybrid Microcarrier for Transmembrane Inner Ear Delivery of Dexamethasone.

Dexamethasone is one of the most often used corticosteroid drugs for sensorineural hearing loss treatment, and is used either by intratympanic injection or through systemic delivery. In this study, a biopolymer lipid hybrid microcarrier was investigated for enhanced local drug delivery and sustained release at the round window membrane level of the middle ear for the treatment of sensorineural hearing loss (SNHL). Dexamethasone-loaded and dexamethasone-free microparticles were prepared using biopolymers (polysaccharide and protein, pectin and bovine serum albumin, respectively) combined with lipid components (phosphatidylcholine and Dimethyldioctadecylammonium bromide) in order to obtain a biopolymer-liposome hybrid system, with a complex structure combining to enhance performance in terms of physical and chemical stability. The structure of the microparticles was evaluated by FTIR, XRD, thermal analysis, optical microscopy, and scanning electron microscopy (SEM). The encapsulation efficiency determination and the in vitro Dexamethasone release study were performed using UV-Vis spectroscopy. The high value of encapsulation efficiency and the results of the release study indicated six days of sustained release, encouraging us to evaluate the in vitro cytotoxicity of Dexamethasone-loaded microparticles and their influence on the cytotoxicity induced by Cisplatin on auditory HEI-OC1 cells. The results show that the new particles are able to protect the inner ear sensory cells.

Current Concepts and Future Trends in Increasing the Benefits of Cochlear Implantation: A Narrative Review.

Hearing loss is the most common neurosensory disorder, and with the constant increase in etiological factors, combined with early detection protocols, numbers will continue to rise. Cochlear implantation has become the gold standard for patients with severe hearing loss, and interest has shifted from implantation principles to the preservation of residual hearing following the procedure itself. As the audiological criteria for cochlear implant eligibility have expanded to include patients with good residual hearing, more attention is focused on complementary development of otoprotective agents, electrode design, and surgical approaches. The focus of this review is current aspects of preserving residual hearing through a summary of recent trends regarding surgical and pharmacological fundamentals. Subsequently, the assessment of new pharmacological options, novel bioactive molecules (neurotrophins, growth factors, etc.), nanoparticles, stem cells, and gene therapy are discussed.

Experimental model for controlled endoscopic subepithelial vocal fold injury in rats.

PURPOSE: To present a detailed, reproducible, cost-efficient surgical model for controlled subepithelial endoscopic vocal fold injury in the rat model. METHODS: Six male Sprague Dawley rats were enrolled in the experiment. The left vocal folds were used to carry out the injury model, and the right vocal fold served as control. After deep sedation, the rats were placed on a custom operating platform. The vocal fold injury by subepithelial stripping was carried out using custom-made microsurgical instruments under endoscopic guidance. Data were analyzed for procedural time and post-procedural pain. Microcomputed tomography (micro-CT) scan and histologic images were obtained to assess the length, area, and depth of injury to the vocal fold. RESULTS: The mean procedural time was 112 s. The mean control vocal fold length was 0.96 ± 0.04 mm. The mean vocal fold injury length was 0.53 ± 0.04 mm. The mean vocal fold surface was 0.18 ± 0.01 mm2 with a mean lesion area of 0.05 ± 0.00 mm2. Mean vocal fold injury depth was 375.4 ± 42.8 µm. The lesion length to vocal fold length ratio was 0.55 ± 0.03, as well as lesion area to vocal fold surface area was 0.29 ± 0.02. CONCLUSIONS: Our described experimental vocal fold injury model in rats is found to be fast, safe, cost-efficient, and reproducible with a rapid learning curve.

Experimental model for controlled endoscopic subepithelial vocal fold injury in rats

Purpose: To present a detailed, reproducible, cost-efficient surgical model for controlled subepithelial endoscopic vocal fold injury in the rat model. Methods: Six male Sprague Dawley rats were enrolled in the experiment. The left vocal folds were used to carry out the injury model, and the right vocal fold served as control. After deep sedation, the rats were placed on a custom operating platform. The vocal fold injury by subepithelial stripping was carried out using custom-made microsurgical instruments under endoscopic guidance. Data were analyzed for procedural time and post-procedural pain. Microcomputed tomography (micro-CT) scan and histologic images were obtained to assess the length, area, and depth of injury to the vocal fold. Results: The mean procedural time was 112 s. The mean control vocal fold length was 0.96 ± 0.04 mm. The mean vocal fold injury length was 0.53 ± 0.04 mm. The mean vocal fold surface was 0.18 ± 0.01 mm2 with a mean lesion area of 0.05 ± 0.00 mm2. Mean vocal fold injury depth was 375.4 ± 42.8 µm. The lesion length to vocal fold length ratio was 0.55 ± 0.03, as well as lesion area to vocal fold surface area was 0.29 ± 0.02. Conclusions: Our described experimental vocal fold injury model in rats is found to be fast, safe, cost-efficient, and reproducible with a rapid learning curve.

