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Background: This study describes the development of output devices for round window middle-ear. To overcome the problems of output devices that apply sound pressure directly to the round window, an acoustic bellows-type round window transducer was implemented by combining a small bellows, acoustic tube, and balanced armature driver.
Methods: The output characteristics of the proposed acoustic bellows-type round window transducer were confirmed through bench tests and distortion measurements. To compare the vibration transmission characteristics of the proposed transducer with those of sound pressure stimulation devices, an experiment was performed using four human temporal bones.
Findings: The average output magnitude of the acoustic bellows-type round window transducer was equivalent to sound pressure levels of 92, 96, and 108 dB for frequency ranges of <1, 1-2, and > 2 kHz, respectively. The results showed that the proposed transducer delivered vibration consistently without reducing the sound pressure level due to leakage, unlike the sound pressure stimulation device.
Interpretation: Therefore, the acoustic bellows-type round window transducer is a more stable and suitable output device for round window middle-ear implants than a sound pressure stimulation device. It is expected to overcome the limitations of sound pressure stimulation devices and to contribute to new technical solutions in the field of round window middle-ear implants development.
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http://dx.doi.org/10.1016/j.clinbiomech.2024.106349 | DOI Listing |
Eur J Pharm Sci
September 2025
Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea. Electronic address:
Intratympanic (IT) delivery of dexamethasone (DEX) is widely used for treating inner ear disorders; however, its therapeutic efficacy is limited by poor permeability of the round window membrane (RWM). This study aimed to evaluate and compare the efficacy and safety of three pharmacological agents-histamine (HIS), 3% hypertonic saline (3% HS), and sodium caprate (SC)-as adjuvants for enhancing RWM permeability and improving IT-DEX delivery in a murine model. Following IT administration of each permeability enhancer followed by DEX injection, perilymph DEX concentrations were measured using ultra-high-performance liquid chromatography, and DEX receptor expression in the organ of Corti was assessed by immunofluorescence.
View Article and Find Full Text PDFOtol Neurotol
August 2025
Department of Radiology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA.
Objective: To investigate the anatomical diversity of the round window (RW) in the pediatric population, focusing on its transcanal trajectory and anatomical angles. The study aims to provide insights into how RW accessibility changes with age, which may impact surgical planning and drug delivery approaches.
Study Design: Retrospective radiologic review of pediatric patients who underwent high-resolution CT scans of the temporal bone.
BMC Vet Res
September 2025
Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, Prague Suchdol, 165 00, Czech Republic.
Background: Pathogenic blood-feeding nematodes, such as Haemonchus contortus and the invasive Ashworthius sidemi, infect a wide range of wild and domestic ruminants. While the spread of A. sidemi among European cervids has been studied, its presence in chamois (Rupicapra rupicapra) remains poorly documented.
View Article and Find Full Text PDFInt J Biol Macromol
August 2025
Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany; Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany; Cluster of Excellence "Hearing4all", German Research Foundation,
The anatomical and structural complexity and variability of the hearing organ pose significant challenges for efficient drug delivery to treat inner ear disorders. To address this issue, we developed a local drug delivery implant (LDDI) fabricated with 3D printing technology. The implant is personalized based on the individual patient's anatomy of the round window niche from where drugs can diffuse into the inner ear.
View Article and Find Full Text PDFAuris Nasus Larynx
August 2025
Department of Radiology, Mie University Graduate School of Medicine, Tsu, Japan.
Objective: To directly compare the image quality of photon-counting detector CT (PCD-CT) and conventional energy-integrating detector CT (EID-CT) for temporal bone imaging within the same patient cohort.
Methods: This retrospective study included seven patients who underwent both EID-CT and PCD-CT for clinical indications. To ensure a valid comparison of the imaging technologies, images of the non-operated, contralateral temporal bone were evaluated.