Comparative Measurements of Cochlear Apparatus

1968 ◽  
Vol 11 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Makoto Igarashi ◽  
Robert G. Mahon ◽  
Shizuo Konishi
Keyword(s):  
Cross Section ◽  
Basilar Membrane ◽  
Stria Vascularis ◽  
The Other ◽  
Tectorial Membrane ◽  
Spiral Ligament ◽  
Scala Tympani ◽  
Basal Turn ◽  
Temporal Bones ◽  
Scala Vestibuli

Micromeasurements of horizontal midmodiolar sections of temporal bones were performed to obtain the dimensions of the different cochlear partitions in the squirrel monkey, the cat, and the rat. The width of the basilar membrane and the tectorial membrane were larger in the apical turn than in the basal turn in all three species. The thickness of the spiral ligament, the width of Reissner’s membrane, and the width of the stria vascularis were larger in the basal turn than in the apical turn. The cross-section areas of scala vestibuli and scala tympani in the three species were larger in the basal turn than in the other turns.

Intercellular Fluid Pathways in the Organ of Corti of Cat and Man

1979 ◽  
Vol 88 (1) ◽  
pp. 2-11 ◽  
Author(s):  
Joseph B. Nadol
Keyword(s):  
Stria Vascularis ◽  
Organ Of Corti ◽  
Intercellular Junctions ◽  
Morphological Evidence ◽  
Spiral Ligament ◽  
Basal Cells ◽  
Scala Tympani ◽  
Supporting Cells ◽  
Cochlear Duct ◽  
Scala Vestibuli

The intercellular junctions in the organ of Corti of cat and man were examined with the electron microscope. In contrast to the zone of tight junctions, or zonulae occludentes, which were present at the surface of cells lining the scala media, there was no tight junctional specialization among the cells of the tympanic lamina, perilymphatic lining cells of the scala vestibuli, basal processes of the supporting cells of the organ of Corti or cells of the spiral limbus and spiral ligament. These findings suggest the possibility of fluid continuity between the scala vestibuli and scala tympani all along the cochlear duct. Morphological evidence for an intercellular diffusion barrier was present only at the endolymphatic surfaces of the cochlear duct and between the processes of the basal cells of the stria vascularis in cat and man.

Comparison of Cochlear Histopathology following Two Implant Designs for Use in Scala Tympani

1980 ◽  
Vol 89 (2_suppl) ◽  
pp. 11-14 ◽  
Author(s):  
Dwight Sutton ◽  
Josef M. Miller ◽  
Bryan E. Pfingst
Keyword(s):  
Basilar Membrane ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Mechanical Damage ◽  
Scala Tympani ◽  
Basal Turn ◽  
Induced Changes

Two designs of intracochlear implants were evaluated for their histopathologic effects in the monkey ear. A molded electrode designed to fit the contour of the basal turn of the scala tympani tended to create basilar membrane fistulas and osseous spiral lamina fracture, along with relatively extensive loss of spiral ganglion cells in sites adjacent to the implant. A delicate, free-fit electrode induced local encapsulation but little or no mechanical damage and limited degeneration of spiral ganglion cells. Both electrode types occasionally induced changes in stria vascularis.

Chronic Intracochlear Electrode Implantation: Cochlear Pathology and Acoustic Nerve Survival

1974 ◽  
Vol 83 (2) ◽  
pp. 202-215 ◽  
Author(s):  
Robert A. Schindler ◽  
Michael M. Merzenich
Keyword(s):  
Hair Cells ◽  
Bone Growth ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Round Window ◽  
Spiral Ganglion ◽  
Nerve Fibers ◽  
Spiral Ligament ◽  
Scala Tympani ◽  
Temporal Bones

The temporal bones of ten cats implanted with intracochlear electrodes for three to 117 weeks were stained with hematoxylin and eosin and examined with light microscopy. The electrodes were embedded in Silastic® which was molded to fill the most basal 9 mm of the scala tympani. They were inserted directly into the scala through the round window. Among our observations were the following: 1) All or nearly all hair cells were lost in the basal coil during the first several weeks after implantation. Some, but not all, supporting cells were also lost. There was extensive hair cell loss in the middle and apical turns, although some hair cells were seen there in all examined cats. 2) There was evidence of degeneration of spiral ganglion cells in the basal cochlea in several animals, but most primary auditory neurons including (with two exceptions) most of those in the region directly over the electrode, survived implantation in every cat. The radial nerve fibers of the spiral ganglion cells also survived long-term implantation. The functional viability of remaining spiral ganglion cells was confirmed in acute neurophysiological experiments conducted just before the animals were sacrificed. 3) More severe degeneration was seen in two cats in which the electrode perforated the basilar partition. In these animals, there was loss of many spiral ganglion cells, and evidence of new bone growth in the region of the perforation. 4) The appearance of the stria vascularis and spiral ligament in some implanted animals paralleled their descriptions following occlusion of the cochlear vein. 5) Connective tissue formed around the electrode surfaces, apparently displacing perilymph and sealing the electrode into the scala tympani. There was no evidence of perilymph fistula in any animal. 6) There was little evidence of progressive degeneration of the organ of Corti or spiral ganglion from three to 34 weeks after implantation. Some of the implications and limitations of these findings are discussed.

