Biomedical subjects

R G Amedee

Publications and source records attributed to R G Amedee.

At least 37 records · Page 2Linked to original sources

PubMed1998

Sudden sensorineural hearing loss: etiologies and treatments.

Sudden sensorineural hearing loss of 30 decibels in three contiguous frequencies, occurring in less than three days, is called sudden hearing loss. Although a number of disease processes can cause a similar hearing loss, true sudden hearing loss is idiopathic in nature. This review of sudden hearing loss will focus on the three main etiologic theories and numerous treatments studied in recent years in order to better enable clinicians to understand, diagnose, and treat the disorder.

Acute Disease↗

PubMed1998

Calcium channel blockers for prevention of noise trauma in otologic surgery.

One hundred patients were tested prior to otologic ear surgery in a prospective, randomized, double-blind study to assess the perioperative efficiacy of a calcium channel blocker (diltiazem) in preventing acoustical trauma during middle ear surgery. The patients were randomly divided into a therapy group (diltiazem), and a control group (placebo). Bone conduction hearing thresholds were examined preoperatively and followed at 1 day and 3 months postoperatively. Frequency-dependent changes in postoperative bone conduction and the number of patients with various degrees of postoperative hearing loss in both groups were statistically analyzed. The results indicated only a small postoperative hearing loss after ear surgery in both groups. There was a tendency for better results in the therapy group but this was not found to be statistically significant. Despite favorable results in animal trials utilizing different kinds of noise with the prophylactic application of diltiazem, further studies in humans will be needed to determine the role of calcium antagonist drugs in the prophylaxis or treatment of acoustical trauma.

Adolescent↗

PubMed1998

Anomalies of the branchial apparatus.

Developmental abnormalities of the branchial apparatus represent a common cause of congenital lateral neck mass. Most often this is seen in the pediatric population but certainly may present at a much later age. The branchial apparatus contributes to major development of the head and neck, and a thorough understanding of embryology and anatomy is essential in treating these patients. Branchial anomalies may present as a cyst, sinus, or fistula; infection frequently complicates successful long-term management. Most often these lesions can be diagnosed by thorough history and physical examination. Complete surgical excision is the treatment of choice; however, recurrences may be encountered especially in those patients with a history of prior surgery or local infection.

Branchial Region↗

PubMed1997

Functional anatomy of the paranasal sinuses.

Paranasal sinus anatomy possesses great complexity and is rather variable from person to person. Significant differences in structure may also exist between the two sides of the same person. Therefore, a detailed knowledge of the anatomy of the sinuses is critical in performing procedures such as functional endoscopic sinus surgery.

Ethmoid Sinus↗

PubMed1997

Orbital complications of sinusitis.

The ethmoid and maxillary sinuses are the sinuses most frequently involved with orbital infections. Routes of spread are by direct extension through bone and indirectly through the valveless venous plexuses of the orbit, nose, and sinus. Classification of orbital infections can be thought of as either preseptal or postseptal and then further subdivided from there. The diagnosis has been greatly improved by the use of CT scans; however this should never be the only entity used for diagnosis. The determination of visual acuity (VA) is the single most important finding and will ultimately determine treatment modality. Orbital infections show different and more virulent bacteria than does non-complicated sinusitis and this should be reflected in the choice of medical and surgical therapy. Medical management is well accepted for infections without abscesses, and surgery is generally needed for infections with an abscess.

Bacterial Infections↗

PubMed1997

Carcinoma of the buccal mucosa: a 30-year analysis at the Medical Center of Louisiana at New Orleans.

Carcinoma of the buccal mucosa is an uncommon malignancy of the oral cavity which is primarily squamous cell in histologic origin. This study represents the first investigation of this lesion in an indigent population. The purpose of this report is to review survival rates, modalities of treatment, and current management of the disease. A retrospective analysis is performed on all patients with this disease diagnosed and treated from 1965 to 1995. Of 28 patients, 75% were white, advanced stages of disease predominated, and no 5-year Stage IV survivors were recorded. Additional conclusions of this study revealed an overall 5-year determinate survival rate which was lower than other studies (25%), with a statistically significant white predominance of disease.

Adult↗

PubMed1997

Percutaneous tracheostomy.

Percutaneous tracheostomy is a new and somewhat controversial procedure which appears to be gaining in popularity. Methods described for this procedure include the single dilator technique, the percutaneous dilational technique, and the dilator forceps technique. The literature has been reviewed to date regarding the successes and failures of each of these methods and suggestions are made for future evaluations to determine the true utility of this procedure.

Dilatation↗

PubMed1997

Schneiderian papilloma.

