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At least 289 records · Page 16Linked to original sources
PubMed1993

Composite graft tympanoplasty in the treatment of ears with advanced middle ear pathology.

In ears with advanced pathology, the functional and anatomical results of surgery are compromised by such factors as total perforation, tympanosclerosis, atelectasis, suppuration, or previous surgery. Perichondrium cartilage composite grafts (PCCGs) were used for membrane grafting in 550 such cases over a period of 5 years. In all, 197 tympanoplastic procedures of type I (25% with previous surgery) and 353 of type III (47% with previous surgery) were carried out. The graft was obtained from the tragus and/or the concha. Two slightly different surgical techniques of grafting were used. Closure of the eardrum perforation was successful in 92% of the procedures. An air-bone gap of less than or equal to 30 dB was obtained in 92.4% of tympanoplasty type I procedures and in 79% of tympanoplasty type III procedures. The conclusion drawn from the results is that PCCG is a reliable graft in cases of advanced destruction of the middle ear.

Cartilage↗
PubMedDate not supplied

Inner ear effects of exogenous hyaluronan in the middle ear of the rat.

1.9% hyaluronan (HA) (mol. wt. 3 x 10(6] was applied repeatedly into the middle ear of rats through a myringotomy. The function and structure of the cochlea was analysed by auditory brainstem recordings (ABR) at 2-31.5 kHz and by light microscopy. The myringotomy significantly impaired the ABR thresholds at frequencies below 8 kHz. Five days after the last application of HA, the ABR thresholds showed minor improvements at 6-8 kHz but were impaired at 12 and 20 kHz, as compared with control levels. One month after the last administration of HA, ABR thresholds were significantly improved as compared with the initial level at 2-6 kHz but normal at all other frequencies. After 3 months, all ABR thresholds had returned to the pre-treatment (normal) level. Five days after the last application of HA, the latencies for almost all frequencies were significantly prolonged for waves II and IV at the ABR threshold. After 3 months all latencies had returned to their pre-treatment (normal) values. Highly concentrated hyaluronan (1.9%) is free from ototoxicity but does have transient functional effects on the inner ear.

Animals↗
PubMed1985

Phasor diagram: a comparative study between normal ears and otosclerotic ears.

The authors report their results from phase angle measurements by admittancemeter obtained by means of the phasor diagram, and conductance and susceptance tympanograms. The study was carried out on normal ears and otosclerotic ears. The authors noted a wide range of phase angle values and an absence of significant difference between the two populations studied.

Acoustic Impedance Tests↗
PubMed1992

[Mechanics and function of the middle ear. 2: Hearing physiologic comments on middle ear surgery].

The reconstruction of the destroyed ossicular chain has the purpose to re-establish an unhindered sound reception and transmission. With respect to the hydraulic factor, the reconstructed chain should be attached to a large effective area of the drum membrane, ideally to the malleus handle. The sensitivity is furthermore diminished in a linear relationship with increasing mass and stiffness. Therefore, cartilage cannot represent an acoustically ideal material for a drum membrane replacement. The reconstructed chain must vibrate without restraint for an unhindered transmission. Furthermore, the interposed prosthesis must be secured firmly to the remnants of the ossicular chain; the reconstructed chain must vibrate like one solid body. A loose contact attenuates the transmission and might result in a dislocation of the prosthesis with excessive ambient air pressure induced displacements of the drum membrane. A solid anchoring might be created by glueing, bony adhesion, special design of the prosthesis or with a wire connection. With unfavorable middle-ear conditions, the piston-like vibrational mode of the footplate has to be met with a direct driving of the stapes by a T-like prosthesis in the extension of the stapedial's vertical (high) axis. Ineffective rocking movements of the footplate are thus reduced. The almost perfect hearing result of the stapesplasty demonstrates that the impedance-matching middle-ear function is determined by the area ratio between the drum membrane and the width of the cochlear scala. Both components are not altered by the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Ear Ossicles↗
PubMedDate not supplied

[Histopathology of the internal ear: role of biopsy in ear neurosurgery].

