Incidence of Complete Insertion in Cochlear Implant Recipients of Long Lateral Wall Arrays

2021 ◽  
pp. 019459982098745
Author(s):  
Michael W. Canfarotta ◽  
Margaret T. Dillon ◽  
Kevin D. Brown ◽  
Harold C. Pillsbury ◽  
Matthew M. Dedmon ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Electrode Array ◽  
Lateral Wall ◽  
Electrode Arrays ◽  
Tertiary Referral ◽  
Insertion Depth ◽  
Future Studies ◽  
Tertiary Referral Center ◽  
Cochlear Duct Length ◽  
Cochlear Morphology

Objective High rates of partial insertion have been reported for cochlear implant (CI) recipients of long lateral wall electrode arrays, presumably caused by resistance encountered during insertion due to cochlear morphology. With recent advances in long-electrode array design, we sought to investigate (1) the incidence of complete insertions among patients implanted with 31.5-mm flexible arrays and (2) whether complete insertion is limited by cochlear duct length (CDL). Study Design Retrospective review. Setting Tertiary referral center. Methods Fifty-one adult CI recipients implanted with 31.5-mm flexible lateral wall arrays underwent postoperative computed tomography to determine the rate of complete insertion, defined as all contacts being intracochlear. CDL and angular insertion depth (AID) were compared between complete and partial insertion cohorts. Results Most cases had a complete insertion (96.1%, n = 49). Among the complete insertion cohort, the median CDL was 33.6 mm (range, 30.3-37.9 mm), and median AID was 641° (range, 533-751°). Two cases of partial insertion had relatively short CDL (31.8 mm and 32.3 mm) and shallow AID (542° and 575°). Relatively shallow AID for the 2 cases of partial insertion fails to support the idea that CDL alone prevents a complete insertion. Conclusion Complete insertion of a 31.5-mm flexible array is feasible in most cases and does not appear to be limited by the range of CDL observed in this cohort. Future studies are needed to estimate other variations in cochlear morphology that could predict resistance and failure to achieve complete insertion with long arrays.

Electrode Migration in Patients with Perimodiolar Cochlear Implant Electrodes

2015 ◽  
Vol 20 (6) ◽  
pp. 349-353 ◽  
Author(s):  
Philipp Mittmann ◽  
Grit Rademacher ◽  
Sven Mutze ◽  
Arneborg Ernst ◽  
Ingo Todt
Keyword(s):  
Cochlear Implant ◽  
Cochlear Implantation ◽  
Electrode Array ◽  
Lateral Wall ◽  
Electrode Arrays ◽  
Insertion Depth ◽  
Lower Extent ◽  
Uncommon Complication

Migration of a cochlear implant electrode is a hitherto uncommon complication. So far, array migration has only been observed in lateral wall electrodes. Between 1999 and 2014, a total of 27 patients received bilateral perimodiolar electrode arrays at our institution. The insertion depth angle was estimated on the initial postoperative scans and compared with the insertion depth angle of the postoperative scans performed after contralateral cochlear implantation. Seven (25.93%) patients were found to have an electrode array migration of more than 15°. Electrode migration in perimodiolar electrodes seems to be less frequent and to occur to a lower extent than in lateral wall electrodes. Electrode migration was clinically asymptomatic in all cases.

scholarly journals Effect of Scala Tympani Height on Insertion Depth of Straight Cochlear Implant Electrodes

2020 ◽  
Vol 162 (5) ◽  
pp. 718-724 ◽  
Author(s):  
William G. Morrel ◽  
Jourdan T. Holder ◽  
Benoit M. Dawant ◽  
Jack H. Noble ◽  
Robert F. Labadie
Keyword(s):  
Cochlear Implant ◽  
Retrospective Review ◽  
Basilar Membrane ◽  
Lateral Wall ◽  
Scala Tympani ◽  
Tertiary Referral ◽  
Insertion Depth ◽  
Tertiary Referral Center ◽  
Relationship Of ◽  
The Relationship

Objective Studies suggest lateral wall (LW) scala tympani (ST) height decreases apically, which may limit insertion depth. No studies have investigated the relationship of LW ST height with translocation rate or location. Study Design Retrospective review. Setting Cochlear implant program at tertiary referral center. Subjects and Methods LW ST height was measured in preoperative images for patients with straight electrodes. Scalar location, angle of insertion depth (AID), and translocation depth were measured in postoperative images. Audiologic outcomes were tracked. Results In total, 177 ears were identified with 39 translocations (22%). Median AID was 443° (interquartile range [IQR], 367°-550°). Audiologic outcomes (126 ears) showed a small, significant correlation between consonant-nucleus-consonant (CNC) word score and AID ( r = 0.20, P = .027), although correlation was insignificant if translocation occurred ( r = 0.11, P = .553). Translocation did not affect CNC score ( P = .335). AID was higher for translocated electrodes (503° vs 445°, P = .004). Median translocation depth was 381° (IQR, 222°-399°). Median depth at which a 0.5-mm electrode would not fit within 0.1 mm of LW was 585° (IQR, 405°-585°). Median depth at which a 0.5-mm electrode would displace the basilar membrane by ≥0.1 mm was 585° (IQR, 518°-765°); this was defined as predicted translocation depth (PTD). Translocation rate was 39% for insertions deeper than PTD and 14% for insertions shallower than PTD ( P = .008). Conclusion AID and CNC are directly correlated for straight electrodes when not translocated. Translocations generally occur around 380° and are more common with deeper insertions due to decreasing LW ST height. Risk of translocation increases significantly after 580°.

