scholarly journals Intracochlear Pressure Changes due to Round Window Opening: A Model Experiment

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
P. Mittmann ◽  
A. Ernst ◽  
I. Todt
Keyword(s):  
Model Experiment ◽  
Round Window ◽  
Pressure Change ◽  
Intraluminal Pressure ◽  
Round Window Membrane ◽  
Electrode Design ◽  
Residual Hearing ◽  
Window Opening ◽  
Intracochlear Pressure ◽  
Pressure Changes

To preserve residual hearing in cochlea implantation, the electrode design has been refined and an atraumatic insertion of the cochlea electrode has become one aspect of cochlea implant research. The opening of the round window can be assumed to be a contributing factor in an atraumatic concept. The aim of our study was to observe intracochlear pressure changes due to different opening conditions of an artificial round window membrane. The experiments were performed in an artificial cochlea model. A round window was simulated with a polythene foil and a pressure sensor was placed in the helicotrema area to monitor intraluminal pressure changes. Openings of the artificial round window membrane were performed using different ways. Opening the artificial round window mechanically showed a biphasic behaviour of pressure change. Laser openings showed a unidirectional pressure change. The lowest pressure changes were observed when opening the artificial round window membrane using a diode laser. The highest pressure changes were seen when using a needle. The openings with the CO2laser showed a negative intracochlear pressure and a loss of fluid. In our model experiments, we could prove that the opening of the artificial round window membrane causes various intracochlear pressure changes.

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.

Rupture of the round Window Membrane

1976 ◽  
Vol 85 (1) ◽  
pp. 105-110 ◽  
Author(s):  
P. H. Taylor ◽  
P. G. Bicknell
Keyword(s):  
Middle Ear ◽  
Surgical Intervention ◽  
Round Window ◽  
Oval Window ◽  
Round Window Membrane ◽  
Physical Effort ◽  
Cochlear Aqueduct ◽  
Definite Improvement ◽  
History Of ◽  
Pressure Changes

A case of sudden deafness due to rupture of the round window membrane is presented. Nineteen similar cases have previously been reported in the literature. In a review of these twenty patients, it is noted that a history of concurrent physical effort or barotrauma was present in eighteen. This supports the view that the injury is produced by pressure changes acting either along the cochlear aqueduct (the explosive route) or, directly on the middle ear structures (the implosive route). At operation, the rupture may be difficult to see, and a separate leak from the oval window may be present. The timing of any surgical intervention is important. The authors recommend that this should be deferred for one week after the onset of symptoms, as the fistula may heal spontaneously. If no definite improvement has occurred at the end of this time, then tympanotomy should be undertaken during the next week.

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.

Effect of Round Window Opening Size on Residual Hearing Preservation in Cochlear Implantation

2020 ◽  
Vol 163 (2) ◽  
pp. 375-381
Author(s):  
Giselle L. Gotamco ◽  
Chuan-Hung Sun ◽  
Yi-Fan Chou ◽  
Chuan-Jen Hsu ◽  
Hung-Pin Wu
Keyword(s):  
Cochlear Implantation ◽  
Round Window ◽  
Hearing Preservation ◽  
Round Window Membrane ◽  
Tertiary Referral ◽  
Tertiary Referral Center ◽  
Window Technique ◽  
Cochlear Implant Surgery ◽  
Window Opening ◽  
Window Approach

Objectives This study aims to compare the hearing preservation outcomes in cochlear implant surgery following slit versus full opening of the round window membrane. Setting Tertiary referral center. Study Design Comparative study. Subjects and Methods Seventy patients (mean, 26.3 years; range, 2-69 years) who underwent cochlear implantation via the round window approach were included in the study. Thirty-five subjects were prospectively enrolled for cochlear implantation via the open round window technique between August 2018 and January 2019. Thirty-five patients who underwent cochlear implantation from January 2017 to July 2018 via the slit round window opening, frequency matched by sex and age, were retrospectively enrolled. Pre- and postoperative thresholds were obtained. The percentage of hearing preservation was computed with the HEARRING Network formula and classified into complete, partial, and minimal hearing preservation. The results between the groups were compared and analyzed at 6 months postoperatively. Results The rate of complete hearing preservation in the open group was statistically significant ( P = .030) at 71.4% (n = 25) as compared with 45.7% (n = 16) in the slit group. Conclusions The widely opened round window may be an optional technique that surgeons can utilize to improve hearing preservation outcomes.

