摘要:

PurposeThe purpose of this study was to analyze the results of malleostapedotomy and to compare them with those of a conventional incus stapedotomy in a series of 82 consecutive surgical revisions in otosclerotic patients.Materials and Methods82 consecutive revision stapes surgery cases over 5 years were evaluated. The preoperative and postoperative audiometric data of 80 (97.5%) of the patients were obtained.Results71 of the patients underwent a functional revision procedure as malleostapedotomy (56, 79%) or as incus stapedotomy (15, 21%). The most common cause of failure of primary surgery was a displaced or malfunctioning prosthesis (86.2%). Pathologic changes of the oval window were found in 80% of the cases. Problems of the incus were identified in 80% and abnormality of the malleus in 48.6% of the cases. The functional success rate of malleostapedotomy (closure within 10 dB) was found to be higher than that of traditional incus stapedotomy (p < 0.05). Overclosure was seen in 12 patients (17%) and a significant sensorineural hearing loss in 2 patients (3%). There were no dead ears in this series. The postoperative hearing results after first revision surgery were better than those after multiple surgical procedures (p < 0.05).ConclusionsMalleostapedotomy yields better functional hearing results than incus stapedotomy in revision surgery for otosclerosis. The detection of many malleus fixations was the result of the systematic exposure of the anterior malleal process and ligament through an endaural approach with superior canaloplasty.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HypothesisThe goals of this study were to identify the effects of hypercholesterolemia on the cochlea and to find out where the pathologic changes first occur.BackgroundSome authors have stated that hypercholesterolemia alone does not produce auditory dysfunction. Others propose that auditory dysfunction is caused by glycogen accumulation and other alterations on cochlear ultrastructure.MethodsTwenty guinea pigs were classified as a control group fed with a normal diet, and a cholesterol group of 24 animals was given a diet composed of 1 g cholesterol per day for 4 months. The hearing acuity of the animals before the diets was compared with that after the diets by means of auditory brainstem responses. The basal and apical turns of the cochleas were examined by light microscopy and transmission electron microscopy.ResultsThe control group showed normal cochlear ultrastructures consistent with normal hearing thresholds, whereas the cholesterol group had profound edema in the strial marginal layer and slight edema in the outer hair cells, in line with data from auditory brainstem responses revealing changes in hearing sensitivity in various degrees. The pathologic changes in the basal turn and the stria vascularis were qualitatively prominent in comparison with those of the apical turn and the outer hair cell.ConclusionsThese observations confirm that hypercholesterolemia alone may cause auditory dysfunction if dietary cholesterol is kept at a high level for a long time. Alterations attributed to hypercholesterolemia begin in the stria vascularis and then spread over the outer hair cells, mainly in the basal turn.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThe purpose of this study was to evaluate the temporal bone findings in individuals with cochlear nerve aplasia.Study DesignRetrospective case review.MethodsTwo individuals with unilateral profound deafness caused by aplasia of the cochlear nerve were identified. The temporal bones were processed, and the cochlear elements were quantified.ResultsHistopathologic study of the temporal bones from these individuals demonstrate that a fully formed cochlea and normal-appearing organ of Corti can occur in the absence of the spiral ganglion and cochlear nerve. Cochlear nerve aplasia can occur in both a narrow or a normal-sized internal auditory canal.ConclusionThese findings suggest that the development of the cochlea and organ of Corti are not dependent on the presence of the cochlear nerve and spiral ganglion. The entity of cochlear nerve aplasia in the presence of a normally formed cochlea must be considered when evaluating individuals as candidates for cochlear implantation.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HypothesisOptimum stimulus parameters for tone burst-evoked myogenic responses can be defined. These optimized responses will be similar to those evoked by clicks in the same subjects.BackgroundLoud tones give rise to myogenic responses in the anterior neck muscles, similar to click-evoked potentials, and are likely to be saccular in origin.MethodsTone burst-evoked and click-evoked myogenic potentials were measured from the sternocleidomastoid muscles of 12 normal subjects (6 men, 6 women) during tonic activation. The effects of tone burst frequency and duration were systematically investigated. Thresholds were measured and compared with click thresholds for the same subjects. Patients with specific lesions were studied using both stimuli.ResultsTone burst-evoked responses showed frequency tuning, with the largest reflex amplitudes at either 500 Hz or 1 kHz. As the stimulus duration was increased, using a constant repetition rate, there was an increase in the reflex amplitudes followed by a decline. The overall optimum stimulus duration was 7 milliseconds. The mean tone burst threshold was 114.4-dB sound pressure level. Stimulus thresholds for click-evoked and tone burst-evoked responses were significantly correlated. Tone burst-evoked and click-evoked responses were present after stimulation of the affected ears of subjects with profound sensorineural hearing loss. Four subjects who had previously undergone vestibular neurectomy had an absence of click and tone burst-evoked responses on the side of the lesion, confirming their vestibular dependence.ConclusionTone burst-evoked myogenic responses are similar to click-evoked responses but require lower absolute stimulus intensities. To be certain of an optimum response, a stimulus duration of 7 milliseconds, an adequate intensity, and frequencies of both 500 Hz and 1 kHz should be used.