Schneiderian papillomas are benign neoplasms that are associated with three key characteristics: tendency to recur, capacity for local destruction, and association with squamous cell carcinoma. They are classified into inverting, fungiform, and oncocytic varieties. The inverting and fungiform varieties are the most common, and the inverting variety has the highest rate of association with malignancy. The inverting and oncocytic varieties are classically found on the lateral nasal wall with extension into the adjacent sinuses. The fungiform lesion is typically found on the nasal septum. Treatment of these lesions is primarily surgical, with rather aggressive surgery mandated in most cases. There may be a limited role for radiation therapy and close follow-up of these patients is mandatory. These neoplasms arise from a unique area of the respiratory epithelium, termed the schneiderian mucosa. Although these are relatively rare lesions, their association with carcinoma and their tendency to be confused with more common lesions make this topic important for all practitioners.

Carcinoma, Squamous Cell↗

PubMed1997

Cerumen impaction.

Cerumen impaction represents the most common otologic problem encountered by physicians. It can affect up to 6% of the general population and a much higher percentage in the mentally retarded population. Cerumen is a mixture of secretory products of two glands in the external auditory canal where it serves a protective function. The external auditory canal possesses a unique anatomy and physiology that permits an efficient self-cleaning system. In most cases, a breakdown in the epithelial migration of the external auditory canal is thought to cause cerumen impaction. The management of cerumen impaction include direct removal, irrigation, and the use of cerumenolytics.

Cerumen↗

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↗

PubMed1996

Malignant otitis externa.

Malignant otitis externa is an uncommon but serious infection involving the external auditory canal, temporal bone, and surrounding soft tissue. Most commonly this infectious process is seen in elderly diabetics. In this article the pathogenesis, clinical features, diagnosis, and therapy are reviewed.

Humans↗

PubMed1995

Studies for estimating the biologic behavior and prognosis of paragangliomas in the head and neck.

Despite a large number of histopathologic and immunohistochemical studies, the biologic behavior and prognosis of paragangliomas (glomus tumors) of the head and neck still remain uncertain. In the present study 36 specimens from 32 patients who underwent surgery for a paraganglioma were examined. The examinations included routine histology, quantitative DNA analysis based on image cytometry, immunohistochemical detection of the proliferating cell nuclear antigen (PCNA) along with visualization of nucleolar organizer regions (AgNOR). According to LeCompte, the paragangliomas were histologically divided into three subcategories: 16 patients had a paragangliomatous tumor. 14 patients had an adenomatous tumor, and 6 patients had an angiomatous tumor. Quantitative DNA analysis revealed three categories of tumors with characteristical DNA pattern; DNA type I tumors were pure diploid, DNA type II tumors had stemlines at 2c and 4c and were therefore recognized as diploid-tetraploid. Aneuploid cells were not apparent in these two groups. DNA type III tumors had stemline ploidies exceeding 2c and 4c. Aneuploid cells were present in all of these tumors. The biologic behavior of these lesions therefore must be recognized as suspicious. DNA type III tumors and adenomatous tumors showed the highest values for the PCNA scores, indicating a higher proliferation rate and a more rapid growth pattern in these lesions. Twenty patients could be followed over a period of up to 110 months. Five of these patients developed a recurrent tumor. All of them had DNA type III tumors. The DNA indices showed significantly higher values in the recurrent tumor group. The 2c deviation index (DI) and the entropy value had the highest prognostic significance. No correlation to clinical follow-up was found for the AgNOR score. Based on these results, prognostic indices for paragangliomas were developed: patients with a tumor having a 2c DI exceeding 2.0, entropy value of more than 4.0. 5c exceeding rate more than 8.0, and a PCNA score more than 20.0% can be recognized as being at high-risk for developing recurrent disease.

Journal Article↗

PubMed1995

Intraoperative monitoring of motor cranial nerves in skull base surgery.

Intraoperative monitoring of cranial nerves is performed to minimize postoperative cranial nerve dysfunction. We performed electrophysiologic monitoring of motor cranial nerves with a NIM 2 unit from Xomed Treace and a patient multiplexer developed in our clinic. This multiplexer allows simultaneous monitoring of four cranial nerves and is additionally equipped with a bipolar stimulation mode. This intraoperative monitoring was used during 102 skull base operations. Of these, 44 operations were acoustic neuroma removals by translabyrinthine approach and 36 by a middle fossa approach. Various operations, including removal of tumors of the jugular foramen and the infratemporal fossa, were performed in the remaining 22 patients. The facial nerve, being the most frequently monitored nerve, was evaluated both preoperatively and intraoperatively. Electrophysiologic data were evaluated with respect to their predictive value for postoperative facial nerve function. The relative percent decrease in amplitude of the electromyogram after resection compared to that observed before resection seems to be of some predictive value for the postoperative facial nerve function. A 50 to 60% decrease or more is associated with an increase in the House classification. Intraoperative monitoring is a useful tool in skull base surgery, allowing for safer and faster identification of motor nerves in pathologic-anatomic conditions. It allows the surgeon a degree of comfort by providing immediate information regarding the status of the nerve. It may also improve postoperative nerve function and shorten operating time. Additionally, neuromonitoring provides some information about expected postoperative facial nerve function.

Journal Article↗

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↗