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Results for “Round Window, Ear”

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At least 19 recordsLinked to original sources
PubMed2001

Imaging of the windows of the temporal bone.

Imaging of the window of the temporal bone has became an important tool in the analysis of hearing loss, vertigo, tinnitus in a context of trauma, malformation, otosclerosis, and chronic otitis media. A good knowledge of the anatomy and a good technical procedure are necessary for making an efficient diagnosis. The increased thickness of the footplate may be delineated in otosclerosis, chronic otitis media, malformation, when it is measured at 0.7 mm or more in horizontal computed tomography (CT) sections. The traumatic displacement of the stapes, particularly within the labyrinths, is easily diagnosed in horizontal CT section. Imaging of the round window is now very important for the detection of otosclerotic foci, congenital stenosis, and perilymphatic fistula with or without fracture. Magnetic resonance imaging (MRI) with the high-resolution T2 plays an important role in the detection of a small amount of fluid in the round window recess, confirming the traumatic perilymphatic fistula without fracture.

Deafness↗
PubMed1981

Permeability of the labyrinthine windows in guinea pigs.

Permeability of the labyrinthine windows in guinea pigs was investigated by electron microscopy using horseradish peroxidase (HRP). In the round window membrane, HRP particles were readily taken up by the epithelial cells and were transported to the subepithelial layer which was regarded as being bathed in the perilymph. The oval window also appears to allow the passage of the macromolecules in view of the HRP-labeled granules in the chondrocytes of the stapediovestibular joint. The transport of the HRP particles from the middle ear to the inner ear was confirmed by the uptake of those in the saccular epithelium after 30--40 min exposure to the tracer.

Animals↗
PubMed1986

Delayed onset hearing loss in a two-year old.

This paper describes a delayed onset sensorineural hearing loss in a baby known to have normal hearing until at least 13 months. A mild high-frequency loss was discovered quite by accident at 25 months. The bilaterally symmetrical loss progressed over the next 6 months to no measurable high-frequency hearing and a 70 dB threshold at 500 Hz. To our knowledge this is the youngest completely documented case of what has been called hereditary delayed onset hearing loss. However, in this instance, and perhaps unsuspected in others, this child had bilateral oval and round window fistulas whose repair may have not only arrested the progression of her loss, but even improved her residual hearing sensitivity.

Audiometry↗
PubMed2006

Locating the scala media in the fixed human temporal bone for therapeutic access: a preliminary study.

OBJECTIVE: To investigate the location of the scala media in relation to the round window niche in human temporal bones. DESIGN: Ten human temporal bones were investigated by radical mastoidectomy and promontory drill-out. SETTING: Temporal bone laboratory. OUTCOME MEASURES: The distance from the scala media to the anterior edge of the round window niche, measured by Fisch's stapedectomy measuring cylinders. RESULTS: The scala media was identified at the transection point of a vertical line 1.6 to 2.2 mm (mean=1.8 mm; standard deviation=0.2) anterior to the anterior edge of the round window niche and a horizontal line 0.2 mm inferior to the lower border of the oval window. CONCLUSION: This report demonstrates the point of entry into the scala media via the promontory in fixed temporal bone models, which may provide a site of entry for stem cells and gene therapy insertion.

Cochlear Duct↗
PubMed1986

Perilymphatic fistulas: are they exclusive to the round and oval windows?

Eleven patients suspected of having perilymphatic fistulas were evaluated. A perilymphatic fistula was demonstrable in ten of these patients. In six patients, fistulas of one of the windows, or both were found. In two patients, combined fistulas of both the round window and lateral semicircular canal were found. In two other patients, fistulas were found only in the lateral semicircular canal. The patients in whom fistulas were found and repaired improved dramatically. The patient without a demonstrable fistula remained symptomatic. We have shown that perilymphatic fistulas can occur in the lateral semicircular canal, and suggest exploring this area when indicated.

Adult↗
PubMed1988

Surgical dimensions of the facial recess in adults and children.

The facial recess approach permits surgical access to the round window area. This route is used in patients who are undergoing cochlear implantation. To evaluate the feasibility of this procedure in children as compared with adults, serial sections of temporal bones were used to measure the surgical dimensions of the facial recess. No statistically significant differences in the dimensions of the facial recess or the extended facial recess approaches were found between children and adults. The relationship of the facial and chorda tympani nerves to the annular plane exhibited no change with postnatal growth. These structures translate posteriorly and laterally toward the annular plane as they descend within the temporal bone. Therefore, the facial recess approach represents no greater hazard in a child than in an adult.

Adult↗
PubMedDate not supplied

Morphometric and ultrastructural findings on human vestibular ganglion cells.

