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Biomedical subjects

R G Amedee

Publications and source records attributed to R G Amedee.

At least 19 recordsLinked to original sources
PubMed1996

Hearing loss as a complication of stapes surgery.

During a 10-year period (1984-1994) 1229 stapes operations for otosclerosis were performed at our respective institutions by experienced surgeons well trained in the various techniques. Procedures included 691 stapedectomies, 234 small-fenestrae stapedotomies, and 304 revision operations. These primary and revision cases resulted in 20 ears with severe sensorineural hearing loss or anacusis noted during the immediate postoperative period. This article will critically evaluate those procedures that resulted in profound hearing loss and attempt to determine possible reasons for this occurrence. It is hoped that these data will allow surgeons to identify before and/or during surgery patients at risk for development of this complication and therefore decrease the overall morbidity rate of this exacting procedure.

Adolescent↗
PubMed1996

Epidermal growth factor receptor expression by acoustic neuromas.

Antibodies directed against epidermal growth factor receptor (EGFr) impede proliferation and induce differentiation of EGFr-positive cancers. To explore the effectiveness of anti-EGFr monoclonal antibodies on acoustic neuromas (ANs), we first sought to evaluate EGFr expression by ANs. The records of all patients with the diagnosis of AN at our institution from January 1989 to July 1994 were reviewed. Immunohistochemical analysis for EGFr was performed on formalin-fixed, paraffin-embedded archival surgical specimens. Skin, liver, and placenta were used as positive tissue controls. Purified rabbit immunoglobulin G replacing the experimental antibody acted as a negative control, and normal eighth cranial nerve was evaluated for background staining. Slides were scored as 0, +, ++, or and for percentage of positive cells by two pathologists, with Antoni A and Antoni B areas scored separately. Results demonstrate that most tumors are revealed to be EGFr positive with a mild degree of staining. Antoni A areas generally have greater staining than Antoni B regions, while normal eighth cranial nerves demonstrate minimal background staining. These results suggest that ANs express low levels of EGFr, with Antoni A areas having the highest levels. While further studies may more accurately quantitate EGFr levels in these tumors, the clinical efficacy of anti-EGFr-based therapies for ANs seems doubtful.

Adolescent↗
PubMed1996

Zenker's diverticula.

Zenker's diverticula, or hypopharyngeal diverticula, have a multifactorial etiology including both mechanical and structural factors. The diagnosis of the diverticula is based on an accurate history and physical examination and is confirmed with contrast radiography. Historically, the management of Zenker's diverticula has been controversial. Nonetheless, if the patient is symptomatic, surgical management is indicated. Surgical procedures include cricopharyngeal myotomy, diverticulopexy, diverticulum resection, and endoscopic diathermy (the Dohlman procedure). Each has its proponents and each has its disadvantages and complication rates. The decision as to which procedure to use hinges on clinical factors such as the patient's age, general state of health, and whether or not the lesion is recurrent. The pathophysiology of Zenker's diverticula is discussed with special reference to the anatomy of the hypopharynx. The evaluation of these patients is reviewed, as are some of the current surgical approaches employed when treating Zenker's diverticula.

Humans↗
PubMed1995

The effects of chronic otitis media with effusion on the measurement of transiently evoked otoacoustic emissions.

Otoacoustic emissions (OAEs) are low-level acoustic sounds of cochlear origin that can be recorded from the external auditory canal under well-controlled conditions. They are a natural by-product of normal auditory physiology and may be divided into two general categories: spontaneous and evoked emissions. These emissions provide an objective, non-invasive measurement of cochlear function that is accurate, rapid, and simple to perform. The clinical utility of OAEs has been extensively described in both normally hearing subjects and subjects with sensori-neural hearing loss. The primary clinical applications of these emissions appear to be in neonatal screening and ototoxic monitoring. In this study, the effects of middle ear effusion on the production of evoked OAEs in children were assessed using preoperative tympanometric and otoacoustic emissions testing. The study subjects were children with a history of chronic otitis media who had otoscopic findings suggestive of middle ear effusion. An attempt was made to correlate the type of middle ear effusion found at surgery with the presence or absence of preoperative otoacoustic emissions. Statistical analysis indicated that the type of effusion in the middle ear does affect the presence or absence of emissions. These results tend to refute previous notions that OAEs are not measurable if the tympanogram is abnormal or fluid is present in the middle ear space. A review of the pertinent literature in included, along with a general description of the types of OAEs and their clinical significance.

Acoustic Impedance Tests↗
PubMed1995

Fungal sinusitis.

Primary and secondary fungal sinusitis occurring in the immunocompromised patient is well documented, yet the incidence of fungal paranasal sinus infections is being increasingly reported in the immunocompetent host. This article will focus on some of the general principles regarding fungal sinusitis while examining the currently accepted classifications and clinical significance of fungal sinusitis in the literature.

Acute Disease↗
PubMed1995

Tumors of the external ear.

