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PubMed1989

[Effect of radiation on the fungal flora of the external ear canal].

A mycological study of external ear canals was performed in 40 patients with head and neck cancer to observe the radiation effect on the fungal flora in external ear canals. The control group consisted of 30 non-cancer patients. The findings were: 1. More Candida sp. and Aspergillus sp. were noted in cancer patients than control group and C. albicans were also found, which didn't exist in normal persons. 2. There were opportunistic fungal flora, Candida sp. and Aspergillus sp., in at least one side of external ear canals in 32.5% of the post-irradiated patients who had aseptic external ear canals before the radiation therapy. The reasons we inferred that the patients with head and neck cancer during the radiation therapy were predisposed to otitis externa, in addition to radiation injury to the canal skin, were: 1. The different fungal flora in external ear canals of patients with head and neck cancer before the radiation therapy. 2. The changes of fungal flora after the radiation therapy.

Adult↗
PubMed1997

CT appearances of external ear canal cholesteatoma.

External ear canal cholesteatoma (EECC) is rare in ear, nose and throat (ENT) practice. Two cases, one bilateral, are described. Computed tomography demonstrates the extent of bony involvement. Erosion of the external canal should not be overlooked when reviewing CT of the petrous bone in cases of discharge from the ear. EECC may necessitate surgery and delay in the diagnosis of EECC can result in progressive bony destruction.

Adult↗
PubMed1994

Myxomas of the external ear and their significance.

Myxomas of the external ear are extremely rare. We describe 27 such tumors in 22 of 152 patients with the complex of myxomas, spotty pigmentation, endocrine tumors, and schwannomas--a familial (autosomal dominant) syndrome. Eleven of the patients were male, and 11 were female; age range was from birth to 41 years. Nine patients were members of three affected families. The external auditory canal and the external ear were involved in 18 and five patients, respectively; in two, the exact ear location was not known. Three patients had both ear canal and external ear lesions. Two patients with ear canal myxomas had bilateral lesions. Six patients had recurrences after simple excision. The ear canal lesions often were accompanied by deafness due to occlusion of the canal; attachment to the canal wall was usually by a pedicle. Grossly, the lesions were mucoid and from 3 mm to 2 cm in greatest dimension. Microscopically, they were circumscribed but not encapsulated and were composed of scattered stellate and spindle cells set in a myxoid, capillary-rich matrix. An epithelial component (epidermal inclusion cysts or basaloid buds or both) was present in 14 tumors. Cardiac myxoma occurred in nine patients, Cushing's syndrome in three, and psammomatous melanotic schwannoma in three. In two patients, the ear myxoma was the presenting sign of the complex. Patients with myxoma of the external ear (and their primary relatives) should be considered at risk for the complex of myxomas, spotty pigmentation, endocrine tumors, and schwannomas and should be examined accordingly.

Adolescent↗
PubMed1997

[External ear abnormalities: syndromic and genetic aspects].

Morphological defects of the external ear represent a significant class of congenital abnormalities because of their overall frequency and their impact on affected people. All types of congenital defects are involved in the study of the ear. The external ear is an important site for the study of minor phenotypic variations. Associated abnormalities are frequent and lead to syndromes identification. Some genes involved in syndromes with abnormal external ear as a feature have been recently cloned by molecular genetics.

Chromosome Aberrations↗
PubMed1986

External ear canal cholesteatoma.

External ear canal cholesteatoma (EECC) is a rare otologic entity. Erosion of the inferior canal wall and accumulation of keratin debris are consistent findings. In the past there had been confusion between EECC and keratosis obturans, and they were thought to represent the same disease process. Currently, based on clinical and pathologic findings, it is believed that they are two different entities. In this article we present our experience in treating eight patients with EECC. For limited lesions, local debridement and curettage of necrotic bone is effective management. For more extensive lesions, canalplasty or tympanomastoidectomy is indicated.

Adult↗
PubMed1984

Changes in the bacterial flora of the external ear canal from the wearing of occlusive equipment.

