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Results for “Oval Window, Ear”

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At least 325 records · Page 18Linked to original sources

PubMed1991

Rapid protein test for perilymph fistula.

The existence of a perilymph fistula may be difficult to prove preoperatively or at surgery, except in obvious cases in which perilymph can be seen coming out of the inner ear around the stapes footplate or round window niche. Some surgeons doubt the common occurrence of spontaneous perilymph fistula. Most surgeons believe that a perilymph fistula is rare and is produced by some type of trauma and pressure change to the inner ear fluids. Analysis of fluid collected from the oval window area and round window niche may be a great help in confirming or disproving the diagnosis of perilymph fistula. After a myringotomy or tympanotomy, fluid collected in micropipets from the oval window or round window area is analyzed for protein concentration, using rapid protein indicator paper. The original technique was developed in the 1960's to analyze the inner ear fluid as a diagnostic procedure (i.e., diagnostic labyrinthotomy) in acoustic neuroma suspects. Normal perilymph has a protein content of approximately 200 mg %, which turns the indicator paper light green, whereas serum or transudate has a protein content of approximately 7000 mg %, which turns the indicator paper dark green. The protein concentration is determined by comparing the color of the indicator paper with the color developed by known protein standards. A middle ear tap may help avoid negative middle ear exploration for perilymph fistula and helps document the presence or absence of perilymph after the exploration.

Cochlear Diseases↗

PubMedDate not supplied

Changes in spontaneous activity and CNS morphology associated with conductive and sensorineural hearing loss in chickens.

The effects of a conductive or mixed (conductive and sensorineural) hearing loss on anatomical and physiological properties of the chicken auditory system were examined. Animals used in the anatomical studies underwent either a columella (ossicle) removal, which produced a moderate conductive hearing loss, or an oval window puncture, which produced a severe mixed hearing loss, at 4 days posthatch. In a companion study, multiunit spike counts were obtained from 3-week-old chickens before, during, and after consecutive tympanic membrane puncture, columella removal, and oval window puncture. Tympanic membrane puncture and columella removal (conductive hearing loss) are not associated with either cell area changes in the nucleus magnocellularis or changes in spontaneous neuronal activity. Conversely, an oval window puncture (sensorineural damage) is associated with a cell area reduction of 20%, as well as a marked decline in activity within auditory nuclei.

Action Potentials↗

PubMed1983

Small fenestra stapedectomy technique: reducing risk and improving hearing.

During the past 25 years many variations have emerged in stapedectomy, most of which centered around either a change in the prosthesis itself or in the type of oval window seal. The small fenestra stapedectomy technique (SFT) represents a change in surgical procedure rather than in prosthetic design. This technique offers the opportunity to improve hearing results while reducing risks in stapedectomy surgery. Four areas of significant improvement are seen in patients in whom the SFT was used: (1) improved hearing in the high frequencies of 2000, 4000, and 8000 Hz, (2) improved speech discrimination scores, (3) a significant reduction in the number of reported vestibular complaints, and (4) a reduction in the number of serious postoperative sensorineural hearing losses.

Ear, Middle↗

PubMed2003

[Vestibulotomy about the displaced facial nerve].

OBJECTIVE: To investigate the feasibility of vestibulotomy above the displaced facial nerve. METHODS: From January 2000 to January 2002, eight patients with severe congenital conductive hearing loss underwent the vestibulotomy above displaced facial nerve and reconstruction of the ossicular chain with a total ossicular replacement prosthesis, which all for the congenital middle ear deformity and the facial nerve overhang and concealed the oval window niche or lied inferior to the oval window. In four of eight cases, the facial nerve was transposed in order to access the oval window niche. RESULTS: Hearing of this patients improved 15 dB in 2 ears, 16-25 dB in 3 ears and 26 dB or more in 3 ears. In no case was there a postoperative facial paresis. With 4 months to 28 months follow-up, the postoperative hearing gain was stable. CONCLUSIONS: Vestibulotomy above displacement of the facial nerve allows a final chance of achieving serviceable hearing through surgery. The lack of facial nerve injury and the potential for hearing restoration make this procedure feasible in otherwise marginal or poor surgical candidates.

Adolescent↗

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↗

PubMed1983

Stapedectomy in osteogenesis imperfecta.

Operative findings and results of stapedectomy in 32 patients (43 ears) with osteogenesis imperfecta are presented. The stapes footplates were in many ears thick and of a very soft consistency. In all the operated ears we found the stapes footplates fixated in the oval window. Brittle and atrophic stapes crura were a common finding, but in only 5 ears fractures of the crura were observed. A thick and vascular middle ear mucosa was seen in several ears. Although the middle ear proved quite different from that of otosclerosis, no major difficulties and no serious complications occurred during stapedectomy. Both the immediate postoperative hearing gain and the long-term hearing results were, in general, satisfactory. Our study supports the statement of others, that stapedectomy in osteogenesis imperfecta is a safe and reasonable alternative to hearing aids.

