PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Oval Window, Ear”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1996

[High resolution computerized tomography of middle ear abnormalities].

BACKGROUND: The aim of this study was to analyze malformed petrous bones with computed tomography and to develop a radiologic score which can help to judge the indication for operative reconstructions. METHODS: One hundred forty-two petrous bones in 71 patients with unilateral or bilateral microtia, atresia of the external auditory canal, and malformations of the middle ear were evaluated with high-resolution CT. RESULTS: In 97% of patients with severe auricular dysplasia, there was dysplasia of the middle ear ossicles; in 70% the stapes was malformed. In 32% the oval window was occluded, and in 7% the round window. In 75%, the canal of the facial nerve was displaced, and 16% also showed abnormalities of the labyrinth. A close correlation between the malformation of the auricle and of the middle ear was not found. CONCLUSIONS: High-resolution CT is necessary for the evaluation of malformed middle ears. Based on the abnormalities described, we propose a radiologic score for the assessment of malformed petrous bones. This consists of the following criteria: external auditory meatus, pneumatization of the mastoid and of the tympanic space, size of the tympanic space, facial nerve, vessels, malleus and incus, stapes, oval and round window. The graded points of each structure are added up to the score, which might range between 0 and 28. This score can help to judge the indication for reconstruction of the middle ear. In bilateral malformation we suggest a middle ear reconstruction of the better hearing ear if the score is greater than or equal to 15, and in unilateral malformation if it is at least 20. In patients with lower scores, we only suggest hearing aids.

Adolescent↗
PubMed2006

Resorption of auditory ossicles and hearing loss in mice lacking osteoprotegerin.

Bones conduct sound in the middle ear. The three ossicles-the malleus, incus, and stapes-form a chain that transmits vibrations from the tympanic membrane to the oval window of the inner ear. Little is known about bone remodeling events in these ossicles and about potential effects of osteoporosis on hearing loss. Osteoclastic bone resorption is enhanced in Opg(-/-) mice lacking osteoprotegerin, which is a soluble decoy receptor for the osteoclastogenic cytokine RANKL. We asked whether auditory ossicles are resorbed in Opg(-/-) mice, and whether these mice suffer from impaired auditory function. All three ossicles in Opg(-/-) mice showed thinning, especially at the malleal manubrium and incus body. Most notably, unlike in the case in wild-type mice, the junction between the stapes and the otic capsule was fixed in Opg(-/-) mice, and the stapedial footplate was thinner and broader. Radiological analyses revealed that malleal cortical thickness was positively correlated with tibial bone mineral density in Opg(-/-) and control littermate mice. Furthermore, progressive hearing loss was detected in Opg(-/-) mice starting at 6 to 15 weeks of age. These data suggest that osteoprotegerin plays a crucial role in hearing by protecting the auditory ossicles and otic capsule from osteoclastic bone resorption.

Acoustic Stimulation↗
PubMed2000

Imaging and clinical evaluation of isolated atresia of the oval window.

BACKGROUND AND PURPOSE: Congenital causes of hearing loss in children commonly are encountered, and imaging aids in diagnosis as well as presurgical evaluation. Atresia of the oval window not associated with atresia of the external auditory canal (EAC) is a rare cause of congenital hearing loss in children. We present the clinical and imaging findings in children with isolated oval-window atresia. METHODS: Atresia of the oval window was defined as the absence of the structure with the presence of a bony plate superimposed between the vestibule and middle ear. The bony plate is within the expected region of the oval window. Using a computerized database, nine patients with isolated oval-window atresia were found. All had been evaluated with high-resolution computed tomography (HRCT) and all had medical records available for review, including audiogram results. Imaging studies were interpreted by the consensus of two pediatric neuroradiologists. RESULTS: Atresia of the oval window was documented in all cases using HRCT criteria. The most common anomalies associated with oval-window atresia were inferomedial malposition of the facial nerve (n = 8), malformed incus (n = 6), and displaced stapes (n = 2). Four patients had symmetric bilateral involvement. Hearing tests were not specific, because conductive, sensorineural, and mixed patterns were found. CONCLUSION: Anomalies of the oval window should be sought in all patients with congenital hearing loss. Associated findings, such as facial nerve aberrancy and ossicular anomalies, are important in both diagnosis and surgical planning.

Adolescent↗
PubMed2001

How do tympanic-membrane perforations affect human middle-ear sound transmission?

Although tympanic-membrane (TM) perforations are common sequelae of middle-ear disease, the hearing losses they cause have not been accurately determined, largely because additional pathological conditions occur in these ears. Our measurements of acoustic transmission before and after making controlled perforations in cadaver ears show that perforations cause frequency-dependent loss that: (1) is largest at low frequencies; (2) increases as perforation size increases; and (3) does not depend on perforation location. The dominant loss mechanism is the reduction in sound-pressure difference across the TM. Measurements of middle-ear air-space sound pressures show that transmission via direct acoustic stimulation of the oval and round windows is generally negligible. A quantitative model predicts the influence of middle-ear air-space volume on loss; with larger volumes, loss is smaller.

