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Primary culture of chinchilla middle ear epithelium.

Chinchilla middle ear epithelium was successfully cultured in medium containing Dulbecco's modified Eagle's medium, Ham's F12 mixture, and fetal bovine serum. After 3 to 5 days, the explants produced outgrowths of primarily flat polygonal and ciliated cells that persisted for up to 10 days in culture. These cells in the outgrowth often formed a "dome" indicating the presence of functional polarization and fluid transportation capability. The ciliated cells were more frequently found near the explant, and were fewer in number in the area distant from the explant. This finding suggests that the ciliated cells in the outgrowth are migrated ciliated cells deriving from the explant. That secretory cells were not identified in the outgrowth indicated that the present culture technique did not support secretory activity. Using the present culture technique, we were able to maintain the explants and primary cultured cells for up to 14 days in a majority of cases; hence, these techniques appear to be applicable to a number of in vitro studies.

Animals↗

Middle ear fluid.

Most middle ear effusions are preceded by an episode of acute otitis media. Craniofacial abnormalities predispose to such problems, and eustachian tube dysfunction is thought to be an important factor as well. Mechanical obstruction of the tube by inflammation or functional obstruction due to increased compliance leads to a failure to clear secretions produced by the middle ear. Removal of the obstruction is essential. If medical management does not clear the fluid, myringotomy with ventilating tubes may be required.

Humans↗

Acoustic reflectometry in the detection of middle ear effusion.

Acoustic reflectometry, a new technique for detecting middle ear effusion, was compared with results from tympanocentesis or myringotomy in 75 patients (141 ears). There was a highly significant association (P less than .0001) for ears having middle ear effusion with high reflectivity (5 through 9 units) and for ears having no middle ear effusion with low reflectivity (0 through 4 units). In a pediatric population with middle ear effusion present in 98 of 141 ears and using reflectivity readings greater than 4 to indicate middle ear effusion, the sensitivity of this technique was 86.7% and the specificity was 69.8%. False-positive errors usually occurred in ears with thick tympanic membranes, or in ears in which reflectivity was determined prior to the induction of anesthesia. False-negative errors usually occurred in ears with both air and fluid. This technique was validated by direct comparison with tympanocentesis or myringotomy and can be used with pneumatic otoscopy and impedance tympanometry to follow children with middle ear effusion.

Adolescent↗

School screening for middle ear effusions.

Early detection of middle ear effusions is highly desirable not only from a medical standpoint, but also educationally, psychologically and socially. Present methods do not appear to be adequate and the proposal has been made that impedance measurement may be of greater effectiveness in detecting abnormalities of middle ear function. Eighty children have been studied over a period of six to seven years during which time the middle ear function has been monitored by means of an impedance meter. Approximately one-half of the children have not indicated any variation in middle ear function over the period of observation. About one-third of the children have had isolated episodes of effusion from which they have recovered spontaneously and without adverse effects. The remaining one-sixth have had repeated episodes of effusion or persistent middle ear malfunction for substantial periods of time. Observation of the middle ear muscle reflexes at suitably chosen time intervals appears to have promise as a method of early detection of effusion in the middle ear.

Audiometry↗

Do Swiftlets have an ear for echolocation? The functional morphology of Swiftlets' middle ears.

The Oilbird and many Swiftlet species are unique among birds for their ability to echolocate. Echolocaters may benefit from improved hearing sensitivity. Therefore, morphological adaptations to echolocation might be present in echolocating birds' middle ears. We studied the functional morphology of the tympano-ossicular chain of seven specimens of four echolocating Swiftlet species and one specimen each of five non-echolocating species. Three dimensional (3D) reconstructions were made from micro-Computer-Tomographic (muCT) scans. The reconstructions were used in functional morphological analyses and model calculations. A two dimensional (2D) rigid rod model with fixed rotational axes was developed to study footplate output-amplitudes and to describe how changes in the arrangement of the tympano-ossicular chain affect its function. A 3D finite element model was used to predict ossicular-chain movement and to investigate the justification of the 2D approach. No morphological adaptations towards echolocation were found in the middle-ear lever system or in the mass impedance of the middle ear. A wide range of middle-ear configurations result in maximum output-amplitudes and all investigated species are congruent with these predicted best configurations. Echolocation is unlikely to depend on adaptations in the middle ear tympano-ossicular chain.

Animals↗

New concepts in the pathophysiology and management of middle ear disease in childhood.

