scholarly journals Cochlearis implantátumok különböző, előre görbített elektródasorainak elhelyezkedése a cochlea tengelyéhez viszonyítva. Radiológiai vizsgálat a perimodiolaritás mértékének megállapítására

2019 ◽  
Vol 160 (31) ◽  
pp. 1216-1222
Author(s):  
Ádám Perényi ◽  
Roland Nagy ◽  
Balázs Dimák ◽  
Miklós Csanády ◽  
József Jóri ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Ganglion Cells ◽  
Round Window ◽  
Electrode Array ◽  
Neural Responses ◽  
Electrode Arrays ◽  
Performance Abilities ◽  
Length Width ◽  
Electrophysiological Result ◽  
The Mean

Abstract: Introduction: The cochlear implants vary in electrodes in terms of length, width and proximity to the modiolus. The precurved electrode arrays could be placed closer to the modiolus and the ganglion cells compared to straight electrodes. The two types of electrode arrays provide different electrophysiological characteristics; however, proximity to the modiolus may lead to better hearing performance. Aim: To investigate our preliminary electrophysiological results that suggest that the Slim Modiolar (SM) electrode array has the potential to elicit similar neural responses as the thicker perimodiolar (Contour Advance, CA) electrode from the same generation of implants. Method: Subjects that were implanted either with CA or SM electrodes were enrolled, 54 consecutive subjects in each group. All electrodes were introduced into the cochlea via the round window. The diameter of the largest turn of the electrode arrays within the cochlea was measured through postoperative radiography. The energy consumption parameters were estimated 2 months after implantation. Results: The mean of the largest turns of the arrays within the cochlea was 4.2 ± 0.5 mm in the SM group and 4.9 ± 1.1 mm in the CA group. ‘Auto power’ was 44.81 ± 5.05% and 50.85 ± 8.35% with SM and CA, respectively. Estimated energy consumption was lower with SM. The differences were statistically significant. Conclusion: Our measurements for a large cohort in each group suggest that the SM electrode array takes a significantly closer position to the modiolus than the CA. This finding supports our earlier electrophysiological result and indicates better performance abilities. Orv Hetil. 2019; 160(31): 1216–1222.

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.

Selection of the appropriate cochlear electrode array using a specifically developed research software application

2018 ◽  
Vol 132 (06) ◽  
pp. 544-549 ◽  
Author(s):  
E H Stefanescu ◽  
S Motoi
Keyword(s):  
Round Window ◽  
Electrode Array ◽  
Cochlear Duct ◽  
X Ray ◽  
Software Application ◽  
Research Software ◽  
Cochlear Duct Length ◽  
The Mean ◽  
Electrode Selection ◽  
Selection Of

AbstractObjectiveTo evaluate the usefulness and reliability of a research software application for the estimation of an individual's cochlear duct length as a basis for electrode selection.MethodsIn this prospective cohort study, 21 consecutive patients (23 ears) implanted with a cochlear electrode were investigated. The study comprised 19 children (2 bilateral) and 2 adults.ResultsThe measured ‘A’ distances (the largest distance from the round window to the contralateral wall) corresponded to cochlear duct lengths of 28.5–36.4 mm. The mean cochlear duct length was 34.05 ± 1.72 mm (33.60 ± 2.27 mm in females and 34.35 ± 1.27 mm in males). Full insertion was achieved in all but two cases. No misplaced electrode array or electrode fold-over was detected. In all but three ears, the electrode was chosen based on the research software application's indication.ConclusionThe results show a good correlation between the pre-operatively predicted insertion depths using the software application and those post-operatively measured using X-ray. The insertion length predicted by the software was always longer than that measured via X-ray.

scholarly journals Manufacturable 32-Channel Cochlear Electrode Array and Preliminary Assessment of Its Feasibility for Clinical Use