Histopathological Observations on the Cochlear Changes in Otosclerosis

1977 ◽  
Vol 86 (6) ◽  
pp. 813-820 ◽  
Author(s):  
F. Antoli-Candela ◽  
T. McGill ◽  
D. Peron
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Cell Population ◽  
Basilar Membrane ◽  
Stria Vascularis ◽  
Spiral Ligament ◽  
Age Group ◽  
Histopathological Findings ◽  
Temporal Bones

Alterations in the dimensions of the basilar membrane and spiral ligament have been implicated in the pathogenesis of sensorineural hearing loss in otosclerosis. The histopathological findings in nineteen temporal bones with otosclerotic involvement of the cochlear endosteum are reviewed. Hyalinization and decrease in the width of the spiral ligament are the only consistent findings related to the otosclerotic focus in these temporal bones. The width of the basilar membrane is normal. The hair cell population and the stria vascularis are normal for the age group.

Electron Microscopic Findings in Presbycusic Degeneration of the Basal Turn of the Human Cochlea

1979 ◽  
Vol 87 (6) ◽  
pp. 818-836 ◽  
Author(s):  
Joseph B. Nadol
Keyword(s):  
Light Microscopy ◽  
Hair Cells ◽  
Basilar Membrane ◽  
Ganglion Cells ◽  
Nerve Fibers ◽  
Degenerative Changes ◽  
Supporting Cells ◽  
Neural Degeneration ◽  
Basal Turn ◽  
Temporal Bones

Three human temporal bones with presbycusis affecting the basal turn of the cochlea were studied by light and electron microscopy. Conditions in two ears examined by light microscopy were typical of primary neural degeneration, with a descending audiometric pattern, loss of cochlear neurons in the basal turn, and preservation of the organ of Corti. Ultrastructural analysis revealed normal hair cells and marked degenerative changes of the remaining neural fibers, especially in the basal turn. These changes included a decrease in the number of synapses at the base of hair cells, accumulation of cellular debris in the spiral bundles, abnormalities of the dendritic fibers and their sheaths in the osseous spiral lamina, and degenerative changes in the spiral ganglion cells and axons. These changes were interpreted as an intermediate stage of degeneration prior to total loss of nerve fibers and ganglion cells as visualized by light microscopy. In the third ear the changes observed were typical of primary degeneration of hair and supporting cells in the basal turn with secondary neural degeneration. Additional observations at an ultrastructural level included maintenance of the tight junctions of the scala media despite loss of both hair and supporting cells, suggesting a capacity for cellular “healing” in the inner ear. Degenerative changes were found in the remaining neural fibers in the osseous spiral lamina. In addition, there was marked thickening of the basilar membrane in the basal turn, which consisted of an increased number of fibrils and an accumulation of amorphous osmiophilic material in the basilar membrane. This finding supports the concept that mechanical alterations may occur in presbycusis of the basal turn.

Ultrastructural Characteristics of Capillaries Entering and Leaving the Stria Vascularis

1986 ◽  
Vol 95 (3) ◽  
pp. 309-312 ◽  
Author(s):  
Kensuke Watanabe
Keyword(s):  
Horseradish Peroxidase ◽  
Basal Cell ◽  
Stria Vascularis ◽  
The Other ◽  
Spiral Ligament ◽  
Perivascular Spaces ◽  
Basal Cells ◽  
Vascular Flow ◽  
Cell Layers ◽  
Ultrastructural Characteristics

Capillaries entering and leaving the stria vascularis were surrounded by layers of basal cells and fibrocytes. The entering capillaries were surrounded by one or two thin basal cells, while the leaving capillaries were surrounded by four or five thicker and interdigitated basal cell layers. Moreover, the layers surrounding the leaving capillaries persisted further into the spiral ligament. Two kinds of filaments were observed in the basal cells, one thin and the other thick. Capillaries were observed to leak horseradish peroxidase before they entered and after they left the stria vascularis. Although the reaction product of horseradish peroxidase was observed in all perivascular spaces of leaving capillaries, very little or no reaction product was observed around some entering capillaries. It is speculated that the layers of basal cells and fibrocytes around entering and leaving capillaries control the vascular flow out of the stria vascularis, although the layers around leaving capillaries may be more contractile than those around entering capillaries.

