Can fresh frozen heads be used to perform hydraulic pressure measurements during cochlear implant electrode insertion?

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.

Download Full-text

Dynamic intracochlear pressure measurements during cochlear implant electrode insertion

10.1055/s-0039-1686526 ◽

2019 ◽

Author(s):

I Todt ◽

F Ordonez ◽

S Müller ◽

H Sudhoff

Keyword(s):

Cochlear Implant ◽

Pressure Measurements ◽

Electrode Insertion ◽

Intracochlear Pressure

Download Full-text

Patterns Seen During Electrode Insertion Using Intracochlear Electrocochleography Obtained Directly Through a Cochlear Implant

Otology & Neurotology ◽

10.1097/mao.0000000000001559 ◽

2017 ◽

Vol 38 (10) ◽

pp. 1415-1420 ◽

Cited By ~ 17

Author(s):

Michael S. Harris ◽

William J. Riggs ◽

Christopher K. Giardina ◽

Brendan P. O’Connell ◽

Jourdan T. Holder ◽

...

Keyword(s):

Cochlear Implant ◽

Electrode Insertion

Download Full-text

Cochlear Implant Revision: Effects of Reimplantation on the Cochlea

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948909801012 ◽

1989 ◽

Vol 98 (10) ◽

pp. 813-820 ◽

Cited By ~ 31

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.

Download Full-text

Angular Electrode Insertion Depth and Speech Perception in Adults With a Cochlear Implant

Otology & Neurotology ◽

10.1097/mao.0000000000002298 ◽

2019 ◽

Vol 40 (7) ◽

pp. 900-910 ◽

Cited By ~ 2

Author(s):

Floris Heutink ◽

Simone R. de Rijk ◽

Berit M. Verbist ◽

Wendy J. Huinck ◽

Emmanuel A. M. Mylanus

Keyword(s):

Speech Perception ◽

Cochlear Implant ◽

Insertion Depth ◽

Electrode Insertion

Download Full-text

Intraoperative Stapedius Reflex Measurements after Deep Electrode Insertion Compared with Postoperative Fitting Values in Cochlear Implant Patients

Advances in Oto-Rhino-Laryngology - Updates in Cochlear Implantation ◽

10.1159/000059202 ◽

2000 ◽

pp. 316-319 ◽

Cited By ~ 1

Author(s):

J. Zupancic ◽

S. Battelino

Keyword(s):

Cochlear Implant ◽

Stapedius Reflex ◽

Electrode Insertion

Download Full-text

Effect of Underwater Insertion on Intracochlear Pressure

Frontiers in Surgery ◽

10.3389/fsurg.2020.546779 ◽

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.

Download Full-text