SEARCH · PubMed Health

Results for “Ear, External”

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 649 records · Page 36Linked to original sources

PubMed2006

Cholesteatoma of the external ear canal: etiological factors, symptoms and clinical findings in a series of 48 cases.

BACKGROUND: To evaluate symptoms, clinical findings, and etiological factors in external ear canal cholesteatoma (EECC). METHOD: Retrospective evaluation of clinical records of all consecutive patients with EECC in the period 1979 to 2005 in a tertiary referral centre. Main outcome measures were incidence rates, classification according to causes, symptoms, extensions in the ear canal including adjacent structures, and possible etiological factors. RESULTS: Forty-five patients were identified with 48 EECC. Overall incidence rate was 0.30 cases per year per 100,000 inhabitants. Twenty-five cases were primary, while 23 cases were secondary: postoperative (n = 9), postinflammatory (n = 5), postirradiatory (n = 7), and posttraumatic (n = 2). Primary EECC showed a right/left ratio of 12/13 and presented with otalgia (n = 15), itching (n = 5), occlusion (n = 4), hearing loss (n = 3), fullness (n = 2), and otorrhea (n = 1). Similar symptoms were found in secondary EECC, but less pronounced. In total the temporomandibular joint was exposed in 11 cases, while the mastoid and middle ear was invaded in six and three cases, respectively. In one primary case the facial nerve was exposed and in a posttraumatic case the atticus and antrum were invaded. In primary EECC 48% of cases reported mechanical trauma. CONCLUSION: EECC is a rare condition with inconsistent and silent symptoms, whereas the extent of destruction may be pronounced. Otalgia was the predominant symptom and often related to extension into nearby structures. Whereas the aetiology of secondary EECC can be explained, the origin of primary EECC remains uncertain; smoking and minor trauma of the ear canal may predispose.

Journal Article↗

PubMedDate not supplied

Comparison of microbial isolates and susceptibility patterns from the external ear canal of dogs with otitis externa.

Otic exudate was obtained from 33 dogs with otitis externa for cytopathology and culture. Two samples were taken from the same location in the external ear canal, for a total of 100 samples. Thirty-six (36%) samples isolated only a single organism, of which 21 (21%) were Malassezia spp. Two organisms were present in 23 (23%) of the samples. Cultures of the two samples agreed in 40 (80%) of the 50 pairs. Cytopathology agreed with culture results only 68% of the time. Cytopathology and culture may not be as definitive as previously assumed because of apparent variability of the microbial population within the external canal.

Animals↗

PubMed2006

Benign vascular lesions involving the external ear canal.

Benign vascular lesions include various forms whose classification has created some controversies in the literature. The observation of two rare cases of vascular bulge of the external ear canal prompted us to analyze the essential features of these lesions. One case was observed during an episode of otitis media, the other one was an incidental finding, and both are still on follow-up without treatment. The lesions are unmodified after 4 and 10 years, respectively. Vascular malformations can be differentiated from vascular tumors since they are present at birth, are generally stable, and do not involute. An attending strategy is justified unless symptoms occur.

Aged↗

PubMed1985

Binaural interactions in cortical area AI of cats reared with unilateral atresia of the external ear canal.

Binaural interactions were recorded in auditory cortical (AI) neurons of anesthetized adult cats that had unilateral atresias created shortly after birth by surgically ligating and cutting one external ear canal. At the time of the recording experiment, the atresia and associated debris were removed and tones were delivered to both tympanic membranes via a sealed and calibrated acoustic system. The majority of neurons recorded were in the cortex ipsilateral to the previously occluded ear. Thresholds for monaural stimulation of either the operated or unoperated ear were within normal range although thresholds to stimulation of the previously operated ear tended to occupy the upper end of the normal distribution. Monotonic and nonmonotonic spike count-vs-intensity functions derived from responses to monaural stimulation of the atretic ear were indistinguishable in their shape from those recorded in normal cats. All binaural classes were represented in our sample in proportions similar to those reported in cats with two normal ears. The forms of the functions relating spike count to interaural intensity differences and interaural phase differences were essentially the same as those seen in normal animals. The main binaural deficit observed under these conditions was a shift in the interaural intensity difference to which an AI neuron was most sensitive. The intensity needed for a stimulus to the atretic ear to participate in the binaural response was as much as 50 dB higher than that at the opposite normal ear in contrast to the nearly equal SPLs required for binaural interactions in cats with two ears intact. It was suggested that elevated thresholds at the previously operated ear could account for much of the shift observed.