Middle ear disease encompasses acute otitis media, recurrent otitis media, and otitis media with effusion. For many children, middle ear disease occurs early in life, is chronic and recurrent and can impair language development and/or school performance. Risk factors for recurrent otitis media include early disease onset, bottle feeding, daycare attendance, exposure to cigarette smoke and immunological defects or immaturity. Antimicrobial therapy in acute otitis media is associated with earlier resolution and a reduction in the frequency of persistent disease and suppurative complications. An antimicrobial agent should be selected according to its activity, tolerability and concentrations achieved in the middle ear. At present, amoxicillin remains the drug of choice for acute otitis media. Antimicrobial prophylaxis is also effective, but only for the duration of therapy. Future challenges for the management of middle ear disease include the treatment of penicillin-resistant Streptococcus pneumoniae, effective prevention of relapses, and the development of a vaccine for S. pneumoniae that has the appropriate serotypes and is immunogenic in young children.

Anti-Bacterial Agents↗

[Application of Optical Coherence Tomography (OCT) in middle ear surgery].

BACKGROUND: Middle ear surgery has reached an advanced stage of development over the last few decades. The use of biocompatible materials offers new possibilities in ossiculoplasty. The exact calculation concerning the length of the implant to be used, however, still poses considerable difficulties and is an additional cause for a remaining air conduction difference or a further surgical intervention. METHODS: Optical coherence tomography (OCT) is a non-invasive imaging procedure for the imaging of tissue structures with a resolution accurate to micrometres. OCT can be operated touch-free and for this reason does not require any means of contact between applicator and sample. In the present study an optical coherence inferometre was coupled to an operating microscope and used in 5 stapedoplasties and 5 tympanoplasties type III in order to determine the length of the prosthesis to be used. RESULTS: The use of OCT implies an intraoperative measuring time of only a few seconds. The coupling in the optical path of an operating microscope allows trouble-free handling. The measurement of middle ear structures has an accuracy of 30 micrometer. The postoperative audiological results show a good auditory performance. CONCLUSIONS: Initial experience with OCT indicates that the technology will be extremely interesting for otosurgery. Improvements in functional pattern will enable routine intervention in connection with an operating microscope. Further OCT applications for tissue differentiation will have to follow.

Equipment Design↗

Applied comparative anatomy of the avian middle ear.

The anatomy of the middle ear has been studied in nine species of birds, with particular reference to the structure of the ossicle and its relationship to the tympanic membrane. The morphology of the avian middle ear has been compared to that of the reconstructed human middle ear. Drum to stapes foot plate assemblies created during ossiculoplasty operations differ from the pattern found in the avian middle ear in a number of important respects and this may help to explain why they are often unsuccessful. It is not technically feasible to reproduce the avian middle ear pattern exactly in the human middle ear and developments in reconstructive technique should therefore be directed towards reproducing the three ossicle pattern of the mammalian ear.

Anatomy, Comparative↗

[Middle ear pressure after rhinoplasty surgery (author's transl)].

Middle ear pressure after rhinoplasty surgery was determined by tympanometry. Measurings were done in 94 patients (total of 177 ears) before the rhinoplasty operation and during the following 6 days respectively in special cases up to three weeks. In 153 ears normal middle ear pressure was found before the operation. After the rhinoplasty in about 2/3 of all cases negative pressure up to 300 mm Ws developed. This negative pressure was equalized in the vast majority of cases (84.3%) after the tamponade was removed. In some cases negative pressure persisted for 6 days after the operation (9.8%); in few cases (5.9%) up to three weeks. In 13 out of 24 patients having negative middle ear pressures together with rhinomanometrically objectified impaired nasal ventilation rhinoplasty led to normal middle ear pressure. Reasons for the development of negative pressures in the middle ear are discussed. The results of the investigations lead to consequences concerning tympanoplasty in connection with rhinoplasty operations. Rhinoplasty and tympanoplasty should not be performed on the same day--there should be an intervall of 4--6 days between these operations. Negative pressure in the middle ear in cases of impaired nasal ventilation can be improved by rhinoplasty.

Airway Obstruction↗

Aggressive papillary middle ear tumour.

A rare middle ear tumour is reported. The clinical presentation was similar to that of a glomus tumour but the pathology that of an aggressive papillary middle ear tumour. This is a recently recognized subgroup of middle ear glandular tumours. Clinical findings, imaging, pathology and treatment are presented.

Adult↗

A syndrome with mixed deafness, Mozart ear, middle and inner ear dysplasias.

A 10-year-old boy presenting a disorder of multiple malformations with an otologic component consisting of mixed deafness, Mozart ear, thin stapes, small oval window and agenesis of the semicircular canals, was studied. A comparative analysis of similar malformation-entities has permitted the delineation of a previously undescribed syndrome.

Abnormalities, Multiple↗

[Experimental middle ear cholesteatoma originated from free skin graft of the external ear].