Electrode design and insertional depth-dependent intra-cochlear pressure changes: a model experiment

2017 ◽  
Vol 132 (3) ◽  
pp. 224-229 ◽  
Author(s):  
P Mittmann ◽  
A Ernst ◽  
I Todt
Keyword(s):  
Cochlear Implant ◽  
Fluid Pressure ◽  
Electrode Array ◽  
Lateral Wall ◽  
Peak Frequency ◽  
Peak Amplitude ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Pressure Peak ◽  
Pressure Changes

AbstractBackground:Preservation of residual hearing is one of the major goals in modern cochlear implant surgery. Intra-cochlear fluid pressure changes influence residual hearing, and should be kept low before, during and after cochlear implant insertion.Methods:Experiments were performed in an artificial cochlear model. A pressure sensor was inserted in the apical part. Five insertions were performed on two electrode arrays. Each insertion was divided into three parts, and statistically evaluated in terms of pressure peak frequency and pressure peak amplitude.Results:The peak frequency over each third part of the electrode increased in both electrode arrays. A slight increase was seen in peak amplitude in the lateral wall electrode array, but not in the midscalar electrode array. Significant differences were found in the first third of both electrode arrays.Conclusion:The midscalar and lateral wall electrode arrays have different intra-cochlear fluid pressure changes associated with intra-cochlear placement, electrode characteristics and insertion.

scholarly journals Radiological evaluation of a new straight electrode array compared to its precursors

2020 ◽  
Author(s):  
Manuel Christoph Ketterer ◽  
A. Aschendorff ◽  
S. Arndt ◽  
I. Speck ◽  
A. K. Rauch ◽  
...  
Keyword(s):  
Round Window ◽  
Electrode Array ◽  
Lateral Wall ◽  
Study Groups ◽  
Cone Beam ◽  
Special Focus ◽  
Electrode Arrays ◽  
Academic Center ◽  
Cochlear Morphology ◽  
Array Position

Abstract Objective The aim of this study is to examine electrode array coverage, scalar position and dislocation rate in straight electrode arrays with special focus on a new electrode array with 26 mm in lengths. Study design Retrospective study. Setting Tertiary academic center. Patients 201 ears implanted between 2013 and 2019. Main outcome measures We conducted a comparative analysis of patients implanted with lateral wall electrode arrays of different lengths (F24 = MED-EL Flex24, F26 = MED-EL Flex26, F28 = MED-EL Flex28 and F31.5 = MED-EL FlexSoft). Cone beam computed tomography was used to determine electrode array position (scala tympani (ST) versus scala vestibuli (SV), intracochlear dislocation, position of dislocation and insertion angle). Results Study groups show no significant differences regarding cochlear size which excludes influences by cochlear morphology. As expected, the F24 showed significant shorter insertion angles compared to the longer electrode arrays. The F26 electrode array showed no signs of dislocation or SV insertion. The electrode array with the highest rate of ST dislocations was the F31.5 (26.3%). The electrode array with the highest rates of SV insertions was the F28 (5.75%). Most of the included electrode arrays dislocate between 320° and 360° (mean: 346.4°; range from 166° to 502°). Conclusion The shorter F24 and the new straight electrode array F26 show less or no signs of scalar dislocation, neither for round window nor for cochleostomy insertion than the longer F28 and the F31.5 array. As expected, the cochlear coverage is increasing with length of the electrode array itself but with growing risk for scalar dislocation and with the highest rates of dislocation for the longest electrode array F31.5. Position of intracochlear dislocation is in the apical cochlear part in the included lateral wall electrode arrays.

