Anatomy of the Round Window Region With Relation to Selection of Entry Site Into the Scala Tympani

2020 ◽  
Author(s):  
Michael B. Pringle ◽  
Katarzyna M. Konieczny
Keyword(s):  
Round Window ◽  
Scala Tympani ◽  
Entry Site ◽  
Window Region ◽  
Selection Of

Anatomical Effects of Sudden Middle Ear Pressure Changes

1979 ◽  
Vol 88 (3) ◽  
pp. 368-376 ◽  
Author(s):  
A. Axelsson ◽  
J. Miller ◽  
M. Silverman
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Round Window ◽  
Applied Pressure ◽  
Positive Pressure ◽  
Air Bubbles ◽  
Scala Tympani ◽  
Middle Ear Pressure ◽  
Contralateral Ear ◽  
Pressure Changes

Acute middle ear (ME) and inner ear changes following brief unilateral phasic ME pressure changes (up to ± 6000/mm H2O) were studied in the guinea pig. Middle ear findings included perforation of the tympanic membrane, serous and serosanguinous exudate and hemorrhage of tympanic membrane and periosteal vessels. Changes were related to magnitude of applied pressure. Perforation and hemorrhage were more commonly seen with negative rather than positive pressure. Air bubbles behind the round window were seen with positive pressures. Occasional distortion, but never perforation of the round window, was noted. Hemorrhage of the scala tympani was observed with both positive and negative pressures; scala vestibuli hemorrhage was found with negative ME pressure. In some instances pressure direction and magnitude related changes were seen in the contralateral ear.

Sudden Deafness and Labyrinthine Window Ruptures

1973 ◽  
Vol 82 (1) ◽  
pp. 2-12 ◽  
Author(s):  
Victor Goodhill ◽  
Irwin Harris ◽  
Seymour J. Brockman ◽  
Oscar Hantz
Keyword(s):  
Hearing Loss ◽  
Surgical Intervention ◽  
Round Window ◽  
Vestibular Function ◽  
Sudden Hearing Loss ◽  
Oval Window ◽  
Sudden Deafness ◽  
Scala Tympani ◽  
Cochlear Aqueduct ◽  
History Of

In 1971, one of the authors reported sudden deafness associated with labyrinthine window membrane ruptures. Eighteen additional cases have been explored surgically since then. Data on 21 cases are presented. Sudden profound cochlear deafness has now been encountered in 21 cases which were surgically explored. In 15 instances, fistulae of round, oval, or both windows were encountered and repaired. In 10 of the 15, there was a definite history of sudden exertion or trauma prior to onset. The oval window alone was ruptured in nine patients, the round window alone in one, and both windows were ruptured in five patients. The oldest patient was 62 years and the youngest 11 years of age. Differential audiological studies showed profound losses in all cases. Almost every case was studied by pure tone AC-BC and speech audiometry, Békésy, and impedance tests. Whenever possible other audiologic tests, such as recruitment, tone decay, and SISI were performed. These findings are presented in detail. Vestibular function was studied by electronystagmography (ENG) in 15 of the 21 cases surgically explored. There was evidence of vestibular dysfunction in almost every case with sudden hearing loss. Significant ENG details are presented. Surgical repairs of ruptured window membranes were followed by improvements in some of the patients. Postoperative audiologic data are presented. The theoretical aspects include discussion of possible cerebrospinal fluid (CSF) perilymph pathways between cochlear aqueduct and scala tympani and between internal auditory meatus and scala vestibuli. It is concluded that spontaneous labyrinthine window ruptures must now be added to the etiologic factors in “sudden hearing loss.” It is premature to set down criteria for surgical intervention in such cases. Further careful studies are necessary.

Cochlear Implant Revision: Effects of Reimplantation on the Cochlea

1989 ◽  
Vol 98 (10) ◽  
pp. 813-820 ◽  
Author(s):  
Robert K. Jackler ◽  
Patricia A. Leake ◽  
William S. McKerrow
Keyword(s):  
Adverse Effects ◽  
Cochlear Implant ◽  
Round Window ◽  
Neural Population ◽  
Scala Tympani ◽  
New Device ◽  
Adult Cats ◽  
Electrode Insertion ◽  
Window Area ◽  
Reimplantation Procedure

The removal of an indwelling cochlear implant electrode followed by reinsertion of a new device has been a maneuver of uncertain cosequences to the cochlea and its surviving neural population. The present study was conducted in an attempt to elucidate the factors at determine whether a reimplantation procedure will be successful. Cochlear implantation followed by explanation and subsequent implantation was performed in eight adult cats. Evaluation of cochlear histopathology suggested a significant increase in electrode insertion trauma when there was proliferation of granulation tissue in the round window area and scala tympani. In other cases, atraumatic insertion was achieved without apparent injury to the cochlea. The results of a survey of cochlear implant manufacturers and surgeons indicate that electrode replacement can usually be accomplished without adverse effects. Difficulties have been encountered, however, in moving implants with protuberant electrodes and when reimplantation was attempted on a delayed basis following explanation.