Pathology of labyrinthine ossification

1991 ◽  
Vol 105 (8) ◽  
pp. 621-624 ◽  
Author(s):  
Christopher deSouza ◽  
Michael M. Paparella ◽  
Pat Schachern ◽  
Tae H. Yoon
Keyword(s):  
Inner Ear ◽  
Otitis Media ◽  
Osseous Tissue ◽  
Scala Tympani ◽  
Fabry’S Disease ◽  
Fabry's Disease ◽  
Basal Turn ◽  
Vascular Compromise ◽  
Temporal Bones

AbstractOssification of the inner ear is the result of multifactorial pathogeneses, such as infection or malignant infiltration, and otosclerosis. Ossification of the innerear spaces is a well documented sequela of suppurative labyrinthitis. In this study of human temporal bones, sections from 14 patients (28 temporal bones)were studied. In additionto the osseous tissue within the inner ear, findings included neoplasms, otosclerosis, otitis media, trauma, and Fabry's disease. We have attempted to correlate these conditions and their influence on the formation of osseous tissue within the spaces of the inner ear. Tympanogenic infection and vascular compromise were found to play an important role in ossification. The scala tympani ofthe basal turn of the cochlea was frequently the site involved.

Inter- and intracompartmental osmotic gradients within the rat cochlea

1984 ◽  
Vol 247 (4) ◽  
pp. F602-F606 ◽  
Author(s):  
O. Sterkers ◽  
E. Ferrary ◽  
C. Amiel
Keyword(s):  
Stria Vascularis ◽  
Extracellular Fluid ◽  
Potassium Transport ◽  
Resting Potential ◽  
Osmotic Gradient ◽  
Basal Turn ◽  
Rat Cochlea ◽  
Scala Vestibuli

The osmolality and the electrochemical composition of the endolymph, a potassium-rich positively polarized extracellular fluid in the cochlea, was studied in the rat. Endolymph of each cochlear turn was hyperosmotic to perilymph and plasma. Osmolalities (mosmol/kg H2O) were 329 +/- 2.9 (mean +/- SE) (n = 13) in basal turn endolymph, 322 +/- 2.7 (n = 9) in middle turn endolymph, 317 +/- 5.2 (n = 3) in apical turn endolymph, 289 +/- 3.1 (n = 14) in perilymph of the scala vestibuli, and 298 +/- 1.8 (n = 7) in plasma. Moreover, differences in osmolality and electrochemical composition of endolymph, involving resting potential and K and Cl concentrations, were observed between the basal and the middle cochlear turns, suggesting the presence of an electrical and osmotic gradient within endolymph, declining from the base to the apex of the cochlea. The active potassium transport into endolymph, located presumably in the stria vascularis, could account for both the internal and external osmotic gradients.

Evaluation of the HiFocus® electrode array with positioner in human temporal bones

2003 ◽  
Vol 117 (7) ◽  
pp. 527-531 ◽  
Author(s):  
Antje Aschendorff ◽  
Thomas Klenzner ◽  
Bernhard Richter ◽  
Ralf Kubalek ◽  
Heiner Nagursky ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Electrode Array ◽  
Scala Tympani ◽  
X Ray ◽  
Temporal Bones ◽  
Scala Vestibuli

The aim of the study presented was to assess the insertion mode and possible intracochlear trauma after implantation of the HiFocus® electrode with positioner in human temporal bones. The study was performed in five freshly frozen temporal bones. The position of electrodes was evaluated using conventional X-ray analysis, rotational tomography and histomorphological analysis. Insertion of the HiFocus® electrode with positioner resulted in considerable trauma to fine cochlear structures including fracture of the osseous spiral lamina, dislocation of the electrode array from the scala tympani into the scala vestibuli and fracture of the modiolus close to the cochleostomy. The implication of the results regarding clinical outcome will be discussed.

Inner Ear Degeneration in Acoustic Neurinoma

1976 ◽  
Vol 85 (3) ◽  
pp. 343-358 ◽  
Author(s):  
Fumiro Suga ◽  
John R. Lindsay
Keyword(s):  
Inner Ear ◽  
Blood Circulation ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Nerve Fibers ◽  
Sensory Cells ◽  
Tectorial Membrane ◽  
Acoustic Neurinoma ◽  
Pathological Findings ◽  
Temporal Bones

The temporal bones of three cases of acoustic neurinoma are described to illustrate histopathological features of inner ear lesions due to chronic partial obstruction of blood circulation by the tumor in the internal auditory meatus. Degenerative changes in the inner ear due to acoustic neurinoma were evaluated and compared with changes in the opposite ear. The main pathological findings in the inner ear which were attributed to the tumor were degeneration of nerve fibers and of ganglion cells, degeneration of the stria vascularis, degeneration of the tectorial membrane, fibrosis and ossification of a semicircular canal. Fairly good preservation of sensory cells was observed in the presence of total degeneration of nerve fibers and ganglion cells and subtotal degeneration of the stria vascularis.

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