scholarly journals Effect of Underwater Insertion on Intracochlear Pressure

2020 ◽  
Vol 7 ◽  
Author(s):  
Conrad Riemann ◽  
Holger Sudhoff ◽  
Ingo Todt
Keyword(s):  
Hyaluronic Acid ◽  
Cochlear Implant ◽  
Middle Ear ◽  
Round Window ◽  
Maximum Amplitude ◽  
Influential Factor ◽  
Fluid State ◽  
Insertion Techniques ◽  
Electrode Insertion ◽  
Intracochlear Pressure

Background: The importance of intracochlear pressure during cochlear electrode insertion for the preservation of residual hearing has been widely discussed. Various aspects of pre-insertional, intra-insertional, and post-insertional relevant conditions affect intracochlear pressure. The fluid situation at the round window during electrode insertion has been shown to be an influential factor.Aims/Objectives: The aim of the study was to compare various insertion techniques in terms of the fluid situation at the round window.Material and Methods: We performed insertion of cochlear implant electrodes in a curled artificial cochlear model. We placed and fixed the pressure sensor at the tip of the cochlea. In parallel to the insertions, we evaluated the maximum amplitude of intracochlear pressure under four different fluid conditions at the round window: (1) hyaluronic acid; (2) moisturized electrode, dry middle ear; (3) middle ear filled with fluid (underwater); and (4) moisturized electrode, wet middle ear, indirectly inserted.Results: We observed that the insertional intracochlear pressure is dependent on the fluid situation in front of the round window. The lowest amplitude changes were observed for the moisturized electrode indirectly inserted in a wet middle ear (0.13 mmHg ± 0.07), and the highest values were observed for insertion through hyaluronic acid in front of the round window (0.64 mmHg ± 0.31).Conclusions: The fluid state in front of the round window influences the intracochlear pressure value during cochlear implant electrode insertion in our model. Indirect insertion of a moisturized electrode through a wet middle ear experimentally generated the lowest pressure values. Hyaluronic acid in front of the round window leads to high intracochlear pressure in our non-validated artificial model.

Effects of Different Insertion Techniques of a Cochlear Implant Electrode on the Intracochlear Pressure

2016 ◽  
Vol 21 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Ingo Todt ◽  
Arneborg Ernst ◽  
Philipp Mittmann
Keyword(s):  
Cochlear Implant ◽  
Maximum Amplitude ◽  
Cochlear Model ◽  
Pressure Peak ◽  
Insertion Techniques ◽  
Intracochlear Pressure ◽  
Pressure Changes

To achieve a functional atraumatic insertion, low intracochlear pressure changes during the procedure are assumed to be important. The aim of this study was to observe intracochlear pressure changes due to different insertion techniques in a cochlear model. Cochlear implant electrode insertions were performed in an artificial cochlear model to record intracochlear pressure changes with a micropressure sensor to evaluate the maximum amplitude and frequency of pressure changes under different insertional conditions. We found statistically significant differences in the occurrence of intracochlear pressure peak changes comparing different techniques. Based on our model results, an insertion should be maximally supported to minimize micromovement-related pressure changes.

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.

Evaluating Intracochlear Trauma after Cochlear Implant Electrode Insertion through Middle Fossa Approach in Temporal Bones

2017 ◽  
Vol 158 (2) ◽  
pp. 350-357 ◽  
Author(s):  
Juan Carlos Cisneros Lesser ◽  
Rubens de Brito ◽  
Graziela de Souza Queiroz Martins ◽  
Eloisa Maria Mello Santiago Gebrim ◽  
Ricardo Ferreira Bento
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Middle Cranial Fossa ◽  
Middle Fossa ◽  
Insertion Depth ◽  
Middle Fossa Approach ◽  
Basal Turn ◽  
Fresh Frozen ◽  
Electrode Insertion ◽  
Temporal Bones

Objective To evaluate cochlear trauma after cochlear implant insertion through a middle fossa approach by means of histologic and imaging studies in temporal bones. Study Design Prospective cadaveric study. Setting University-based temporal bone laboratory. Subjects and Methods Twenty fresh-frozen temporal bones were implanted through a middle cranial fossa basal turn cochleostomy. Ten received a straight electrode and 10 a perimodiolar electrode. Samples were fixed in epoxy resin. Computed tomography (CT) scans determined direction, depth of insertion, and the cochleostomy to round window distance. The samples were polished by a microgrinding technique and microscopically visualized to evaluate intracochlear trauma. Descriptive and analytic statistics were performed to compare both groups. Results The CT scan showed intracochlear insertions in every bone, 10 directed to the middle/apical turn and 10 to the basal turn. In the straight electrode group, the average number of inserted electrodes was 12.3 vs 15.1 for the perimodiolar group ( U = 78, P = .0001). The median insertion depth was larger for the perimodiolar group (14.4 mm vs 12.5 mm, U = 66, P = .021). Only 1 nontraumatic insertion was achieved and 14 samples (70%) had important trauma (Eshraghi grades 3 and 4). No differences were identified comparing position or trauma grades for the 2 electrode models or when comparing trauma depending on the direction of insertion. Conclusion The surgical technique allows a proper intracochlear insertion, but it does not guarantee a correct scala tympani position and carries the risk of important trauma to cochlear microstructures.