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThis study was designed to assess the value of high-resolution multislice computed tomography (MSCT) data of the petrous bone for the virtual endoscopic visualization of the tympanic cavity.BackgroundThe recently introduced MSCT technology has improved spatial resolution in the z axis as well as scan speed in computed tomography. Three-dimensional rendering of high-resolution MSCT data of the petrous bone may be expected to provide endoluminal views of superior image quality, thus competing with transtympanic endoscopy (otoendoscopy).SettingThis study was conducted at a university teaching hospital.Materials and MethodsCadaveric phantom studies in a MSCT scanner were performed to define a data acquisition protocol, combining adequate detail resolution with low tube current. Subsequently, the cadaveric phantom underwent otoendoscopy. The postprocessing parameters of the three-dimensional rendering protocol were chosen to produce views closely resembling the corresponding otoendoscopic images. High-resolution data from 18 patients with pathologic conditions of the middle ear, as suggested by clinical findings and assessment of cross-sectional data, were postprocessed using the volume rendering technique to generate standardized virtual endoscopic views. A total of 36 virtual endoscopic scans of the tympanic cavity were generated.ResultsWith regard to intermediate and high-density structures, virtual endoscopic images, based on MSCT data, yielded endoluminal views closely resembling corresponding otoendoscopic views. Virtual endoscopy seems useful for imaging ossicular pathologic conditions such as dysplasia and chain disruption as well as for assessing patient status before and after otosurgery.ConclusionMSCT data sets allow for generating virtual endoscopic views closely resembling otoendoscopic images. The technique is especially useful when ossicular pathologic changes are present as well as for preoperative and postoperative imaging of otologic procedures.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThe etiopathogenesis in audiovestibular symptoms can be elusive, despite extensive differential diagnosis. This article addresses the value of magnetic resonance imaging (MRI) in analysis of the complete audiovestibular pathway.Study DesignRetrospective evaluation.SettingTertiary referral center.PatientsConsecutive sample of 354 patients (mean age 49 years, range 8 to 86 years) with audiovestibular disorders.InterventionContrast-enhanced MRI of the head with thin-slice investigation of the inner ear, internal auditory meatus, and cerebellopontine angle.Main Outcome MeasureAll MRIs were evaluated by experienced independent investigators. Statistical analysis was performed using the Statistical Package of Social Sciences data analysis 9.0.ResultsMRI abnormalities were seen in 122 of 354 patients (34.5%). The MRIs revealed the following: 4 pathologic conditions (1.1%) of the cochlea/labyrinth, 23 abnormalities (6.5%) at the internal auditory meatus/cerebellopontine angle, 12 pathologic lesions (3.4%) that involved the central audiovestibular tract at the brainstem, 78 microangiopathic changes of the brain (22%), 3 focal hyperintensities of the brain that turned out to be the first evidence of multiple sclerosis in 2 patients and sarcoidosis in 1 patient, and 1 temporal metastasis. Other pathologic conditions, such as parotid gland or petrous bone apex tumors, were unrelated to the audiovestibular symptoms.ConclusionsThis study indicates that contrast-enhanced MRI can be used to assess a significant number of different pathologic conditions in patients with audiovestibular disorders.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HypothesisHigh-resolution magnetic resonance imaging (MRI) at 1.5 T preferentially enhances the perilymph over endolymph after administration of contrast with gadodiamide, which allows for differentiation of the membranous labyrinth. Furthermore, this imaging allows for the detection of endolymphatic hydrops.BackgroundEndolymphatic hydrops is believed to be associated with a number of ear diseases, including Ménière's disease. Although the pathologic changes of overaccumulation of endolymph in the inner ear are obvious on postmortem histologic examination of the temporal bone, they have yet to be observed in a living organism. Previous attempts to visualize this condition with high-resolution contrast-enhanced computed tomographic imaging and MRI have been unsuccessful.MethodsHealthy pigmented guinea pigs underwent a unilateral surgical ablation of the endolymphatic sac to create endolymphatic hydrops in the ear. High-resolution temporal bone imaging was performed by use of a 1.5-T MRI system. Two-dimensional images were acquired by a spin-echo technique with and without contrast enhancement by gadodiamide.ResultsT1-weighted gadodiamide contrast-enhanced MRI of the midmodiolar level of the cochlea demonstrated that the perilymph appeared to be preferentially enhanced relative to the endolymph, resulting in a clear distinction between the scalae of the inner ear. The contrast-enhanced T1-weighted MRI of the midmodiolar level of the hydropic cochlea demonstrated a significantly enlarged scala media in comparison with the normal cochlea in the same animal.ConclusionThe demonstration of endolymphatic hydrops has been possible for the first time in vivo by the use of a standard 1.5-T MRI system. This research has important clinical implications: Specifically, this technique may allow for the noninvasive diagnosis of Ménière's disease.