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At least 865 records · Page 48Linked to original sources
PubMed1991

The impact of a syndromal diagnosis on surgery for congenital minor ear anomalies.

Between 1964 and 1986, 104 ears of 86 patients with a minor congenital ear anomaly underwent an exploratory tympanotomy at the Institute of Otorhinolaryngology of the University Hospital Nijmegen. A classification of these anomalies is proposed based on the surgical findings and results. The 4 groups in this classification are: isolated stapes ankylosis, stapes ankylosis associated with an anomaly of the malleus and incus, an isolated anomaly of the malleus and incus with a mobile stapes footplate and finally, aplasia of the oval and/or round window. In a total of 29 ears (22 patients) out of these 104 ears, the anomaly formed part of a syndrome. The various syndromes and the anomalies encountered are discussed. The impact of a syndromal diagnosis on the outcome of reconstructive ear surgery is discussed per syndrome.

Abnormalities, Multiple↗
PubMed1996

[Histopathology of the temporal bone in adhesive otitis media].

To understand the histopathological changes of adhesive otitis media (AOM) in human, temporal bone sections processed with the celloidin-embedding technique were reviewed. In the 338 pairs of temporal bone specimens, 20 cases (26 ears) showed characteristics of AOM. The results showed that the lesions of AOM were extensive, involving all middle ear structures including tympanic muscles, round and oval windows. There were various pathological changes, in every stage of inflammation and tissue repair. According to the main pathological characteristics, histopathological changes of the 26 ears were staged as exudation, inflammatory grannlation formation, histocyte response and collegen proliferation. As the process progressed, the amount of inflammatory cells and exudate decreased with the increase of fibroblasts. Certain factors were speculated to play an important role in the process of fibrosis. The authors analysed the difficulties in the management of AOM and causes of the unsatisfactory therapeutic results. Possible measures to improve treatment results were proposed.

Adult↗
PubMed1999

Morphological changes induced by administration of a Na+,K+-ATPase inhibitor in normal and hydropic inner ears of the guinea pig.

The objective of this study was to determine the effects of ouabain, a Na+,K+-ATPase inhibitor, in inner ears. Administering ouabain locally through the round window and vestibule, resulted in degenerative changes in cochlear and vestibular sensory cells and limbal fibrocytes, but the stria vascularis and spiral ligament were less affected. The position of Reissner's membrane was rarely changed. Vacuolar spaces in the sensory epithelia of cristae, maccula utriculi and macula sacculi increased in number. Nystagmus was a common occurrence with or without demonstrating degeneration of vestibular sensory cells. By administering ouabain systemically, the course of developing endolymphatic hydrops could not be altered in the ears with endolymphatic duct blockage. Edema of nerve endings of inner hair cells and vestibular sensory cells was frequently observed with administration of a high concentration of ouabain in both normal and hydropic ears, but edema was reversible. Degeneration of some vestibular sensory cells were observed in hydropic ears with a long survival time. The mechanism of selective sensitivity or non-sensitivity of inner ear tissues to ouabain is discussed.

Animals↗
PubMed1984

[Clinical aspects of sudden deafness].

Sudden deafness is a disease of multifactorial genesis. The cause remains as ever unknown. In addition to the vascular theory, the possibility of a perilymphatic fistula due to rupture of the oval or the round window membranes has gained more significance. Therefore the treatment of sudden deafness should begin as soon as possible. We treat such patients with infusions of Dextran 40. BVK and Complamin in increasing amounts, in addition to stella-ganglion block. It is not justifiable, for legal reasons to withhold treatment, and therapy should begin immediately.

Adult↗
PubMed1987

[Rupture of the membrane of the round window in stapes fixation].

A case of sudden deafness is described. Examination showed a mixed deafness on the left side, suspected to be due to fixation of the stapes and a simultaneous perilymph fistula. These lesions were proved by an exploratory tympanotomy. The interesting aspects of the case are emphasized: firstly recruitment caused by a perilymph fistula, present for 5 months without causing complete deafness; secondly improvement of hearing after surgical treatment of both pathological conditions; and finally the complete absence of vestibular signs.

Adult↗
PubMed2002

Isolated congenital round window absence.

Absence of the round window as a congenital defect is a rare entity that causes a conductive hearing loss. To the best of our knowledge, isolated and nonsyndromal round window absence has only been reported 3 times; the diagnoses were made during surgery. We are reporting on another case that was diagnosed before operation by virtual endoscopy of the middle ear during a high-resolution computed tomography scan. Although this new technique requires further validation, it may be an alternative to surgery as a means of confirming this rare diagnosis.

Adult↗
PubMed2003

Effect of round window membrane application of nitric oxide on hearing and nitric oxide concentration in perilymph.

