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Biomedical subjects

A J Duvall

Publications and source records attributed to A J Duvall.

At least 37 records · Page 2Linked to original sources

Juvenile nasopharyngeal angiofibroma: diagnosis and treatment.

Juvenile nasopharyngeal angiofibroma (JNA) is an uncommon, histologically benign vascular tumor that occurs almost exclusively in adolescent males. While occasional mention is made of the occurrence of JNA in females and in older males, only four cases have withstood rigorous clinicopathological review. This neoplasm accounts for less than 0.05% of all benign lesions that originate in the nasopharynx. Its clinically malignant behavior is a result of its propensity for locally destructive growth and fatal hemorrhage. The evolution in the management of these tumors has been the subject of much interest and much confusion. The advents of computed tomographic (CT) scanning, selective angiography with embolization, and refinements in surgical approaches have revolutionized operative management of these lesions by allowing more realistic selection of surgical candidates, better preoperative planning, and more flexible (yet aggressive) primary surgical treatment. The attendant reduction in morbidity and mortality of contemporary surgical management of this disease has largely obviated the argument of those who advocate use of radiotherapy as the primary treatment modality for this benign lesion. This latter view is based on the reports of massive hemorrhage, significant incidence of incomplete removal, and mortality reported in the older surgical literature. This article details our experience with a series of 31 patients who had clinicopathological diagnoses of JNA and were treated between 1954 and 1984. It furthermore represents an update of our previously reported series.

Adolescent↗

Long-term results with nasofrontal duct reconstruction.

The findings and results of 50 consecutive nasofrontal duct reconstructions are analyzed and presented. Postoperative recurrence of frontal sinus disease occurred in 14% of the cases and there were no significant postoperative or intraoperative complications. There was no instance of failure in patients with a history of trauma to the nasofrontal duct and only two recurrences in patients with mucocele or pyocele. Nasofrontal duct reconstruction offers more direct access to the ethmoid cell system than osteoplastic flap obliteration. In addition, it is a lesser procedure with fewer complications. The physiologic function of the sinus is restored without the risk of burying disease. Nasofrontal duct reconstruction is an effective option for the treatment of chronic frontal sinus disease if the sinus mucosa is not irreversibly damaged.

Adult↗

The human round window membrane. An electron microscopic study.

The normal adult human round window membrane was examined by transmission electron microscopy. The membrane consists of the following three layers: (1) an outer squamous epithelial layer with an underlying basement membrane; (2) a middle fibrous layer containing collagen, elastin, fibrocytes, vessels, and nerves; and (3) an inner layer of mesothelial cells. Mucosal membrane veils that cover the round window membrane, forming "false" round window membranes, are also described. These membranes are also three layered, including (1) an outer epithelial layer with an underlying basement membrane, (2) a middle fibrous layer containing collagen, elastin, fibrocytes, vessels, and nerves, and (3) an inner epithelial layer with an underlying basement membrane. Ultrastructural differences between these two structures are discussed.

Aged↗

The normal chinchilla round window membrane.

The chinchilla round window membrane consists of three layers: (1) an outer epithelial layer facing the middle ear cavity with tight junctions and numerous desmosomes, (2) a middle connective-tissue layer consisting of fibroblasts, fibrocytes, collagen, elastin, capillaries, and myelinated and unmyelinated nerves, and (3) an inner cellular layer with thin cytoplasmic processes containing numerous micropinocytotic vesicles and dark granules similar in form to alpha-type glycogen. Studies of the fine structure of the normal round window membrane in animals are prerequisites to understanding the role of the round window membrane in both normal function and in diseased states such as otitis media.

Animals↗

Mannitol-induced stria vascularis edema.

After administration of mannitol, an osmotic diuretic, edema of the stria vascularis occurs, which is morphologically indistinguishable from the stria edema observed after administration of loop-inhibiting diuretics. Similar edema also was observed after glycerin administration. Both mannitol and glycerin may act osmotically to draw fluid from the endolymph into the stria. Temporary improvement in the hearing level and discrimination from the glycerin test in endolymphatic hydrops could be explained by this potential mechanism of endolymph volume reduction.

Animals↗

Medial canthoplasty: early and delayed repair.

Naso-orbital trauma can cause medial orbital wall disruption and detachment of the medial canthal ligament. Damage to the nasolacrimal drainage apparatus, cerebrospinal fluid rhinorrhea and frontal sinusitis can occur. Twelve cases of naso-orbital trauma have been reviewed. There is a high incidence of associated injury to adjacent structures. Medial canthal ligament separation was missed acutely in a number of cases leading to the necessity of delayed repair. Important diagnostic and therapeutic points are stressed in the acute and delayed management, particularly medial canthal ligament separation. A wire to intranasal button technique for the delayed repair of traumatic telecanthus is presented.

Adolescent↗

Usher's syndrome type III.

We describe a rare example of Usher's syndrome type III in a 9-year-old boy. This type is characterized by retinitis pigmentosa and progressive sensorineural deafness.

Audiometry↗

The "chronic" ear: how to manage mild to severe otitis.

Otitis media initially involves only the mucosa, but if unchecked, may eventually spread to bone, causing bony erosion and severe osteitis that can have life-threatening CNS complications. Placement of a PE tube generally is all that is necessary to eliminate middle ear fluid and restore normal hearing in serous otitis media and adhesive otitis media. Mastoidectomy is required in more advanced chronic ear disease; if disease is not too extensive, hearing may be restored by tympanoplasty.

Cholesteatoma↗

Morphological alteration of the stria vascularis after administration of the diuretic bumetanide.

Chinchillas were given either a single injection of the diuretic bumetanide (18 mg/kg body weight) or saline-sodium hydroxide and sacrificed at 10 min, 1 hr and 24 hr after the injection. Slight stria edema was present at 10 min, marked edema at 1 hr and no edema 24 h after bumetanide. The edema began in the first cochlear turn at 10 min and spread to the second turn by 1 hr. Along with edema, marginal cell bulging, potential capillary constriction and the formation of marginal cell membranous structures occurred after bumetanide treatment.

Animals↗

Mucoceles with intracranial and extracranial extensions. Report of two cases.

Two cases of unusual childhood mucocele are presented. These serve to illustrate the great potential these lesions have for slow, insidious development and insinuation of themselves into regions of the head and face where they are difficult to remove surgically. A description of the staged surgical excision is presented to emphasize the importance of radical removal of these benign lesions.

Adolescent↗

Transnasal transsphenoidal approach to the sella.

The transnasal transsphenoidal approach to the sella turcica has been refined and perfected through advances in medicine and technology. Originally performed for excision of pituitary adenomas, its present primary use is pituitary ablation is hormonally dependent diseases. Our study of 55 patients who have undergone this procedure during the years 1970-1975 demonstrates that this microscopic technique gives excellent exposure and visualization of intrasellar contents. Our method gives excellent exposure and visualization of intrasellar contents. Our method with several instrument modifications is discussed. It is technically an easy procedure with a minimum of morbidigy and mortality.

Adenoma↗

An endoscopically-introducible T-tube for tracheal stenosis.

Five cases of tracheal stenosis are presented, and aspects of etiology and pathophysiology of the disease are discussed. A new soft, flexible T-tube is described along with a method of endoscopic introduction. Although many patients with tracheal stenosis will eventually need tracheal reconstruction, stenting may be definitive in selected cases.

Adult↗