Action Potentials↗

PubMed2005

Malassezia pachydermatis isolated from normal and diseased external ear canals in dogs: a comparative analysis.

To investigate the role of Malassezia pachydermatis as a pathogenic agent in canine otitis, a comparative analysis of isolates from normal and diseased external ear canals in dogs was undertaken. Specimens were collected from the ears of dogs with unilateral or bilateral otitis and from healthy dogs. Mycological analysis was by direct microscopy and fungal culture on Sabouraud's dextrose agar and Dixon's agar. Of the otitis specimens, 63.7% showed typical Malassezia cells on cytological examination. In samples taken from the healthy ears of dogs with unilateral otitis, only 21.43% (P<0.05) showed evidence of Malassezia. M. pachydermatis was identified cytologically and culturally in 57.53% (P<0.05), 14.29% and 30.0% of samples from the ears of dogs with otitis, from the healthy ears of dogs with unilateral otitis and from the ears of healthy dogs with no otitis. In the group with otitis associated with M. pachydermatis, the poodle was the most common breed (39.29%; P<0.05), whereas in the group without otitis, the German Shepherd breed was prominent (although this observation was not statistically significant). In both groups, the majority of dogs with M. pachydermatis were aged between 1 and 3 years (P<0.05). The higher incidence of M. pachydermatis isolated from the ears of dogs with otitis externa suggests a putative pathogenic role of this yeast in this condition.

Animals↗

PubMed1992

[Bacterial flora of the external ear canal. 2. Effect of irradiation].

A group of 34 patients with nasopharyngeal cancer was studied to observe the influence of the radiation effect on the bacterial flora of the external ear canal. The effects were observed before and after radiation therapy. The Gram-positive aerobes, especially the Staphylococcus epidermidis, were found to have decreased (57.1% to 37.7%). Though there was a slight increase of the Gram-negative aerobes (44.6% to 50.8%), it was not statistically significant. We concluded that the higher incidence of otitis externa induced by irradiation is due to the local radiation reaction, but not the shifted colonization of the potentially pathologic flora.

Adolescent↗

PubMed1987

An update on the external ear resonance in infants and young children.

The diffuse field to ear canal sound pressure transformations determined for 26 children (34 ears) from birth to 3 years old, confirm the earlier findings [Kruger B. Ruben RJ. Acta Otolaryngol (Stockh) 1987; 103:578-85] that the external ear fundamental resonance frequency is significantly higher at birth (about 6 kHz), and decreases with age to adult values (2.7 kHz) by the second year. The transformations were measured with either single or double probe tubes (coupled to miniature microphones) that were placed in the ear canal of sleeping infants. The accuracy of the magnitude of the transformations is discussed. Previously reported implications for hearing aid selection are supported.

Acoustic Stimulation↗

PubMed1993

Cytokeratin expression patterns in the human tympanic membrane and external ear canal.

Immunohistochemical investigations were carried out to further reveal the pattern of cytokeratin (CK) expression in middle ear cholesteatoma. Using chain-specific monoclonal antibodies and the indirect immunoperoxidase technique, 10 out of 19 CK polypeptides were screened in cryoslices of fresh postmortem eardrums and external ear canal specimens. Our data, combined with those published before, indicate an intimate relationship between middle ear cholesteatoma lesions and epidermal tissues in the immediate vicinity. Our CK data do not favor the metaplastic origin of cholesteatoma, because the CK complement of cholesteatoma lesions does not include major and typical CK constituents of the middle ear mucosa.

Antibodies, Monoclonal↗

PubMed1993

Fungal infections of the external ear.

