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Biomedical subjects

E L Applebaum

Publications and source records attributed to E L Applebaum.

At least 19 recordsLinked to original sources

Virtual temporal bone: creation and application of a new computer-based teaching tool.

The human temporal bone is a 3-dimensionally complex anatomic region with many unique qualities that make anatomic teaching and learning difficult. Current teaching tools have proved only partially adequate for the needs of the aspiring otologic surgeon in learning this anatomy. We used a variety of computerized image processing and reconstruction techniques to reconstruct an anatomically accurate 3-dimensional computer model of the human temporal bone from serial histologic sections. The model is viewed with a specialized visualization system that allows it to be manipulated easily in a stereoscopic virtual environment. The model may then be interactively studied from any viewpoint, greatly simplifying the task of conceptualizing and learning this anatomy. The system also provides for simultaneous computer networking that can bring distant participants into a single shared virtual teaching environment. Future directions of the project are discussed.

Computer Simulation

The virtual temporal bone.

The human temporal bone is a 3-dimensionally complex portion of the skull that contains delicate and vital anatomic structures imbedded within dense bone. Current teaching tools have proven to be only marginally adequate for the needs of the aspiring otologic surgeon in learning this anatomy. A variety of image processing and reconstruction techniques were used to reconstruct an anatomically accurate 3-dimensional model of the human temporal bone from serial histologic sections. Using CAVE technology, the model can be manipulated in a stereoscopic virtual environment so that it can be studied from any viewpoint, greatly simplifying the task of learning this anatomy. Applications in surgical planning and Internet based teaching are discussed.

Anatomy

Indications for the surgical repair of unilateral aural atresia in children.

OBJECTIVE: This study aimed to clarify the indications for elective surgical repair of unilateral aural atresia in children and to review the rates of successful repair in the literature. DATA SOURCES: A search of the published English language literature, 1966-1997, was conducted using the key words aural atresia. STUDY SELECTION: Articles were selected on the basis of their inclusion of the authors' indications for surgical repair of aural atresia or the inclusion of surgical series that showed outcomes. DATA EXTRACTION: Articles reviewed in the review had to either provide specific guidelines for surgical repair of unilateral aural atresia or provide postoperative pure-tone averages, air-bone gaps, or speech reception thresholds. DATA SYNTHESIS: The authors compiled the relevant data into summary tables and extracted conclusions from these data. CONCLUSIONS: Elective surgical repair of unilateral aural atresia should only be attempted in children who meet specific anatomic criteria that predict that they are the most likely to benefit from the results of surgery. Otherwise, repair should be delayed until the age at which the patient can make an informed decision, knowing the risks, benefits, and consequences of this difficult surgery. Parents and surgeons must have a realistic expectation of the surgical results and the practiced benefit to be expected with a normal, contralateral ear.

Adolescent

Tracheal reconstruction using an epithelial equivalent.

The application of a rapidly vascularized epithelial equivalent that inhibits wound contraction would have great potential in the prevention and repair of tracheal stenosis. An animal model was developed to simulate the effects of circumferential tracheal injury and an autologous epithelial equivalent was created from a fibroblast-collagen matrix and subsequently implanted in the traumatized site in an attempt to prevent stenosis. Postinjury physiologic and histologic evaluation revealed near-normal mucosal flow analysis in the treated sites and an area of less than 20% stenosis versus 95+% in controls. This study's findings indicate that tracheal stenosis can be limited by the use of an epithelial equivalent.

Animals

Meningeal carcinomatosis producing bilateral sudden hearing loss: a case report.

Meningeal carcinomatosis is characterized by diffuse infiltration of the leptomeninges by metastatic cancer in patients usually with a previous history of malignancy. Primary tumors are usually adenocarcinomas of the breast or lung, or malignant melanoma. Meningeal carcinomatosis can present with headache and/or a variety of cranial neuropathies. We report a case of meningeal carcinomatosis presenting as a complete, bilateral, sudden hearing loss without other cranial nerve findings--a previously unreported presentation. Our patient also exhibited an unusual primary tumor site (esophagus) and histopathology for meningeal carcinomatosis. The case was impressive for the subsequent abrupt onset of a series of cranial neuropathies and the rapid deterioration in the patient's condition.

Acute Disease

The submandibular triangle in squamous cell carcinoma of the larynx and hypopharynx.

A 15-year retrospective analysis was carried out at the University of Illinois College of Medicine, Chicago, reviewing the tumor staging and pathology data of 239 patients treated for carcinoma of the larynx and hypopharynx requiring laryngectomy alone, laryngectomy with neck dissection, or laryngopharyngectomy and neck dissection. Surgery was the primary treatment modality in 205 of the 239 cases, with the remaining 34 having surgery to treat radiation therapy failure. Primary tumors were located within the supraglottic region, the glottic region and, less commonly, the pyriform sinus. Ninety-five of the 239 patients either presented with or developed nodal metastases following initial treatment. Of these, only two had tumors within the lymph nodes of the submandibular triangle. This data corroborates impressions that tumors of the larynx and hypopharynx rarely metastasize to the submandibular triangle and that sparing this area during neck dissection for lesions of the larynx would seem justified.

