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Cholesteatoma of the external ear canal is rare in otological practice. The case of a 62-year-old woman with local extension but scant symptoms or signs is reported. The literature is reviewed and the cause and treatment are discussed.
Amplitudes of odd order distortion products (DPs) that are detected in animal ear canals have been used to probe cochlear health, to search for cochlear amplification, and to measure aspects of cochlear mechanical frequency response. Like the DP amplitude, DP phase is also an important measure of the cochlear mechanical response. Reported here are measurements of DP phase in the ear canal of the cat. The phase data show frequency-dependent time delays. One of these delays is a function of f2, the frequency of the higher-frequency primary. Hence the DP phase phi d is of the form phi d = phi 0 + omega d tau, where omega d is the DP angular frequency and tau is a fixed time delay. Our results show that phi d is independent of input level a2 as long as the ratio a2/a1 < or = 2, where a2 and a1 are the amplitudes of the input tones. As a2/a1 becomes greater than two, the fixed time delays increase for DPs whose frequencies are less than the frequencies of the input tones. When both levels are varied together the delay increases as the levels decrease. There can be phase changes as large as pi associated with deep nulls in the DP magnitude for the two lower-frequency DPs. Features of the nulls may be modeled assuming that there is partial reflection of the DP wave from the DP place. The assumption of energy remitted from the DP place also explains amplitude-ratio-dependent time delays and 2 pi level-dependent bifurcations in phase. The DP phase shows different dependencies for f2 < 1 kHz compared to f2 > 2 kHz.
The records of 60 dogs that had a resection of the lateral wall of the vertical ear canal (Zepp) were examined. The surgical outcomes were evaluated in association with the following variables: breed, sex, age of onset of the otitis externa, duration of the disease before the surgery was performed, treatment received for the otitis externa, the status of the ear and tympanic membrane at the time of the surgery, the culture results, and concurrent medical problems. The outcome of surgery was acceptable in 45% and unacceptable in 55% of the cases. Breed was the only factor that could be correlated with the outcome. The procedure failed in 86.5% of the cocker spaniels. When surgical outcomes in breeds other than cocker spaniels were evaluated, 63% were acceptable and 37% were unacceptable. Sharpeis were found to have an ear canal of small diameter compared with that of other breeds and a tendency to have better outcomes.
With a "plastic leaf" electrode, cochlear summating potential (SP) and auditory nerve action potential (AP) responses to rectangular-pulse clicks were recorded from the ear canal skin surface of 96 normal-hearing ears of 48 subjects. The main goals of this investigation were to develop a more precise characterization of the relationship between SP and AP amplitudes across normal ears and to determine the confidence limits of this relationship so that a more accurate "normal limit" could be established for clinical testing. The results suggest that the across-subjects SP-AP amplitude relationship is linear. Also, SP scatter increases as AP amplitude increases, but the scatter is equalized by log transforming the data. The distance of the SP from the log-transformed SP-AP estimating line in SE ("AP-normalized SP amplitude") was found to be superior to the SP/AP amplitude ratio as a method of adjusting SP to AP amplitude, because the SP/AP ratio varied significantly with AP amplitude both across subjects and with different ear canal electrode positions.
This study compared three methods of pain relief in dogs that had total ear canal ablation with lateral bulla osteotomy. The hypothesis was that systemic opioids with preoperative local nerve blocks would provide superior pain relief. Thirty-one dogs with chronic otitis externa were included in the study. Dogs were randomly assigned to one of three protocols: systemic opioids alone (10 dogs, group 1), systemic opioids with bupivacaine splash block (11 dogs, group 2), and systemic opioids with preoperative local bupivacaine nerve blocks (10 dogs, group 3). Twenty-one dogs had bilateral ear ablation and 10 had unilateral ablation. Pain was assessed preoperatively, at extubation, 2 hours postextubation, and 1 day postoperatively by a single observer blinded to the analgesic protocol used. Pain scores were not significantly different within or between groups, nor did unilateral versus bilateral ablation have a significant effect on the score. Mean scores were less than 3 (scale 1 to 5) for all groups at all observation times. Rough recoveries were noted in 30% of group 1 dogs, 0% of group 2, and 20% of group 3 dogs. Ninety-four percent of dogs were moderately to heavily sedated at extubation. Sixty percent of group 3 dogs remained moderately to heavily sedated 2 hours postextubation. Rectal temperature, pulse rate, respiratory rate, and postoperative change in serum cortisol levels were not significantly different between groups. Postoperative increase in blood glucose was significantly higher in groups 1 and 3 compared with preoperative levels. Twenty-three percent of the dogs required additional analgesia or tranquilization after surgery, as determined by the anesthetist; 1 dog in group 1, 2 in group 2, and 4 in group 3. Each of the three analgesic protocols provided similar pain relief in dogs undergoing total ear canal ablation.
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Movement of the external ear canal, associated with jaw motion, relative to the concha region of the pinna has been studied. Pairs of open-jaw and closed-jaw impressions were taken of 14 ears from 10 subjects. Three-dimensional coordinate data were obtained from the concha and the anterior surface of the canal using a reflex microscope. Proprietary area-based matching software was used to evaluate distortion of the two surfaces between the two jaw positions. The canal data from each pair were placed into the same coordinate system with their respective concha regions aligned. Difference maps of the canal data were used to demonstrate the amount of anterior-posterior (A-P), superior-inferior (S-I), and medial-lateral (M-L) movement, relative to the concha, that occurred between the open- and closed-jaw impressions. The concha regions did not undergo significant deformation. The canal regions underwent varying amounts of deformation with all canals conforming within an rms of 136 microm across the entire surface. The majority of canals underwent significant movement relative to the concha. M-L movement ranged from +2.0 to -3.8 mm; eight canals moved laterally, five moved medially, and two showed no movement. S-I movement ranged from +3.7 to -2.7 mm; nine canals moved inferiorly, two moved superiorly, and three showed no movement. A-P movement ranged between +7.5 and -8.5 mm, with five canals moving anteriorly, three posteriorly, and four in a mixed fashion. This study has shown the variability of canal movement relative to the concha and does not support previous reports that suggest that the ear canal only widens with jaw opening.