Ultrastructural evaluation is a tool which provides useful information which can lead to understanding of the different physio-pathological mechanisms involved in various otological disorders. After a short review of the procedures presently available for histopathology of human temporal bones from cadavers and indication of their related problem, the authors define the pros and cons of intra-operative biopsies of the membranous structures of the inner ear. The different histopathological methods are presented which may be applied on each specimen along with some technical details which make their use feasible for any otoneurosurgical center. The different membranous inner ear structures are taken into consideration; structures which can be approached by different otoneurosurgical procedures. Emphasis is placed on some technical hints to minimize artifacts. Finally, a more continuous, widespread use of intra-operative biopsies is proposed in order to obtain a fairly large amount of specimens as this would contribute to elucidate the unresolved problems inherent to many otological disorders.

Biopsy↗
PubMed1995

Middle ear and inner ear effects on clinical bone-conduction threshold.

The measurement of bone-conduction thresholds is an integral part of audiologic evaluation. The relationship between bone-conduction and air-conduction thresholds is the differentiating diagnostic indicator between conductive and sensorineural hearing loss. At the same time, the influence of middle ear and inner ear structures upon the bone-conduction response has been well documented. We present two cases illustrating this influence and attempt to explain the clinical bone-conduction thresholds with operative findings.

Acoustic Impedance Tests↗
PubMed1992

Chronic ear pathology in a model of neonatal amniotic fluid ear inoculation.

Human histopathologic studies have demonstrated that amniotic fluid cellular contents, keratinized squamous epithelial cells and lanugo hair, induce an intense inflammatory reaction including granulation tissue in the neonatal temporal bone. To investigate this reaction over a prolonged period, an animal model was studied. An aliquot of sterilized autologous hair and keratinized epithelial cells was placed into 14 gerbil bullae; saline was used as a contralateral control. The animals were sacrificed at intervals up to 6 months and the temporal bones were studied by light microscopy. All animals demonstrated nonpurulent inflammatory changes on the experimental side including granulation tissue, osteoneogenesis, tympanosclerosis, and cholesteatoma; the control side demonstrated minimal middle ear changes. We conclude that in this model autologous keratinized tissue provokes a foreign body response similar to the granulation tissue observed in human infants and, further, that over a prolonged period the middle ear demonstrates more severe pathologic consequences.

Amniotic Fluid↗
PubMed1992

The ear in subterranean insectivora and rodentia in comparison with ground-dwelling representatives. I. Sound conducting system of the middle ear.

Compared to acoustically unspecialized mammals (soricids and murids), the middle ear of subterranean insectivores and rodents (twelve species of six families examined) was clearly distinguished and characterized by many common features: rather round and relatively larger eardrum without a pars flaccida; reduced gonial; loose or no connection between the malleus and the tympanic bone; reduced and straightened transversal part of the malleus; enlarged incus; increased and rather flat incudo-mallear joint; rather parallel position of the mallear manubrium and incudal crus longum in some species (and their fusion in bathyergids); reduced or even missing middle ear muscles. Convergent occurrence of these structural features in taxa of different origin and their generally derived character suggest that they cannot be categorized as degenerative. The form of the stapes can be considered as a non-adaptive trait; it was taxon specific yet remarkably polymorphous in some species and exhibited no convergent features among subterranean mammals. Structural retrogression resulting in a columella-like stapes was observed in some species lacking the stapedial artery. The stapedial base was relatively larger than in unspecialized mammals. The subterranean mammals did not exhibit conspicuously enlarged eardrums as would be required for sensitive tuning to low frequencies. It is, however, argued that while selective pressures in the subterranean ecotope promoted hearing of low frequencies, hearing sensitivity did not have to be enhanced.

Animals↗
PubMed2003

Immunohistochemical localization of two otolith matrix proteins in the otolith and inner ear of the rainbow trout, Oncorhynchus mykiss: comparative aspects between the adult inner ear and embryonic otocysts.

