ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Purpose:Tympanic membrane perforations are very common and often require surgical treatment. Recent studies have suggested that growth factors may be an effective nonsurgical alternative for treating chronic perforations. The purpose of this study was to assess the efficacy of a platelet releasate in the treatment of chronic nonhealing perforations in the chinchilla model.Methods:Bilateral perforations were created in 47 chinchillas by excising 80% of the tympanic membrane with a thermal myringotomy knife. Bilateral perforations >50% of its surface area persisted for 10 weeks in 34 animals, and unilateral perforations >50% of its surface area, in nine animals. Only animals with bilateral chronic perforations were included in this study. After deepithelializing the perforation and packing the middle ear and external ear canals with Gelfoam, we treated the perforations with either platelet releasate or buffered saline. Each animal served as its own control.Results:The tympanic membranes were evaluated over a 12- week period by microscopy, photography, tympanometry, and histology. No statistical difference between treated and control ears in the incidence of perforation closure was evident. Histologically, the treated tympanic membranes consistently had a thicker fibrous layer than the controls.Conclusions:These data suggest that platelet releasate is not effective in enhancing closure of chronic tympanic membrane perforations in the chinchilla model.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Summary:Thirty temporal bones were dissected under the operating microscope, and four whole temporal bone specimens were studied by light microscopy for evaluation of the lateral malleal space and Prussak's space. In all specimens Prussak's space showed a blind end toward the anterior pouch and communicated with the posterior pouch. Its roof consisted of the lateral malleal ligamental fold, which was always strongest in its anterior half and as a rule had a thin area in its posterior portion. In four ears there was a membrane defect connecting Prussak's space to the lateral malleal space. The latter did not contain additional folds and communicated freely with the upper attic. The pathways for spread of an acquired primary cholesteatoma from Prussak's space are outlined.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Purpose:Findings of a prior study indicated that neither choice of pre- versus postoperative bone-conduction scores nor choice of frequencies to include in averaging makes a substantial difference in reported outcomes of chronic ear surgery.Methods:In this study, audiologic data from 240 stapes surgery patients at three different institutions were used to generate a variety of outcome measures.Results:Use of preoperative rather than postoperative bone-conduction values in computing postoperative air-bone gap resulted in an ~5-dB smaller mean gap and a 2% higher success rate. Frequencies included in averaging made little difference in mean computed air-bone gap, although success rate (gap ≤ 10 dB) was lower by 6% when 4 kHz was used in a four-frequency average rather than 3 kHz. Results for air conduction were similar to those for air-bone gap regarding choice of frequencies to include in averaging. When we used air-conduction pure-tone average (PTA) as the outcome measure, those with normal preoperative sensorineural hearing had a >20% higher success rate than the general population of patients with stapes surgery.Conclusions:The greatest differences in success rate were based on definition of and criteria for success. Success rate was higher when based on air-bone gap than when based on air-conduction PTA. As in the prior chronic ear study, differences in outcome were more drastically affected by criteria for “success” than by frequencies included. Unlike similar data from chronic ear surgery, however, success rate differed depending on choice of air-bone gap or air-conduction PTA as the definition for success. Further, air and bone scores from the same test interval must be used accurately to reflect air-bone gap in stapes surgery.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Summary:Most cases of sudden sensorineural hearing loss (SHL) are idiopathic. Consequently, the otologist may be asked to predict hearing recovery and select a treatment strategy without fully understanding the disease process. We retrospectively reviewed the charts of 837 patients with SHL to evaluate the prognostic value of specific clinical parameters and the effectiveness of steroid and vasodilator treatments. Treatment response was defined by the patient's subjective response and audiological criteria. Patients who were treated with steroids and/or vasodilators were more likely to improve. Patients who improved had a worse initial puretone average (PTA) than those who did not improve. In addition, those with poorer initial speech discrimination scores, worse initial thresholds at 4,000 Hz, younger age, and greater number of treatments were more likely to improve. Neither the electronystagmogram results nor the initial audiogram shape were valuable indicators. Recognition of prognostic indicators can help in counselling patients and in the evaluation of treatment response.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Purpose:The origin of acute/sudden hearing loss is multi-factorial. The association of vestibular symptoms does not necessarily isolate the pathologic condition to the inner ear. The audiogram provides a screen for differentiating conductive from sensorineural loss but often fails to provide more localizing information.Methods:Three unusual patients with a variety of retrocochlear presentations of hearing loss are presented. Along with conventional auditory brainstem response (ABR) testing, newer auditory tests, including otoacoustic emissions and three-dimensional ABR analysis, can facilitate site-of-lesion testing. Magnetic resonance imaging (MRI) also provides graphic documentation for sources of retrocochlear hearing loss.Results:One patient had gamma-knife treatment of an arteriovenous malformation, incurring a localized lesion to the inferior colliculus contralateral to the side of hearing loss. This effectively eliminated wave V, as confirmed by three-dimensional ABR analysis. A second patient with human immunodeficiency virus developed sudden complete hearing loss with retained otoacoustic emissions, confirming a retrocochlear lesion. A third patient with acute otitis media with sudden hearing loss and vertigo had an abnormal ABR and “mass lesion” on MRI. Hearing subsequently returned to normal, as did a repeated scan.Conclusions:The unique aspects of each case of retrocochlear hearing loss and the applied auditory electrophysiologic tests are reviewed..

