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At least 343 records · Page 19Linked to original sources
PubMed1984

Duane's syndrome associated with crocodile tear and ear malformation. A case of stapes anomaly and its reconstruction.

Duane's syndrome is a congenital eye movement disorder characterized by marked limitation or absence of abduction, variable limitation of adduction, and narrowing of the palpebral fissure with retraction of the globe on attempted adduction. We treated a patient with bilateral Duane's syndrome associated with crocodile tear and external, middle, and inner ear anomalies. Exploratory tympanotomy showed an absence of the oval window and a rudimentary superior structure of the stapes that was connected to the abbreviated incudal lenticular process with connective tissue. A small hole was drilled into the vestibulum and the ossicular chain was reconstructed by inserting a Teflon wire piston to minimize the air-bone gap. Pertinent literature is reviewed, and the pathogenesis of Duane's syndrome and the aspect of concomitant anomalies are discussed.

Abnormalities, Multiple↗
PubMed1987

Pressures exerted by experimental cholesteatomas.

Previous studies have shown that transmitted pressure may be an important factor in the induction of osteoclastic bone resorption by cholesteatoma. However, the ability of cholesteatomas to actually exert pressure on adjacent structures has not been studied. Implantable pressure gauges were used to measure static pressure exerted by induced gerbilline cholesteatomas. Cholesteatomas were found to exert pressures between 1.31 mm Hg and 11.88 mm Hg. Osteoclastic bone resorption was observed in areas where the pressure gauge transmitted these pressures to bone. Thus, pressure exerted by an expanding cholesteatoma may be an important factor in the induction of osteoclastic bone resorption.

Animals↗
PubMed1987

Volumetric analysis of the tympanic isthmus in human temporal bones.

A volumetric study on the tympanic isthmus and its relationship to temporal bone pneumatization was conducted in 110 serially sectioned temporal bones with and without middle ear pathology. With a microcomputer and digitizing tablet, the area of the tympanic isthmus and the degree of pneumatization in sample sections were calculated. Nonpathologic temporal bones showed a significant correlation between the volume of the tympanic isthmus and the degree of pneumatization. The narrowest area of the tympanic isthmus and the degree of pneumatization were also highly correlated. The result indicated a definite inhibition of pneumatization due to chronic middle ear infection when compared with nonpathologic temporal bones.

Aged↗
PubMed1988

Correlation between high-resolution computed tomography and surgical findings in congenital aural atresia.

Congenital aural atresia poses a great challenge, even to a competent otologic surgeon, due to innumerable types of malformations affecting the conduction and perception of sound. Roentgenographic evaluation by plain roentgenography is inconclusive in most cases; polytomography is helping to some extent. Recent generations of high-resolution computed tomographic (CT) scanners are probably the best. Seven cases of unilateral and three cases of bilateral congenital aural atresia were evaluated with high-resolution CT. Subsequently, ten ears were operated on. Surgical findings were correlated with CT scan findings with respect to atresia plate, extent of pneumatization, ossicular anomalies, bony facial nerve canal, and inner ear. Use of CT scans bears considerable importance in the management of these types of cases. High-resolution CT scan, when targeted for maximal bony detail, is possibly the method of choice in congenital aural atresia when surgical correction is contemplated.

Adolescent↗
PubMed1992

Predictors of residual-recurrent cholesteatoma in children.

The aggressive nature of childhood cholesteatoma has generated much controversy regarding the optimal management of this challenging disorder. To identify potential predictors of residual-recurrent disease, we studied 232 children (244 ears) treated with 427 surgical procedures between 1973 and 1990. Cause of the primary cholesteatoma was congenital in 43 patients (18%), acquired in 83 (36%), and unknown in 106 (46%). Of 90 patients with residual-recurrent disease, 21 (23%) instances were detected during a second-look surgical exploration. The 3- and 5-year residual-recurrence rates were 48% and 57%, respectively. Development of residual-recurrent disease was associated with ossicular erosion (Cox regression) but not with status of the canal wall (up vs down) during tympanomastoidectomy. This study suggests a need for intense and prolonged postoperative follow-up of children with cholesteatoma, especially those with ossicular erosion.

Adolescent↗
PubMed2004

Primate auditory diversity and its influence on hearing performance.

The auditory region contains numerous structures that have proven useful for phylogenetic classification at various taxonomic levels. However, little work has been done in primates relating differences in morphology to variations in hearing performance. This study documents anatomical and physiological distinctions within primates and begins to address the functional and evolutionary consequences of these and other auditory features. The dimensions of the outer ear (pinna) were measured in cadaveric specimens representing nearly every primate family and used to calculate a shape ratio (height/width). It was found that nonanthropoids have a significantly higher ratio than anthropoids, although the actual height was not found to differ. This indicates that most nonanthropoids have ears that are tall and narrow, whereas monkeys and apes are characterized by ears with more equal height and width dimensions. Eardrum area, stapedial footplate area, and ossicular lever arm lengths were measured in dried specimens to calculate an impedance transformer ratio. A distinction was found between anthropoids and strepsirrhines, with the latter group having a transformer ratio indicative of a higher percentage of acoustic energy transmission through the middle ear. Audiogram data were gathered from the literature to analyze hearing sensitivity and it was found that platyrrhines illustrate more low-frequency sensitivity than like-sized lorisoids. The effects of intraspecific variation on the audiogram results were also examined and were found to produce similar results as the analysis using species mean threshold values. Lastly, correlations between morphological and audiogram variables were examined. Several measures of hearing sensitivity were found to be correlated with pinna shape but correlations with middle ear transmission properties were weaker. In addition to using traditional statistical techniques, phylogenetic corrective methods were applied to address the problem of statistical nonindependence of the data and the results of both analyses are compared. These findings are discussed with respect to how sensory adaptations and phylogenetic history may be related to the current radiation of primates.

