Anatomy of the round Window with Respect to Cochlear Implant Surgery

1987 ◽  
Vol 96 (1_suppl) ◽  
pp. 17-19 ◽  
Author(s):  
A. R. Clifford ◽  
W. P. R. Gibson
Keyword(s):  
Round Window ◽  
Electrode Array ◽  
Careful Analysis ◽  
Cochlear Duct ◽  
Video Recordings ◽  
Cochlear Implant Surgery ◽  
Electrode Insertion ◽  
Channel Electrode ◽  
Temporal Bones ◽  
Insertion Length

Twenty-three human temporal bones were dissected to study the anatomy of the round window with respect to cochlear implantation. Information was also gathered concerning the passage of a 22-channel electrode array along the cochlear duct by using cochlear surface dissection preparations. The insertion length and any insertion trauma were noted both by observation at the time of insertion and by careful analysis of video recordings. The crista semilunaris did not interfere with smooth electrode insertion. The recommendation is made that enlarging the round window anteroinferiorly is unnecessary and potentially hazardous in most cases.

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.

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.

Selection of the appropriate cochlear electrode array using a specifically developed research software application

2018 ◽  
Vol 132 (06) ◽  
pp. 544-549 ◽  
Author(s):  
E H Stefanescu ◽  
S Motoi
Keyword(s):  
Round Window ◽  
Electrode Array ◽  
Cochlear Duct ◽  
X Ray ◽  
Software Application ◽  
Research Software ◽  
Cochlear Duct Length ◽  
The Mean ◽  
Electrode Selection ◽  
Selection Of

AbstractObjectiveTo evaluate the usefulness and reliability of a research software application for the estimation of an individual's cochlear duct length as a basis for electrode selection.MethodsIn this prospective cohort study, 21 consecutive patients (23 ears) implanted with a cochlear electrode were investigated. The study comprised 19 children (2 bilateral) and 2 adults.ResultsThe measured ‘A’ distances (the largest distance from the round window to the contralateral wall) corresponded to cochlear duct lengths of 28.5–36.4 mm. The mean cochlear duct length was 34.05 ± 1.72 mm (33.60 ± 2.27 mm in females and 34.35 ± 1.27 mm in males). Full insertion was achieved in all but two cases. No misplaced electrode array or electrode fold-over was detected. In all but three ears, the electrode was chosen based on the research software application's indication.ConclusionThe results show a good correlation between the pre-operatively predicted insertion depths using the software application and those post-operatively measured using X-ray. The insertion length predicted by the software was always longer than that measured via X-ray.

Cochlear Implant Surgery Through Round Window Approach Is Always Possible

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 38S-44S ◽  
Author(s):  
Seong-Cheon Bae ◽  
You-Ree Shin ◽  
Young-Myoung Chun
Keyword(s):  
Cochlear Implant ◽  
Standard Procedure ◽  
Round Window ◽  
Lateral Wall ◽  
Anatomical Variations ◽  
Implant Surgery ◽  
Cochlear Implant Surgery ◽  
Alternative Procedures ◽  
Electrode Insertion ◽  
Window Approach

Objectives: The benefit of round window (RW) approach for cochlear implant (CI) has been well studied. Because the RW represents a natural door to scala tympani, it facilitates precise electrode insertion. Atraumatic electrode insertion can also be performed without drilling the cochlear lateral wall. However, the RW approach has several limitations. The purpose of this study is to describe successful CI surgeries utilizing the RW approach except for severe cases of temporal bone anomaly. The authors’ successful surgical solution for cases involving difficult RW access is also described. Materials and Methods: We retrospectively analyzed 377 consecutive surgeries of cochlear implantation performed between June 2010 and December 2018 by a single experienced surgeon. Standard and alternative procedures were used according to anatomical variations. Standard procedures included modified techniques of mastoidectomy in the RW approach, opening of facial recess, exposure of RW membrane, and electrode insertion. Difficult cases involving severe rotated cochlea or hypoplastic mastoid were successfully treated with RW insertion using alternative procedures such as external auditory canal (EAC) wall mobilization and endomeatal approach. Results: We performed CI surgery through a reproducible RW technique in two cases involving endomeatal approach and three cases of EAC mobilization. Other cases were treated using the standard procedure. Conclusion: Cochlear implant surgery through RW is reliable, safe, and effective. The RW technique is reproducible via several surgical procedures in most CI cases. Identification and safe exposure of RW membrane is a prerequisite for successful electrode insertion in cochlear implant surgery.

scholarly journals Advances to Electrode Pullback in Cochlear Implant Surgery

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Ingo Todt ◽  
Dietmar Basta ◽  
Rainer Seidl ◽  
Arne Ernst
Keyword(s):  
Cochlear Implant ◽  
Initial Position ◽  
Electrode Position ◽  
Video Capture ◽  
Insertion Technique ◽  
Tertiary Referral ◽  
Tertiary Referral Center ◽  
Cochlear Implant Surgery ◽  
Electrode Insertion ◽  
Temporal Bones

