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At least 19 recordsLinked to original sources
PubMed1992

Penetrating wounds of the ear with oval window fistulas. Reports of 2 cases.

In 2 patients with penetrating wounds of the ear lesions involved the tympanic membrane and the ossicular chain. The long process of the incus was lying on the fallopian canal and the stapes was deeply depressed into the vestibule. In spite of a large oval window fistula, cochleovestibular signs were minimal. The fistula was sealed with adipose tissue and the stapes replaced by a Teflon-platinum piston prosthesis. The incus was repositioned and supported by a fat graft placed between the fallopian canal and the long process. This original technique of reconstructing the ossicular chain gave satisfactory functional results in both patients.

Adolescent↗
PubMed1977

Proplast in the middle ear and oval window of cats.

Poly(tetrafluoroethylene) carbon fiber implant material (Proplast), an all-plastic material, was evaluated for use in otologic surgery. Response to the implant was studied in the middle ear and vestibule of 14 cats by placing the Proplast in the oval window after stapedectomy. After a one year follow-up, it appears that Proplast was tolerated well, causing no inflammatory reaction in either the vestibule or cochlea, or in the middle ear cavity. Fibrous tissue ingrowth was found throughout the implant, and a fibrous tissue membrane covered both the vestibular and the tympanic surfaces of the Proplast. Being well tolerated by both middle ear and inner ear tissues, this porous, all-plastic material offers several otologic applications.

Animals↗
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↗
PubMed1989

Tolerance of membranous inner ear structures to pressure.

Pressure tolerance of round and oval labyrinthine windows and a cochlear segment represented by a part of the cochlear duct were investigated in experiments on cadaveric human temporal bones. The cochlear segment is less resistant than both the windows. Inner ear spaces are protected from pressure changes in the surroundings of the temporal bone by a system of narrow and comparatively long connections and some of them include also other structures strengthening the protective function (the valve described near the place where the cochlear aqueduct leads to scala tympani). Experiments with guinea pigs showed significance of inner ear integrity in protection from pressure changes. Tolerance of both windows was significantly higher in live animals than in cadaveric guinea pig bullae. Pressure tolerance of the windows was in turn higher in bullae than in isolated inner ear labyrinth. Conclusions were arrived at on the basis of the above facts that the inner ear is considerably resistant to pressure changes around it under normal circumstances. Ruptures in its parts appear only under special conditions and a number of factors participate in them. Window ruptures accompany most frequently injuries in other inner ear structures to which different degrees of hearing loss correspond. An isolated injury of windows is, from this viewpoint, rare even though it can be found and treated surgically best.

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↗
PubMed1989

Mechanics of a single-ossicle ear: I. The extra-stapedius of the pigeon.

The motion of the conical peak of the tympanic membrane (TM) at the tip of the extra-stapedius (ES) and of the columella footplate (CFP) were measured in the pigeon using the Mössbauer technique. The dimensions of middle-ear structures were measured in some of the experimental animals. The averaged velocity response at the ES for frequencies of 0.25-2.378 kHz was that of a second order, mass and stiffness controlled, resonant system with resonant frequency of 1.2 kHz and Q3 dB of 1.2. The mean velocity amplitude at resonance was 3.7 mms-1 at 100 dB SPL, which is approximately equal to the theoretical value of 3.5 mms-1 required for maximum energy transfer from a uniform plane acoustic wavefront in air. For the frequency regions 0.125-0.25 kHz and 2.378-5.657 kHz, the mean amplitude slopes for the velocity at the ES were 2 dB oct-1 and -3 dB oct-1, respectively. Above 5.657 kHz there was considerable inter-animal variation in the ES velocity responses. The direction of motion at the ES was frequency dependent above 1 kHz. For frequencies up to 1 kHz the ratio of CFP to ES velocity was independent of frequency; the mechanical lever ratio was 2.7, which was attributed to the geometry of the middle ear. At these frequencies the total transformer ratio for the middle ear, expressing the ratio of fluid pressure at the CFP to sound pressure at the ES, was estimated to be 35 dB.

Acoustic Stimulation↗
PubMed1991

[Bifenestration--a hearing-improving operation in severe ear malformations].

Bifenestration as an operation for hearing improvement is described in a case of congenital absence of the oval and round window. Besides the classical fenestration of the horizontal semicircular duct, an artificial round window was performed in the middle ear. Due to the acoustic resonance of the mastoid cavity, the resulting conductive loss in the higher frequencies was only 20-30 dB.

Adult↗
PubMed1988

Pressure transmission properties from the externa ear canal to the inner ear. An experimental study using guinea pigs.

The inner ear pressure (PIE) in response to pressure changes in the external ear canal was measured in guinea pigs while alternatively opening and closing the perforation of the otic bulla. When the bulla was opened, only a transient degree of applied pressure was transmitted to the inner ear and the amplitude of the PIE was smaller than that of the corresponding PIE when the bulla was closed. This was because the applied pressure was exclusively transmitted to the inner ear via the ossicular chain. When the otic bulla was closed, the pressure was transmitted not only via the ossicular chain but also via the round window (RW) through the middle ear cavity. When the bulla was closed, the amplitude of PIE was larger by a positive pressure load than by the corresponding negative one. The amplitude of PIE showed a linear relationship to ear canal pressure of at least within the +/- 200 mmH2O range, as long as pressure was slowly applied to the ear canal. When the loading pressure was abruptly changed, a bouncing response, possibly reflecting elasticity of the RW, was evoked, which diminished or disappeared when the round window was artificially ruptured.

Acoustic Impedance Tests↗
PubMed1978

TORPs and PORPs in tympanoplasty.

In an attempt to improve results in ossicular reconstruction, a newly introduced material, PlastiPore, has been evaluated over a short term. The techniques employed are described in detail and the use of a lateral covering material such as tragal cartilage is advocated as a means of preventing extension of this foreign material. The results in over 100 ears are better than those obtained with previous methods.

Ear Cartilage↗
PubMed1978

[About rupture and lesion of the labyrinthine windows (author's transl)].

After the extensive discussion of the last published literature on the different possibilities of a lesion of the labyrinthine windows, four own cases are discussed. In case of a typical anamnesis of single patients with sudden deafness after sudden exertion or trauma prior to onset the surgical exploration is recommended. It is concluded that spontaneous labyrinthine window ruptures must be added to the etiologic factors in sudden hearing loss.

Adult↗
PubMed1980

Oval and round window changes in otitis media. Potential pathways between middle and inner ear.

A longitudinal sequential study of oval and round window changes in otitis media in an experimental animal (cat) using Eustachian tube obstruction was done. Thirty-two animals were used. In this first sequential study of the oval and round windows in otitis media, the continuum of round window membrane changes from 1 day to 6 months after obstruction revealed changes to be gradual and similar to those of the mucoperiostium. These changes are suitable for changes in permeability and suggest that this membrane is a very likely pathway from the middle to the inner ear. Bony fistulas were not observed and the oval window remained essentially unchanged in time, thus they were not considered routes into the inner ear. Other possible routes are discussed.

Animals↗