Nitric oxide (NO), a free radical, has been found to be important in the development of middle ear effusions. However, the effect of NO in the middle ear effusion on cochlear function and on perilymph concentrations of NO has not been reported. We placed S-nitroso-N-acetylpenicillamine (SNAP), a NO donor compound, on the round window membrane (RWM) of adult chinchillas. Auditory brainstem response (ABR) thresholds were measured before and after the placement of SNAP on the RWM and hourly for 8 h after SNAP placement. Samples of perilymph were collected 2 h after application of SNAP and were assayed for total nitrate and nitrite, the end products of NO. Experimental ears demonstrated significant ABR threshold elevations after 5 h and elevated nitrate/nitrite in the perilymph. These findings suggest that NO present in the middle ear passes through the RWM into the inner ear and can cause significant hearing loss.

Animals↗
PubMed1985

Intermodulation distortion in the cochlea: could basal vibration be the major cause of round window CM distortion?

Acoustic and cochlear microphonic (CM) distortion products (DPs) have been measured at the meatus and round window, respectively, in the gerbil. It was hoped to deduce the relationship between round window CM distortion and vibrational energy of cochlear origin recorded as acoustic DP emissions in the meatus. Five different distortion components have been studied. For moderate intensities of stimulation, correlation between ear canal acoustic and CM distortion signals in respect of level and delay provides evidence of a common transmission path. One explanation of this is that the CM is being generated as a direct result of cochlea-generated vibration which reaches the base of the cochlea. The basalward propagation of these signals is discussed.

Acoustic Stimulation↗
PubMed1976

Herniation of the singular nerve into the round window niche.

We report two cases of herniation of the singular nerve into the round window niche and one case of bony dehiscence without herniation between the round window niche and the posterior canal ampulla. It is believed that the middle ear and the inner ear are completely separate. However, in the temporal bone of a 10- to 15-week-old human fetus, a communication between the round window niche and the posterior canal ampulla is observed. Later, the mesenchymal tissue in the communication is replaced by cartilage from near the posterior canal ampulla. If the communication does not fill with cartilage, ossification is not able to begin behind the posterior canal crista. When there is bony dehiscence behind the crista, the singular nerve fibers are easily pressed out by ossified endosteal bone and herniated into the round window niche.

Ear↗
PubMed1990

Permeability of the round window membrane to horseradish peroxidase in experimental otitis media.

The permeability of the round window membrane (RWM) was studied by using horseradish peroxidase (HRP) in the different stages of otitis media developed in guinea pigs, and it was compared with normal RWM under transmission electron microscopic examination. The experimental model of otitis media was developed by inoculation of a Pseudomonas aeruginosa suspension. When HRP could penetrate into the inner layer of a normal RWM, the duration of HRP instillation into the round window niche was 10 minutes. The permeability of the RWM in otitis media was as follows: 3-day animals showed penetration of HRP into the middle layer. In 1-week animals, HRP had penetrated into the inner layer in all 10 ears. In 2-week animals, HRP had penetrated into the inner layer in 6 of 11 ears. In 4-week animals, however, HRP was not seen in 6 of 7 ears. HRP had penetrated through the damaged focus of the epithelial cells by inflammation. These results suggest that any derangement of the epithelial linings could increase the penetration of HRP and also ototoxic materials into the inner ear through the RWM.

Animals↗
PubMed1993

Temporal bone pathology in scuba diving deaths.

Scuba diving has long been associated with otologic injuries; however, little is known about temporal bone pathology in diving-related deaths. We examined 18 temporal bones from 11 divers who died, primarily from complications of rapid ascent. Bleeding into the middle ear and mastoid air cells was nearly universal. Inner ear damage included hemorrhage around Reissner's membrane and the round window membrane and rupture of the utricle and saccule. Most of the observed inner ear damage was not surgically treatable.

Adolescent↗
PubMed1994

Sensorineural hearing loss from quinolinic acid: a neurotoxin in middle ear effusions.

Quinolinic acid (QUIN) is an endogenous metabolite that exerts a neurotoxic effect by binding to specific neuronal receptors. Studies involving a broad spectrum of infectious and inflammatory central nervous system diseases have suggested a role for QUIN in causing neuronal injury. Since there is evidence for presence of the QUIN receptor in mammalian cochleas, QUIN was measured in middle ear effusions (MEEs). Gas chromatography/mass spectrometry detected QUIN in each of 65 diluted human MEEs, with a mean of 482 +/- 75 (SEM) nmol/L and a range from 15 to 2667 nmol/L. QUIN was also detected in each of 197 chinchilla MEEs from five different models of otitis media, with a mean of 10.6 +/- 1.3 (SEM) mumol/L and a range from 0.23 to 146.0 mumol/L (corrected for dilution). To determine whether QUIN causes sensorineural hearing loss (SNHL), QUIN solutions were placed on round window membranes (RWM) for 20 to 240 minutes, in 20 chinchillas. SNHL was detected by electrocochleography in QUIN-exposed animals, but not in saline controls. We conclude that QUIN is present in MEEs and that QUIN in the middle ear has the potential to cross the RWM and cause sensorineural hearing loss, possibly by binding to specific neuronal receptors in mammalian cochleas.

