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Biomedical subjects

W L Meyerhoff

Publications and source records attributed to W L Meyerhoff.

At least 55 records · Page 3Linked to original sources
PubMed1990

Asymmetric pneumatization of the petrous apex.

Three patients with high-intensity MR signals from one petrous apex, but nonpathologic fine-cut computed tomography are reported. In two of the three patients, normal bone marrow within the petrous apex on one side is believed to have generated the high-intensity signal. In one of the three patients, the etiology of the MR image remains obscure, but may represent the earliest stages of petrous cholesterol granuloma or mucocele. We have reviewed 500 head CT scans performed for non-otologic reasons, in an attempt to establish the frequency of this finding. The literature on MR and CT imaging of the petrous apex and asymmetric pneumatization of the petrous apex is reviewed.

Adult↗
PubMed1989

The ototoxicity of ceftazidime in the chinchilla middle ear.

Ceftazidime (Tazicef) is a broad-spectrum cephalosporin antibiotic that may be useful as a topical agent in the treatment of otorrhea. To test the potential ototoxicity of the drug, 0.5 mL of a 10% solution of ceftazidime was introduced into the bullae of 22 chinchillas. The organ of Corti was normal in 20 temporal bones examined at 1 week after administration of the ceftazidime solution. Only 2 of 24 temporal bones examined after 4 weeks showed minor outer hair cell loss of the basal turn of the organ of Corti. Focal hemorrhage and occasional serous effusions were found in the middle ears of all animals after 1 week; these findings had mostly cleared after 4 weeks. Our results indicate that ceftazidime causes reversible middle ear inflammation, and may have some minor ototoxic potential under these experimental conditions.

Administration, Topical↗
PubMed1989

Audiologic threshold monitoring of patients receiving ototoxic drugs. Preliminary report.

An effort was made to determine the efficacy of auditory threshold monitoring of patients receiving ototoxic drugs. Forty-four patients treated with either tobramycin or vancomycin for osteomyelitis were tested at the beginning of treatment, following treatment, and twice weekly during treatment when possible. All patients had renal function carefully monitored. Peak and trough drug levels were kept out of the toxic range throughout the study. In no patient did indisputable ototoxicity occur, and therefore, no conclusion about the most efficacious schedule for auditory monitoring of patients receiving ototoxic drugs was made, and what constitutes a significant intratherapeutic threshold shift is still in question. Until further data are collected, monitoring of renal function and peak and trough drug levels, as well as patient counseling, is recommended. Pretherapy and posttherapy auditory monitoring and intratherapeutic monitoring of high-risk patients and those who develop aural symptoms may prove beneficial.

Adolescent↗
PubMed1989

Spinal fluid profile following surgery in the subarachnoid space.

Neurotologic and skull base procedures that include dissection within the subarachnoid space carry with them the potential for meningitis. Postoperative aseptic leptomeningitis occurs more frequently than purulent bacterial meningitis. Differentiation between these two conditions early in the postoperative period is important to avoid delay in or unnecessary treatment. The definitive diagnosis is made with cerebral spinal fluid culture. Early differentiation between postoperative aseptic leptomeningitis and purulent bacterial meningitis on the basis of results of cerebral spinal fluid profile before cerebral spinal fluid culture would result in earlier appropriate therapy.

Anti-Bacterial Agents↗
PubMed1989

Magnetic resonance imaging in the diagnosis of temporal bone and skull base lesions.

