ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypothesis:The attic compartments, except for Prussak's space, are aerated through the tympanic isthmus. The aim of this study was to develop aeration pathways that would bypass the isthmus in surgery for chronic inflammatory ear disease and cholesteatoma.Background:Microdissection of the epitympanum has shown that the anterior attic and the supratubal recess are separated by the tensor fold, the excision of which creates a large new aeration pathway.Methods:Earlier surgical experience was reexamined as to the access to the tensor fold. Twenty temporal bones were dissected to create clinically useful new surgical routes for tensor fold removal in the presence of an intact ossicular chain.Results:An endaural atticotomy, extended to the supratubal recess, allows excision of the tensor fold; however, the excision must be performed blindly. Cutting the neck of the malleus to allow lateral lifting of the manubrium exposes the tensor tendon and allows rapid excision of the fold. The elasticity of the tendon assists in approximation of the cut edges. In canal wall up surgery, removal of the lateral attic bone until the root of the zygoma exposes the anterior surface of the head of the malleus and the lateral portion of the transverse crest. Drill-out of the crest leads directly to the posterior side of the tensor fold, allowing its excision under direct vision. Thinning of the attic bone lateral to the body and short process of the incus allows simultaneous removal of the lateral incudomalleal fold.Conclusions:When the ossicular chain is discontinuous, tensor fold resection can be made under direct vision. With an intact chain, cutting of the neck of the malleus used in tympanic glomus tumors causes no hearing changes, allows complete fold excision, and is adaptable to chronic ear surgery. The frontolateral attic route for removal of tensor fold, together with the lateral incudomalleal fold, can be used in the canal wall up surgery to improve attic aeration.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypothesis:The inflammatory response to acute otitis media (AOM) is a chain reaction involving, among others, macrophages, B lymphocytes, and T lymphocytes that vary in number on different days during the infection. The response is thought to eventually contribute to tympanosclerosis (TS).Background:In humans, TS and myringosclerosis (MS) are obscure sequelae of chronic otitis media. MS is also commonly seen in children who have had acute purulent otitis media or secretory otitis media or after treatment with ventilation tubes in the tympanic membrane (TM). It causes hearing disability, especially if the ossicles or the inner ear are affected. No successful treatment is available. This study was performed to evaluate the inflammatory stages that may lead to TS or MS.Methods:Sprague Dawley rats were exposed to a Pneumococcus type 3 solution into the middle ear. Groups of rats were killed at 3,6, and 10 days after inoculation. Sections from the TM specimen were stained immunohistochemically according to the avidin-biotin method. Antibodies used were directed against macrophages, T cells, and B cells. Positive cells were counted and a mean value was estimated for each slide and section for each antibody in each rat.Results:Results showed that macrophages, T cells, and B cells were presented time-dependently in the acute inflammatory response in AOM. At day 3, dendritic cells, macrophages, T cells, B cells, and other major histocompatibility complex (MHC)-restricted cells were richly expressed in the whole submucosal layer and especially in the annulus fibrosus. At day 6, the amount of all positive cells decreased except for B cells and other MHC-restricted cells, which slightly increased in number. At day 10, all of the cells were lower in number than at days 3 and 6. Macrophages and possible T cells could be detected in the TM, which has not been observed earlier. Large osteoclastlike cells were present close to the bone.Conclusions:Macrophages were the first cells to invade the tissue after AOM induction. Some cells were found in the TM. Large osteoclastlike cells could be seen adjacent to the bone in the submucosa. T cells and B cells were seen in the submucosa.