Electrode ChoiceS
    BOOKLET

    by the hearring Group

    Discover a practical guide to choosing the right cochlear implant electrode, tailored to the unique anatomy of every patient. Developed by the HEARRING Group, this booklet reflects state-of-the-art expertise and clinical insight. It highlights a range of electrode designs, explores common anatomical variations, and offers clear, experience-based recommendations for each scenario. Designed to support confident decision-making, it’s a valuable resource for clinicians seeking more personalized and effective outcomes.

    An educational slide titled "Incomplete Partition (IP) Type II" detailing its association with enlarged vestibular aqueduct (EVA) and electrode choices. Includes axial and coronal CT scans and 3D anatomical models of the cochlea highlighting the malformation.
    Educational slide for IP Type III. The text explains that the cochlea lacks the central modiolar trunk and the IAC is wide, opening directly into the basal turn without bony separation, which leads to a "gusher." Electrode choice: Recommends 15 mm to 24 mm electrodes, preferably from a sealing series. Advises against modiolar electrodes to prevent migration into the IAC and suggests intra-operative imaging. Visuals show the absence of internal cochlear structure on radiology and 3D models.
    An educational slide for Cochlea Hypoplasia Type I. Text Summary: It describes a severe form of CH with a bud-like or very short basal turn. Electrode choice: It recommends an Auditory Brainstem Implant (ABI) if electrophysiology results are negative, or a very short electrode if electrophysiology results are positive. Visuals: Four panels on the right show axial and coronal CT scans alongside green 3D reconstructions. The models show a very small, simplified inner ear structure with a lack of any significant cochlear spiral. The slide is numbered 32 and 33.
    Concise: A medical slide titled "Incomplete Partition (IP) Type II" (Mondini’s) detailing its association with enlarged vestibular aqueduct (EVA). Features CT scans and 3D models highlighting the malformed inner ear structures. Detailed: A slide explaining IP Type II, also known as Mondini’s. Key points note it is always associated with an enlarged vestibular aqueduct (EVA) and features a normal basal turn with a cystic middle and apical turn. For electrode choice, it recommends sealing electrodes to handle potential CSF leaks from the EVA or electrodes matched to cochlea size. Four panels show axial/coronal CT scans and 3D models with the enlarged vestibular aqueduct highlighted in red.
    An educational slide regarding Cochlea Hypoplasia (CH) Type III. Text Summary: This is a moderate-to-mild form where the cochlea has 1.5 to 2 turns. A "gusher" (CSF leak) is unlikely. It notes that facial malformations and changes in the facial nerve trajectory are expected. For electrode choice, it recommends a medium-length electrode (24 mm) or a flexible 26 mm electrode for safe and effective coverage. Visuals: Four panels on the right show imaging. The axial and coronal CT scans show a smaller-than-normal cochlear spiral. The corresponding green 3D models illustrate a cochlea that is noticeably shorter than a typical 2.5-to-2.75 turn cochlea. The slide is numbered 36 and 37.
    An educational slide regarding Cochlea Hypoplasia (CH) Type IV. Text Summary: It states that the basal turn is normal in size, but the middle and apical turns are severely hypoplastic or absent. For electrode choice, it recommends a medium-length electrode, such as a 24 mm or flexible 26 mm, to cover the cochlea safely. Visuals: The right side shows four panels: Axial and Coronal grayscale CT scans of the inner ear, and corresponding green 3D models. The Coronal 3D model clearly shows a developed basal spiral that ends prematurely. The slide is numbered 38 and 39.
    An educational slide regarding Common Cavity (CC) malformations of the inner ear. Text Summary: In a "true" CC, the cochlea and vestibular portions fuse into one cavity. A line drawn along the posterior canal wall of the Internal Auditory Canal (IAC) separates the cochlea portion from the vestibular portion. For electrode choice, it suggests a custom-made device to optimally place the electrode along the interior wall of the cochlea portion. Visuals: Four panels on the right show imaging. The axial CT scan and its 3D model counterpart use a red diagonal line across the cavity to illustrate the anatomical division. The coronal views show the single, large fused space. The slide is numbered 40 and 41.
    An educational slide about Cochlea Aplasia with Vestibular Cavity. Text Summary: The text notes that the cavity falls completely posterior to a line drawn along the posterior canal wall of the IAC, representing a vestibular cavity with the absence of the cochlea. It mentions this is often mistaken for a "common cavity." For electrode choice, it suggests a length matching the cavity's circumference, placed in a "loopy format." Visuals: On the right, four images show the anatomy. An axial CT scan and its corresponding green 3D model show a red diagonal line marking the IAC wall. Below these are coronal views showing the absence of the normal cochlear spiral.
    An educational slide outlining four classifications of Ossified Cochlea: Type I: Involves the Round Window (RW). Suggests drilling the RW and using a regular length electrode. Type II-a: Involves the basal turn. Suggests drilling a short length and considering a medium or flexible 26 mm electrode. Type II-b: Basal portion is completely ossified. Suggests a shorter electrode implanted in the second turn. Type III: Fully ossified cochlea. Suggests considering a short length double-branch electrode. Four CT scan images correspond to each type, with red circles identifying the pathology in the inner ear.
    Pre-operative Analysis: Includes oblique coronal and axial CT scans alongside 3D models. A 10.0 mm ossified portion is identified in the scala tympani (highlighted in red on the 3D model). Post-operative Analysis: Shows a 3D model of the electrode covering an angular insertion depth of 540°, with a label indicating the "Electrode entering SV" (scala vestibuli). Key Points: The text explains that while ossification occludes the scala tympani, the scala vestibuli remains visible in imaging. If the scala vestibuli is open, electrodes of 24 mm–28 mm can often be fully inserted despite the obstruction in the scala tympani.
    Text Summary: The stiff blue side of the probe dilates the lumen up to 20 mm. The transparent side confirms access up to 31.5 mm. Diagram Details: A schematic of the "Insertion Probe Dummy Device" shows a total length of 112.0 mm. The blue end (20.0 mm long) tapers from a diameter of 1.3 mm to 0.6 mm. The transparent end (31.5 mm long) includes markers at 20.0, 24.0, 28.0, and 31.5 mm, tapering to a tip of 0.4 mm. The slide is numbered 48 and 49 at the bottom.
    Text Summary: The probe can dilate tissue to provide access up to a depth of 31.5 mm. The instructions specify placing the tip in the cochlea opening and carefully inserting the array as deeply as necessary. Diagram Details: A schematic of the "Insertion Probe L Dummy Device" labels the "Array" and "Handling section." Dimensions are shown in millimeters: markers are placed at 20.0, 24.0, 28.0, and a maximum depth of 31.5. The tip diameter is 0.5 mm, widening to 1.3 mm at the base of the array. The handling section is 50.0 mm long. A note attributes the design to Prof. Dr. med. Thomas Lenarz.
    A reference list slide from a medical presentation. It contains a numbered list of nine citations. Authors include Van de Heyning, Dhanasingh, Sennaroglu, and others. The references cover topics such as individualized cochlear implants, robotic-assisted surgery, electrode insertion depth, and inner ear malformations. The slide includes page numbers 52 and 53 at the bottom corners.
    Title slide for a presentation titled "Electrode Choices For Various Inner Ear Anatomies" by HEARRING. The background features a close-up of a surgeon's hands putting on sterile white gloves in a blurred operating room setting.
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