The influence of cochlear morphology on the final electrode array position

2017 ◽  
Vol 275 (2) ◽  
pp. 385-394 ◽  
Author(s):  
M. C. Ketterer ◽  
A. Aschendorff ◽  
S. Arndt ◽  
F. Hassepass ◽  
T. Wesarg ◽  
...  
Keyword(s):  
Electrode Array ◽  
Cochlear Morphology ◽  
Array Position

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.

scholarly journals CT-Derived Estimation of Cochlear Morphology and Electrode Array Position in Relation to Word Recognition in Nucleus-22 Recipients

2002 ◽  
Vol 3 (3) ◽  
pp. 332-350 ◽  
Author(s):  
Margaret W. Skinner ◽  
Darlene R. Ketten ◽  
Laura K. Holden ◽  
Gary W. Harding ◽  
Peter G. Smith ◽  
...  
Keyword(s):  
Word Recognition ◽  
Electrode Array ◽  
Cochlear Morphology ◽  
Array Position

scholarly journals Electrode array design determines scalar position, dislocation rate and angle and postoperative speech perception

2021 ◽  
Author(s):  
Manuel Christoph Ketterer ◽  
Antje Aschendorff ◽  
Susan Arndt ◽  
Rainer Beck
Keyword(s):  
Speech Perception ◽  
Significant Influence ◽  
Electrode Array ◽  
Dislocation Rate ◽  
Speech Discrimination ◽  
Electrode Arrays ◽  
Insertion Depth ◽  
Array Design ◽  
Cochlear Morphology ◽  
Array Position

Abstract Purpose The aim of this study is to examine the scalar dislocation rate in straight and perimodiolar electrode arrays in relation to cochlear morphology. Furthermore, we aim to analyze the specific dislocation point of electrode arrays depending on their design and shape and to correlate these results to postoperative speech perception. Methods We conducted a comparative analysis of patients (ears: n = 495) implanted between 2013 and 2018 with inserted perimodiolar or straight electrode arrays from Cochlear™ or MED-EL. CBCT (cone beam computed tomography) was used to determine electrode array position (scalar insertion, intra-cochlear dislocation, point of dislocation and angular insertion depth). Furthermore, cochlear morphology was measured. The postoperative speech discrimination was compared regarding electrode array dislocation, primary scalar insertion and angular insertion depth. Results The electrode array with the highest rate of primary SV insertions was the CA; the electrode array with the highest rate of dislocations out of ST was the FlexSoft. We did not find significantly higher dislocation rates in cochleostomy-inserted arrays. The angle of dislocation was electrode array design-specific. A multivariate nonparametric analysis revealed that the dislocation of the electrode array has no significant influence on postoperative speech perception. Nevertheless, increasing angular insertion depth significantly reduced postoperative speech perception for monosyllables. Conclusion This study demonstrates the significant influence of electrode array design on scalar location, dislocation and the angle of dislocation itself. Straight and perimodiolar electrode arrays differ from each other regarding both the rate and place of dislocation. Insertion via cochleostomy does not lead to increased dislocation rates in any of the included electrode arrays. Furthermore, speech perception is significantly negatively influenced by angular insertion depth.

scholarly journals Retinal Anatomy and Electrode Array Position in Retinitis Pigmentosa Patients After Argus II Implantation: An International Study

2018 ◽  
Vol 193 ◽  
pp. 87-99 ◽  
Author(s):  
Ninel Z. Gregori ◽  
Natalia F. Callaway ◽  
Catherine Hoeppner ◽  
Alex Yuan ◽  
Aleksandra Rachitskaya ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Electrode Array ◽  
International Study ◽  
Argus Ii ◽  
Array Position

Adult Auditory Brainstem Implant Outcomes and Three-Dimensional Electrode Array Position on Computed Tomography

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Dana Egra-Dagan ◽  
Isabeau van Beurden ◽  
Samuel R. Barber ◽  
Christine L. Carter ◽  
Mary E. Cunnane ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Electrode Array ◽  
Auditory Brainstem ◽  
Auditory Brainstem Implant ◽  
Array Position

Differential Projections of Thermoreceptive and Nociceptive Lamina I Trigeminothalamic and Spinothalamic Neurons in the Cat