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 778
Author(s):  
Soowon Shin ◽  
Yoonhee Ha ◽  
Gwangjin Choi ◽  
Junewoo Hyun ◽  
Sangwoo Kim ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Signal Transmission ◽  
Round Window ◽  
Electrode Array ◽  
Lead Wire ◽  
Layer By Layer ◽  
Electrode Arrays ◽  
Insertion Force ◽  
Vertical Stiffness ◽  
Channel Electrode

(1) Background: In this study, we introduce a manufacturable 32-channel cochlear electrode array. In contrast to conventional cochlear electrode arrays manufactured by manual processes that consist of electrode-wire welding, the placement of each electrode, and silicone molding over wired structures, the proposed cochlear electrode array is manufactured by semi-automated laser micro-structuring and a mass-produced layer-by-layer silicone deposition scheme similar to the semiconductor fabrication process. (2) Methods: The proposed 32-channel electrode array has 32 electrode contacts with a length of 24 mm and 0.75 mm spacing between contacts. The width of the electrode array is 0.45 mm at its apex and 0.8 mm at its base, and it has a three-layered arrangement consisting of a 32-channel electrode layer and two 16-lead wire layers. To assess its feasibility, we conducted an electrochemical evaluation, stiffness measurements, and insertion force measurements. (3) Results: The electrochemical impedance and charge storage capacity are 3.11 ± 0.89 kOhm at 1 kHz and 5.09 mC/cm2, respectively. The V/H ratio, which indicates how large the vertical stiffness is compared to the horizontal stiffness, is 1.26. The insertion force is 17.4 mN at 8 mm from the round window, and the maximum extraction force is 61.4 mN. (4) Conclusions: The results of the preliminary feasibility assessment of the proposed 32-channel cochlear electrode array are presented. After further assessments are performed, a 32-channel cochlear implant system consisting of the proposed 32-channel electrode array, 32-channel neural stimulation and recording IC, titanium-based hermetic package, and sound processor with wireless power and signal transmission coil will be completed.

scholarly journals Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window

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
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Electrode Array ◽  
Hearing Preservation ◽  
Round Window Membrane ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Minimal Trauma ◽  
Electrode Insertion ◽  
Temporal Bones

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.

scholarly journals Histological evaluation of a cochlear implant electrode array with electrically activated shape change for perimodiolar positioning

2018 ◽  
Vol 4 (1) ◽  
pp. 145-148
Author(s):  
Thomas S. Rau ◽  
N.úha Suzaly ◽  
Nick Pawsey ◽  
Silke Hügl ◽  
Lenarz Majdani ◽  
...  
Keyword(s):  
Shape Memory ◽  
Inner Ear ◽  
Shape Change ◽  
Round Window ◽  
Small Diameter ◽  
Electrode Array ◽  
Electrical Heating ◽  
Histological Evaluation ◽  
Electrode Arrays ◽  
Nitinol Wire

AbstractFor the treatment of deafness or severe hearing loss cochlear implants (CI) are used to stimulate the auditory nerve of the inner ear. In order to produce an electrode array which is both atraumatic and reaches a perimodiolar final position a design featuring shape memory effect was proposed. A Nitinol wire with a diameter of 100 μm was integrated in a state of the art lateral wall electrode array. The wire serves as an actuator after it has been ‘trained’ to adopt the spiral shape of an average human cochlea. Three small diameter platinum-iridium wires (each 20 μm) were crimped to the Nitinol wire in order to produce thermal energy. An insertion test was pursued using a human temporal bone specimen. The prototype electrode array was cooled down by means of immersion in ice water and freeze spray to enable sufficient straightening. Thereafter, insertion into the cochlea through the round window as performed. Insertion was feasible but difficult as premature curling of the electrode occurred during the movement towards the inner ear while passing the middle ear cavity. Therefore, the insertion had to be performed faster than usual. The shape memory actuator was subsequently activated with 450mA current at 5V for 3 seconds. After insertion the specimen was embedded in epoxy resin, microgrinded and all histological slices were assessed for trauma. Perimodiolar position was achieved. No insertion trauma was observed and there were no indications of thermal damage caused by the electrical heating. To the best of our knowledge, this is the first histological evaluation of the insertion trauma caused by an electrically activated shape memory electrode array. These promising results support further research on shape memory CI electrode arrays.