Fungal infections of the external auditory canal can pose a great clinical challenge both in diagnosis and in therapy. Most infections present in patients who have undergone previous medical treatment of the external canal, which has changed the pH and normal canal flora, or in those who have diminished capacity for resisting infections. Diagnosis is made by clinical inspection and selective cultures. Therapy consists of complete cleaning followed by use of topical antimycotic agents. Systemic therapy is rarely required.

Humans↗

PubMed1997

Composition of lipids from the glands of the external ear canal of the adult chicken.

Six classes of neutral lipids, i.e. triacylglycerol (TG), free fatty acids (FFA), monoester waxes (MW), free- and esterified sterols (FST and SE), and squalene (SQ) were identified by thin layer chromatography of the lipid materials extracted separately from the secretion as well as from the isolated whole glands present in the skin of the floor of the external ear canal of the domestic fowl. Secretory lipids contained considerable proportions of MW fractions (17.03%), TG (22.23%), and SQ (14.66%), while TG was the major component (41.10%) in the lipids from the isolated glands. Polar lipids, which comprised about 16-20% of total glandular lipids, were shown to be composed primarily of sphingomyelin.

Animals↗

PubMed2003

[Malignant tumors of external ear. Review of cases in 1991-2001].

Carcinoma of the external auditory canal is a rare tumor. Owing to the rarity of this disease, the literature provides very few publications of series. There is not a widely accepted staging system. The lack of a standarized staging system impedes meaningful interpretation of the literature. It is very difficult to compare different treatment strategies and results. The study is a retrospective case review. Seven patients with external auditory canal malignancies were studied. We used the staging system proposed by Arriaga et al. for both the Squamous cell carcinoma and non-SCC. We describe the risk factors, the symptoms, the treatment and the outcome and prognosis for our patients.

Ear Neoplasms↗

PubMed1988

Severe hypertrichosis of the external ear canal during minoxidil therapy.

Minoxidil is a potent peripheral vasodilator used to treat patients with severe hypertension that is unresponsive to other medications. Hypertrichosis of the forehead, face, neck, shoulders, upper part of the arms, and legs is a frequent side effect that occurs in the majority of patients that use this drug. This phenomenon appears to be due to increased blood flow to hair follicles, with resultant excessive hair growth. We describe a patient with severe hypertrichosis of the external ear canal resulting in chronic otitis externa and hearing loss.

Ear, Middle↗

PubMed1984

Tissue culture of migratory skin of the external ear and cholesteatoma: a new research tool.

There has been considerable research interest in cholesteatoma in recent years but an understanding of the pathology has been handicapped by the lack of a suitable research model. Animal experiments are unsatisfactory as they may not fully represent the human pathology. In 1975 Rheinwald and Green devised a method of growing skin in tissue culture, using a feeder layer of lethally irradiated fetal mouse fibroblasts. This technique has been adapted for use with otological surgical specimens so that a comparison can be made between skin colonies derived from cholesteatoma matrix, migratory epithelium of the external ear, and normal skin from an extraconchal incision, as well as foreskin from neonatal circumcision as a control. The colonies so produced are then available for study by phase contrast microscopy, conventional light microscopy, and scanning and transmission electron microscopy. Differences in behavior and morphology between the various colonies grown in tissue culture have been demonstrated.

Adult↗

PubMed2000

[Contact allergies in patients with eczema of the external ear canal. Results of the Information Network of Dermatological Clinics and the German Contact Allergy Group].

BACKGROUND AND OBJECTIVE: The Information Network of Departments of Dermatology (IVDK) centrally collects patch tests results in cooperation with the German Contact Dermatitis Research Group (DKG). Data of patients, who underwent patch testing to evaluate otitis externa were analyzed. PATIENTS/METHODS: Data of 145 patients that had been recorded between 1992 and 1997 were evaluated. The evaluation included data yielded by standardized patch testing as well as by patch testing of products that the patients had used. RESULTS: Allergic contact dermatitis was diagnosed in one third of patients suffering from otitis externa. Topical drugs were shown to be the most important allergens. In comparison to the entire IVDK collective, the population-adjusted frequency of sensitization (PAFS) of neomycin sulfate was higher in the study population whereas that of nickel sulfate was lower. That shows that in a very specific topographic area, different allergens may be of clinical significance. CONCLUSIONS: Whereas nickel sulfate represents an important allergen in the contact dermatitis of the external ear, topical therapeutical agents, especially neomycin sulfate and, as evaluation of the patch tests of the patient's own products revealed, probably polymyxin B are the dominating allergens in otitis externa.

