Biomedical subjects

G A Ator

Publications and source records attributed to G A Ator.

9 recordsLinked to original sources

PubMed2000

Clinical indicators useful in predicting response to the medical management of Meniere's disease.

OBJECTIVES: To identify factors that may correlate with responsiveness to medical management of Meniere's disease. STUDY DESIGN: Retrospective chart review. METHODS: The 1995 guidelines of the American Academy of Otolaryngology-Head and Neck Surgery (AAOHNS) Committee on Hearing and Equilibrium were used for data acquisition and measuring clinical response. New patients with 2 years' follow-up were evaluated and grouped as either medically or surgically treated. Patients were excluded for inadequate follow-up or prior otological surgery. Dietary sodium restriction (<1,500 mg/d) and a diuretic were employed initially. A compliance rating system was devised to evaluate diet adherence. Patients whose medical management failed were offered surgery. RESULTS: Of 65 patients reviewed, 29 patients qualified for analysis. Seventeen patients were treated medically (patients had either definite or possible Meniere's disease), and 12 patients required surgery. Patients with definite Meniere's disease were at a higher stage (based on audiogram) than patients with possible Meniere's disease (P = .002). Patients who required surgery for Meniere's disease were at a higher stage than patients with either definite or possible disease (P < .001). Patients with definite disease had lower compliance than patients with possible disease (P = .004), but both groups showed symptom improvement. Patients with possible disease had better control than patients with definite disease (P < .001). Hearing was stabilized in patients with possible disease and improved at 500 Hz in patients with definite disease (P = .04). CONCLUSIONS: Sodium restriction and diuretic treatment response are correlated to clinical measures of Meniere's disease. Patients with possible Meniere's disease should be treated with aggressive medical therapy to prevent disease progression.

Adult↗

PubMed1997

Middle-ear lipoma as a cause of otomastoiditis.

We present a case report which describes a rare cause of a common clinical problem; eustachian tube dysfunction. A seven-year-old child presented with a history of chronic draining ears, despite rigorous medical therapy and multiple ventilation tubes. At myringotomy a mass was noted in the middle ear, and she was taken to the operating room for exploration. The patient was found to have a pedunculated lipoma arising from the anterior medial aspect of the middle-ear cleft producing intermittent obstruction of the eustachian tube orifice. This case represents the fourth case of a middle-ear lipoma in the world literature. We present a review of the literature and an exploration of possible aetiologies of this unusual entity in the differential diagnosis of eustachian tube dysfunction.

Child↗

PubMed1996

Characterizing cochlear mechano-electric transduction using a nonlinear systems identification procedure.

A nonlinear systems identification technique [J. S. Bendat, Nonlinear System Analysis and Identification from Random Data (Wiley, New York, 1990)] provided the frequency-domain parameters of a third-order system polynomial equation describing cochlear mechano-electric transduction (MET) in Mongolian gerbils. The magnitude of the linear system term was the largest followed by the cubic and quadratic terms. The phase of the linear and cubic system terms differed by approximately 180 deg and the phase of the quadratic term lay between. Between-animal and within-animal variability was smallest for the linear and cubic terms, and largest for the quadratic term. Summing linear and nonlinear coherence functions revealed that the third-order system polynomial equation characterized approximately 83% of MET for low frequencies and 92% for high frequencies. Animals exposed to a 4-kHz pure tone at 100 dB SPL for 20 min showed changes in the magnitude and phase of the parameters of the third-order polynomial equation. An increase in linear coherence and a decrease in nonlinear coherence occurred at frequencies centered at the exposure frequency. Below the exposure frequency, linear coherence decreased and nonlinear coherence increased. Summation of the coherence functions showed that the third-order polynomial equation characterized MET better after exposure to the pure tone.

Animals↗

PubMed1993

Menière's disease.

Menière's disease is one of the most common etiologies for dizziness in the United States. The mainstay of therapy for Menière's is medical therapy. Symptomatic treatment is employed, but long-term prophylaxis is emphasized, with salt restriction and diuretic administration as needed. A prophylactic approach can prevent many attacks and ameliorate those that do occur. Patients with moderate to severe symptoms who fail medical therapy may be candidates for endolymphatic sac surgery, since this procedure is successful in a majority of patients and has low morbidity. Those patients in whom an endolymphatic shunt fails and who continue to have severe symptoms may undergo selective sectioning of the vestibular nerve, while patients with no residual hearing may be offered translabyrinthine nerve section.

Female↗

PubMed1992

The exacerbation of symptoms in Menière's disease during the premenstrual period.