Animals↗
PubMed1979

Sudden hearing loss in divers and fliers.

Many papers have been written about sudden sensory hearing loss and the effect of barotrauma on the inner ear. Fistulae of the round and oval window membranes have been implicated in the great majority of these cases. It has usually been recommended that the patient be treated with conservative therapy, such as bed rest, for a period of as long as 30 days and that the final hearing results are as good or better than those that have been surgically explored and corrected. In our experience immediate surgical exploration and correction of sudden severe or profound sensorineural deafness in the diver or flier is absolutely essential and the excellent results of hearing improvement in this select group certainly corroborates this theory. Other cases with the hearing loss limited to the high frequencies most notably have tinnitus and surgical exploration does not improve the hearing but may improve vertigo if present. Numerous cases are presented to support these supositions.

Adolescent↗
PubMed1994

Basal nitric oxide production in regulation of cochlear blood flow.

Nitric oxide (NO), recently identified as endothelium-derived relaxing factor, has been shown to influence both vascular and neural function. In blood vessels, NO is produced by endothelial and smooth muscle cells and may play a role in regulation of cochlear blood flow. In the central nervous system, NO functions as a neurotransmitter involved in long term potentiation. The principle hypothesis tested in this study was that basal NO production in the cochlear blood vessels contributes to regulation of CBF. Since NO is a vasodilator, diminished NO synthesis may decrease the level of CBF. Application of a competitive inhibitor of NO synthase either intravenously or to the round window membrane caused a reduction in CBF. The application to the round window membrane did not affect compound action potential thresholds. With intravenous administration, the effect on CBF was dose-related and could be reversed with the physiologic substrate, L-arginine. These data indicate that NO is produced in the cochlear blood vessels and contributes to the regulation of CBF.

Action Potentials↗
PubMed1991

Otic preparations altered permeability and thickness of the round window membrane of the chinchilla.

The effects of topical otic preparations (Cortisporin, Coly-Mycin, Aristocort, and Bestron) upon the permeability of the round window membrane (RWM) in chinchillas were investigated. Using K(+)-selective microelectrodes, the concentration of tetraethylammonium (TEA) ions was measured. Changes in the thickness of the RWM were measured using light microscopy. The RWM permeability was reduced significantly in Cortisporin- and Coly-Mycin-treated ears. Moreover, these two drugs resulted in a marked thickening of the RWM. In contrast, Aristocort or Bestron resulted in no alteration of the RWM permeability.

Animals↗
PubMed1990

Structural changes in the round window membrane following exposure to Escherichia coli lipopolysaccharide and hydrocortisone.

The present study focused on structural changes of the round window membrane (RWM) from agents that evoke transient or permanent impairment of the auditory brainstem response when applied into the RW niche. Escherichia coli (E. coli) lipopolysaccharide (LPS) in sterile water (SW) and a 2% suspension of hydrocortisone (CORT), micronized in SW, were instilled into the round window (RW) niche of Sprague-Dawley rats. The morphology of the RWM was analyzed 3 to 21 days after instillation of either substance. Both substances caused minor structural alterations at the light microscopic level. The RWM showed a slight thickening and an invasion of inflammatory cells. At the ultrastructural level, the CORT-treated specimens showed an increased epithelial height and numerous microvilli, whereas the epithelium of the LPS-treated specimens was extended and contained few microvilli resembling those in the normal RWM. We postulate that the RWM may undergo dynamic structural changes when exposed to various agents. The structural alterations per se can influence the passage of substances from the middle ear to the inner ear.

Animals↗
PubMed2003

Effects of trolox, locally applied on round windows, on cisplatin-induced ototoxicity in guinea pigs.

OBJECTIVE: Cisplatin (CDDP), an antitumor agent widely used in the treatment of pediatric solid tumors, has dose-limiting side effects such as ototoxicity and nephrotoxicity. Recently, evidence has been accumulated to demonstrate that these side effects are closely related to oxidative stress. In the present study, we attempted to suppress CDDP-induced ototoxicity in guinea pigs by administering trolox, a water-soluble analogue of alpha-tocopherol which is a natural lipid-soluble antioxidant, locally on round windows. METHODS: Hartley albino guinea pigs (250-300 g) were treated with CDDP (0.3 mg/ml) in the presence or absence of a combined treatment of trolox (5 mM). Both drugs were administered locally on round windows. RESULTS: The combined treatment of trolox distinctly improved the ototoxic side effects induced by CDDP. These were: elevation of auditory brain stem response threshold at 4, 8 and 16 kHz and substantial losses of outer hair cells with the base-to-apex gradient. CONCLUSION: Trolox, locally applied on round windows, showed a suppression on CDDP-ototoxicity. The results obtained in the present study suggest that a local application of trolox in the tympanic cavity can be a promising candidate to prevent the CDDP-ototoxicity in the future.

Administration, Topical↗