2001 ◽  
Vol 86 (2) ◽  
pp. 856-870 ◽  
Author(s):  
A. D. Craig ◽  
J. O. Dostrovsky
Keyword(s):  
Electrode Array ◽  
Zona Incerta ◽  
Antidromic Activation ◽  
Lamina I ◽  
Ventral Aspect ◽  
Medial Nucleus ◽  
Anatomical Localization ◽  
Array Position ◽  
I Cells ◽  
Support Evidence

The projections of 40 trigeminothalamic or spinothalamic (TSTT) lamina I neurons were mapped using antidromic activation from a mobile electrode array in barbiturate anesthetized cats. Single units were identified as projection cells from the initial array position and characterized with natural cutaneous stimuli as nociceptive-specific (NS, n = 9), polymodal nociceptive (HPC, n = 8), or thermoreceptive-specific (COOL, n = 22; WARM, n = 1) cells. Thresholds for antidromic activation were measured from each electrode in the mediolateral array at vertical steps of 250 μm over a 7-mm dorsoventral extent in two to eight (median = 6.0) anteroposterior planes. Histological reconstructions showed that the maps encompassed all three of the main lamina I projection targets observed in prior anatomical work, i.e., the ventral aspect of the ventroposterior complex (vVP), the dorsomedial aspect of the ventroposterior medial nucleus (dmVPM), and the submedial nucleus (Sm). The antidromic activation foci were localized to these sites (and occasional projections to other sites were also observed, such as the parafascicular nucleus and zona incerta). The projections of thermoreceptive and nociceptive cells differed. The projections of the thermoreceptive-specific cells were 20/23 to dmVPM, 21/23 to vVP, and 17/23 to Sm, whereas the projections of the NS cells were 1/9 to dmVPM, 9/9 to vVP, and 9/9 to Sm and the projections of the HPC cells were 0/8 to dmVPM, 7/8 to vVP, and 6/8 to Sm. Thus nearly all thermoreceptive cells projected to dmVPM, but almost no nociceptive cells did. Further, thermoreceptive cells projected medially within vVP (including the basal ventral medial nucleus), while nociceptive cells projected both medially and more laterally, and the ascending axons of thermoreceptive cells were concentrated in the medial mesencephalon, while the axons of nociceptive cells ascended in the lateral mesencephalon. These findings provide evidence for anatomical differences between these physiological classes of lamina I cells, and they corroborate prior anatomical localization of the lamina I TSTT projection targets in the cat. These results support evidence indicating that the ventral aspect of the basal ventral medial nucleus is important for thermosensory behavior in cats, consistent with the view that this region is a primordial homologue of the posterior ventral medial nucleus in primates.

scholarly journals Microfocus X-ray for Electrode Array Position Control During Cochlear Implantation

2017 ◽  
Vol 9 (3) ◽  
pp. 39
Author(s):  
V.N. Sokolova ◽  
H.M.A. Diab ◽  
N.N. Potrakhov ◽  
A.Y. Gryaznov ◽  
N.E. Staroverov ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Position Control ◽  
Electrode Array ◽  
X Ray ◽  
Array Position

Radiological and NRT-Ratio–Based Estimation of Slim Straight Cochlear Implant Electrode Positions

2016 ◽  
Vol 126 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Philipp Mittmann ◽  
Ingo Todt ◽  
Arneborg Ernst ◽  
Grit Rademacher ◽  
Sven Mutze ◽  
...  
Keyword(s):  
Electrode Array ◽  
Controlled Study ◽  
Data Sets ◽  
Scala Tympani ◽  
Tertiary Referral ◽  
Flat Panel ◽  
Tomography System ◽  
Neural Response Telemetry ◽  
Intracochlear Electrode Array ◽  
Array Position

Objectives: An intraoperative neural response telemetry-ratio (NRT-ratio) was established, which can provide information about the intraoperative intracochlear electrode array position for perimodiolar electrodes. Methods: In a retrospective controlled study in 2 tertiary referral centers, the electrophysiological data sets of 50 patients with measured intraoperative auto-NRTs and postoperative radiological examinations were evaluated. All patients were implanted with Nucleus slim straight electrodes. The NRT-ratio was calculated by dividing the average auto-NRT data from electrodes 16 to 18 with the average from electrodes 5 to 7. Using a flat panel tomography system or a computed tomography, the position of the electrode array was certified radiological. Results: Radiologically, 2 out of 50 patients were identified with an electrode translocated from the scala tympani into the scala vestibuli. The radiologically estimated electrodes indicating a scalar change showed a regular NRT-ratio but nonspecific NRT-level changes at the localization of translocation.

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.

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