A variety of medical specialists are exposed to patients who seek treatment of external ear neoplasms. They are uncommon occurrences, and malignancies of the external ear are even rarer. Only 1 patient in 10,000 with an ear complaint will have a pathologically proven malignancy of the external ear. Tumors of the external ear, both malignant and benign, commonly resemble one another. A timely and correct diagnosis is necessary to avoid affecting the external ear's ability to collect sound, but also to avoid the more morbid and mortal complications of an external ear malignancy. This paper briefly outlines the epidemiology of external ear tumors, their etiology, related histopathology, and treatment, which encompasses a myriad of modalities and specialties.

Ear Diseases↗
PubMed1995

Otoacoustic emissions: an emerging diagnostic tool.

Otoacoustic emissions are acoustic signals detectable in the external auditory canal that reflect the state of health of the cochlea. Transiently-evoked otoacoustic emissions and distortion-project otoacoustic emissions are two types of otoacoustic emissions currently under investigation as well as in limited clinical use. These objective tests of cochlear function add significantly to the armamentarium currently in place for the evaluation of hearing. The clinical use of these diagnostic tools will likely increase dramatically in the coming years. The following review provides a basis for understanding the nature and clinical utility of otoacoustic emissions.

Cochlea↗
PubMed1995

Deep neck space infections.

The incidence of deep neck space infections has dramatically decreased since the advent of antibiotics, but with delayed treatment they carry the potential for significant morbidity and mortality. Odontogenic infections with involvement of the submandibular space are the most common source of deep neck space infections in adults, whereas in the pediatric population the most common cause is acute tonsillitis with involvement of the peritonsillar space. The newest group of patients at risk for deep neck space infections are intravenous drug abusers who inject the major vessels of the neck. Knowledge of neck spaces and fascial relationships is important in understanding the presentation, treatment, and complications of deep neck space infections. The spaces, which are created by various fasciae of the head and neck, are only potential spaces in that under normal conditions they cannot be examined clinically or radiographically. As the spaces are invaded by bacteria, a cellulitis or abscess occurs, and this infection may travel through paths of least resistance from one space to another.

Adult↗
PubMed1995

Hemoptysis and pseudohemoptysis: the patient expectorating blood.

Patients expectorating blood seek evaluation and treatment from a variety of clinicians. Although the bleeding may arise either from the lungs (hemoptysis) or from the upper aerodigestive tract (pseudohemoptysis), the evaluation commonly focuses on exclusion of a pulmonary neoplastic source. Likewise, most literary reviews only focus on hemoptysis as it relates to pulmonary malignancies. The present retrospective review identifies 471 patients with the diagnosis of hemoptysis over a six-year period, and 10% were ultimately found to have UAT etiologies for their bleeding. UAT cancers were identified as the source in 2.1% of all patients, either due to primary lesions or via metastases. The majority of UAT cancers had been previously diagnosed prior to this episode of hemoptysis. This review indicates that a thorough UAT history and exam is warranted in the hemoptysis patient because of the significant occurrence of UAT causes. However, the likelihood of finding an occult UAT cancer in this patient population is very low with the only risk factor being a previous history of a UAT neoplasm.

Adolescent↗
PubMed1994

Comparison of cytophotometric characteristics to histology and proliferation markers in acoustic neuromas.

Specimens of histologically confirmed acoustic neuromas obtained during operation in 25 patients were examined. Quantitative DNA measurements were performed with an image analysis system. From the single cell measurements, the mean DNA content of all tumor cells, 2c deviation index (2c DI), DNA entropy, DNA grade of neoplasia, and percentage of tumor cells with a DNA content of more than 5c (5c exceeding rate) were derived, as well as the mean nuclear area of the tumor cells. Proliferating cell nuclear antigen (PCNA) was identified immunohistochemically. A PCNA score was developed in determining PCNA-positive cells in a total amount of 1,000 cells. Results of quantitative DNA measurements and PCNA scores were compared to clinical symptoms, histology, and time between first onset of symptoms and diagnosis of the tumor. Quantitative DNA measurements revealed the existence of hyperdiploid tumor cells in all neuromas. According to the frequency with which they occurred, tumors could be divided into two categories: 1) tumors with a high percentage of hyperdiploid cells ("hyperdiploid tumors") and 2) those with a low percentage ("diploid tumors"). Hyperdiploid tumors showed increased values for the 2c DI, mean DNA content, DNA grade of neoplasia, and DNA entropy as signs of increased proliferation. In addition, the PCNA scores were higher in these tumors, indicative of increased DNA synthesis. The mean nuclear area was higher in these tumors. No correlation was found between the results of the DNA analysis and the PCNA score, or the clinical data and the predominant histologic subtype.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Neoplasm↗
PubMed1994

Hearing results in surgery for primary petrous apex lesions.