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypothesis:The bone destruction in cholesteatoma is multifactoral. This study was undertaken to define the role of tumor necrosis factor-alpha (TNF-α) in bone destruction associated with cholesteatoma.Background:Tumor necrosis factor-alpha is an important inflammatory cytokine secreted by activated macrophages. It stimulates keratinocytes as an autocrine growth regulator. Few authors have localized TNF-α in aural cholesteatoma. An attemp was made in this study to show a correlation between TNF-α and cholesteatoma associated bone destruction by localizing TNF-α in cholesteatoma and measuring its serum level.Methods:Serum TNF-α levels were measured in 20 patients with cholesteatoma of temporal bone and histochemical staining was used to localize TNF-α in pathologic tissue excised at surgery.Results:Serum TNF-α levels in patients with cholesteatoma were significantly higher than in controls. In addition, TNF-α levels in patients with bone destruction were higher than in those without bone destruction. However, there was no correlation between age of the patient and serum TNF-α levels. The TNF-α was localized in various layers of cholesteatoma epithelium using indirect immunoperoxidase staining.Conclusion:TNF-α is one of the cytokines produced by cholesteatoma that may be an important mediator of bone destruction associated with cholesteatoma. TNF-α has been localized in various layers of cholesteatoma and exerts a locally destructive effect on bone. Serum TNF-α levels are related to the extent of bone destruction.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypothesis:Otosclerosis does not occur outside the temporal bone.Background:The widely accepted assumption that otosclerosis is confined to the temporal bone has never been tested. It is important to investigate this issue, particularly because of evidence that otosclerosis may be a systemic (genetic) disease that could affect other bones.Methods:Biopsies from 9 to 11 skeletal sites were obtained from 2 patients with clinical otosclerosis. Two hundred forty-one nontemporal bone sections were examined by light microscopy.Results:No nontemporal skeletal bone section showed histologic evidence of otosclerosis. The data indicate, with 95% confidence, that the true prevalence of otosclerosis in the extratemporal skeleton of the 2 patients examined was<3%.Conclusions:These findings suggest that otosclerosis is unlikely to occur outside the temporal bone. Factors unique to the otic capsule that may predispose it to otosclerosis are lack of bone remodeling and the presence of globuli interossei.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypothesis:Experiments in guinea pigs were performed to clarify which, if any, of the CO2 lasers in different modes (continuous wave [cw] and superpulse) can damage the inner ear on application of the laser parameters required for stapedotomy and to determine their application safety.Methods:The laser effect connected with perforating the basal convolution of the guinea-pig cochlea (cochleostomy) was examined. Acoustic evoked potentials (compound action potentials [CAPs]) yielded information on inner-ear function.Results:In cw mode, even single applications of an approximately four times higher power density (60,000 W/cm2) than necessary for stapedotomy at a pulse duration of 50 msec (energies up to 1 J) and 20-fold applications of effective parameters for a footplate perforation (power density 16,000 W/cm2; energy 0.2 J) did not cause CAP changes. Experimental studies with the CO2 superpulse laser used (peak pulse powers: ca. 300 W) have demonstrated that irreversible CAP alterations already occur in the effective laser range in>40% of the animals.Conclusions:2 J) than those used clinically, the CO2 laser in cw mode has a high application safety for laser stapedotomy. The application of the CO2 laser in superpulse mode with peak pulse powers of approximately 300 W in stapedotomy appears to be more unreliable and dangerous for the inner ear.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypothesis:Western blot assay for beta-2 transferrin protein is a clinically useful method for the detection of human perilymph and should be used for the diagnosis of perilymph fistulas (PLFs).Background:Considerable controversy exists regarding the diagnosis of PLF. Recent studies suggest that the detection of beta-2 transferrin protein may be useful in the identification of perilymph.Methods:To evaluate the usefulness of the beta-2 transferrin assay for identifying human perilymph, paired perilymph samples and negative controls were collected on Gelfoam pledgets from 20 patients who had surgery that opened the inner ear. Blinded immunoelectrophoretic assay (Western blot) for beta-2 transferrin was performed on each specimen.Results:Only one (5%) of the known perilymph samples and none of the control specimens were definitely positive for beta- 2 transferrin. Combined with historical data, this assay has 29% sensitivity, 100% specificity, 100% positive predictive value, and 31 % negative predictive value.Conclusions:These findings suggest that the beta-2 transferrin protein assay may not be a reliable method for detecting human perilymph when performed using this technique.