Six patients are presented in whom total reliance on magnetic resonance imaging (MRI) interpretations would have resulted in less than ideal treatment. The misleading information on magnetic resonance imaging could be divided into two types; as follow: type I were those in which there was no signal but nonosseous pathology was present, and in type II an abnormal signal was present but misinterpreted. In three of these patients (cases, 2, 3, and 5), information gained from more traditional means (history, physical examination, audiologic and vestibular testing, and computed tomography) led to proper treatment, whereas, in two patients (cases 4 and 6), treatment exceeded that required by the disease process. In one patient (case 1), ideal therapy resulted, despite a negative magnetic resonance imaging study, when a small intracanalicular tumor was found fortuitously during a translabyrinthine vestibular nerve section for vertigo. Although magnetic resonance imaging provides excellent supplemental information to more traditional means of diagnosis, it cannot be used entirely in their place. As gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) becomes more readily available, as the resolution of magnetic resonance imaging improves, and as we gain more familiarity with this diagnostic modality, misleading information from these studies should decrease.

Diagnostic Errors↗
PubMed1988

Ototoxicity of Vasocidin drops applied to the chinchilla middle ear.

Some widely used ototopical preparations are potentially toxic to the middle and inner ear. Vasocidin Ophthalmic Solution (sulfacetamide sodium and prednisolone sodium phosphate) has been advocated as an alternative agent that may have fewer toxic side effects in the treatment of otorrhea. Vasocidin was introduced into the bullae of nine chinchillas to investigate the effects on the middle and inner ear. The organ of Corti and stria vascularis were found to be entirely normal in 17 of the 18 temporal bones studied. Changes observed in the middle ears at one week included inflammation, hemorrhage, and effusion. Examination of specimens at four weeks revealed resolution of most of the inflammatory changes. The results of this experimental study indicate that Vasocidin causes reversible middle ear inflammation with little or no toxic effect on inner ear structures.

Animals↗
PubMed1988

Effects of otic drops on chinchilla tympanic membrane.

Experimental studies have shown that if antibiotic otic drops reach the middle ear cavity they produce severe inflammation. However, the effects of these preparations on the tympanic membrane have not been thoroughly investigated. This study was designed to assess morphological changes in the chinchilla tympanic membrane two to 21 days after a single 0.2-mL application of an antibiotic otic preparation (Cortisporin Otic Suspension) to the middle ear cavity. At two days, the epidermal and the mucosal layers were destroyed. By four days, reepithelialization had occurred and all layers of the tympanic membrane subsequently became markedly hyperplastic. Disruption of the fibrous layer, invasion of keratinizing epidermis to the medial surface, and perforation were observed at three weeks. These findings indicate that tympanic membrane damage is a potentially significant aspect of the ototoxic properties of topical otic preparations.

Animals↗
PubMed1988

Abnormal oculovestibular response.

In normal individuals, the visual and vestibular systems interact through a common subcortical center located near the vestibular nuclei. When the patient is healthy, this interaction allows appropriate integration of what might otherwise be conflicting information regarding environmental motion and moving within the environment. In patients with active peripheral vestibular lesions, such as those seen in Meniere's disease, this delicate interaction loses effectiveness. In such patients, optokinetic stimuli are capable of precipitating episodes of incapacitating vertigo with its associated vegetative symptoms (abnormal oculovestibular response--AOVR). Since the brainstem is unable to accommodate for active peripheral lesions, suffering may be prolonged for many years. Vestibular nerve section, however, converts this active lesion to a static peripheral lesion, allowing for brainstem compensation and cessation of optokinetic-induced vertiginous symptoms.

Adult↗
PubMed1988

Vascular decompression of the cochlear nerve in tinnitus sufferers.

An estimated 40 million Americans suffer from tinnitus, and approximately 20% of these sufferers feel that the quality of their life is significantly impaired by this symptom. Despite thorough evaluation, the underlying etiology in the majority of these patients remains obscure or conjectural. Most of these patients will, however, benefit from consultation and avoidance of caffeine, nicotine, and salt, while others require biofeedback, amplification, masking, and even psychotherapy. On rare occasions, physicians are presented with a patient complaining of unilateral tinnitus of undetermined etiology who, in spite of a thorough evaluation and all conventional therapies, continues to be severely handicapped by that symptom. Early findings suggest that these patients may be suffering from vascular loop compression of the cochlear division of the eighth cranial nerve. When patients are carefully selected, retrosigmoid decompression of that vascular loop has provided gratifying relief.