Adaptation, Physiological↗
PubMed2006

Multidetector row CT demonstration of inner and middle ear structures.

The aim of this study is to evaluate the anatomical details of the inner ear and middle ear, using multidetector row CT. Temporal bone CT scans were obtained using 16-detector row CT scanner (Lightspeed 16, General Electric Medical Systems, Milwaukee, WI) in 30 patients with dizziness, vertigo, or hearing loss. The three-dimensional (3D) images were reconstructed with volume rendering techniques. The 3D images were reviewed by two radiologists and scored by using a three-point quality rating for qualitative assessment of the 23 representative structures of the middle and inner ear. The malleus, incus, and facial nerve canal were identified in all patients. The incudomalleolar joint appeared fused in all patients. The stapes were seen clearly in 27 (90%) of 30 patients except in three patients. Among the three remaining patients, there was one who had effusions in the middle ear cavity. Another patient had left cholesteatoma. The third patient had normal middle ear cavity. The cochlea and the three semicircular canals (anterior, posterior, and lateral) were well demonstrated in 29 (97%) of 30 patients except for one old woman with osteoporosis. Sixteen-detector row CT imaging of temporal bone with advanced 3D reformation yields state-of-the-art anatomical details of the temporal region useful to address anatomical localization issues and ease conceptual structural learning.

Adult↗
PubMed2004

Genetic background has a major effect on the penetrance and severity of craniofacial defects in mice heterozygous for the gene encoding the nucleolar protein Treacle.

Treacher Collins syndrome (TCS) is a craniofacial disorder that results from mutations in TCOF1, which encodes the nucleolar protein Treacle. The severity of the clinical features exhibits wide variation and includes hypoplasia of the mandible and maxilla, abnormalities of the external ears and middle ear ossicles, and cleft palate. To determine the in vivo function of Treacle, we previously generated Tcof1 heterozygous mice on a mixed C57BL/6 and 129 background. These mice exhibited a lethal phenotype, which included abnormal development of the maxilla, absence of the eyes and nasal passages, and neural tube defects. Here, we show that placing the mutation onto different genetic backgrounds has a major effect on the penetrance and severity of the craniofacial and other defects. The offspring exhibit markedly variable strain-dependent phenotypes that range from extremely severe and lethal in a mixed CBA/Ca and 129 background, to apparently normal and viable in a mixed BALB/c and 129 background. In the former case, in addition to a profoundly severe craniofacial phenotype, CBA-derived heterozygous mice also exhibited delayed ossification of the long bones, rib fusions, and digit anomalies. The results of our studies indicate that factors in the different genetic backgrounds contribute extensively to the Tcof1 phenotype.

Animals↗
PubMed1975

Auditory systems of Heteromyidae: postnatal development of the ear of Dipodomys merriami.

Serial histological sections of kangaroo rats of postnatal ages 0-, 3-, 7-, 10-, and 14-days were prepared and studied. At birth the middle ear is mostly filled with mesenchyme and small in size, having only a small hypotympanum and a very small epitympanic recess. During the first postnatal two weeks, much of the hypertrophy found in the adult middle ear develops. Because an entotympanic element is nev er formed, the previously called entotympanic chamber is here renamed the hypotympanum. The epitympanic recess greatly expands to form what has been called the dorsal (or anterior) mastoid sinus. Since this chamber has no relation to the mastoid, it is here renamed the epitympanum. Posteriorly, the previously called posterior mastoid sinus develops from the growth of the hypotympanum into and beyond the region of the posterior and horizontal semicircular canals. In development and adult position it is comparable to the primate antrum and so is here renamed the antrum. At birth the organ of Corti is very immature but its major cell types can be identified. During the first two weeks of development the following events occur: (1) the vas spirale disappears, (2) the inner spiral sulcus cells atrophy, (3) the hair cells and supporting cells mature, (4) the cells of Hensen differentiate with their apical processes elevating the reticular lamina, (5) the innermost cell of Claudius migrates under and supports the Hensen's cells, and (6) the hyaline mass of the zona pectinata of the basilar membrane loses its connective tissue cells and expands in size. The developmental events support the previous description and identification of Hensen's and Claudius' cells.

Age Factors↗
PubMed1993

Facial nerve monitoring in surgery for congenital auricular atresia.

Surgery for congenital auricular atresia places the facial nerve at risk because of its potential aberrancy; iatrogenic facial paralysis is a well-known potential risk. Five cases of congenital auricular atresia are presented. All patients had intraoperative monitoring of the facial nerve. The facial nerve was found to be abnormally displaced, usually due to hypoplasia of the tympanic ring. Preoperative and postoperative facial nerve function was unchanged by surgery. Facial nerve monitoring is an important adjunct in congenital ear surgery because it allows for early and precise identification of the nerve in the absence of normal surgical landmarks and provides for continuous monitoring of the nerve.

Adult↗
PubMed1982

An anatomical study of three cases of alobar holoprosencephaly.

One case of median cleft lip with hypotelorism and two cases of cyclopia, all with brains exhibiting alobar holoprosencephaly, were examined by detailed anatomical dissection. The results indicate that the variations of the skull and associated soft structures form a continuum, as do the brain, eye, and face, from the mild to severe end of the syndrome. At the mild end, the bony malformations were primarily limited to the structures derived from the frontonasal promience, within which the ethmoid bone was the focal point. Malformed soft structures included the muscles of the anterior and posterior neck regions. At the severe end of the spectrum, these structures were more severely malformed, and the sphere of malformations widened to include more peripherally located bones and soft structures such as the mandible, ear ossicles, muscles of mastication, and salivary glands. Possible mechanisms for the generation of the malformations are addressed.

Abnormalities, Multiple↗