Electrical Cochlear Stimulation in the Deaf Cat: Comparisons Between Psychophysical and Central Auditory Neuronal Thresholds

2000 ◽  
Vol 83 (4) ◽  
pp. 2145-2162 ◽  
Author(s):  
Ralph E. Beitel ◽  
Russell L. Snyder ◽  
Christoph E. Schreiner ◽  
Marcia W. Raggio ◽  
Patricia A. Leake
Keyword(s):  
Electrical Stimulation ◽  
Auditory System ◽  
Pulse Rate ◽  
Auditory Nerve ◽  
Round Window ◽  
Electrode Array ◽  
Scala Tympani ◽  
Behavioral Thresholds ◽  
Current Pulses ◽  
Stimulation Of

Cochlear prostheses for electrical stimulation of the auditory nerve (“electrical hearing”) can provide auditory capacity for profoundly deaf adults and children, including in many cases a restored ability to perceive speech without visual cues. A fundamental challenge in auditory neuroscience is to understand the neural and perceptual mechanisms that make rehabilitation of hearing possible in these deaf humans. We have developed a feline behavioral model that allows us to study behavioral and physiological variables in the same deaf animals. Cats deafened by injection of ototoxic antibiotics were implanted with either a monopolar round window electrode or a multichannel scala tympani electrode array. To evaluate the effects of perceptually significant electrical stimulation of the auditory nerve on the central auditory system, an animal was trained to avoid a mild electrocutaneous shock when biphasic current pulses (0.2 ms/phase) were delivered to its implanted cochlea. Psychophysical detection thresholds and electrical auditory brain stem response (EABR) thresholds were estimated in each cat. At the conclusion of behavioral testing, acute physiological experiments were conducted, and threshold responses were recorded for single neurons and multineuronal clusters in the central nucleus of the inferior colliculus (ICC) and the primary auditory cortex (A1). Behavioral and neurophysiological thresholds were evaluated with reference to cochlear histopathology in the same deaf cats. The results of the present study include: 1) in the cats implanted with a scala tympani electrode array, the lowest ICC and A1 neural thresholds were virtually identical to the behavioral thresholds for intracochlear bipolar stimulation; 2) behavioral thresholds were lower than ICC and A1 neural thresholds in each of the cats implanted with a monopolar round window electrode; 3) EABR thresholds were higher than behavioral thresholds in all of the cats (mean difference = 6.5 dB); and 4) the cumulative number of action potentials for a sample of ICC neurons increased monotonically as a function of the amplitude and the number of stimulating biphasic pulses. This physiological result suggests that the output from the ICC may be integrated spatially across neurons and temporally integrated across pulses when the auditory nerve array is stimulated with a train of biphasic current pulses. Because behavioral thresholds were lower and reaction times were faster at a pulse rate of 30 pps compared with a pulse rate of 2 pps, spatial-temporal integration in the central auditory system was presumably reflected in psychophysical performance.

Scala-Tympani Phantom With Cochleostomy and Round-Window Openings for Cochlear-Implant Insertion Experiments

2014 ◽  
Vol 8 (4) ◽  
Author(s):  
Lisandro Leon ◽  
Matt S. Cavilla ◽  
Michael B. Doran ◽  
Frank M. Warren ◽  
Jake J. Abbott
Keyword(s):  
Cochlear Implant ◽  
Coordinate System ◽  
Round Window ◽  
Scala Tympani ◽  
Electrode Arrays ◽  
Angular Measurements ◽  
Insertion Techniques

Experiments with scala-tympani (ST) phantoms are used to evaluate new electrode arrays and cochlear-implant insertion techniques. To date, phantoms have not accounted for clinical orientations and geometric differences between round-window (RW) insertions and anteroinferior cochleostomy insertions. For improved assessments of insertion experiments, we present a scala-tympani phantom that offers three distinct benefits over previous phantoms: it mimics the standard otologic position, it accommodates for both round-window and anteroinferior cochleostomy insertions, and it incorporates a visual coordinate system based on industry consensus making standardized angular measurements possible.