Adult↗
PubMed1987

Ototoxicity of neomycin and polymyxin B following middle ear application in the chinchilla and baboon.

Previous experimental studies have demonstrated structural damage of the organ of Corti and stria vascularis following application of combination antibiotic otic drops to the middle ear. In this investigation the ototoxic effects of neomycin and polymyxin B (two antibiotics often used together in ototopical preparations) were separately evaluated after administration of each agent to the middle ear cavities of chinchillas and baboons. The antibiotics were administered in saline solution at the same concentrations used in Cortisporin Otic Suspension (3.5 mg/ml neomycin base, 10,000 units/ml polymyxin B). In both the rodent and primate, polymyxin B consistently produced greater cochlear damage than did neomycin. In fact, the extent of hair cell loss and strial injury produced by polymyxin B alone was, in many cases, comparable to that previously observed after application of Cortisporin Otic Suspension itself. Hair cell loss in the baboon was markedly less severe than in the chinchilla. It is believed that differences in position and structure of the round window membrane are important factors in the differing levels of ototoxicity observed in the rodent and primate.

Animals↗
PubMed1987

Ototoxicity of an ototopical preparation in a primate.

Severe ototoxicity has been observed in laboratory rodents after middle ear application of ototopical preparations or their constituents. Owing to their relatively high susceptibility, these animals may not be ideal experimental models. In the present study the ototoxicity of Cortisporin Otic Suspension (neomycin, polymyxin B, hydrocortisone) was studied using the baboon as a primate model. Middle and inner ear pathologic changes were assessed after a single application of the suspension to the tympanic cavity. Inner and outer hair cell loss occurred in all the experimental animals; it was, however, confined to the basal turn of the organ of Corti. Relative to previously studied rodents, the thicker, more densely structured round window membrane of the primate appears to provide better protection against penetration of ototoxic agents. Nonetheless, the results of this study indicate that ototopical preparations must be used with caution in clinical situations in which they may reach the middle ear.

Animals↗
PubMed1987

Fulminant infections of odontogenic origin.

The dentition is a common source of infection in the head and neck and most odontogenic infections respond uneventfully to proper dental therapy. Some more fulminant odontogenic infections can produce complications including airway obstruction, necrotizing fasciitis, and extension of the infection to the orbits, intracranial structures, and thorax. Six such cases treated by the authors are presented and recommendations for management including aggressive antimicrobial, therapy-based bacteriology and surgical drainage and debridement are made.

Airway Obstruction↗
PubMed1986

Should the membranous labyrinth be destroyed because of vertigo?

The purpose of this article is to determine if any change has occurred in the role labyrinthectomy plays in the therapeutic armamentarium of members of the American Neurotologic Society. Questionnaires were sent to all members and 42% of these were returned. Analysis of the questionnaires suggests that labyrinthectomy still remains an important tool in the surgical management of vertigo, although it is less frequently employed now than 10 years ago. This seems to be the consequence of increased valuation of even minimal levels of residual hearing.

Ear, Inner↗
PubMed1986

Cholesteatoma staging.

Manuscripts reporting results of surgery for chronic otitis media would be more meaningful if standardized nomenclature were used in describing the type of surgery performed and if standardized classifications were used for the disease process. Standardized nomenclature for surgery type and classifications for chronic otitis media exists. A Classification for cholesteatoma, based on pathophysiology, location, eustachian tube function, ossicular defects, and presence or absence of complications is proposed. Congenital cholesteatoma is that which has its nidus of trapped squamous epithelium present at birth. Primary acquired cholesteatoma is associated with a defect in the pars flaccida, while secondary acquired cholesteatoma is associated with a defect in the pars tensa. Tertiary acquired cholesteatoma is defined as that which occurs behind a normal appearing tympanic membrane as the result of implantation or an antecedent middle ear inflammation.

Cholesteatoma↗