The pathophysiology of the characteristic episodic symptoms of vertigo, low-frequency hearing loss, and tinnitus in Menière's disease remains poorly understood. It is likely that the manifestation of this condition may be multifactorial and related to elements affecting the inner ear beyond the underlying pathology of endolymphatic hydrops. We have identified a subgroup of female patients with Menière's disease in which the symptoms of this disorder are correlated with the late luteal phase of the menstrual cycle (premenstrual period). Through audiometric and vestibular testing, we have documented these inner ear effects in six women. Although many hormonal effects occur during the premenstrual period, compartmental fluid redistribution within the body may be the most pertinent. Endolymphatic hydrops represents a fluid imbalance within the inner ear and, when combined with an additional fluid shift, may produce symptomatic dysfunction. Case histories demonstrating the correlation of the symptoms of Menière's disease and the premenstrual period will be presented along with theoretical mechanisms of pathophysiology.

Adolescent↗

PubMed1990

Evaluation of mandibular tumor invasion with magnetic resonance imaging.

Evaluating the extent of tumor invasion of the mandible is clinically important in the management of mandibular tumors. Conventional imaging studies including panoramic radiography, bone scans, and computed tomography, as well as clinical evaluation can be unreliable in defining the extent of neoplastic marrow invasion. This study presents the initial UCLA, Los Angeles, Calif, experience with magnetic resonance imaging in evaluating mandibular invasion by benign and malignant neoplasms. Magnetic resonance imaging, using T1 and T2 images, was compared with conventional imaging methods in 11 patients with malignant lesions and nine patients with benign lesions. In all cases, magnetic resonance imaging most accurately determined the full extent of tumor invasion in the mandibular marrow spaces. Magnetic resonance imaging appears to be superior to offer clear benefits over conventional imaging methods, including computed tomography, for the evaluation of tumor invasion of the mandible.

Adult↗

PubMed1985

Carbon dioxide laser stapedotomy. Thermal effects in the vestibule.

Small-fenestra stapedotomy has recently been popularized in efforts to reduce the incidence of sensorineural hearing loss following stapes surgery for otospongiosis. Lasers have been advocated as a tool to fenestrate the stapes footplate. Conversion of radiant energy from the laser into heat in the vestibule represents the greatest potential risk to the inner ear. Using a carbon dioxide laser with a focal point of 150 microns at 300 mm, fenestrations of the stapes footplate were performed in a series of 14 anesthetized cats. The laser power output ranged from 0.47 to 3.05 W, with pulse durations of 0.2 and 0.5 s. Resultant temperature elevations in the vestibule, measured by a thin-wire thermocouple, ranged from 0 to 4.4 degrees C (0 to 8 degrees F) and directly correlated to wattage and duration of the laser-beam pulse. Temperature changes could be reduced by use of lower wattage, shorter pulse duration, timed intervals between pulses, and convection cooling of the promontory.

Animals↗

PubMedDate not supplied

Thermal injury to the intratemporal facial nerve following CO2 laser application.

The carbon dioxide (CO2) laser has been advocated for removal of diseased tissue from the middle ear cleft. The effect of CO2 electromagnetic radiation on mucosa and the otic capsule, however, is thermal, and the dissipation of heat into tissue surrounding the area of impact is potentially deleterious to normal structures. A CO2 laser with a 150-microns spot size at a focal length of 300 mm and a power output ranging from 0.25 to 1.5 watts was used to vaporize the mucosa overlying the horizontal portion of the fallopian canal with pulses of 0.2- to 0.5-second duration. Damage to the facial nerve was directly related to laser pulse energy and was most pronounced adjacent to the area of impact but spread distally and proximally at higher energy levels because of the heat conductivity of the bony fallopian canal. Facial movement was an unreliable indicator of injury during the vaporization process. Because the application of electromagnetic energy over the fallopian canal can result in facial paralysis, a knowledge of facial nerve anatomy remains a prerequisite to the safe extirpation of diseased tissue in the middle ear cleft.

Animals↗

PubMedDate not supplied

Carbon dioxide laser stapedotomy: a histopathologic study.

The effect of carbon dioxide electromagnetic radiation on biological tissues is thermal. The heat generated from vaporization dissipates into the surrounding tissues and can produce alterations of structure and function. Carbon dioxide laser fenestrations were performed in the footplates of 11 cat ears. Morphologic changes included discoloration and reactive hemorrhage in the saccular wall and disruption of the saccular and utricular walls. The clinical consequences of these findings and the role of the carbon dioxide laser in laser stapedotomies for patients with otospongiosis remain unresolved.

Animals↗