External otitis has been associated with wearing obstructive gear covering the earlobe and external ear canal. In this study we investigated the changes in the bacterial flora of the external ear canal after wearing rubber hoods. The bacterial flora of external ear canals surfaces was investigated in a group of 19 volunteers who wore rubber hoods for a period of 25 to 30 minutes while doing manual work. The protective effect of 2% acetic acid was tested by instilling it in the left ear of all participants. Staphylococcus epidermidis, Propionibacterium acnes, and alpha-hemolytic streptococci were the predominant isolates from the ear samples. After hoods were worn, there was a substantial increase in the number of these organisms in 7 (36.8%) of the external ears. However, an increase in the bacterial counts in the external ear canals occurred in only 2 (10.5%) of the individuals treated prophylactically with acetic acid drops (P less than 0.02).

Acetates↗
PubMed1988

The radiation impedance of the external ear of cat: measurements and applications.

The configuration of external ears varies dramatically among mammalian species. In order to relate these structural differences to acoustic performance, it is useful to determine the "output" (radiation) impedance of the external ear. Measurements were made of the radiation impedance ZE of the cat external ear looking out from the location of the tympanic membrane. Freshly excised external ears were coupled to a calibrated sound source at the tympanic ring, and the resulting sound pressure at the source was measured. The ZE calculated from these measurements is masslike at frequencies below 2 kHz and approximately resistive above 4 kHz. The contributions of anatomically distinct sections of the external ear to ZE were assessed by measuring the impedance before and after surgical removal of the pinna flange and of the concha. Mean measurements of the lengths and cross-sectional areas of components of the external ear are used in a simple model that consists of a uniform tube and an exponential horn; the radiation impedance of the model shows many of the features of the measured ZE's. Measurements of the input impedance of the middle ear are combined with ZE to infer the diffuse-field absorption cross section ADF, which is a measure of the ear's performance as a coupler of acoustic power. It is suggested that ADF is useful for across-species comparisons of the performance of external and middle ears.

Acoustics↗
PubMed1995

Tumors of the external ear.

A variety of medical specialists are exposed to patients who seek treatment of external ear neoplasms. They are uncommon occurrences, and malignancies of the external ear are even rarer. Only 1 patient in 10,000 with an ear complaint will have a pathologically proven malignancy of the external ear. Tumors of the external ear, both malignant and benign, commonly resemble one another. A timely and correct diagnosis is necessary to avoid affecting the external ear's ability to collect sound, but also to avoid the more morbid and mortal complications of an external ear malignancy. This paper briefly outlines the epidemiology of external ear tumors, their etiology, related histopathology, and treatment, which encompasses a myriad of modalities and specialties.

Ear Diseases↗
PubMed1993

External ear resonance as a screening technique in children with otitis media with effusion.

External ear resonance can be quickly and accurately measured using real ear insertion gain equipment. It has been previously shown that external ear resonance characteristics are often altered by the presence of middle ear fluid. The external ear resonance characteristics of 84 children with a history of chronic middle ear disorder were determined. Results were compared to other audiological data and otological findings recorded during surgery. External ear resonance peak amplitude was significantly correlated with the presence or absence of middle ear fluid. It was found that peak amplitude of > or = 24 dB was associated with only 15% of dry ears and peak amplitude of < or = 22 dB associated with 79% of ears without fluid. The use of external ear resonance measures as a potential screening procedure is discussed.

Acoustic Impedance Tests↗
PubMed1978

External ear injuries.

The unique shape of the external ear depends on the underlying cartilaginous framework. Injuries of the external ear are common. In dealing with lacerations, subperichondrial hematomas, perichondritis, burns and frostbite, particular care should be taken to maintain the cartilaginous framework and to prevent infection. In this way cosmetic deformities of the external ear can be prevented.

Burns↗
PubMedDate not supplied

Preliminary observations on isotretinoin-induced ear malformations and pattern formation of the external ear.