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:Hearing loss caused by combined rupture of Reissner's membrane and the round window (RW) membrane (the double-membrane rupture) may differ depending on the site of the lesion on Reissner's membrane. The purpose of this experimental study was to reveal the relationship between the hearing impairment and the site of the lesion on Reissner's membrane.Background:According to experimental studies on perilymphatic fistula (PLF), profound hearing loss is not induced by rupture of RW alone, but by the double-membrane rupture. However, the mechanism responsible for hearing loss in the double-membrane rupture remains unclear.Methods:Compound action potentials (CAPs) of the cochlear nerve in response to tone pip stimuli (1, 2, 4, and 8 kHz) were recorded before the lesion, 90 minutes after the Reissner's membrane rupture, and 90 minutes after subsequent laceration of the RW. Reissner's membrane was ruptured at one of the four turns for comparison.Results:The double-membrane rupture caused a more severe increase in CAP thresholds than seen with separate ruptures, when the Reissner's membrane was ruptured at the second turn. Such pronounced increase in threshold was not seen in ears with the rupture at other turns.Conclusions:The double-membrane rupture causes varying degrees of hearing loss depending on the site of the lesion of Reissner's membrane. When the Reissner's membrane was ruptured at the second turn, the most severe hearing loss was detected.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:This study describes the effectiveness of a multielectrode cochlear implant prosthesis (Cochlear; Cochlear Pty., Lane Cove, Australia) for providing hearing to children with deafness caused by large vestibular aqueduct syndrome (LVAS).Study Design:The study design was a retrospective study.Setting:All the children attended The Children's Cochlear Implant Center (NSW), which is a specialist center that provides audiologic testing, speech therapy, habilitation, and medical assistance for children with cochlear implants.Patients:Ten children were studied who had profound hearing loss and radiologic evidence of a vestibular aqueduct larger than 2 mm in width in its intraosseous portion.Intervention:The children received a multielectrode (Cochlear) cochlear implant prosthesis, and the associated programming of the device and habitation were performed postoperatively. No significant problems were encountered at any of the surgeries, although there was an initial gush of perilymph when the otic capsule was opened in 7 ears.Main Outcome Measures:Postoperative audiologic performance at six monthly intervals and school performance were assessed.Results:The postoperative auditory performance was improved in all children. At 6 months, their average BKB score had increased from 31% to 79%; average word score, from 8% to 43%; and average phoneme score, from 38% to 70%. The older children were able to continue their education in their usual setting with less reliance on hearing support staff.Conclusion:Children with a deteriorating hearing loss caused by LVAS can derive considerable benefit from a cochlear implant.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To describe methods of assessing cochlear implant candidacy in patients with potentially significant peripheral and central nervous system (CNS) degeneration.Study Design:A patient with a degenerative CNS disease (MELAS syndrome) undergoing evaluation for cochlear implantation is described.Setting:This study took place at a tertiary care center.Patient:A patient with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) who had cortical blindness and profound sensorineural hearing loss was evaluated and rehabilitated with cochlear implantation.Interventions:Pure-tone audiogram, behavioral responses to promontory stimulation electrical auditory brainstem response, and electrically evoked middle-latency responses (MLRs) were used to assess eighth nerve, auditory brainstem, and cortical auditory pathways. Cochlear implantation with Cochlear Corporation mini 22 implant was performed.Results:Repeatable electrically evoked MLRs and behavioral responses to promontory stimulation documented the presence of auditory cortical responses. Successful implantation resulted in open set speech recognition and communication using the auditory/oral mode.Conclusion:This report describes successful implantation in a patient with MELAS syndrome and demonstrates the ability to preoperatively confirm the integrity of brainstern and cortical auditory pathways despite significant CNS degeneration.

ISSN:0192-9763    

出版商:OVID    

年代:1999

数据来源: OVID