The fish otolith consists mainly of calcium carbonate and organic matrices, the latter of which may play important roles in the process of otolith formation. We previously identified two otolith matrix proteins, named otolith matrix protein-1 (OMP-1) and otolin-1, from the rainbow trout, Oncorhynchus mykiss, and the chum salmon, O. keta. In this study, recombinant proteins corresponding to OMP-1 and otolin-1 were synthesized using yeast and bacterial expression systems, respectively, to produce specific antibodies against each protein. Immunohistochemical analysis using these antisera revealed that in the otoliths of adult fish, OMP-1 and otolin-1 were colocalized along the daily rings possibly formed by alternate deposition of calcium carbonate and organic matrices. In the adult inner ear, OMP-1 was produced at most of the saccular epithelium, while otolin-1 was produced at a limited part of cylindrical cells located at the marginal zone of the sensory epithelium. In the embryonic inner ear, these proteins had already existed in the otolith primordia when calcification had commenced. In addition, otolin-1 was localized in the fibrous materials connecting otolith primordia and sensory epithelium at this stage. These results indicate that these proteins are required as essential components for otolith formation and calcification.

Animals↗
PubMed1982

Spontaneous improvement in ears with middle ear disease.

The 'healthy-baby-clinics' in Göteborg, as in all Sweden, test all 4-year-olds with pure tone screening (failure criterion greater than 20 dB). Those who fail are referred to an oto-audiological health center. In an effort to prevent over-referrals of false positives as well as under-referrals of false negatives all referred children in this study have been tested with pure tone audiometry supplemented by tympanometry. At the oto-audiological health center a test program including 3 tests with intervals of 6 weeks was initiated. Failure criteria were middle ear pressure less than - 150 mm H2O and hearing loss (HL) in the frequency range 0.125-8 kHz greater than 20 dB. In Göteborg (430,000 inhabitants) 5928 4-year-olds were tested at the 'healthy-baby-clinics' during 1980. Of these 498 (8.4%) failed in pure tone screening, 248 of which are included in the present study. At the first check in our test program, which was performed 3-8 weeks after referral, only 45% of the children were abnormal. Of these 60% normalized during the test program. Thus of the ears referred following the pure tone screening at the 'healthy-baby-clinics' only 18% remained after 15-20 weeks for referral to an ENT-doctor.

Acoustic Impedance Tests↗
PubMed2003

Rabbit and pig ear skin sample cryobanking: effects of storage time and temperature of the whole ear extirpated immediately after death.

The post-mortem temporal and thermal limits within which there will be ample guarantees of rescuing living skin cells from dead specimens of two species, rabbit and pig, were studied. Post-mortem extirpated whole ears were stored (in non-aseptic conditions) either at 4 degrees C or at room temperature (from 22 to 25 degrees C) or at 35 degrees C for different time lapses after animal death. In both species, the post-mortem maximum time lapses where cell viability was not significantly reduced were 240, 72, and 24 h post-mortem (hpm) for 4, 22-25 and 35 degrees C, respectively. Once the post-mortem temporal limits for each tested thermal level at which cells from skin samples are able to grow in culture were defined, the survival ability of skin samples submitted to these temporal limits and cryopreserved were tested. In the pig, skin samples stored at the three tested thermal levels survived after vitrification-warming, reaching confluence in culture. In rabbit, only tissue samples from ears stored at 35 degrees C for 24 hpm did not survive after vitrification-warming. In conclusion, we should remark that cell survival rates obtained according to the assayed post-mortem time lapses and thermal levels are sufficient to collect and to cryopreserve skin samples from the majority of dead specimens.

Animals↗
PubMed2000

Reconstruction of the upper portion of the ear by using an ascending helix free flap from the opposite ear.