Hearing preservation is a frequently mentioned phrase in the growing field of skull base surgery. Many authors have attempted to identify prognostic factors for successful hearing preservation, and many have suggested alternative procedures for preserving serviceable hearing. Few have mentioned hearing improvement with skull base surgical procedures. In this article we present the hearing results of 25 surgical procedures for primary petrous apex lesions. These include 13 cholesterol granulomas, 5 cholesteatomas, 4 mucoceles, and 3 eosinophilic granulomas. Surgical approaches included 14 transmastoid/infralabyrinthine, 6 transphenoid, 3 suboccipital, and 2 transmastoid/translabyrinthine. Hearing was maintained in 14 patients (56%), improved in 9 patients (36%), and worse in 1 patient with nonserviceable hearing before surgery (4%); 1 patient had profound hearing loss before surgery (4%). Results of this review should have significant implications on the choice of surgical approach for petrous apex lesions. Additionally, the standard method of determining salvageable hearing for most skull base procedures may not apply for this specific group of lesions. Implications for future treatment plans will be discussed in detail.

Adolescent↗
PubMed1994

Ultrasonography for evaluation of the carotid artery in head and neck cancer.

The dynamic relationship of lymph node metastases to surrounding vascular structures in the neck is important for preoperative patient assessment. When carotid artery involvement is suspected, this relationship often determines whether or not to operate. In the case of adhesive neck metastases along the internal jugular vein, it becomes possible to predict preoperatively if the integrity of this vein may be preserved. Ultrasonography has the ability to differentiate subtle from gross adherence, or simple compression from vascular invasion. This is done by manually palpating the tumor mass and asking the patient to perform various maneuvers while observing on a monitor the relationship of the tumor mass to the nearby artery. This article correlates the preoperative computed tomography/magnetic resonance imaging (CT/MRI) and ultrasound findings in 41 patients with large nodal metastases which were subsequently confirmed during surgery. In case of positive ultrasonographic invasion of the carotid artery, a transcranial Doppler ultrasonography (TCD) exam was performed to confirm adequate crossflow. Our experience with ultrasonography and TCD in patients with suspected involvement of the carotid artery shows reliable results and obviates in our hands the routine need for more complex, invasive, and expensive tests.

Carotid Arteries↗
PubMed1994

Disorders of taste and smell.

Chemosensory dysfunction involves deficits in taste or smell. Aberrations in these senses can be quite distressing to the patient and can negatively impact on nutritional well-being. A thorough history and physical examination are important in isolating the etiology of the sensory loss from the numerous causes of taste and smell disorders. The diagnosis can be simplified by the fact that only a few causes (nasal and sinus disease, viral-induced loss, and head trauma) are responsible for the vast majority of chemosensory dysfunctions. Therapy is limited, but one should be aware of the existing medical and surgical treatment modalities.

Humans↗
PubMed1994

Choanal atresia.

The epidemiology of choanal atresia is not always clear. it is a rare phenomenon having an incidence of between 1 in 6,000 to 1 in 8,000 live births. It exhibits a slightly female-to male preponderance, 51% to 53% versus 49% to 47%, in some studies. The unilateral form of choanal atresia is more common than bilateral, 60% to 64% versus 40% to 36%. The right nasal passage is affected more often than the left in unilateral lesions, and in 90% and more of lesions the atretic portion is bony rather than membranous.

Choanal Atresia↗
PubMed1994

Sudden idiopathic sensorineural hearing loss.

Sudden loss of hearing can be a very frightening experience for the patient and frustrating for the physician. The etiology is often difficult to identify and several theories have been proposed to explain sudden "idiopathic" sensorineural hearing loss. These theories include the viral theory, the vascular theory, and the membrane rupture theory. As the etiology is uncertain, many treatment modalities have been proposed. Steroids are the only effective medical treatment to date. Surgery may be employed when evidence of perilymphatic fistula exists. Controlled studies are needed to determine the effectiveness of proposed treatment modalities.

Animals↗
PubMed1994

Head and neck manifestations of neurofibromatosis.

The neurofibromatoses are one of four neurocutaneous syndromes inherited in an autosomal dominant pattern and characterized by generalized cutaneous neurofibromas. They are often associated with central and peripheral nervous system tumors, café-au-lait spots, skeletal abnormalities, and a myriad of associated abnormalities. Neurofibromatosis 1 (NF-1) and neurofibromatosis 2 (NF-2) are clinically and genetically distinct diseases. The diseased gene for NF-1 is the long arm of chromosome 17 and for NF-2 it is the long arm of chromosome 22. Universal signs for NF-1 include Lisch nodules (melanocytic iris hamartomas), optic nerve gliomas, and axillary freckling. The hallmark of NF-2 is bilateral acoustic neuromas. The incidence of head and neck lesions in NF-1 and NF-2 is approximately 37% with a 3.5% malignant transformation rate. A team approach is essential for management of both NF-1 and NF-2 due to multiple organ system involvement.

Head and Neck Neoplasms↗
PubMed1994

A review of odontogenic infections.

Odontogenic infections continue to affect a substantial portion of the population. These infections may be due to pulpal or periodontal involvement, and may occur after extraction of a tooth. Usually self-limiting and spatially confined, infection occasionally spreads due to a highly virulent organism leading to serious or potentially lethal conditions. Treatment priorities include establishing an airway if the airway is compromised, obtaining specimen for appropriate aerobic and anaerobic sensitivity, employing antibiotics empirically, and draining infection surgically. A discussion of the pathophysiology of odontogenic infection follows, along with a review of the anatomy basic to treatment of infection which may extend to the deep neck spaces.

Drainage↗