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 ◽  
...  
1989 ◽  
Vol 98 (10) ◽  
pp. 813-820 ◽  
Author(s):  
Robert K. Jackler ◽  
Patricia A. Leake ◽  
William S. McKerrow

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.


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

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.


2020 ◽  
Vol 7 ◽  
Author(s):  
Conrad Riemann ◽  
Holger Sudhoff ◽  
Ingo Todt

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.


2016 ◽  
Vol 37 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Georgios Mantokoudis ◽  
Markus E. Huth ◽  
Christian Weisstanner ◽  
Hergen M. Friedrich ◽  
Claude Nauer ◽  
...  

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 38S-44S ◽  
Author(s):  
Seong-Cheon Bae ◽  
You-Ree Shin ◽  
Young-Myoung Chun

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.


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

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.


2007 ◽  
Vol 117 (8) ◽  
pp. 1397-1402 ◽  
Author(s):  
Peter S. Roland ◽  
Charles G. Wright ◽  
Brandon Isaacson

1987 ◽  
Vol 96 (1_suppl) ◽  
pp. 15-17 ◽  
Author(s):  
B. K-H. G. Franz ◽  
G. M. Clark

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.


2011 ◽  
Vol 12 (sup2) ◽  
pp. S36-S39 ◽  
Author(s):  
J Addams-Williams ◽  
L Munaweera ◽  
B Coleman ◽  
R Shepherd ◽  
S Backhouse

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