The round window region and contiguous areas: endoscopic anatomy and surgical implications

2014 ◽  
Vol 272 (5) ◽  
pp. 1103-1112 ◽  
Author(s):  
Daniele Marchioni ◽  
Matteo Alicandri-Ciufelli ◽  
David D. Pothier ◽  
Alessia Rubini ◽  
Livio Presutti
Keyword(s):  
Round Window ◽  
Endoscopic Anatomy ◽  
Window Region

Electrical Properties of Wall of Endolymphatic Space of the Cochlea (Guinea Pig)

1958 ◽  
Vol 194 (2) ◽  
pp. 396-402 ◽  
Author(s):  
George A. Misrahy ◽  
Kenneth M. Hildreth ◽  
Edward W. Shinabarger ◽  
William J. Gannon
Keyword(s):  
Electrical Properties ◽  
Guinea Pig ◽  
Round Window ◽  
Potential Drop ◽  
Constant Current ◽  
Scala Tympani ◽  
Loud Sound ◽  
The Third ◽  
Average Resistance ◽  
Endolymphatic Space

By measuring potential drop produced by a constant current across the partition between scala media and scala tympani the average resistance of this partition was found to be 4700 ohms at the round window, 3500 ohms at the first turn, 1200 ohms at the second turn and 600 ohms at the third turn. Just preceding or simultaneously with a drop in d.c. potential there was a drop in resistance in response to loud sound. Recovery of the resistance preceded recovery of d.c. potential. Anoxia first lowered d.c. potential, then resistance. Both appeared to recover at nearly the same time. Destruction of the fourth, third and second cochlear turns did not affect d.c. potential or microphonics in scala media recorded from the first turn through the round window. Both were abolished upon destruction of the first turn. No spread of current was found from one turn to another. Implications of these results are discussed.

scholarly journals Surgical anatomy of the round window with special reference to cochlear implantation

1987 ◽  
Vol 101 (2) ◽  
pp. 97-102 ◽  
Author(s):  
Burkhard K. H. Franz ◽  
Graeme M. Clark ◽  
David M. Bloom
Keyword(s):  
Cochlear Implant ◽  
Special Reference ◽  
Cochlear Implantation ◽  
Round Window ◽  
Surgical Anatomy ◽  
Round Window Membrane ◽  
Scala Tympani ◽  
Good View ◽  
Posterior Tympanotomy ◽  
Round Window Niche

AbstractWhen the multi-channel cochlear implant electrode is inserted into the scala tympani through the round window the operation is best performed via a posterior tympanotomy. The view of the round window membrane, however, is incomplete because of its orientation and the fact that it has a conical shape. Nevertheless, a good view along the basal turn is obtained after the antero-inferior overhang of the round window niche and the crista fenestrae have been removed. It might be damaging to drill away the postero-superior overhang as the osseous spiral lamina lies extremely close to the round window membrane.

scholarly journals Cochlear microdialysis for quantification of dexamethasone and fluorescein entry into scala tympani during round window administration

2006 ◽  
Vol 212 (1-2) ◽  
pp. 236-244 ◽  
Author(s):  
Hartmut Hahn ◽  
Bernd Kammerer ◽  
Andre DiMauro ◽  
Alec N. Salt ◽  
Stefan K. Plontke
Keyword(s):  
Round Window ◽  
Scala Tympani

Histopathological and audiological effects of mechanical trauma associated with the placement of an intracochlear electrode, and the benefit of corticosteroid infusion: prospective animal study

2014 ◽  
Vol 128 (8) ◽  
pp. 702-708 ◽  
Author(s):  
G Malkoc ◽  
A Dalgic ◽  
M Koc ◽  
T Kandogan ◽  
S Korkmaz ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Topical Corticosteroid ◽  
Animal Study ◽  
Hair Cells ◽  
Normal Saline ◽  
Round Window ◽  
Osmotic Pump ◽  
Mechanical Trauma ◽  
Round Window Membrane ◽  
Scala Tympani

AbstractObjective:This study aimed to present the histopathological and audiological effects of mechanical trauma associated with the placement of a model electrode in the scala tympani in rats, and the effects of continuous topical corticosteroid application.Method:The study comprised three groups of rats. The round window membrane was perforated in all three groups and a model electrode was inserted in the round window. Group one received no further treatments. Groups two and three also had an intrathecal microcatheter compatible with a mini-osmotic pump inserted; in group two this was used to release normal saline and in group three the pump released 400 µg/ml dexamethasone.Results:Dexamethasone infusion given after implantation of the intracochlear model electrode was more effective for preventing hearing loss than the administration of just one dose of dexamethasone.Conclusion:The findings suggest that continuous dexamethasone infusion is beneficial for preventing the loss of hair cells and neurons associated with early and late periods of intracochlear electrode trauma.

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