Ear, Middle↗
PubMed1990

Fitness of civil aviation passengers to fly after ear surgery.

Movements of the tympanic membrane caused by changes in air pressure are conducted to the ossicles of the middle ear. The gliding mechanism of the malleus-incus articulation converts in-and-out movements of the eardrum into up-and-down movements of the stapes, thereby protecting the inner ear from static pressures. In certain ear operations, the replacement of a middle ear ossicle by a prosthesis disjoints the malleus-incus articulation or makes it rigid. Pressure is then transmitted in unattenuated form from the eardrum through the oval window to the inner ear. Impairment of pressure equilibration, for example due to obstructed eustachian tubes, can lead to prosthesis displacement with severe injury to the vestibulocochlear apparatus. Thus, patients should be advised to begin equilibration of pressure at the beginning of descent of commercial airlines or civil aviation flights, and to repeat it a brief intervals.

Acoustic Impedance Tests↗
PubMedDate not supplied

Temporal bone histopathologic findings in congenital anomalies of the oval window.

The histopathologic findings in five temporal bones from three cases showing various stages of oval window development arrest are presented. The anomalies ranged from complete absence of the oval window to congenital cartilaginous fixation of the stapedial footplate. Surgical approaches fro establishment of a new oval window must take into consideration the frequent association of facial nerve anomalies with anomalies of the oval window.

Ear, Inner↗
PubMedDate not supplied

Computed tomographic image analysis of ears with otosclerosis.

To evaluate the usefulness of quantitative analysis of computed tomographic images in diagnosing stapedial otosclerosis, high-resolution temporal bone computed tomography (CT) of 32 ears with otosclerosis and 19 control ears was used. The images on the section containing the oval window were digitized using a scanner, and the ratio of the mean gray scale value of 5 areas in the optic capsule including the area anterior to the oval window to that of the cortical bone was calculated. The mean value of the ratio of the area anterior to the oval window was significantly lower in the otosclerosis group (0.85 +/- 0.10) than in the control group (1.03 +/- 0.03; Student t test: t = 7.94, p < 0.0001). In 30 of 32 (93.7%) otosclerotic ears, the values were lower than the normal range calculated in the control group. This method of quantitative CT image analysis comparing the area anterior to the oval window was considered useful in diagnosing stapedial otosclerosis.

Adolescent↗
PubMedDate not supplied

Mucormycosis of the temporal bone.

Mucormycosis of the temporal bone is described in a 60-year-old female with uncontrolled diabetes mellitus whose symptoms related to cranial nerve palsies and hearing loss, following spread of infection from the nasopharynx. The infection spread along the eustachian tube and tensor tympani muscle to the base of the skull, involving the internal carotid artery with mycotic thrombosis and rupture. Subsequent spread occurred from this area predominantly along nerve pathways and as mycotic emboli in blood vessels of the labyrinth and middle ear. Infection also spread from the anterior middle ear wall through the oval window into the vestibule. The temporal bone changes were those of granulomatous inflammation with necrosis and ischemic infarction.

Ear, Middle↗
PubMed1993

The role of KTP laser in revision stapedectomy.

In recent years, the safety and efficacy of revision stapedectomy has come under scrutiny. Experienced surgeons report that the results of such surgery are often worse than the results after primary surgery and that the risks of sensorineural hearing loss, tinnitus, and vertigo are increased. With the addition of laser technology to revision stapes surgery, the procedure to open the neomembrane over the oval window and gain access to the inner ear can now be performed safely. This allows positive identification of the oval window and assures placement of the prosthesis through the fenestra rather than on an intermediate segment of scar or bone in the region of the footplate. Our studies have shown the laser to be an important tool that enhances the safety and efficacy of revision stapedectomy.

Audiometry↗
PubMed1988

The effect of fibrin tissue adhesive on the middle and inner ears of chinchillas.

The purpose of this study was to examine potential toxic effects of fibrin tissue adhesive to the middle and inner ears. Using the chinchilla as our experimental model, we placed fibrin sealant on either the footplate or the round window membrane in one ear, and placed similar amounts of normal saline in the same area of the opposite ear. In addition, the fibrin adhesive was used to anchor a fascia lata graft for myringoplasty. Both fibrin adhesive and normal saline produced mild reactions in the middle and inner ears when they were placed on the round window membrane; little reaction occurred when fibrin adhesive was placed on the oval window or when it was used for myringoplasty.

Animals↗
PubMed2003

Why is otosclerosis of low prevalence in Japanese?