Auditory and Vestibular Disorders Due to Barotrauma

1988 ◽  
Vol 97 (2) ◽  
pp. 146-152 ◽  
Author(s):  
Tsutomu Nakashima ◽  
Michio Itoh ◽  
Masahiro Sato ◽  
Yusuke Watanabe ◽  
Noriyuki Yanagita
Keyword(s):  
Round Window ◽  
Organ Of Corti ◽  
Pressure Change ◽  
Spontaneous Nystagmus ◽  
Round Window Membrane ◽  
Absolute Pressure ◽  
Vestibular Disorders ◽  
Auditory Brain Stem Response ◽  
Membrane Rupture ◽  
Auditory Dysfunction

In order to investigate auditory and vestibular disorders caused by barotrauma, 12 guinea pigs were exposed to compression and decompression between 1 absolute pressure (ATA) and 2 ATA in a pressure chamber. During the atmospheric pressure change spontaneous nystagmus occurred in two thirds of the animals. Auditory dysfunction that showed the difference between the right and left ears was confirmed by auditory brain stem response and Preyer's reflex in the animals with spontaneous nystagmus. Damage to the organ of Corti was the most significant cause for the auditory dysfunction. Though findings attributed to the rupture of the round window membrane were recognized in four ears, the rupture or hemorrhage of the round window membrane was not the direct cause of the auditory dysfunction. The significance of the round window membrane rupture is discussed.

scholarly journals Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Graziela de Souza Queiroz Martins ◽  
Rubens Vuono Brito Neto ◽  
Robinson Koji Tsuji ◽  
Eloisa Maria Mello Santiago Gebrim ◽  
Ricardo Ferreira Bento
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Electrode Array ◽  
Hearing Preservation ◽  
Round Window Membrane ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Minimal Trauma ◽  
Electrode Insertion ◽  
Temporal Bones

Hypothesis. This study aimed to evaluate whether there is a difference in the degree of intracochlear trauma when the cochlear implant electrode arrays is inserted through different quadrants of the round window membrane.Background. The benefits of residual hearing preservation in cochlear implant recipients have promoted the development of atraumatic surgeries. Minimal trauma during electrode insertion is crucial for residual hearing preservation.Methods. In total, 25 fresh human temporal bones were subjected to mastoidectomy and posterior tympanotomy. The cochlear implant electrode array was inserted through the anterosuperior quadrant of the round window membrane in 50% of the bones and through the anteroinferior quadrant in the remaining 50%. The temporal bones were dehydrated, embedded in epoxy, serially polished, stained, viewed through a stereomicroscope, and photographed with the electrode arraysin situ. The resulting images were analyzed for signs of intracochlear trauma.Results. Histological examinations revealed varying degrees of damage to the intracochlear structures, although the incidence and severity of intracochlear trauma were not influenced by the quadrant of insertion.Conclusions. The incidence and severity of intracochlear trauma were similar in all samples, irrespective of electrode array insertion through the anterosuperior or anteroinferior quadrant of the round window membrane.

The Effects of Gusher-Related Intracochlear Pressure Changes on Hearing Preservation in Cochlear Implantation: A Comparative Series

2018 ◽  
Vol 23 (3) ◽  
pp. 181-186 ◽  
Author(s):  
William Crohan ◽  
Jay Krishnaswamy ◽  
Gunesh Rajan
Keyword(s):  
Cochlear Implantation ◽  
Large Change ◽  
Lateral Wall ◽  
Hearing Preservation ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Significant Drop ◽  
Speech Performance ◽  
Intracochlear Pressure ◽  
Pressure Changes

Aim: To investigate and compare residual hearing preservation between patients based on the presence of intraoperative gusher. Methodology: We retrospectively compared 2 cohorts of cochlear implant recipients significantly distinguished by whether or not they experienced gusher intraoperatively. Patients underwent cochlear implantation using 24-mm lateral wall electrode arrays as well pharmacologic steroid protection. All patients were assessed by a hearing implant MDT. Hearing preservation rates and speech perception outcomes were assessed at 1, 6, 12, 24, 36, 48, and 60 months. Results: The patients with no gusher demonstrated complete hearing preservation. The patients with gusher demonstrated significant postoperative reduction of hearing thresholds, which declined at a significantly higher pace during follow-up. All patients demonstrated significantly better speech performance after cochlear implantation. Conclusion: The present study suggests that intraoperative gusher is associated with a significant drop in residual hearing, both immediately and over time, which may be related to the large change in intracochlear pressure intraoperatively.

Intracochlear Pressure Changes due to 2 Electrode Types: An Artificial Model Experiment

2016 ◽  
Vol 156 (4) ◽  
pp. 712-716 ◽  
Author(s):  
Philipp Mittmann ◽  
Marlene Mittmann ◽  
Arneborg Ernst ◽  
Ingo Todt
Keyword(s):  
Model Experiment ◽  
Intracochlear Pressure ◽  
Pressure Changes ◽  
Artificial Model

The Patterns of Simultaneous Intraluminal Pressure Changes in the Human Proximal Small Intestine

1964 ◽  
Vol 47 (3) ◽  
pp. 258-268 ◽  
Author(s):  
Gerald Friedman ◽  
Jerome D. Waye ◽  
Leonard A. Weingarten ◽  
Henry D. Janowitz
Keyword(s):  
Small Intestine ◽  
Intraluminal Pressure ◽  
Proximal Small Intestine ◽  
Pressure Changes
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