摘要:

Recently, it has been suggested that otosclerosis represents the host's ongoing immunologic response to measles or other viral antigens. Documentation of past inflammation within the inner ear would serve as further evidence that this mechanism may be at play in the pathogenesis of the disease. Among the characteristic signs of prior inflammation in the inner ear is the presence of lamellar bone at the site of inflammation. This has been described in the temporal bone of a patient with immunemediated deafness and with the temporal bones of experimental models of immunemediated inner ear disease. Review of temporal bones with round window otosclerosis from the Eastern Temporal Bone Bank at the Massachusetts Eye and Ear Infirmary show that in four of ten cases there are characteristic signs of a prior severe inflammatory event centered in the scala tympani adjacent to the otosclerotic lesion. Otosclerosis, therefore, may have an inflammatory stage that is the consequence of a host response to an inciting event.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Stapedectomy for otosclerosis is one of the most demanding otologic procedures, especially for residents in training. The reported series in the literature, as well as our own experience with the traditional resident-performed complete stapedectomy, have been disappointing. The number of patients available to train residents in stapedectomy techniques has steadily declined. The challenge to the otologist involved in teaching residents and fellows is to find a method that will be safe and effective. Over the past 5 years, we have had an opportunity at the University of Texas Medical Branch at Galveston to compare two methods of performing a laser stapedotomy. The two methods involve using the KTP-532 laser with a micromanipulator and using the hand-held argon laser. Although the wavelengths of these two lasers are similar, the methods used in applying them are very different. Twenty-five consecutive cases in each group were reviewed with regards to technical difficulty, complication rate, operative time, and air-bone gap closure. The hand-held argon laser emerged as the preferred technique for teaching a routine stapedotomy to residents.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Some surgeons have altered their technique for small fenestra stapedotomy in order to avoid footplate complications. This study aimed to determine what surgical step changes reduced footplate complications and improved hearing results. Operative reports provided data on surgical technique and complications in 151 consecutive primary stapes surgery patients. Comparisons of preoperative and postoperative audiograms provided hearing results of surgery. Fenestrating the footplate after, rather than before, stapes arch removal and fracturing the stapes arch after dividing one crus with a nipper were two surgical steps that reduced fractures. Hearing results were better after fenestration of the footplate with a microdrill compared to results with a hand drill.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

This study describes the endoscopic anatomy of the cerebellopontine angle (CPA). Endoscopes were introduced into the basal cisterns and it was found that the neurovascular structures of this angle could be seen in detail. Endoscopy is likely to complement contemporary microsurgical procedures. The need for minimally invasive surgery may mandate further study of the application of this type of endoscopy in surgical practice. It is stressed that considerable cadaver experience should be obtained with this technique prior to any application in the operating room.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Cholesteatomas are invasive, locally destructive skin-like lesions that, after operative removal, have a significant recidivistic rate. These aggressive characteristics suggest a fundamental alteration in the biology of one or more of its constituents (i.e., keratinocytes, fibroblasts, and inflammatory cells). The cholesteatoma matrix was studied by subculturing it into its main cellular components. Short-term cell cultures of fibroblasts from cholesteatoma matrix and controls from ear canal and postauricular skin were established. These cultured fibroblasts were tested for invasiveness using the Boyden Chamber Assay of Albini. The cells were evaluated for their ability to migrate, attach to, and invade a basement membrane. Results of the motility and attachment of fibroblasts cultured from cholesteatoma, canal wall, and postauricular skin did not differ. However, fibroblasts from 12 of 12 cholesteatoma specimens were highly invasive, while those from postauricular and ear canal skin were either weakly invasive or not invasive. This represents the first report of an intrinsic defect in the biology of cholesteatoma. Invasive fibroblasts that demonstrate a loss of growth control, may provide a contact guidance mechanism that aggressively mobilizes the squamous keratinizing epithelium contributing to the invasive, aggressive behavior of cholesteatoma.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Acoustic neuromas account for 75 to 80 percent of cerebellopontine angle tumors and 8 to 10 percent of all intracranial neoplasms. These tumors arise from the Schwann cell sheath that surrounds the peripheral portion of the facial, cochlear, superior, and inferior vestibular nerves. Theoretically, a schwannoma may arise from Schwann cells anywhere along these nerves from the glial-Schwann cell junction to the end organ. Clinically, however, they most frequently originate from the vestibular nerves, occasionally from the facial, and only rarely from the cochlear nerve. This investigation utilized light microscopy, immunochemistry, and digital optical morphologic analysis to determine the distribution of Schwann cells along the facial and vestibulocochlear nerves in an attempt to explain the observed distribution of tumors, and to evaluate currently accepted theories. No direct correlation between the distribution of Schwann cells and the observed distribution of schwannomas was found. Thus, this study did not confirm the currently held theories regarding schwannoma distribution in these nerves.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