OBJECTIVE: This study aimed to clarify the reasons why clinical otosclerosis, a very common disease among Caucasians, is not prevalent among Japanese. STUDY DESIGN: The incidence, site, activity, and volume of otosclerotic foci were examined in 1011 temporal bone sections from 507 Japanese individuals. SETTING: This study was prepared at the temporal bone laboratory, Fukushima Medical University, Fukushima. RESULTS: Otosclerotic foci were observed in 2.56% of individuals and in 1.48% of the ears. The most common site of involvement was anterior to the oval window region, but this was only in 38.9% of the ears with otosclerotic foci. The otosclerotic foci were not involved in the stapediovestibular articulation or the endosteal layer of the otic capsule in any ears. An active change of the otosclerotic focus was seen in 33.3% of ears with otosclerosis. The volume of otosclerotic foci at the site anterior to the oval window region was less than 0.8 mm3 in 5 out of 7 ears. CONCLUSION: The incidence of histologic otosclerosis among Japanese seemed to be almost the same as that among Caucasians. Three reasons why clinical otosclerosis was not as prevalent among Japanese as among Caucasians are suggested: low incidence of involvement of foci anterior to the oval window, low activity, and small lesion without involvement of the footplate and/or membranous labyrinth of the inner ear.

Aged↗
PubMed1985

[Normal position of the stapes in the oval window niche in man].

A study of mastoid bones showed a central position of stapes only at 67%. At 21% a deviation exist to the side of promontorium and at 12% a position directly at the promontorium. Secondly is to remark the position of the posterior crus incudis lateral on the footplate to the side of promontorium. The cause is to see the movement of the labyrinth in connection with the upright posture.

Ear Ossicles↗
PubMed2005

Acoustic-structural coupled finite element analysis for sound transmission in human ear--pressure distributions.

A three-dimensional (3D) finite element (FE) model of human ear with accurate structural geometry of the external ear canal, tympanic membrane (TM), ossicles, middle ear suspensory ligaments, and middle ear cavity has been recently reported by our group. In present study, this 3D FE model was modified to include acoustic-structural interfaces for coupled analysis from the ear canal through the TM to middle ear cavity. Pressure distributions in the canal and middle ear cavity at different frequencies were computed under input sound pressure applied at different locations in the canal. The spectral distributions of middle ear pressure at the oval window, round window, and medial site of the umbo were calculated and the results demonstrated that there was no significant difference of pressures between those locations at frequency below 3.5 kHz. Finally, the influence of TM perforation on pressure distributions in the canal and middle ear cavity was investigated for perforations in the inferior-posterior and inferior sites of the TM in the FE model and human temporal bones. The results show that variation of middle ear pressure is related to the perforation type and location, and is sensitive to frequency.

Acoustic Stimulation↗
PubMed1985

Afferent influences on brain stem auditory nuclei of the chicken: effects of conductive and sensorineural hearing loss on n. magnocellularis.

Nucleus magnocellularis is the avian homologue of the spherical cell region of the mammalian anteroventral cochlear nucleus. Its primary excitatory synaptic input is from large end bulbs of Held from the eighth nerve ganglion cells. We have examined the effects of three peripheral manipulations--middle ear ossicle (columella) removal (monaural and binaural), columella removal and oval window puncture (monaural), and monaural earplug--on cross-sectional cell area ("cell size") of second-order auditory neurons in n. magnocellularis of the chicken. Manipulations were performed between embryonic day 19 and posthatch day 4. Survival time was varied from 2 to 60 days. Air conduction and bone conduction thresholds were determined to assess for conductive and sensorineural hearing loss associated with each of these manipulations. Hair cell counts were made from basilar papillae of each experimental group. We found that a columella removal alone, which produced a 50-55-dB purely conductive hearing loss, was not associated with changes in cell size of n. magnocellularis neurons. Similarly, chronic monaural earplugging did not affect the cross-sectional area of these second-order auditory neurons. Conversely, a combined columella removal and oval window puncture, which produced a mixed hearing loss with a 15-40-dB sensorineural component was associated with an 18-20% reduction in n. magnocellularis cell area. Hair cell counts for experimental ears were not significantly different from control ears. These results, in conjunction with measurements of multiunit activity recorded in n. magnocellularis, suggest that manipulations which markedly attenuate extrinsic auditory stimulation, but do not result in chronic change in the average activity levels, also do not influence the size of n. magnocellularis cell bodies. On the other hand, a manipulation which influences overall activity levels, but does not result in degeneration of receptor cells, resulted in marked changes in n. magnocellularis cell size.

Afferent Pathways↗
PubMed1995

Transposition of the facial nerve in congenital aural atresia.

It is generally recognized that surgery for congenital aural atresia is difficult. The success or failure of the operation is often directly related to the degree of development of the middle ear. In poorly developed middle ears, the facial nerve may overhang and conceal the oval window niche, making this area inaccessible to inspection, let alone manipulation. The criteria for transposing the facial nerve are; (1) the atresia must be bilateral, (2) there must be preoperative imaging evidence of a stapes and/or patent oval window, (3) there must be no large blood vessels feeding or draining the facial nerve, and (4) facial nerve monitoring must be available. Over the past 2 years, 6 of 94 patients undergoing surgery for atresia were operated with an intent to transpose the facial nerve in order to access the oval window. In all patients, it was impossible to see the oval window niche due to a displaced nerve. In four of six cases, the facial nerve was transposed. The ossicular chain was reconstructed with a total ossicular replacement prosthesis. In no case was there a postoperative facial paralysis or paresis. Facial nerve transposition 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.

Ear Canal↗