Retinoic acid is a morphogenic substance capable of inducing a variety of limb malformations, including duplications and reduction-type defects. Whether retinoic acid plays a similar role in controlling pattern formation of other vertebrate structures is unclear. Many fetuses and infants exposed to isotretinoin (13-cis-retinoic acid) in utero have a characteristic pattern of anomalies, chiefly involving brain, craniofacial, and thymic morphogenesis. Among the craniofacial anomalies, external ear malformations are common and the specific types of auricular malformations include partial duplications, and tissue reductions and displacements. These similarities to the types of limb malformations that retinoic acid can induce suggest that retinoic acid may play an important role in controlling pattern formation of facial structures.

Ear, External↗
PubMedDate not supplied

[Basal cell and basosquamous carcinomas of the external ear. Immunohistochemical study].

Malignant neoplasms of the external ear are difficult diseases of the cervical-facial area to study clinically and therapeutically. The most frequent malignant histological patterns are spinocellular and basocellular carcinomas. Melanomas, basosquamous or "metatypical" carcinomas are less frequent. The latter have a transition histological pattern halfway between a basocellular and spinocellular carcinoma. In our experience, some external ear neoplasms, diagnosed as basocellular, were clinically more invasive (aggressive). Therefore we studied the immunohistochemistry of operative specimens with monoclonal antibodies (MoAb) with the purpose of revaluating the diagnosis after follow-up, and of detecting unrecognized basosquamous carcinomas. We studied 4 patients (2 male and 2 female) aged between 58 and 78, examined in the period 1990-92 an a diagnosed as having an external ear basocellular carcinoma. The immunohistochemical study was carried out using anti-CEA (carcinoembryonal antigen) monoclonal antibodies, high molecular weight acid anticytokeratins (anti-AE3) and low molecular weight basic anticytokeratins (anti-AE1). Appendage origin of the neoplasms was excluded after carrying out MoAb anti-CEA tests, negative in all patients. Epithelial origin of the neoplasms were confirmed after carrying out MoAb anti-AE3 tests, positive in all patients. After carrying out MoAb anti-AE1 tests, positive in 3 patients out of 4, we reviewed the classification of 2 basocellular carcinomas out of 4. These tumors evidenced an atypical dyskeratosis and a positivity for intracellular keratinization. These aspects were not evidenced in the previous histological examinations using routine stains and could be an index of unfavourable clinical evolution of these two cases from a basocellular carcinoma toward a more aggressive basosquamous carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

The fetal external ear.

The ridge pattern of the external ear was evaluated in 50 normal subjects during the second half of pregnancy. Definition was found to progress with gestational age, with a fully defined pattern implying maturity beyond 33 weeks. The external ear was edematous in patients with severe fetal hydrops. Anomalous shape or unusual prominence of the ear was observed antenatally in 4 cases of lethal dwarfism.

Congenital Abnormalities↗
PubMed1990

[Transmission of changes in the external ear atmospheric pressure to the perilymph].

Using guinea pig, pressures in the external ear canal, in the middle ear and in the perilymph were registered simultaneously, while pressure was applied to the external ear canal using an impedance audiometer. In the first experiment, applied pressure was changed in the range from 200 mmH2O to -200 mmH2O with and without the opening of the otic bulla. The change in the perilymphatic pressure with the opening was smaller than that without the opening. The result indicates that the external ear pressure is transmitted to the perilymph not only via the ossicular chain but also via the middle ear cavity without the opening, while it is exclusively transmitted via the ossicular chain with the opening. Pressure transmission to the perilymph was significantly impaired either by disrupting the ossicular chain or by closing the round window niche, especially by the latter. Thus the middle ear cavity itself plays an important role in pressure transmission from the external ear canal to the perilymph mainly via the round window. In the second experiment, applied pressure to the external ear canal was changed in the range from 1000 mmH2O to -1000 mmH2O after the Eustachian tube being closed. Between 400 mmH2O and -200 mmH2O, the middle ear and perilymphatic pressures paralleled well with the applied pressure. Beyond these levels, the middle ear pressure increased or decreased in response to the applied pressure but the perilymphatic pressure reversed against the middle ear pressure. Communication between perilymph and cerebrospinal fluid via the cochlear aqueduct is thought to be a major factor causing this reversal which, in turn, aggravates pressure gradient between the middle ear and the perilymph.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