In the past, otologists have reported the results of middle ear surgery to improve hearing, either by tympanoplasty or by stapes surgery, mainly in terms of closure of the air-bone gap. This is valid as a measure of the technical success of the operation provided any change in the bone conduction thresholds, particularly at the higher frequencies, is also reported. Unfortunately, technical success in surgery does not always equate with patient benefit, primarily because, in most conditions, listening is a binaural condition. Disability in such circumstances is dictated by the hearing in the better hearing ear, which, quite correctly, is usually the nonoperated ear. Hence, it is important to define the relationship, before and after surgery, between the hearing in the operated and that in the nonoperated ear. This is the basis of the Glasgow Benefit Plot, which is drawn up from pure-tone audiometric data before and after surgery.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

In an attempt to define the clinical parameters and relevance of ototopical medications, including their usefulness in permanent inner ear damage, a questionnaire survey was sent to 7463 otolaryngologists within the United States, of which 2235 responded. The four main categories were demographic data, patterns of practice, factors influencing use of ototopicals, and opinions/impressions of ototopicals under various circumstances. The vast majority of respondents use ototopical preparations in the presence of a draining perforation (84.1%), in the presence of drainage through a ventilation tube (93.7%), and in the presence of an open, draining tympanomastoid cavity (92.8%). A significant number of clinicians use ototopicals with intraoperative packing (75.3%) and postoperative prophylaxis against infection (57.9%). Eighty percent of respondents indicate that the risks for ototoxicity of otitis media is as great as, or greater than, the risks for ototoxicity of an ototopical preparation. Seventy-five percent of respondents stated that ototopicals are safe in a fresh postoperative ear. Some respondents (3.4%) reported that they had witnessed irreversible inner ear damage unquestionably related to ototopicals.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The recent development of simple, low-cost methods for producing autologous fibrin glue have given rise to a variety of uses in routine otologic and neurotologic procedures. Some of the current applications used by the authors are discussed, and a brief review of the literature is presented. Included are methods of positioning and securing implants, closure of wound edges, and application as an adjunct to achieving watertight dural closures with intracranial procedures. Representative cases are presented. No adverse reactions or specific problems related to the glue have been noted. A simple production method is included, as well as comparison with other commonly available tissue glue products.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The development of cochlear implants for use in very young children (1-2 years old) will require techniques designed to accommodate temporal bone growth. Previous anatomic studies have shown that the leadwire of a cochlear implant must be capable of expanding up to 20 mm between the round window and the implanted receiverstimulator in response to skull growth. In the present study morphologic and biomechanical evaluation of five expandable leadwire designs was conducted following their implantation in young cats. Two helical shaped leadwire designs frequently exhibited extensive fibrous tissue adhesions and broke during long-term implantation. In contrast, thin, flexible Silastic envelopes were effective in minimizing tissue adhesions. Residual V- and Z-shaped leadwires, placed in these envelopes, showed little evidence of fibrous tissue adhesions following implantation periods of up to 2 years. Moreover, these leadwires readily expanded both during the growth of the animal and when biomechanical expansion studies performed at the completion of the implant period. These expandable leadwire designs appear to be appropriate candidates for use in pediatric cochlear implants.

ISSN:0192-9763    

出版商:OVID    

年代:1993

数据来源: OVID