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Biomedical subjects

W L Meyerhoff

Publications and source records attributed to W L Meyerhoff.

At least 19 recordsLinked to original sources
PubMed1992

Complications of lumbar spinal fluid drainage.

Cerebrospinal fluid fistula is an unfortunate, yet well-recognized, complication of basilar skull fracture, skull base surgery, and neurotologic procedures. Treatment commonly involves the use of continuous lumbar drainage. A retrospective chart review of 32 consecutive patients who required placement of lumbar drain by the otorhinolaryngology and neurosurgical services from March 1988 through July 1991 was undertaken to assess possible complications. The complications found were readily separated into minor and major categories on the basis of the possibility of permanent morbidity or mortality. Minor complications, including subjective complaints of headache, nausea, vomiting, etc., were noted in 59% of patients. Major complications were observed in four of 32 patients (12.5%), including unilateral occlusion of the posterior cerebral artery and unilateral true vocal cord paralysis. Alleviation of all complications was achieved by cessation of lumbar drainage. These cases are presented with discussion of pathogenesis. These findings demonstrate the possibility of potentially serious complications that mandate close monitoring of patients who require continuous lumbar drainage.

Adult↗
PubMed1991

Modified Rambo meatoplasty in translabyrinthine tumor removal.

Spinal fluid otorrhea and otorhinorrhea are morbid complications that occur in up to 18% of patients after removal of translabyrinthine tumor. Both of these problems can be significantly reduced if, during the initial surgery, the posterior canal wall is taken down and the tympanic membrane and external auditory canal skin are removed for better exposure of the eustachian tube orifice. The external auditory meatus can then be sealed by a previously described modification of the Rambo procedure. This additional procedure adds about 20 minutes to the surgery and presents a small risk of retained squamous epithelium. Fifty consecutive patients were divided into two equal groups and studied retrospectively. In group I, the patients underwent a modified Rambo meatoplasty at the time of the removal of their translabyrinthine tumor, whereas patients in group II had the tympanic orifice of their eustachian tube obstructed through the facial recess. Review of the postoperative course of these fifty patients indicated that the addition of the modified Rambo meatoplasty was justified by the overall reduction in morbidity and expense it provided.

Adult↗
PubMed1991

Catastrophic otologic injury from oral jet irrigation of the external auditory canal.

Jet irrigation is an accepted method for removal of cerumen from the external auditory canal. Even at a submaximal power setting, oral jet irrigators can generate enough force to rupture the tympanic membrane. Parameters for safe use of these irrigators have never been established. Three cases are reported in which, in addition to tympanic membrane rupture, oral jet irrigators caused ossicular disruption, round and oval window fistulae, and subluxation of the stapedial footplate. A prospective study performed on 25 fresh cadavers demonstrated a 6% incidence of tympanic membrane perforation when the power setting was one-third full power or greater. Recommendations are made for safe use of oral jet irrigators for removal of external auditory canal cerumen.

Aged↗
PubMed1991

Tympanic membrane microstructure in experimental cholesteatoma.

This study assessed changes in tympanic membrane microstructure associated with cholesteatoma development following middle ear application of 50% propylene glycol in chinchillas. Although the epidermal layer of the tympanic membrane (TM) was destroyed immediately after propylene glycol application, the epidermal basal lamina remained intact and appeared to serve as a substrate for regrowth of epidermis over the TM. During the initial phase of epidermal repair (4 to 7 days after propylene glycol administration), pseudopodial processes from the epidermal cells occasionally penetrated the basal lamina; however, no migration of epidermis into the lamina propria occurred at that time. The basal lamina remained largely intact until about 2 weeks, when it became fragmented in some areas, so that sizable gaps appeared. Hyperplastic epidermal cells then migrated through the gaps into the rapidly proliferating connective tissue of the lamina propria. At 2 to 4 weeks, degenerative changes were observed in portions of the fibrous layer, which underwent phagocytosis by foreign body giant cells. This process created defects in the fibrous layer which permitted invasion of epidermis to the medial portion of the lamina propria. The epidermis subsequently reached the medial side of the TM in areas where there was incomplete repair of the mucosal layer.