Objective. To observe the intracochlear behavior of a cochlear implant electrode insertion technique (called “pullback”) in temporal bones.Study Design. Experimental.Settings. Tertiary referral center.Method. The change of the intracochlear electrode position was investigated under various conditions of an electrode pullback (N=54) in 9 radiologically, size-estimated temporal bones (TBs). Those TBs were prepared by removal of the cochlear scalar roof to apply digital video capture procedures to monitor the pullback procedures. The digitally captured pictures were analyzed with specific software.Results. An optimal pullback of the electrode varied between 1.37 mm and 2.67 mm. While a limited pullback is without risk, an extended pullback bears the risk of removing the electrode tip out of its initial position or out of the cochlea. A correlation between cochlear size and the amount of pullback was not found.Conclusion. An initial insertion to the first or the second marker on the electrode followed by a limited pullback of about 1.37 mm to 1.5 mm can be recommended to achieve an optimized perimodiolar position. A pullback of up to two marker positions bears the risk of removing the electrode tip out of its initial position.

scholarly journals Manufacturable 32-Channel Cochlear Electrode Array and Preliminary Assessment of Its Feasibility for Clinical Use

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 778
Author(s):  
Soowon Shin ◽  
Yoonhee Ha ◽  
Gwangjin Choi ◽  
Junewoo Hyun ◽  
Sangwoo Kim ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Signal Transmission ◽  
Round Window ◽  
Electrode Array ◽  
Lead Wire ◽  
Layer By Layer ◽  
Electrode Arrays ◽  
Insertion Force ◽  
Vertical Stiffness ◽  
Channel Electrode

(1) Background: In this study, we introduce a manufacturable 32-channel cochlear electrode array. In contrast to conventional cochlear electrode arrays manufactured by manual processes that consist of electrode-wire welding, the placement of each electrode, and silicone molding over wired structures, the proposed cochlear electrode array is manufactured by semi-automated laser micro-structuring and a mass-produced layer-by-layer silicone deposition scheme similar to the semiconductor fabrication process. (2) Methods: The proposed 32-channel electrode array has 32 electrode contacts with a length of 24 mm and 0.75 mm spacing between contacts. The width of the electrode array is 0.45 mm at its apex and 0.8 mm at its base, and it has a three-layered arrangement consisting of a 32-channel electrode layer and two 16-lead wire layers. To assess its feasibility, we conducted an electrochemical evaluation, stiffness measurements, and insertion force measurements. (3) Results: The electrochemical impedance and charge storage capacity are 3.11 ± 0.89 kOhm at 1 kHz and 5.09 mC/cm2, respectively. The V/H ratio, which indicates how large the vertical stiffness is compared to the horizontal stiffness, is 1.26. The insertion force is 17.4 mN at 8 mm from the round window, and the maximum extraction force is 61.4 mN. (4) Conclusions: The results of the preliminary feasibility assessment of the proposed 32-channel cochlear electrode array are presented. After further assessments are performed, a 32-channel cochlear implant system consisting of the proposed 32-channel electrode array, 32-channel neural stimulation and recording IC, titanium-based hermetic package, and sound processor with wireless power and signal transmission coil will be completed.

Microfissure in the Oval Window Area

1981 ◽  
Vol 90 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Takehiko Harada ◽  
Isamu Sando ◽  
Eugene N. Myers
Keyword(s):  
Temporal Bone ◽  
Round Window ◽  
Vertical Plane ◽  
Careful Analysis ◽  
Oval Window ◽  
Annular Ligament ◽  
Round Window Niche ◽  
Window Area ◽  
Most Probable Explanation ◽  
Temporal Bones

Examination of 331 human temporal bones revealed the presence of a microfissure in the oval window area in 25%. The youngest temporal bone in which the microfissure was observed was from a child eight years old and the oldest temporal bone was from an individual 102 years old. It appears that the microfissure in this area occurs extremely rarely before 10 years of age, that it begins to be observed after the age of 10, and that the incidence of this fissure increases sharply at about age 40. In 61% of the bones in which the microfissure was observed, it was present both superior and inferior to the oval window in almost the same vertical plane. In none of the bones, however, did it extend beyond the annular ligament to the footplate. The histological appearance of the microfissure in this area was quite similar to that of the microfissure between the posterior canal ampulla and round window niche, although the latter appeared to be wider in general. The histogenesis of the microfissure is still unknown, but upon careful analysis of the results of this study and literature review, the authors consider nontraumatic spontaneous fracture by mechanical stress to be the most probable explanation for its occurrence. Possible clinical significance of the microfissure is also discussed.