The pathogenesis of middle ear cholesteatoma has been thought to be invasion of squamous epithelium originated from the external ear skin including the tympanic membrane. There is no evidence, however, that the external ear skin has more potential to form cholesteatoma than that of other sites. In this report experimental middle ear cholesteatoma of guinea pigs originated from the external ear skin was histologically compared with that originated from the auricular skin. Cholesteatoma as dermal cyst was seen in the middle ear of almost all animals (25/28 = 89.3%), using a free skin graft (3 x 3 mm), regardless of the skin taken from superior (group A) or inferior (group B) part of the external ear, or the auricle (group C) eight weeks after skin implantation. The activity of epithelium such as keratinization was evident in group C. There is, however, no obvious difference in surrounding granulation tissues among group A, B, and C. In a half of this series, cyst wall was broken and its contents (debris) mainly consisted of keratin were put on surrounding granulation tissues three weeks after skin implantation. Striking keratinized epithelium and subepithelial inflammations in relation to the amount of debris were observed at the eighth week. These findings suggest that the external ear skin does not have specific potential to form cholesteatoma and keratin plays some roles in growth of cholesteatoma.

Animals↗

Screening procedure for detection of middle ear and cochlear disease.

Experiences from a six-year study in which 11,772 seven-year-olds have been tested with a combination of the pure tone sweep check test and impedance audiometry (tympanometry and stapedius reflex test) are presented. During the study there has been a gradual change in the screening level. The goal has been to find an ideal screening level in which the results from the screening procedure correspond as much as possible to the findings of the otologist. Analysis of the results from the stapedius reflex test demonstrated that in ears in which the middle ear pressure was within +/- 50 mm H2O the stapedius reflex test could not be elicited in 1.9% of the ears when the maximum output of the audiometer was used (110 dB SPL ipsilateral stimulation); in the ears with middle ear pressure within +/- 150 mm H2O the stapedius reflex could not be elicited in 6.1% using the maximum output of the audiometer. Based on the experiences from our studies it is therefore recommended that the stapedius reflex test be excluded from the test battery and that pure tone screening supplemented by tympanometry be used. A middle ear pressure of less than or equal to -150 mm H2O or a flat tympanogram and/or tone screening levels > 20 dB HTL at 0.5 kHz and/or 4 kHz are considered as indicative of ear pathology.

Acoustic Impedance Tests↗

A histopathological study of the inner ear after the administration of hyaluronan into the middle ear of the guinea pig.

Hyaluronan, 19 mg/ml, was administered into the middle ear cavity of guinea pigs. A control group was subjected to a sham operation. Fourteen days after administration the animals were killed and a macroscopic examination of all middle ears was performed. Surface preparations of the organ of Corti were made and examined by light microscopy. Hair cell loss along the length of the sensory epithelium was quantified. No toxic effect of hyaluronan could be detected either in the middle ear or in the sensory cells in the cochlea. Thus hyaluronan is potentially useful for facilitating middle ear surgery.

Animals↗

[Congenital external and middle ear malformation-with 62 ears report].

OBJECTIVE: To determine the relationship between external ear malformation and middle ear abnormality, and also the results of surgical treatment. METHOD: Fifty-two cases with external ear malformation (62 ears) was dividied into two groups:the minor group and severe group. All the patients received surgical treatment, 48 ears by transmastoid approach and 14 ears by "direct entrance" approach. RESULT: The middle ear abnormality was minor in minor group,and severe in the patients with severe external ear malformation. In 93.5% cases the hearing threshold improved more than 15 dB in 3 months after operation, and reduce to 85.5% in 3 years follow up. CONCLUSION: The middle ear malformation is corresponding to external ear malformation. The effect of surgical treatment is different according to the degree of malformation and surgical complication.

Adolescent↗

Linear and nonlinear model of the human middle ear.

The measurement of the middle ear transfer function usually requires invasive methods. An equivalent analog equivalent model enables us to evaluate its characteristics without damaging any part of the ear. A linear and a nonlinear model of the middle ear have been developed to predict intracochlear pressure and the stapes volume velocity for various sound pressure levels (SPL). The linear model results have been compared with human eardrum impedance and middle ear transfer function data. The nonlinear phenomena due to the contraction of the stapedius muscle over 80 dB and to the stapes clipping displacement above 120 dB are represented by a set of variable electrical components. The model of the acoustic reflex is based on experimental observations. The study of the annular ligament behavior was performed on cats and extrapolated to humans with some hypothetical restrictions. These approximations provide information on the middle ear transfer function and enable us to better understand the nonlinear middle ear mechanisms in an intense acoustic field.

Ear, Middle↗