Carcinoma, Squamous Cell

Indications for and techniques of tracheotomy.

Although the operation has been practiced for centuries, the modern technique of tracheotomy was introduced and popularized in the beginning of the 20th century. The initial indication for tracheotomy was limited to impending airway obstruction resulting from trauma, but current indications are broader. Tracheotomy is one of four methods available to intubate the trachea and is associated with physiologic changes that are dependent on the duration of tracheotomy. Although surgical in nature, it is employed to relieve or prevent airway obstruction and to offer ventilatory support. Tracheotomy may be performed as an elective or an emergency procedure. Ideally, it is done in a controlled situation. However, when performed in an emergency setting, variations of the procedure, such as minitracheotomy or cricothyroidotomy, may be temporarily substituted. Preferably, tracheotomy is performed in an operating room; however, it may be carried out successfully in an intensive care unit as well.

Airway Obstruction

Further studies on the effects of magnetic resonance imaging fields on middle ear implants.

We investigated the effects of magnetic resonance imaging (MRI) fields on 21 stapedectomy prostheses and other middle ear implants and two different receiver-stimulator modules from 22-channel cochlear implants. None of the middle ear implants was displaced by the magnetic field, except for one platinum-stainless steel stapedectomy piston. Magnetism was not induced in any of the middle ear implants subjected to prolonged exposure in the MRI scanner. We conclude that MRI could pose a hazard to patients who have had stapedectomy using certain platinum-stainless steel piston prostheses and to patients with cochlear implants. Magnetic resonance imaging should pose no hazard to patients who have had the other middle ear implants reported on in this and our previous investigation.

Cochlear Implants

Radiotherapy or surgery for subclinical cervical node metastases.

This retrospective study compared elective neck dissection with elective neck radiotherapy for the control of subclinical nodal metastases. Four hundred ninety-eight patients with head and neck primary cancers and no clinically apparent neck metastases on initial presentation comprised the study population. Each patient was followed up for at least 5 years to detect failure to control neck metastases and control of the primary tumor at the time of neck recurrence. Analysis of neck recurrences occurring in patients with control of the primary tumor showed that there was no statistically significant difference between elective radiation therapy to the neck and elective neck dissection for oral cavity, oropharyngeal, and laryngeal cancers. The only statistically significant difference was noted for hypopharyngeal cancers, with radiation therapy being more effective than surgery.

Carcinoma, Squamous Cell

Implantation of a recurrent laryngeal nerve stimulator for the treatment of spastic dysphonia.

Spastic dysphonia, a rare speech disorder, is characterized by strained phonation with excessively adducted vocal cords. Recurrent laryngeal nerve section, botulinum toxin injection into the vocalis-thyroarytenoid muscle complex, and other techniques have been used to treat this disorder. We have used percutaneous electrical stimulation of the recurrent laryngeal nerve with good results. Previous dog studies demonstrated the relative safety of an implantable recurrent laryngeal nerve stimulator. In this study, we directly stimulated the recurrent laryngeal nerve and vagus nerve in a dog without change in cardiorespiratory status. A Medtronic peripheral nerve stimulator was implanted in a patient with abductor spastic dysphonia. The cuff electrode was positioned around the recurrent laryngeal nerve and stimulation resulted in improvement in her voice. Extensive cardiopulmonary monitoring did not reveal any adverse response to stimulation and there was no discomfort to the patient. On the basis of the good results of this preliminary study, further study with long-term follow-up is under way.

Adult

[Epiglottitis in the adult. A proposition for a clinical classification and therapeutic strategy].

Because lack of criteria for staging and treatment of epiglottitis can lead to unnecessary morbidity and mortality, we have introduced a staging system for early classification and appropriate management of adult epiglottitis patients. We retrospectively staged 20 adults with epiglottitis to see in their final outcome would have been altered using our protocol. We found that staging and management according to our protocol were appropriate and possibly could have reduced mortality from 10% to nearly 0%.

Adult

Intracranial and intratemporal meningiomas with primary otologic symptoms.

Intratemporal extensions of cerebellopontine angle (CPA) meningiomas are unusual and primary intratympanic meningiomas are extremely rare. The initial symptoms of both types are otologic. The presenting symptoms of even large meningiomas of the cerebellopontine angle can also be otologic. In this article we report the clinical features, diagnosis, and management of five CPA meningiomas, three combined intratemporal and CPA meningiomas, and one primary intratympanic meningioma.

Adolescent