Adolescent↗

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↗

PubMed1990

Summating potential/action potential ratio in perilymph fistula.

A prospective study of electrocochleography in patients with clinically suspected perilymph fistula was undertaken to determine its predictive value in that disorder. One hundred forty-four patients suspected of having perilymph fistula had electrocochleography performed--34 of these (39 ears) had exploratory tympanotomy. Of the 19 ears with normal preoperative summating potential/action potential (SP/AP) ratio, ten had perilymph fistula identified at the time of surgery. Of the 20 ears with abnormal SP/AP ratio, 16 had perilymph fistula confirmed at exploration, 18 had resolution of symptoms after oval window and round membrane grafting, and only one ear had postoperative persistence of the abnormal SP/AP ratio. This study suggests that an abnormal SP/AP ratio is not only predictive of endolymphatic hydrops, but also of perilymph fistula (both problems of inner ear fluid imbalance). This study also suggests that, while abnormal SP/AP ratio is fairly specific for inner ear fluid imbalance, it is not sensitive.

Adolescent↗

PubMed1995

Cerebrospinal fluid leak after acoustic neuroma surgery.

BACKGROUND: CSF rhinorrhea is a common complication of acoustic neuroma surgery. METHODS: Twenty cases of persistent cerebrospinal fluid rhinorrhea, 2 of transient leaks, and 2 of late meningitis occurring in a series of 156 posterior fossa acoustic neuroma removals were studied. Prophylaxis of leaks was usually attempted by filling opened air cells in the drilled internal auditory canal (IAC) with bone wax. Communications were repaired by rewaxing the IAC, or by fat packing of either the mastoid or the eustachian tube, middle ear, and mastoid. RESULTS: Most leaks were diagnosed within 1 week of surgery, although 1 occurred 4 years postoperatively. Those seen later were usually recurrences of a previously repaired leak or cases of meningitis. Leaks were more common later in the series when a more lateral unroofing of the IAC was used. The communication usually occurred through air cells opened while unroofing the canal, but two were via the vestibule and oval window. Treatment failed in 38% of cases in which canal rewaxing was used. There were no failures when the communication was sealed by fat obliteration of the eustachian tube, middle ear, and mastoid. CONCLUSIONS: Leaks are more common with a more lateral unroofing of the IAC. A leak may occur into the middle ear via the oval window. Optimal treatment is packing of the middle ear and mastoid with fat.

Cerebrospinal Fluid Rhinorrhea↗

PubMed1990

Congenital absence of the oval window.

From 1983 to 1987, seven patients with conductive hearing loss were found to have congenital absence of the oval window. Six of these patients underwent vestibulotomies and reconstruction with House wires or total ossicular reconstruction prostheses. Surgical findings included absent or rudimentary stapes in all cases, abnormal facial nerves in four cases, and abnormal long processes of the incus in four cases. All patients had normal external ear canals and tympanic membranes. Hearing initially improved 20 to 45 dB in four of the six patients reconstructed. Over time, however, much of this initial hearing gain was lost. A marked difference in hearing results was evident between this series of absent oval window cases and a recent series of major atresia cases.

Adolescent↗

PubMed2000

[Comparison of microfissures between the oval and round window niche areas in human temporal bone].

There are numerous reports on microfissures in the round window niche area, but not many reports have appeared on microfissures in the oval window niche area. In addition, few studies have compared microfissures between the oval and round window niche areas in the same subjects. Hence, the present study investigated the prevalence of microfissures in both areas in human temporal bones. The study was conducted on the 637 ears of 333 cases. Specimens were prepared according to the conventional methods: after fixation, decalcification and dehydration, each specimen was embedded in Celloidin, and the temporal bones were sectioned horizontally at 25-micron intervals. Every 10th section was stained with hematoxylin & eosin, and each section was analyzed under a light microscope. The prevalence of microfissures was analyzed in relation to the sex, left/right differences and age of the subjects. Microfissures were seen in the oval window niche area in 66.2%, and in the round window niche area in 92.0%. When a microfissure was seen in the oval window niche area, it was also detected in the round window niche area in every case. There were no sex or left/right differences in the prevalence of microfissures, and microfissures occurred bilaterally in most cases. The youngest subject with a microfissure in the oval window niche area was a 14-year-old, and the prevalence increased with age up to approximately 60 years. On the other hand, microfissures in the round window niche area were seen in a 3-year-old, and were seen in most cases over the age of ten. These findings suggest that microfissures are more likely to occur in the round window niche area as compared to the oval window niche area. However, the prevalence of microfissures in the oval window niche area was not low either, and it is important to pay attention to both the oval and round niche areas when microfissures are involved in the formation of perilymph fistulae. Given that the prevalence of microfissures in the oval window niche area increased up to about 60 years of age, not only growth, but also mastication, may be involved in the occurrence of microfissures.

Adult↗

PubMed1962