Comparison of the HiFocus Mid-Scala and HiFocus 1J Electrode Array: Angular Insertion Depths and Speech Perception Outcomes

2016 ◽  
Vol 21 (5) ◽  
pp. 316-325 ◽  
Author(s):  
M. Annerie van der Jagt ◽  
Jeroen J. Briaire ◽  
Berit M. Verbist ◽  
Johan H.M. Frijns
Keyword(s):  
Speech Perception ◽  
Cochlear Implant ◽  
Electrode Array ◽  
Lateral Wall ◽  
Neural Stimulation ◽  
Insertion Depth ◽  
Optimal Distance ◽  
Frequency Mismatch ◽  
The Mean

The HiFocus Mid-Scala (MS) electrode array has recently been introduced onto the market. This precurved design with a targeted mid-scalar intracochlear position pursues an atraumatic insertion and optimal distance for neural stimulation. In this study we prospectively examined the angular insertion depth achieved and speech perception outcomes resulting from the HiFocus MS electrode array for 6 months after implantation, and retrospectively compared these with the HiFocus 1J lateral wall electrode array. The mean angular insertion depth within the MS population (n = 96) was found at 470°. This was 50° shallower but more consistent than the 1J electrode array (n = 110). Audiological evaluation within a subgroup, including only postlingual, unilaterally implanted, adult cochlear implant recipients who were matched on preoperative speech perception scores and the duration of deafness (MS = 32, 1J = 32), showed no difference in speech perception outcomes between the MS and 1J groups. Furthermore, speech perception outcome was not affected by the angular insertion depth or frequency mismatch.

scholarly journals Clinical investigation of the Nucleus Slim Modiolar Electrode

2017 ◽  
Vol 22 (3) ◽  
pp. 169-179 ◽  
Author(s):  
Antje Aschendorff ◽  
Robert Briggs ◽  
Goetz Brademann ◽  
Silke Helbig ◽  
Joachim Hornung ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cochlear Implant ◽  
Temporal Bone ◽  
Clinical Investigation ◽  
Round Window ◽  
Electrode Array ◽  
Lateral Wall ◽  
Scala Tympani ◽  
Flat Panel ◽  
Insertion Depth

Aims: The Nucleus CI532 cochlear implant incorporates a new precurved electrode array, i.e., the Slim Modiolar electrode (SME), which is designed to bring electrode contacts close to the medial wall of the cochlea while avoiding trauma due to scalar dislocation or contact with the lateral wall during insertion. The primary aim of this prospective study was to determine the final position of the electrode array in clinical cases as evaluated using flat-panel volume computed tomography. Methods: Forty-five adult candidates for unilateral cochlear implantation were recruited from 8 centers. Eleven surgeons attended a temporal bone workshop and received further training with a transparent plastic cochlear model just prior to the first surgery. Feedback on the surgical approach and use of the SME was collected via a questionnaire for each case. Computed tomography of the temporal bone was performed postoperatively using flat-panel digital volume tomography or cone beam systems. The primary measure was the final scalar position of the SME (completely in scala tympani or not). Secondly, medial-lateral position and insertion depth were evaluated. Results: Forty-four subjects received a CI532. The SME was located completely in scala tympani for all subjects. Pure round window (44% of the cases), extended round window (22%), and inferior and/or anterior cochleostomy (34%) approaches were successful across surgeons and cases. The SME was generally positioned close to the modiolus. Overinsertion of the array past the first marker tended to push the basal contacts towards the lateral wall and served only to increase the insertion depth of the first electrode contact without increasing the insertion depth of the most apical electrode. Complications were limited to tip fold-overs encountered in 2 subjects; both were attributed to surgical error, with both reimplanted successfully. Conclusions: The new Nucleus CI532 cochlear implant with SME achieved the design goal of producing little or no trauma as indicated by consistent scala tympani placement. Surgeons should be carefully trained to use the new deployment method such that tip fold-overs and over insertion may be avoided.

Preservation of residual hearing following cochlear implantation: comparison between three surgical techniques

2007 ◽  
Vol 122 (3) ◽  
pp. 246-252 ◽  
Author(s):  
S Berrettini ◽  
F Forli ◽  
S Passetti
Keyword(s):  
Cochlear Implant ◽  
Cochlear Implantation ◽  
Surgical Techniques ◽  
Electrode Array ◽  
Lateral Wall ◽  
Hearing Preservation ◽  
Acoustic Stimulation ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Electrode Insertion

AbstractThe preservation of residual hearing is becoming a high priority in cochlear implant surgery. It allows better speech understanding and ensures long-lasting and stable performance; it also allows the possibility, in selected cases, of combining electro-acoustic stimulation in the same ear.We present the results of a retrospective study of the conservation of residual hearing in three different groups of patients who had undergone cochlear implantation using three different cochlear implant electrode arrays, combined with three different surgical techniques for the cochleostomy. The study aimed to evaluate which approach allowed greater preservation of residual hearing.The best residual hearing preservation results (i.e. preservation in 81.8 per cent of patients) were achieved with the Contour Advance electrode array, using the Advance Off-Stylet technique and performing a modified anterior inferior cochleostomy; this combination enabled reduced trauma to the lateral wall of the cochlea during electrode insertion.

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