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThe goal of this investigation was to provide evidence that magnetic resonance imaging (MRI) can be performed safely and effectively on cochlear implant patients who require diagnosis of additional diseases.Study DesignA retrospective study was performed over 5 years. In a total of 300 patients with cochlear implants at the authors' center, MRI was performed whenever it was medically indicated.SettingAll patients underwent scanning in a Philips Gyroscan T10-NT MRI machine, using commercially available Powertrac 3000 software.PatientsAll patients with cochlear implants for whom MRI was indicated (n = 30) were included in this study. They had a wide variety of conditions necessitating MRI, including cervical discus prolapse, hypophyseal adenoma, epipharynx carcinoma, knee degeneration, parotid tumor, and preoperative evaluation for reimplantation and bilateral implantation.ResultsNo adverse effects from the MRI were reported by any of the patients. The cochlear implants all retained their function. All images were of diagnostic value. Because of the MRI, the patients did not need to undergo additional, more invasive and expensive diagnostic procedures. Examples of MRI images from 5 patients are shown.ConclusionsMRI on cochlear implant patients, using the Med El Combi 40 and Nucleus mini 22 series at 1 Tesla, can be a safe procedure. Removal of any magnet is not necessary.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveEvaluation of auditory performance and its evolution over time in patients with the auditory brainstem implant.Study DesignProspective study.SettingTertiary referral center.Patients and MethodsBetween May 1996 and April 2000, 14 patients with neurofibromatosis type 2 underwent implantation with a multichannel auditory brainstem implant. Auditory performance data were obtained in 13 patients who had used their device on a regular daily basis for 1 to 41 months (average 19 months). Hearing evaluation was based on the results of four tests (vowel confusion, consonant confusion, Freiburger numbers, and speech-tracking test), which were performed with and without lip-reading at regular intervals after device activation.Results12 patients received auditory sensation through the auditory brainstem implant immediately after device activation. In one patient, because of postoperative electrode migration, device activation was not successful. In this case, after the electrode array was repositioned, activation was successful. The results of the audiovisual mode 2 weeks after device activation revealed a lip-reading enhancement above the chance level in about 50% of the patients in the vowel confusion and speech-tracking tests and in 70% of the patients in the consonant confusion test. Lip-reading enhancement improved within the first 6 months and then entered a plateau phase, which was more prominent in the monosyllabic vowel and consonant tests. In the auditory alone mode, more than half of the patients showed their first positive result in the vowel test 3 months after device activation, but it took about 6 months until half of the patients revealed a result above the chance level in the consonant and Freiburger numbers tests. Open set speech recognition in the auditory alone mode (in the speech-tracking test) was not common and happened relatively late (within 1 year or later).Discussion and ConclusionAlthough auditory sensation appeared immediately after device activation, a period of 6 months was necessary for relearning and adaptation of the central auditory system to the altered form of auditory information presented by the auditory brainstem implant.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThis study assesses the results of cochlear implantation in children with cochlear malformations.Study DesignRetrospective, matched-pairs analysis of prospectively collected data.SettingUniversity-based regional cochlear implant center.PatientsSeventeen children with osseous cochlear malformations who had undergone implantation were matched and compared with a group of children with normal cochleae who had undergone implantation.InterventionsAll subjects received a multichannel cochlear implant and habilitation.Main Outcome MeasuresAll subjects were tested with the Early Speech Perception test, and the Glendonald Auditory Speech Perception tests for words and sentences. Patients were classified in a standardized speech perception category based on performance on the Early Speech Perception test.ResultsAll subjects demonstrated improving performance on all measures of speech perception over time. Overall, the two groups showed no statistically significant differences in performance at 6 and 24 months. However, subjects with malformed cochleae evidenced slower rates of improvement than did their matched control subjects. Subjects with more severe malformations demonstrated poorer performance, but this may have been attributable to preoperative factors rather than to implant performance.ConclusionsChildren with radiographic cochlear malformations benefit from cochlear implantation with multichannel devices. They ultimately perform as well as their matched counterparts with normal cochleae, although they may improve more slowly over time.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID