1/288. Sudden deafness. A histopathological study.Histopathological studies were performed in the temporal bones from a 77-year-old woman who had bilateral sudden deafness 31 years before her death. The common findings in both cochleas were atrophy of the organ of corti and stria vascularis, and degeneration of the tectorial membrane. pathology of the tectorial membrane consisted of atrophy and droplet formation of the middle and marginal zones. In one area, an atrophied tectorial membrane was lifted up by a mass on the limbus. The saccular wall in the left temporal bone was ruptured. There was no pathology in the vascular system in the labyrinths except for moderate degeneration of sensory epithelium. The pathogenesis of sudden deafness was discussed in the light of the present findings. Alteration of the tectorial membrane seemed to be the main factor as a possible cause of sudden deafness. Histopathological findings were reviewed from the literature.- - - - - - - - - - ranking = 1keywords = cochlea (Clic here for more details about this article) |
2/288. Contralateral deafness following unilateral suboccipital brain tumor surgery in a patient with large vestibular aqueduct--case report.A 68-year-old female developed contralateral deafness following extirpation of a left cerebellopontine angle epidermoid cyst. Computed tomography showed that large vestibular aqueduct was present. This unusual complication may have been caused by an abrupt pressure change after cerebrospinal fluid release, which was transmitted through the large vestibular aqueduct and resulted in cochlear damage.- - - - - - - - - - ranking = 1keywords = cochlea (Clic here for more details about this article) |
3/288. Intraoperative loss of auditory function relieved by microvascular decompression of the cochlear nerve.BACKGROUND: Brainstem auditory evoked potentials (BAEP) are useful indicators of auditory function during posterior fossa surgery. Several potential mechanisms of injury may affect the cochlear nerve, and complete loss of BAEP is often associated with postoperative hearing loss. We report two cases of intraoperative auditory loss related to vascular compression upon the cochlear nerve. methods: Intra-operative BAEP were monitored in a consecutive series of over 300 microvascular decompressions (MVD) performed in a recent twelve-month period. In two patients undergoing treatment for trigeminal neuralgia, BAEP waveforms suddenly disappeared completely during closure of the dura. RESULTS: The cerebello-pontine angle was immediately re-explored and there was no evidence of hemorrhage or cerebellar swelling. The cochlear nerve and brainstem were inspected, and prominent vascular compression was identified in both patients. A cochlear nerve MVD resulted in immediate restoration of BAEP, and both patients recovered without hearing loss. CONCLUSION: These cases illustrate that vascular compression upon the cochlear nerve may disrupt function, and is reversible with MVD. awareness of this event and recognition of BAEP changes alert the neurosurgeon to a potential reversible cause of hearing loss during posterior fossa surgery.- - - - - - - - - - ranking = 9keywords = cochlea (Clic here for more details about this article) |
4/288. Direct measurement of cerebrospinal fluid pressure through the cochlea in a congenitally deaf child with Mondini dysplasia undergoing cochlear implantation.OBJECTIVE: perilymph/cerebrospinal fluid (CSF) "gushers" may occur at cochleostomy during cochlear implant surgery, particularly in patients with congenital cochlear duct malformation in which CSF in the internal auditory meatus is in direct communication with the perilymphatic space in the cochlea. The object of the study was to measure the pressure and flow of a CSF gusher at cochleostomy. STUDY DESIGN: The design was a preoperative pressure measurement. SETTING: The setting was a multidisciplinary cochlear implant program. PATIENT: A 4-year-old girl with bilateral Mondini deformity undergoing cochlear implantation was studied. INTERVENTION: A size 23 FG intravenous cannula was inserted into the cochlea and connected to a pediatric drip set to form an improvised manometer. MAIN OUTCOME MEASURE: Intracochlear fluid pressure was measured at 14 cm H2O, equivalent to the normal CSF pressure that would be recorded in a child of this age at lumbar puncture. An indirect measurement of the likely size of the CSF/perilymph defect was made. RESULTS: This technique may allow better assessment of the risk of postoperative CSF leakage and meningitis. CONCLUSION: This simple technique of measuring the pressure in a perilymph gusher can be used to assess the need for careful sealing of the cochleostomy, to measure the reduction in pressure produced by head elevation or a spinal drain, and to assess the probable size of a defect in the lamina cribrosa.- - - - - - - - - - ranking = 15keywords = cochlea (Clic here for more details about this article) |
5/288. Narrow and vacant internal auditory canal.A case of unilateral congenital deafness revealing a narrow vacant internal auditory canal and a more anterior and superior second canal where the facial and vestibulocochlear nerves are well visualised is presented. Having reviewed the scientific and embryological data, the authors consider the mechanism of this malformation.- - - - - - - - - - ranking = 1keywords = cochlea (Clic here for more details about this article) |