OBJECTIVES/HYPOTHESIS: Described is the first reported case of an angiofibrolipoma of the ear canal in a patient who presented with right-sided conductive hearing loss and a medial canal stenosis. STUDY DESIGN: Case report. RESULTS/CONCLUSION: This variant of lipoma contains mature adipocytes, blood vessels, and dense collagenous tissue. The physical examination can be misleading, and the diagnosis requires histopathological examination. The patient was treated with complete surgical excision, tympanoplasty, canalplasty, and skin grafting to the external auditory canal. His pure-tone average improved from 37 to 11 dB, and his air-bone gap was closed completely. The lipoma has not recurred in the 6-month period following surgery.
A lateral approach was used successfully in seven of 10 dogs to resolve fistulas which developed after total ear canal ablations and bulla osteotomies. The approach facilitated identification and removal of horizontal ear canal remnants in four of the 10 cases. Facial nerve function was worsened temporarily by lateral exploration in two cases. Seven cases had no fistula recurrence during follow-up, which ranged from 12 to 72 months. Three cases each had fistula recurrence one-to-two months after fistula exploration.
In contrast to evoked otoacoustic emissions, acoustic distortion products (DPs) recorded from the ear canal are present at predictable frequencies with respect to their primary tones, f1 and f2. Such specificity may provide detailed frequency-place information concerning the functional state of limited regions of the organ of Corti following experimental intervention. However, to date, it is not clear whether emitted DPs solely reflect activity at the basilar-membrane regions of primary tones or if the remote DP site makes a significant contribution to the emitted signal measured in the ear canal. We have investigated a number of the general features of acoustic-DP generation in the rabbit so that, in later experiments, the contributions of specific basilar-membrane regions involved in generating these DPs can be identified using techniques designed to manipulate their normal properties. The first report describes the outcome of systematic manipulations of a number of stimulus conditions and alterations to the physiological state of the cochlea by exposure to fatiguing sound or anoxia. Experimental findings for the 2f1-f2 DP showed that, in general, the relations of the levels and frequency of the primary tones to DP magnitude were consistent with previously published data from other mammalian species. Additional observations for other odd-order intermodulation DPs at the 3f1-2f2 and 2f2-f1 frequencies suggested that the basic attributes of the acoustic DPs were similarly affected by systematic manipulation of the basic parameters of the primary tones and the general metabolic state of the cochlea. General anesthesia, however, did not affect DP amplitude. A companion paper describes the results of a series of subsequent experiments using response-suppression, interfering-tone, and temporary threshold shift techniques which address more directly the issue of which basilar-membrane sites contribute to the generation of different acoustic DPs.
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.
Thirty dogs with end-stage otitis were treated by either unilateral or bilateral total ear canal ablation and lateral bulla osteotomy. Otitis was considered end stage when the horizontal ear canal was collapsed, stenotic, or occluded in conjunction with chronic infection of the external and middle ear. The dogs were evaluated clinically and radiographically for 4 to 63 months. The frequency of scratching, head shaking, aural drainage, and para-aural fistulation was significantly decreased. Abnormal ear carriage and head tilt were not changed. The results in 23 dogs were graded as excellent or improved. One dog died of intraoperative hemorrhage. Complications during the period from suture removal to follow-up included para-aural fistulation (3 dogs), facial nerve paralysis (5 dogs), and head tilt (3 dogs).
This study examined the relationship between objective changes in electrocochleographic (ECochG) parameters and subjective changes in symptoms in a group of patients with Menière's disease/endolymphatic hydrops (MD/ELH) after application of positive and negative atmospheric pressure changes to the sealed ear canal. Our goals were to further examine the therapeutic effects of atmospheric pressure change on the treatment of MD/ELH, as reported by a series of Swedish studies, and to examine the utility of ECochG for monitoring these effects. By combining a clinical immittance unit and an evoked potential unit, ECochG responses were obtained from the tympanic membrane while different atmospheric pressures were applied indirectly to the middle ear via the external ear canal. For comparison, ECochG responses at various atmospheric pressures also were obtained for otologically normal subjects. For the MD/ELH group, there was a significant (p < 0.01) reduction in the abnormal summating potential/action potential (SP/AP) amplitude ratio, although the amplitude ratios did not become "normal." There was no significant effect of ear canal pressure change on ECochG components for the normative subjects. Although these findings were encouraging regarding the therapeutic effects of overpressure, they were not accompanied with changes in MD/ELH symptoms.
To assess whether or not the reduction of threshold to bone-conducted sound on occlusion of the ears (the occlusion effect) is due to compression of the auditory meatus by the jaw, measurements of movement of the skull and mandible and sound in the ear canal are reported from four subjects. The change in bone-conducted sound in the ear canal was also measured when the mandible was moved out and in (presenting more or less of the mandible to compress the auditory meatus) and when vibration was applied directly to the mandible. Sound pressure increased when the jaw was moved out and when vibration was applied to the mandible.
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