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.

scholarly journals Round window electrocochleography before and after cochlear implant electrode insertion

2015 ◽  
Vol 126 (5) ◽  
pp. 1193-1200 ◽  
Author(s):  
Oliver F. Adunka ◽  
Christopher K. Giardina ◽  
Eric J. Formeister ◽  
Baishakhi Choudhury ◽  
Craig A. Buchman ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Before And After ◽  
Electrode Insertion

scholarly journals Effect of cochlear implant electrode insertion on middle-ear function as measured by intra-operative laser Doppler vibrometry

2009 ◽  
Vol 123 (7) ◽  
pp. 723-729 ◽  
Author(s):  
N Donnelly ◽  
A Bibas ◽  
D Jiang ◽  
D-E Bamiou ◽  
C Santulli ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Middle Ear ◽  
Low Frequency ◽  
Laser Doppler ◽  
Frequency Function ◽  
Laser Doppler Vibrometry ◽  
Variable Effect ◽  
Custom Made ◽  
Electrode Insertion ◽  
The Impact

AbstractHypothesis:The aim of this study was to investigate the impact of cochlear implant electrode insertion on middle-ear low frequency function in humans.Background:Preservation of residual low frequency hearing with addition of electrical speech processing can improve the speech perception abilities and hearing in noise of cochlear implant users. Preservation of low frequency hearing requires an intact middle-ear conductive mechanism in addition to intact inner-ear mechanisms. Little is known about the effect of a cochlear implant electrode on middle-ear function.Methods:Stapes displacement was measured in seven patients undergoing cochlear implantation. Measurements were carried out intra-operatively before and after electrode insertion. Each patient acted as his or her own control. Sound was delivered into the external auditory canal via a speaker and calibrated via a probe microphone. The speaker and probe microphone were integrated into an individually custom-made ear mould. Ossicular displacement in response to a multisine stimulus at 80 dB SPL was measured at the incudostapedial joint via the posterior tympanotomy, using an operating microscope mounted laser Doppler vibrometry system.Results:Insertion of a cochlear implant electrode into the scala tympani had a variable effect on stapes displacement. In three patients, there was little change in stapes displacement following electrode insertion. In two patients, there was a significant increase, while in a further two there was a significant reduction in stapes displacement. This variability may reflect alteration of cochlear impedance, possibly due to differing loss of perilymph associated with the electrode insertion.Conclusion:Insertion of a cochlear implant electrode produces a change in stapes displacement at low frequencies, which may have an effect on residual low frequency hearing thresholds.

scholarly journals Effects of Round Window Opening Size and Moisturized Electrodes on Intracochlear Pressure Related to the Insertion of a Cochlear Implant Electrode

2016 ◽  
Vol 6 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ingo Todt ◽  
Arneborg Ernst ◽  
Philipp Mittmann
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Pressure Change ◽  
Hearing Preservation ◽  
Round Window Membrane ◽  
Cochlear Model ◽  
Window Opening ◽  
Hydrophilic Character ◽  
Intracochlear Pressure ◽  
Pressure Changes

Intracochlear pressure changes during the cochlear implant insertion are assumed to be an important contributor to hearing preservation. The aim was to observe intracochlear pressure changes by different round window opening sizes and different hydrophilic electrode conditions. The experiments were performed in a cochlear model with a micropressure sensor in the helicotrema area. Different artificial round window membrane and different moisturized electrode conditions were compared. A punctured round window causes a significantly higher and an indirect moisturized electrode condition a significantly lower intracochlear pressure change. The degree of round window opening and the hydrophilic character of an electrode during insertion affect the intracochlear pressure significantly in a model.

FINITE ELEMENT ANALYSIS OF THE EFFECT OF ACTUATOR COUPLING CONDITIONS ON ROUND WINDOW STIMULATION

2015 ◽  
Vol 15 (04) ◽  
pp. 1550048 ◽  
Author(s):  
JIABIN TIAN ◽  
XINSHENG HUANG ◽  
ZHUSHI RAO ◽  
NA TA ◽  
LIFU XU
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Round Window ◽  
Round Window Membrane ◽  
Fe Model ◽  
Ear Canal ◽  
Sound Stimulation ◽  
Fe Method ◽  
Coupling Conditions ◽  
Intracochlear Pressure

The finite element (FE) method was used to analyze the effect of coupling conditions between the actuator and the round window membrane (RWM) on the performance of round window (RW) stimulation. A FE model of the human ear consisting of the external ear canal, middle ear and cochlea was firstly developed, and then validation of this model was accomplished through comparison between analytical results and experimental data in the literature. Intracochlear pressure were derived from the model under normal forward sound stimulation and reverse RW stimulation. The equivalent sound pressure of RW stimulation was then calculated via comparing the differential intracochlear pressure produced by the actuator and normal ear canal sound stimulus. The actuator was simulated as a floating mass and placed onto the middle ear cavity side of RWM. Two aspects about the actuator coupling conditions were considered in this study: (1) the cross-section area of the actuator relative to the RWM; (2) the coupling layer between the actuator and the RWM. The results show that smaller actuator size can improve the implant performance of RW stimulation, and size requirements of the actuator can also be reduced by introducing a coupling layer between the actuator and RWM, which will benefit the manufacture of the actuator.

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