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Summary:High-resolution computed tomography (HRCT) is the standard imaging technique used in cochlear implantation. However, cochlear and retrocochlear soft-tissue abnormalities may not be detected with HRCT alone. To determine whether magnetic resonance imaging (MRI) provides clinically significant information in addition to HRCT in the evaluation of candidates for cochlear implants, we performed a prospective study of 13 consecutive patients with cochlear implant patients receiving preoperative, high-resolution fast spin-echo T2-weighted MRI scans of the temporal bone. MRI identified unanticipated cochlear fibrosis in one patient, vestibular schwannoma in one patient, patency in the second turn of the cochlea in a patient with labyrinthitis ossificans, and disproved cochlear fibrosis suspected on HRCT imaging in one patient. These findings were significant for clinical decisions regarding candidacy for surgery, side selection for surgery, and surgical technique in cochlear implantation. Our experience suggests a high-resolution T2-weighted MRI of the temporal bone should be used preoperatively in addition to HRCT before cochlear implantation.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Summary:Electrically evoked stapedius reflex measurements were obtained in 19 children during surgery for cochlear implantation. They all received the Nucleus device. Stapedius reflexes could be elicited in all the children with congenital deafness but not in all the children with an etiology of meningitis. The intraoperative stapedius reflex thresholds were compared with postoperative values obtained after fitting of the speech processor and with the children's long-term behavioral most comfortable levels (C-levels). The intraoperative reflex thresholds were considerably higher than the postoperative reflex thresholds (44 “stimulus level steps” on the average), which could in part be ascribed to the influence of anesthetics used during surgery. It was concluded that, especially in children with an etiology of meningitis, the intraoperative stapedius reflex threshold (even after corrections for the concentration of the volatile anesthetics used) was a weak predictor of the C-level.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Purpose:The speech-perception abilities of 36 French children, whose onset of deafness occurred before 2 years of age, was longitudinally examined after they received a Nucleus multichannel cochlear implant.Methods:Speech perception was assessed in four areas: phoneme detection, closed-set word and sentence recognition; and modified open-set recognition.Results:All children achieved phoneme detection by 3 months after implantation. Closed-set word and sentence recognition appeared initially less accurate in children with congenital deafness than in the prelingually deafened children; however, these differences disappeared by 18 months after implantation. Some modified open-set recognition was evident by 12 months after implantation and continued to improve 3 years after implantation.Conclusions:Data demonstrate significant improvements in speech perception with implant experience: 15 (60%) of 25 of the children identified sentences in closed sets, 22 (88%) of 25 identified words in closed sets after 12 months' experience, and 13 (81%) of 16 demonstrated open-set recognition after 24 months of implant use.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Summary:Vascular compression of the eighth cranial nerve is increasingly recognised as a possible cause of incapacitating audiovestibular symptoms. There have been few reports of the efficacy of surgical microvascular decompression for tinnitus, and the practise is controversial. During the last 6 years, investigation by air computed tomography (CT) cisternography initially, and fast spin-echo magnetic resonance imaging (MRI) latterly has resulted in the diagnosis of cochlear nerve vascular compression in nine patients with a primary complaint of severe tinnitus who have subsequently undergone vascular-decompression surgery. The duration of symptoms ranged between 1 and 10 years, whilst their subjective tinnitus perception varied between 30 to 60 dB above threshold. Microvascular decompression was carried out by a retrolabyrinthine approach in four and by a retrosigmoid approach in the remaining five cases, with a postoperative follow-up of 1.3 to 5 years. Tinnitus was completely abolished in three (33%), very significantly improved to a sensation level of ≤ 10 dB in four (33%), significantly improved to a level of 15 dB in one (11%), and unchanged in two (22%). Both failures had had tinnitus for 6 years and had transient abolition for 10 days after surgery. Subsequent revision decompression surgery was also unsuccessful. This small study suggests that cochleovestibular vascular compression may result in severe tinnitus, which can often be ameliorated surgically.

ISSN:0192-9763    

出版商:OVID    

年代:1996

数据来源: OVID