Optimal Path Planning for Robotic Insertion of Steerable Electrode Arrays in Cochlear Implant Surgery

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Jian Zhang ◽  
J. Thomas Roland ◽  
Spiros Manolidis ◽  
Nabil Simaan
Keyword(s):  
Path Planning ◽  
Cochlear Implant ◽  
Optimal Path ◽  
Electrode Array ◽  
Scala Tympani ◽  
Electrode Arrays ◽  
Insertion Force ◽  
Optimal Path Planning ◽  
Cochlear Implant Surgery ◽  
Electrode Insertion

This paper presents an optimal path planning method of steerable electrode arrays for robot-assisted cochlear implant surgery. In this paper, the authors present a novel design of steerable electrode arrays that can actively bend at the tip. An embedded strand in the electrode array provides an active steering degrees-of-freedom (DoF). This paper addresses the calibration of the steerable electrode array and the optimal path planning for inserting it into planar and three-dimensional scala tympani models. The goal of the path planning is to minimize the intracochlear forces that the electrode array applies on the walls of the scala tympani during insertion. This problem is solved by designing insertion path planning algorithms that provide best fit between the shape of the electrode array and the curved scala tympani during insertion. Optimality measures that account for shape discrepancies between the steerable electrode array and the scala tympani are used to solve for the optimal path planning of the robot. Different arrangements of DoF and insertion speed force feedback (ISFF) are simulated and experimentally validated in this paper. A quality of insertion metric describing the gap between the steerable electrode array and the scala tympani model is presented and its correspondence to the insertion force is shown. The results of using 1DoF, 2DoF, and 4DoF electrode array insertion setups are compared. The 1DoF insertion setup uses nonsteerable electrode arrays. The 2DoF insertion setup uses single axis insertion with steerable electrode arrays. The 4DoF insertion setup allows full control of the insertion depth and the approach angle of the electrode with respect to the cochlea while using steerable electrode arrays. It is shown that using steerable electrode arrays significantly reduces the maximal insertion force (59.6% or more) and effectively prevents buckling of the electrode array. The 4DoF insertion setup further reduces the maximal electrode insertion forces. The results of using ISFF for steerable electrodes show a slight decrease in the insertion forces in contrast to a slight increase for nonsteerable electrodes. These results show that further research is required in order to determine the optimal ISFF control law and its effectiveness in reducing electrode insertion forces.

scholarly journals The Pull-Back Technique for the 532 Slim Modiolar Electrode

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
C. Riemann ◽  
H. Sudhoff ◽  
I. Todt
Keyword(s):  
Temporal Bone ◽  
Round Window ◽  
Spiral Ganglion ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Current Spread ◽  
Temporal Bones ◽  
Hearing Outcomes ◽  
White Marker

Introduction. The distance between the modiolus and the electrode array is one factor that has become the focus of many discussions and studies. Positioning the electrode array closer to the spiral ganglion with the goal of reducing the current spread has been shown to improve hearing outcomes. The perimodiolar electrode arrays can be complemented with a surgical manoeuvre called the pull-back technique. This study focuses its attention on the recently developed 532 slim modiolar electrode. Objective. To investigate the intracochlear movements and pull-back technique for the 532 slim modiolar electrode. Material and Methods. A decapping procedure of the cochlea was performed on 5 temporal bones. The electrode array was inserted, and the intracochlear movements were microscopically examined and digitally captured. Three situations were analysed: the initial insertion, the overinsertion, and the pull-back position. The position of the three white markers of the electrode array in relation to the round window (RW) was evaluated while performing these three actions. Results. The initial insertion achieved an acceptable perimodiolar position of the electrode array, but a gap was still observed between the mid-portion of the array and the modiolus (the first white marker was seen in the RW). When we inserted the electrode more deeply, the mid-portion of the array was pushed away from the modiolus (the second and third white markers were seen in the RW). After applying the pull-back technique, the gap observed during the initial insertion disappeared, resulting in an optimal perimodiolar position (the first white marker was once again visible in the RW). Conclusion. This temporal bone study demonstrated that when applying the pull-back technique for the 532 slim modiolar electrode, a closer proximity to the modiolus was achieved when the first white marker of the electrode array was visible in the round window.

scholarly journals Refined Surgical Technique for Insertion of Banded Electrode Array

1987 ◽  
Vol 96 (1_suppl) ◽  
pp. 15-17 ◽  
Author(s):  
B. K-H. G. Franz ◽  
G. M. Clark
Keyword(s):  
Surgical Technique ◽  
Cochlear Implant ◽  
Round Window ◽  
Electrode Array ◽  
Scala Tympani ◽  
Insertion Technique ◽  
Electrode Insertion ◽  
The Right

A refined electrode insertion technique is presented for the multichannel cochlear implant. It comprises two basic steps. The first step is the removal of the anteroinferior overhang of the round window and crista fenestrae, or alternatively an opening drilled into the scala tympani anteroinferior to the round window. The second is rotation of the electrode during insertion, counterclockwise in the right ear and clockwise in the left ear.

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