Reconstruction of partial, marginal defects of the ear has been a challenge. The ascending helix free flap based on superficial temporal vessels has been described and used solely to repair nose defects. We used reversed pedicle helical free flap for the repair of a major loss of the upper one-third of the opposite auricle. The method permits the transfer of tissue of the same quality with satisfactory cosmetic result. The equalization of the ears in dimension was accomplished with minimal donor-site deformity.

Amputation, Traumatic↗
PubMed2003

Tympanometry versus direct middle ear pressure measurement in an artificial model: is tympanometry an accurate method to measure middle ear pressure?

HYPOTHESIS: Indirect tympanometric pressure measurements of the middle ear (ME) do not correspond to direct pressure measurements. BACKGROUND: Tympanometry is an accepted method for estimating ME pressures. These pressure values are different, however, when measurements are made directly. MATERIALS AND METHODS: Negative pressures were induced by volume changes in an artificial ME model with various "mastoid" volumes. Both tympanometric and direct pressure measurements were obtained simultaneously. RESULTS: A substantial difference was demonstrated between tympanometric and direct pressure measurements. There was a linear correlation between tympanometry and direct pressures between -46.8 and -93.6 mmH2O, with a tympanometric overestimation of 40% to 20%, respectively. The smaller the "mastoid" volume, the greater the overestimation. The correlation was not linear for direct pressures between zero and -46.8 mmH2O. Tympanometric overestimation was greatest (i.e., 4-14-times the actual pressure) in the pressure range between zero and -12 mmH2O. CONCLUSIONS: Tympanometry does not yield precise ME pressure values. In a model with a larger "mastoid" and an actual pressure range of -46.8 to -93.6 mmH2O tympanometric readings are somewhat less unreliable (error of 40%-20%). However, tympanometry is in error of more than 400% in a model with a small mastoid in which the actual ME pressure is only slightly negative (i.e., range between -3.9 and -46.8 mmH2O). Therefore, this study implies that tympanometry has little use for measuring ME pressure especially in chronic ears or their sequelae that are usually characterized by having small negative pressures and small mastoids.

Acoustic Impedance Tests↗
PubMed1986

Preoperative swabs for the treatment of draining ears after middle ear surgery.

The value of a preoperative swab for the treatment of postoperative infection after middle ear surgery was investigated. In a selected group of 80 patients with postoperative infection a preoperative swab was available, and the variability was analysed for each species. The well-known pathogens Pseudomonas aeruginosa, Staphylococcus aureus, Proteus and Escherichia coli showed good correlation between pre- and postoperative swabs. In contrast to this all other species found in preoperative swabs were of little value postoperatively. This observation is important for the treatment of infection after middle ear surgery, and should be considered if prophylactic antibiotics are planned.

Bacteria↗
PubMed2005

A blinded in-vitro study to compare the efficacy of five topical ear drops in clearing grommets blocked with thick middle ear effusion fluid.

OBJECTIVE: To compare the efficacy of 5% NaHCO3, 3% H2O2, Sofradex (dexamethasone sodium metasulphobenzoate 0.05%, framycetin sulphate 0.5%, gramicidin 0.005%), 0.33% acetic acid and 0.9% NaCl eardrops in clearing grommets blocked with harvested thick middle ear effusion fluid. STUDY DESIGN: A blinded in-vitro study. SETTING: District general hospital. PARTICIPANTS: A total of 473 grommets were blocked with freshly harvested unpooled thick middle ear effusion fluid obtained from 68 patients. MAIN OUTCOME MEASURES: Patency of the grommets before and 7 days after intervention was ascertained by tympanometry and close visual inspection. RESULTS: Instillation of eardrops leads to a statistically significant increase in the clearance of grommets as compared with not using any drops (chi2 = 14.3, d.f. = 5, P = 0.006). The numbers needed to treat were 2.8 for NaHCO3, 3.2 for 0.9% NaCl, 3.9 for 0.33% acetic Acid, 4.4 for Sofradex and 9.5 for H2O2 eardrops. Pair-wise comparison was only significant for comparison between 5% NaHCO3 and 3% H2O2 eardrops (Bonferroni corrected P = 0.01, odds ratio = 4.3, CI = 1.9-9.9). CONCLUSIONS: Use of eardrops leads to a clinically and statistically significant increase in the clearance of blocked grommets. Of the five drops used, 5% NaHCO3 was the most efficacious and 3% H2O2 the least efficacious. Limitations of this in-vitro study are recognized and a prospective in-vivo double blind randomized controlled trial is planned.