6/288. Hearing without hair cells? A case report.Audiograms from a five year old accident victim with a profound hearing loss are compared to temporal bone and brain stem histological findings. One temporal bone was evaluated using surface preparation and transmission electron microscope techniques. The other temporal bone was evaluated using serial section procedures. No sensory cells were present in either cochlea. This unusual finding is discussed. Evaluation of ventral cochlear nuclei showed a 50 per cent loss of neurons on both sides.- - - - - - - - - - ranking = 2keywords = cochlea (Clic here for more details about this article) |
7/288. Labyrinthine involvement in Langerhans' cell histiocytosis.BACKGROUND: Langerhans' cell histiocytosis, a rare condition caused by the proliferation of abnormal Langerhans' cells ('LCH cells') and an accompanying granulomatous infiltrate, can affect several organs including the ear. External and middle ear involvement are common with a reported incidence as high as 61%. The bony labyrinth is resistant to erosion by the granulation tissue, thereby protecting the cochlea and vestibular structures. Probably for this reason, involvement of the inner ear is rare, with few case reports in the literature. patients: We report two girls, one with bilateral and the other with unilateral mastoid involvement, in whom there was invasion of the labyrinth. The first girl had 'single system' LCH affecting only bone and developed an acute hearing loss due to invasion of the cochlea, while the second had both bone and skin involvement and labyrinthine involvement was diagnosed on imaging prior to the onset of labyrinthine symptoms. CONCLUSION: Inner ear involvement can lead to permanent deafness, which may be prevented by early institution of treatment. Threatened inner ear involvement requires urgent systemic medical therapy with steroids, possibly combined with chemotherapy.- - - - - - - - - - ranking = 2keywords = cochlea (Clic here for more details about this article) |
8/288. The Scheibe cochlea deformity with macrocephaly: a case for single channel implantation.An 11-year-old congenitally deaf child with bilateral primitive common cavity (Scheibe type) cochleosaccular dysplasia and benign familial macrocephaly was implanted with an extracochlear single channel device with an ear level speech processor. This paper describes the assessment, findings, dilemmas in decision making, surgical procedure and the favourable outcome after implanting. The relevant literature has been reviewed and our case is presented for the unusual combination of features.- - - - - - - - - - ranking = 5keywords = cochlea (Clic here for more details about this article) |
9/288. Electrical impedance measurements with the CI24M cochlear implant for a child with Mondini dysplasia.Electrical impedance measurements can give useful information about the status of individual electrodes of a cochlear implant. Impedances within the normal range (when measured in the common ground mode of stimulation) suggest that current flow occurs in the tissue and fluid of the cochlea. Low impedance measurements may suggest that particular electrodes are short circuiting, whereas high impedances might be due to a broken electrode wire or an electrode only in contact with air. In the case discussed, low impedance measurements were recorded intra-operatively from a child with Mondini dysplasia on electrodes 1-13 of a Nucleus CI24M device. Post-operatively the impedances had returned to the expected range and were comparable with other patients implanted with the CI24M device. Possible reasons for this are discussed. It was thought that impedances were low intra-operatively due to a larger-than-normal proportion of fluid surrounding the electrode array, rather than short circuits occurring along the array, as suggested by the dps7 software.- - - - - - - - - - ranking = 6keywords = cochlea (Clic here for more details about this article) |
10/288. Minimizing wound complications in cochlear implant surgery.OBJECTIVE: An extended postauricular incision has replaced the standard C-shaped scalp flap for cochlear implant surgery at our institution. The postoperative wound complication rates of the two incisions were evaluated. STUDY DESIGN: This study was a retrospective case review. SETTING: This study was performed in a tertiary referral center. patients: A total of 256 adult and pediatric patients who underwent cochlear implantation during a 10-year period (1986 to 1996) were reviewed. MAIN OUTCOME MEASURE: Postoperative wound complications were identified. Major complications included flap necrosis, wound dehiscence with or without implant exposure, and wound infection requiring hospitalization. hematoma, seroma, or superficial wound infections were considered minor complications. RESULTS: There were 6 major and 6 minor complications among 116 patients with the standard scalp flap (complication rate, 10.3%). There was only 1 minor complication among 140 implants using the postauricular incision (0.7%). CONCLUSION: The extended postauricular incision appears to significantly reduce the incidence of wound complications in cochlear implant surgery.- - - - - - - - - - ranking = 7keywords = cochlea (Clic here for more details about this article) |
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