Relevant anatomical details in rats regarding otologic research / Detalles anatómicos relevantes en ratas para la investigación otológica

SUMMARY: The objective of the study was to provide a detailed anatomical description of the rat's ear anatomy that will prove insightful to different experimental otologic surgical procedures regardless of scope. Three male Wistar rats were enrolled in the study. Candidates were screened for systemic and otologic pathology. External ear canal endoscopy was carried out with a 30˚ rigid endoscope through an image capture system. Middle ear anatomical elements were analyzed under stereomicroscopy. 3D computer tomography image reconstruction was realized with a micro-CT to describe the anatomy. Image data from all three rats were analyzed. Anatomical annotations and surgical exposure recommendations were added for key elements. The most relevant images from all three rats were selected for representation. Detailed visualization of the structural elements of the tympanic cavity were clearly visible: promontory, round window, stapedial artery, stapes, incus, and tympanic membrane were all constant findings. We describe a step wise ventral surgical approach of the middle and inner ear for which we found that the clavotrapezius muscle was a reliable landmark. For the transtympanic approach the endoscopic transcanal access was an easy and reliable method for which a detailed anatomical representation was depicted. Further, anatomical similarities to humans were observed by stereomicroscopy and Micro-CT imaging reiterating that the rat model is suitable for otologic research. The endoscopic approach to the tympanic membrane is comfortable and less expensive than a microscope. The tendon of the clavotrapezius muscle can be a reliable landmark for discovering the tympanic bulla when considering a ventral approach. 3D Micro-CT reconstruction allows intact evaluation of the samples, simultaneously being a diagnostic and also a learning tool.

RESUMEN: El objetivo de este trabajo fue proporcionar una descripción anatómica detallada de la anatomía del órgano vestíbulococlear de la rata que resultará útil para diferentes procedimientos quirúrgicos otológicos experimentales, independientemente del alcance. En el estudio se usaron tres ratas Wistar macho. Los ejemplares fueron evaluados por patología sistémica y otológica. La endoscopía del meato acústico externo se realizó con un endoscopio rígido de 30˚ a través de un sistema de captura de imágenes. Los elementos anatómicos del oído medio se analizaron bajo estereomicroscopía. La reconstrucción de la imagen de tomografía computarizada en 3D se realizó con un micro-CT para describir la anatomía. Se analizaron los datos de imagen de las tres ratas. Se agregaron anotaciones anatómicas y recomendaciones de exposición quirúrgica para elementos clave. Las imágenes más relevantes de las tres ratas fueron seleccionadas para su representación. La visualización detallada de los elementos estructurales de la cavidad timpánica era claramente visible: promontorio timpánico, ventana coclear, arteria estapedial, estapedio, yunque y membrana timpánica eran hallazgos constantes. Describimos un abordaje quirúrgico ventral escalonado del oído medio e interno para el cual encontramos que el músculo clavotrapecio era un punto de referencia confiable. Para el abordaje transtimpánico, el acceso transcanal endoscópico fue un método fácil y confiable para el cual se describió una representación anatómica detallada. Además, se observaron similitudes anatómicas con los humanos mediante estereomicroscopía e imágenes Micro-CT, lo que reitera que el modelo de rata es adecuado para la investigación otológica. El abordaje endoscópico de la membrana timpánica es cómodo y menos costoso que un microscopio. El tendón del músculo clavotrapecio puede ser un punto de referencia fiable para descubrir la bulla timpánica cuando se considera un abordaje ventral. La reconstrucción 3D Micro- CT permite la evaluación intacta de las muestras, siendo simultáneamente una herramienta de diagnóstico y también de aprendizaje.

Multilayered Porous Titanium-Based 3rd Generation Biomaterial Designed for Endosseous Implants.

This work proposes a novel complex multi-layered material consisting of porous titanium as a substrate and a complex coating consisting of a chitosan film engulfing microsphere loaded with growth factors such as BMP2 (bone morphogenic protein 2) and IGF1 (insulin-like growth factor-1). The microspheres were obtained through deposition of dual layers of calcium cross linked pectin-chitosan/pectin polyelectrolyte onto a BSA (bovine serum albumin) gel core. The multilayer was conceived to behave like a 3rd generation biomaterial, by slow delivery of viable growth factors around implants, and to assist the healing of implantation wound and the development of new vital bone. The biologic effect of the delivery of growth factors was studied in vitro, on MSC-CD1 mesenchymal stem cells, and in vivo, on CD1 mice. Proliferation and differentiation of cells were accelerated by growth factors, especially IGF1 for proliferation and BMP2 for differentiation. In vivo tests analyzed histologically and by MicroCT show a more structured tissue around BMP2 samples. The present concept will give the best clinical results if both growth factors are delivered together by a coating film that contains a double population of microcarriers.

Latest advances in chronic rhinosinusitis with nasal polyps endotyping and biomarkers, and their significance for daily practice.

The term chronic rhinosinusitis (CRS) comprises of an assortment of diseases that share a common feature: inflammation of the sinonasal mucosa. The phenotype classification of CRS, based on the presence of polyps, has failed to offer a curative treatment for the disease, particularly in refractory cases. Chronic rhinosinusitis with nasal polyps (CRSwNP) remains a challenging entity. Researchers have made efforts trying to characterize subtypes of the disease according to the endotypes, which are delineated by different immunological pathways, using biomarkers. Even if the inflammatory processes controlling CRSwNP are not fully understood, data suggested that the disease associated with a type 2 inflammatory mechanisms can be also linked to the type 1 or type 3 pathomechanism, being highly heterogeneous. Biomarkers for CRSwNP are proposed, such as: eosinophil count, cytokines, metalloproteinases, bitter and sweet taste receptors, and the nasal microbiome. For endotyping to be clinically applicable and simply determined, biomarkers referring to the intrinsic biomolecular mechanism still need to be found. Precision medicine is becoming the new standard of care, but innovative therapies such as biologics may be rather challenging for the clinicians in their daily practice. This new approach to CRSwNP implies patient selection and a simple algorithm for deciding the right treatment, easy to implement and adjust. Our review points out the ongoing new research on the pathophysiology of CRSwNP, biomarkers and treatment opportunities. It allows clinicians to keep abreast of current evidence-based knowledge and to individualize the management of CRSwNP, especially in refractory cases.