Publications by authors named "Dunnebier E"

Objectives: Endolymphatic sac tumors (ELSTs) are rare adenomatous tumors arising in the petrous bone, either spontaneously (isolated) or in association with von Hippel-Lindau (VHL) disease. For 9 patients, this study describes the typical features and management of ELST and the clinical outcome of treatment. Similarities and differences are identified for ELST in isolation and in association with VHL disease.

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Choice of the most appropriate ear for CI in postlingually hearing-impaired adults is becoming more relevant as more patients are considered eligible for intervention. The aim of this study is to review factors that influence this choice and to formulate a flowchart. An extensive Medline search was performed.

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Although in the past cochlear implantation was considered contraindicated in patients with acute (AOM) or chronic suppurative otitis media (CSOM) with or without middle ear cholesteatoma, recent developments now make it possible to perform cochlear implantation in these patients. Various procedures are available to make the ears of patients with either acute or CSOM suitable for cochlear implantation and to minimize the risk of recurrence of the disease, device extrusion, or intracranial complications. This review discusses these different approaches for optimizing implant survival and preventing complications related to otitis media.

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Conclusions: Open-set speech perception in children with an inner ear malformation is equal to that of other congenitally deaf children after an average of 2 years follow-up.

Objective: To analyze audiological performance after cochlear implantation in a sample of children with radiographically detectable malformations of the inner ear compared to performance in prelingually deafened children at large.

Materials And Methods: Nine children with osseous inner ear malformations were compared to 22 congenitally deaf children, all of whom underwent cochlear implantation.

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Objective: With cochlear implantation, insertion of the electrodes can be hampered by cochlear obstructions. The aim of this study was to investigate the effects of these obstructions on the number of activated electrodes and postoperative speech perception.

Study Design And Setting: Retrospective analysis of the operation reports and CT-scans of patients who underwent cochlear implantation, at the Department of Otorhinolaryngology of the University Medical Center of Utrecht (n = 295).

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Vascular malformations of the cerebello-pontine angle (CPA) arising from the capillary plexus surrounding Scarpa's ganglion are rare tumors. We report a case of so-called "hemangioma" of the CPA which was operated on via a trans-labyrinthine approach based on a preoperative diagnosis of vestibular schwannoma. Although there are some differences between these tumors in terms of the clinical, biological and especially MRI findings, surgery is usually performed based on an assumption of vestibular schwannoma.

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Endolymphatic hydrops continues to be considered as a pathological factor in the etiology of Meniere's disease. We have developed the two-phase endolymphatic hydrops model, which seems to represent a functional model combining multiple etiologies, and which may resemble the fluctuating characteristics of Meniere's disease. A transmission electron microscopic study was performed on the endolymphatic sacs of four groups of guinea-pig cochleas: (1) controls, (2) non-operated, aldosterone-treated cochleas, (3) operated (dissection of the endolymphatic sac) cochleas, (4) operated and aldosterone-treated cochleas.

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Hypothesis: The aim of this study was to create a more dynamic animal model of Ménière's disease combining multiple causes, such as the role of endocrine factors and endolymphatic sac dysfunction, that may mimic the fluctuant characteristics of Ménière's disease.

Background: Endolymphatic hydrops remains to be considered a pathologic substrate in the etiology of Ménière's disease. The classic guinea pig model of inducing hydrops by total destruction of the endolymphatic sac is a nonphysiologic rigid model of Ménière's disease.

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Two-phase endolymphatic hydrops is a subtle experimental model for Meniere's disease. Chronic dysfunction of the endolymphatic sac, induced by dissection of the most distal part without causing damage to the intermediate part, is combined with increased endolymph production induced by administration of aldosterone which stimulates the N/K-ATPase in the stria vascularis. A transmission electron microscopic study was performed on the endolymphatic sacs of four groups of guinea pig cochleas: controls: non-operated aldosterone-treated cochleas; operated (dissection of the endolymphatic sac) cochleas; operated and aldosterone-treated cochleas.

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The classical guinea pig model for Meniere's disease, in which endolymphatic hydrops was achieved by destruction of the endolymphatic sac and obliteration of the endolymphatic duct, is a non-physiological profound model with shortcomings in relation to Meniere's disease as seen in patients. We developed a more subtle animal model; the two-phase endolymphatic hydrops. This model is based on a combination of chronic endolymphatic sac dysfunction, induced by slight destruction of the most distal part of the endolymphatic sac, and acute stress-induced endolymph production by stimulation of the Na/K-ATPase in the stria vascularis with aldosterone.

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In this study, a more subtle animal model of Menière's disease is investigated by damaging the distal portion of the endolymphatic sac by dissection or cauterization to produce mild dysfunction of endolymphatic outflow. Cauterization resulted in low degrees of hydrops without any correlation with the inflicted damage. Total dissection of the distal portion of the sac adjacent to the sigmoid sinus produced moderate to severe endolymphatic hydrops with interanimal variation.

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A combined perfusion- and immersion prefixation with glutaraldehyde followed by a tannic acid/arginine/osmium tetroxide (TAO) treatment of the guinea pig cochlea is described for field-emission gun scanning electron microscopy (FEG-SEM) observation of the fine structure of the stereocilia of the organ of Corti. Conventional osmium tetroxide postfixation methods in combination with a thin conductive coating failed to show the fine structure of the glycocalyx of the epithelial lining in the endolymphatic compartment of the cochlea, in particular, on the stereocilia surface. The antennulae-like glycocalyx covering of the stereocilia surface of the more pronounced rows of outer hair cells has been demonstrated only in ultrathin sections by means of cationic markers.

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Article Synopsis
  • The study used low-voltage field-emission scanning electron microscopy (SEM) to analyze the stereocilia in the guinea-pig cochlear organ of Corti, employing various fixation techniques and dissection methods.
  • A combination of glutaraldehyde fixation and specific treatments yielded optimal imaging results, revealing intricate surface structures of stereocilia for the first time.
  • Key discoveries included various cross-links and tip links, as well as a network of filamentous structures that may represent glycocalyx, contributing to understanding mechanoelectrical transduction processes.
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To determine whether closing the scleral flap with extra sutures can reduce the risk of overfiltration after trabeculectomy, we divided 339 trabeculectomies into three groups based on the number of scleral flap sutures used in the procedure, and studied the postoperative complications and results. The incidence of shallow or flat anterior chamber was significantly less in eyes that had received seven to nine sutures than in those that had received from two to six. Also, the incidence of cornea-lens touch was significantly less in the eyes with seven to nine sutures (P = .

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Chemical burning of the external eye by a strong acid or alkali often results in symblepharon formation despite conventional therapy. We report a case with application of a Megasoft Bandage Lens to prevent symblepharon reformation after surgical correction. Complete epithelial healing was established after 3 months, when the lens could be removed.

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Kangaroo care for preterm infants has great benefits for the parents and for the parent-infant bonding process. A clinical observational study was conducted in which several physiological variables were collected, including among others transcutaneous oxygen pressure, heart rate, respiratory rate, occurrence of apneic attacks, breathing pattern (studied with power spectrum analysis), behavioral states and rectal temperature, during kangaroo care in small preterm infants. Kangaroo-care did not significantly affect any of these physiological variables comparing the period of 1 h before, 1 h during and 1 h after kangaroo care.

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