Acetic Acid↗
PubMed2006

Leaving a lasting impression: ear mold impressions as middle ear foreign bodies.

OBJECTIVES: We describe a series of otologic complications from impression material used to make hearing aid molds. METHODS: We examined a retrospective case series of patients presenting to a tertiary care academic medical center. RESULTS: The presentation, clinical course, and treatment outcomes of 6 patients with complications related to ear molds are discussed. These patients had preexisting abnormalities in their aural anatomy, including tympanic membrane perforations, retraction pockets, and mastoidectomy cavities. CONCLUSIONS: Although the majority of patients who have ear canal impressions taken experience no adverse outcomes, hearing aid dispensers should perform a thorough history-taking and physical examination to discern those with abnormal anatomy at risk for complications. These patients may benefit from evaluation in conjunction with an otolaryngologist.

Aged↗
PubMed1988

Ear-to-ear derivation in short latency brainstem auditory evoked responses.

We utilized an ipsilateral to contralateral earlobe (Ai-Ac) derivation in addition to the scalp to ipsilateral ear (Cz-Ai) and scalp to contralateral ear (Cz-Ac) derivations, in 12 normal hearing community volunteers and 36 patients with a variety of referrals and varying degrees of hearing loss. In normal subjects, the latency of wave I in the Ai-Ac derivation was identical to that in Cz-Ai, but amplitude was consistently smaller (0.21 +/- 0.1 vs. 0.30 +/- 0.13 microV, p less than 0.005). The wave III behaved in a reverse manner. These data can be easily explained based on traditional principles of near- and far-field potentials. The amplitude differences of the wave I in Cz-Ai and Ai-Ac derivations were, however, small and the phase-reversals of that wave between the 2 derivations were striking and consistent in all subjects and patients. This observation indicates that the addition of Ai-Ac derivation to the conventional 1 or 2 channel montage may aid in the identification of wave I.

Adolescent↗
PubMed2005

Expression and functional phenotype of mouse ERG K+ channels in the inner ear: potential role in K+ regulation in the inner ear.

An outcome of the intricate K+ regulation in the cochlear duct is the endocochlear potential (EP), approximately 80 mV, the "battery" that runs hair-cell transduction; however, the detailed molecular mechanisms for the generation of the EP remain unclear. We provide strong evidence indicating that the intermediate cells (ICs) of the stria vascularis (StV) express outward K+ current that rectifies inwardly at positive potentials. The channel belongs to the ether-a-go-go-related gene (erg) family of K+ channels. We cloned an ERG1a channel in the mouse inner ear (MERG1a). The cellular distribution of MERG1a in the cochlea displayed the highest levels of immunoreactivity in the ICs and modest reactivity in the marginal cells as well as in several extrastrial cells (e.g., hair cells). Functional expression of the StV-specific MERG1a channel reveals a current that activates at relatively negative potentials (approximately-50 mV) and shows rapid inactivation reflected as inward rectification at depolarized potentials. The current was sensitive to the methanesulfonanilide drug E-4031 (IC50, approximately 165 nM) and the recombinant peptide rBeKm-1 (IC50, approximately 16 nM), and the single-channel conductance in symmetrical K+ was approximately 14 pS. The site of expression of MERG1a and its functional phenotype (e.g., modulation of the current by external K+ make it one of the most likely candidates for establishing the high throughput of K+ ions across ICs to generate EP. In addition, the property of the channel that produces marked K+ extrusion in increased external K+ may be important in shaping the dynamics of K+ cycling in the inner ear.

Amino Acid Sequence↗