Design of an integral computer-based wheelchair controller/linear synchronous motor system.

The purpose of this paper is to illustrate the advantages of designing computer-based motor controllers together with innovative motors, such that maximum controller/motor system benefits are obtained. Specifically, this paper describes how a computer-based controller/drive system for powered wheelchairs has been designed and is being built and tested. This type of integral controller/drive system has been possible to build into a wheelchair only with the advent of the microprocessor-based feedback motor controller. The type of motor chosen for this project was a linear synchronous motor (LSM), which is highly efficient (90%+) and could easily be made an integral part of a wheelchair wheel, providing a "no-moving-parts" drive system. However, an LSM cannot be variable-speed-controlled without knowledge of, and controlled adjustment to, the absolute rotor versus stator position at each point in time. Microprocessor-based feedback motor controllers make precise, efficient control of LSMs possible at a reasonable cost. In addition, this combination of controller and motor provides a very flexible wheelchair control/drive system that may be easily programmed to suit the needs and necessities of the wide variety of over 200,000 persons now using powered wheelchairs.

Thyroglossal duct cyst of the tongue.

Thyroglossal duct cysts commonly present as midline neck masses with or without infection. The presentation of thyroglossal duct cyst on the tongue is quite uncommon. The present report reviews the embryology of thyroglossal duct cyst development and describes two cases of lingual thyroglossal duct cyst. They presented in an infant of two months of age with feeding problems and also in an older child four years of age with a mass in the base of the tongue. Both patients were managed by marsupialization of the cyst of the tongue. The complications of tongue and mandible splitting or cervical approaches were avoided and satisfactory control was obtained. It is important to distinguish thyroglossal duct cyst of the tongue from other conditions that can affect this region.

Cervical vertebrae subluxation.

Rotary subluxation of the atlantoaxial joint is an uncommon complication of head and neck surgery and infections. Reported sequelae of this disorder range from torticollis to death from compression of the spinal cord. Two cases of C1-C2 rotary subluxation will be discussed. These complications occurred following otitis media, repair of choanal atresia, and an adenoidectomy. The literature is reviewed.

Intraoperative laryngeal photographic techniques.

We present two simple techniques for intraoperative laryngeal photography. New developments in high-intensity flash units coupled to recently developed high-quality optical telescopes or through a new fiberoptic light guide to an operating microscope have made this possible. Either method makes high-quality documentation of intraoperative laryngeal procedures a convenient routine operation. We describe the instruments, the techniques, and the past literature leading to these results.

Approaches to the diagnosis and treatment of tumors of the parapharyngeal space.

Tumors of the parapharyngeal space appear as painless massess bulging into the tonsillar, nasopharyngeal, or retromandibular area. Most are benign and represent a wide range of tumor growth, from parotid extension to intrinsic growth of nerves, blood vessels, and salivary gland tissues within or around the parapharyngeal area. The anatomy of this area and diagnostic procedures are discussed. Sinus films, tomograms of the skull base and lateral pharyngeal area, CT scans with simultaneous parotid sialograms, and angiograms are part of the evaluation of these rarely seen tumors. The approach to therapy is discussed.

Eosiophilic granuloma in the head and neck.

Eosinophilic granuloma is an unusual lesion which is thought to be a reticulo-endothelial hyperplasia of the bone and which is most frequently encountered in children. First described by Lichtenstein and Jaff, this disease entity was placed into the category of histocytosis X along with Hand-Schuller-Christian and Letter-Siwe disease. More recently eosinophilic granuloma has been classified by some authors as a separate disorder of histocytic proliferation which is localized in bones as solitary and occasional multifocal granulomas. The course of this disease is usually benign with spontaneous recovery reported. However, fatal cases of this disorder are found in the literature. This paper was prompted by the presentation of a 3 1/2 year old child with symptoms similar to that of acute dacrocystitis or ethmoiditis.

Rupture of the carotid artery from a hypopharyngeal foreign body.

A 16-year-old boy ruptured his common carotid artery after ingestion of an open safety pin. This unusual occurrence is presented, along with a review of the literature and recommendations for proximal and distal ligation of the involved artery.

Approaches to diagnosis and management of a lumg in the neck.

Malignancies of the head and neck constitute 15 percent of the malignancies of all patients seen with cancer. Those individuals who present with neck masses deserve appropriate physical and diagnostic work-up before any surgical or therapeutic approaches are contemplated. In the series of patients presented here, only six percent had unknown primary lesions.