Animals↗
PubMed1991

Ototoxicity of an ototopic preparation--experimental results and clinical facts.

The ototoxicity of "Cortisporin Otic Suspension" containing 3.5 ml neomycin base, 10,000 units/ml polymyxin B was studied using the baboon (papio ursinus) as an experimental animal. Inner and outer hair cell loss occurred in all cochleas of the ears which received cortisporin. Most lesions were confined to the basal turn of the organ of Corti. Separate evaluation of polymyxin B and neomycin at the same concentration as in cortisporin showed that polymyxin B produced greater cochlear damage. The results of this study and clinical reports of sensorineural hearing loss due to commercially available ear drops indicate that ototopical preparations must be used with caution in clinical situations in which they may reach the middle ear.

Animals↗
PubMed1990

Effect of topical fosfomycin on polymyxin B ototoxicity.

Fosfomycin is an antibiotic that has been found to reduce the ototoxicity of aminoglycoside antibiotics and cisplatin when systemically coadministered. Polymyxin B, an antibiotic frequently used in ototopical preparations, has been shown to be ototoxic in experimental studies. To investigate the effect of fosfomycin on polymyxin B ototoxicity, topical administration of the two agents into the middle ear cavity was performed. Two groups of chinchillas were used. One group received applications of polymyxin B alone, and the second group received polymyxin B combined with fosfomycin. It was found that application of polymyxin B produces severe damage to the cochlea. However, when polymyxin B was given in combination with fosfomycin, cochlear damage was dramatically reduced. It is likely that in clinical use, a combination of polymyxin B and fosfomycin would demonstrate reduced risk of ototoxicity.

Administration, Topical↗
PubMed1990

A patient-oriented approach to perilymph fistula.

The subject of perilymph fistula is controversial in part because the preoperative diagnosis of perilymph fistula is difficult. Patients suffering auditory and vestibular symptoms secondary to perilymph fistula, therefore, present a dilemma to the practicing physician. In some instances, patients with auditory and vestibular symptoms in the absence of perilymph fistula will be subjected to middle ear exploration without benefit, while in other instances patients with auditory and vestibular symptoms secondary to perilymph fistula will be denied surgical treatment. Auditory and vestibular symptoms are a quality of life issue. Therefore, in an effort to provide care of the highest quality the patient must be actively involved in the decision process. Such involvement can be meaningful only after the patient is carefully counseled as to the pros and cons of surgery, as well as the alternatives. A prognostic paradigm based on the personal experience of one of us (W.L.M.) with perilymph fistula patients is described and is used in patient consultation in an effort to facilitate decision making.

Fistula↗
PubMed1990

Summating potential/action potential ratio in perilymph fistula.

A prospective study of electrocochleography in patients with clinically suspected perilymph fistula was undertaken to determine its predictive value in that disorder. One hundred forty-four patients suspected of having perilymph fistula had electrocochleography performed--34 of these (39 ears) had exploratory tympanotomy. Of the 19 ears with normal preoperative summating potential/action potential (SP/AP) ratio, ten had perilymph fistula identified at the time of surgery. Of the 20 ears with abnormal SP/AP ratio, 16 had perilymph fistula confirmed at exploration, 18 had resolution of symptoms after oval window and round membrane grafting, and only one ear had postoperative persistence of the abnormal SP/AP ratio. This study suggests that an abnormal SP/AP ratio is not only predictive of endolymphatic hydrops, but also of perilymph fistula (both problems of inner ear fluid imbalance). This study also suggests that, while abnormal SP/AP ratio is fairly specific for inner ear fluid imbalance, it is not sensitive.

Adolescent↗
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↗