Adult↗

PubMed1999

Individual differences in external-ear transfer functions reduced by scaling in frequency.

This study examined inter-subject differences in the transfer functions from the free field to the human ear canal, which are commonly know as head-related transfer functions. The directional components of such transfer functions are referred here to as directional transfer functions (DTFs). The DTFs of 45 subjects varied systematically among subjects in regard to the frequencies of spectral features such as peaks and notches. Inter-subject spectral differences in DTFs were quantified between 3.7 and 12.9 kHz for sound-source directions throughout the coordinate sphere. For each pair of subjects, an optimal frequency scale factor aligned spectral features between subjects and, thus, minimized inter-subject spectral differences. Frequency scaling of DTFs reduced spectral differences by a median value of 15.5% across all pairs of subjects and by more than half in 9.5% of subject pairs. Optimal scale factors showed a median value of 1.061 and a maximum of 1.38. The optimal scale factor between any pair of subjects correlated highly with the ratios of subjects' maximum interaural delays, sizes of their external ears, and widths of their heads.

Adult↗

PubMed2001

[Carcinoma of the external ear canal and middle ear as interdisciplinary challenge for ear surgery and radiotherapy].

BACKGROUND: Carcinoma of the external auditory canal are tumours considered to have a poor prognosis. Improvement of the survival rate by surgical means alone is not possible. Individual therapy modalities as a result of an interdisciplinary approach between otosurgeon and radiotherapist are necessary. PATIENTS AND METHODS: A series of 30 patients (3 patients pretreated at other institutions) with carcinoma of the external auditory canal and middle ear treated between 1978 and 1997 in our institutions was analysed with particular reference to tumour size and its relation to surrounding tissues, patterns of neck node involvement, surgical procedures, and radiation techniques. Clinical endpoints were freedom from local failure, overall survival, disease-free survival. The mean follow-up was 4.7 years (range: 0.1 to 18.8 years), median 3 years. RESULTS: Treatment by surgery and radiotherapy resulted in an overall 5-year survival rate of 51%. According to Pittsburgh classification the 5-year survival rate for early disease (T1- and T2-tumours) was 89%, for stage III 67% and for stage IV 39%. Most important prognostic factors were dural infiltration (all patients with dural invasion died within 2.2 years) and the infiltration of surgical margins (the 5-year survival rate of patients with complete tumour resection was 100%, but 54% in patients with tumour beyond surgical margins). 192-iridium HDR afterloading brachytherapy based on 3D CT-treatment planning is an effective tool in the management of local recurrences following surgery and a full course of external beam radiotherapy. CONCLUSIONS: Surgical resection followed by radiotherapy adapted to the stage of disease and grade of resection is the preferred treatment of cancer of the external auditory canal and middle ear.

Adult↗

PubMed1998

[Application of polymeric endoprostheses in surgery of external ear].

Biocompatible polymeric endoprostheses EFOS are offered for endoprosthetic reconstruction of the external acoustic meatus in atresia. Such endoprostheses are safe for the adjacent tissues. Moreover, such prostheses contain antibacterial drugs (quinoxidine, dioxidin) and substances promoting tissue regeneration (orotic acid derivatives). This provides good epithelization of the walls of the newly established external acoustic meatus and sufficient lumen of the organ. The removal of the endoprosthesis is recommended on the postoperative day 90-120 in the outpatient setting.

Adolescent↗

PubMed2001

[Tumors of external ear canal. Case reports].

The authors described two rare cases of tumors of the external auditory meatus. All patients were male 40 and 51 years old. The tumors were removed via external auditory canal approach and extraauricle approach with successful.

Adult↗