Eight human temporal bones (4 patients) were fixed within 2 h after death by perilymphatic perfusion through the oval and round windows. After preparation, 30-micron-thick sections were cut for light microscopy and ultrathin sections for ultrastructural evaluation. Under the light microscope, the diameter, the circumference and the area of the vestibular ganglion cells were measured. The data were statistically analyzed. The histograms of cell measurements showed two maxima. When observing the diameter of cells, one was at 40 microns and the other at 28 microns. Under the light microscope, we could distinguish two cell types, which mainly differed in size and content of granules in the cytoplasm. Ultrastructurally we identified also two cell types: larger cells with many mitochondria, dark clusters of endoplasmic reticulum and a varying amount of dark-stained lysosomes in the cytoplasm and smaller cells with only few mitochondria, no lysosomes and an extended rough endoplasmic reticulum. None of the ultrastructurally analyzed ganglion cells were myelinated.

Cell Nucleus↗
PubMed1989

Perilymphatic fistulas in children: rationale for therapy.

We report 26 consecutive patients (32 ears) who were identified in a 2 year period (July 1, 1985-June 30, 1987) with unexplained sudden, fluctuating, or progressive sensorineural hearing loss (SNHL). All patients underwent an exploratory tympanotomy and a perilymphatic fistula was identified in 13 patients (14 ears). The mean change of 14 +/- 27 dB in speech reception threshold before and after surgery was significant at p = 0.08 among children with fistula and ranged from -30 to 80 dB. In children with sudden, progressive or fluctuating SNHL and multiple sensory deficits, including blindness or contralateral SNHL, or prior head trauma, prompt surgical exploration is mandatory. Additionally, the aggressive management of otitis media with effusion is essential in such patients to minimize fluctuations in hearing caused by superimposed conductive hearing loss. Caution must be exercised to separate fluctuating hearing loss from fluctuations in audiologic testing.

Adolescent↗
PubMedDate not supplied

Otosclerosis: comparison of complex-motion tomography and computed tomography.

A prospective computed tomographic and complex-motion tomographic evaluation was performed in 18 suspected or proven cases of otosclerosis. Although there was good agreement between both methods, there was no greater diagnostic accuracy with computed tomography. However, computed tomography demonstrated the changes better than complex-motion tomography.

Evaluation Studies as Topic↗
PubMed1978

Spontaneous labyrinthine window rupture.

Spontaneous labyrinthine window rupture has been increasingly recognized in recent years. Seven such case histories and details of subsequent management by tympanotomy and fat graft plugging of the fistulae are reported. The importance of a history of physical stress preceding onset of symptoms is emphasized in the case of certain patients who presented with sudden hearing loss accompanied, in some cases, by tinnitus or vertigo. The first 5 patients were reported in a paper presented in October 1977 at the First South African National Otorhinological Congress in Cape Town.

Adult↗
PubMedDate not supplied

Middle ear structure in the chinchilla: a quantitative study.

The anatomic features of the chinchilla middle ear were identified and various aspects of the conductive apparatus were measured in a number of specimens by different methods. These aspects included area measures of the tympanic membrane, stapes footplate, oval window, and round window; middle-ear volume; dimensions of the ossicles, the length of their rotational axes as well as the malleus to incus lever ratio. We also weighed the ossicles. The findings are discussed with reference to their possible significance for auditory signal processing in the chinchilla.

Animals↗
PubMed2002

Analysis of gentamicin kinetics in fluids of the inner ear with round window administration.

HYPOTHESIS: That a theoretical basis for quantifying drug distribution in the inner ear with local applications can be established. BACKGROUND: As methods of local drug delivery to the inner ear gain wider clinical acceptance it becomes important to establish how drugs are distributed in the ear as a function of time and for different delivery methods. METHODS: The time course of gentamicin concentration in the inner ear fluids was simulated with a program that considered general pharmacokinetic principles and incorporated inner ear dimensions and drug dispersal processes, including diffusion, clearance, and intercompartmental exchange. RESULTS: Cochlear fluid space dimensions of the chinchilla were derived from three-dimensional magnetic resonance images and were incorporated into the simulator. The published time course of gentamicin in vestibular perilymph of chinchillas was closely approximated by the adjustment of parameters defining round window membrane permeability, clearance, and interscala exchange. To simulate the time course, it was necessary for drug entry into the vestibule to be dominated by interscala exchange rather than longitudinal spread through the helicotrema. The effects of different round window delivery methods were also calculated. Perilymph drug levels and spatial distribution in the ear were shown to be markedly influenced by the time the applied drug remained in the middle ear. CONCLUSION: The development of local inner ear drug application strategies requires consideration of inner ear pharmacokinetic characteristics, delivery methods, and therapeutic range of the drug.

Animals↗
PubMed1994

The deafness, pre-auricular sinus, external ear anomaly and commissural lip pits syndrome--otological, vestibular and radiological findings.

Commissural lip pits, pinna dysplasia, pre-auricular sinus and hearing loss constitute a recently described autosomal dominant branchial arch syndrome. In a large family, eight out of the 74 members were also affected by conductive hearing loss. No inner ear abnormalities could be demonstrated on the CT scans. In three patients (four ears) out of four patients (six ears), exploratory tympanotomy revealed serious ossicular chain anomalies. In one ear, round window aplasia was also present. Long-term hearing improvement could only be achieved in one ear.

Abnormalities, Multiple↗