scholarly journals The Pull-Back Technique for the 532 Slim Modiolar Electrode

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
C. Riemann ◽  
H. Sudhoff ◽  
I. Todt
Keyword(s):  
Temporal Bone ◽  
Round Window ◽  
Spiral Ganglion ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Current Spread ◽  
Temporal Bones ◽  
Hearing Outcomes ◽  
White Marker

Introduction. The distance between the modiolus and the electrode array is one factor that has become the focus of many discussions and studies. Positioning the electrode array closer to the spiral ganglion with the goal of reducing the current spread has been shown to improve hearing outcomes. The perimodiolar electrode arrays can be complemented with a surgical manoeuvre called the pull-back technique. This study focuses its attention on the recently developed 532 slim modiolar electrode. Objective. To investigate the intracochlear movements and pull-back technique for the 532 slim modiolar electrode. Material and Methods. A decapping procedure of the cochlea was performed on 5 temporal bones. The electrode array was inserted, and the intracochlear movements were microscopically examined and digitally captured. Three situations were analysed: the initial insertion, the overinsertion, and the pull-back position. The position of the three white markers of the electrode array in relation to the round window (RW) was evaluated while performing these three actions. Results. The initial insertion achieved an acceptable perimodiolar position of the electrode array, but a gap was still observed between the mid-portion of the array and the modiolus (the first white marker was seen in the RW). When we inserted the electrode more deeply, the mid-portion of the array was pushed away from the modiolus (the second and third white markers were seen in the RW). After applying the pull-back technique, the gap observed during the initial insertion disappeared, resulting in an optimal perimodiolar position (the first white marker was once again visible in the RW). Conclusion. This temporal bone study demonstrated that when applying the pull-back technique for the 532 slim modiolar electrode, a closer proximity to the modiolus was achieved when the first white marker of the electrode array was visible in the round window.

scholarly journals Hydraulic insertions of cochlear implant electrode arrays into the human cadaver cochlea: preliminary findings

2021 ◽  
Author(s):  
M. Geraldine ◽  
Thomas Lenarz ◽  
Thomas S. Rau
Keyword(s):  
Cochlear Implant ◽  
Outcome Measurement ◽  
Round Window ◽  
Handling Time ◽  
Human Cadaver ◽  
Hydraulic Actuator ◽  
Electrode Arrays ◽  
Non Invasive ◽  
Insertion Tool ◽  
Set Up

Abstract Objectives (1) To evaluate the feasibility of a non-invasive, novel, simple insertion tool to perform automated, slow insertions of cochlear implant electrode arrays (EA) into a human cadaver cochlea; (2) to estimate the handling time required by our tool. Methods Basic science study conducted in an experimental OR. Two previously anonymized human cadaver heads, three commercially available EAs, and our novel insertion tool were used for the experiments. Our tool operates as a hydraulic actuator that delivers an EA at continuous velocities slower than manually feasible. Intervention(s): the human cadaver heads were prepared with a round-window approach for CI surgery in a standard fashion. Twelve EA insertion trials using our tool involved: non-invasive fixation of the tool to the head; directing the tool to the round window and EA mounting onto the tool; automated EA insertion at approximately 0.1 mm/s driven by hydraulic actuation. Outcome measurement(s): handling time of the tool; post-insertion cone-beam CT scans to provide intracochlear evaluation of the EA insertions. Results Our insertion tool successfully inserted an EA into the human cadaver cochlea (n = 12) while being attached to the human cadaver head in a non-invasive fashion. Median time to set up the tool was 8.8 (7.2–9.4) min. Conclusion The first insertions into the human cochlea using our novel, simple insertion tool were successful without the need for invasive fixation. The tool requires < 10 min to set up, which is clinically acceptable. Future assessment of intracochlear trauma is needed to support its safety profile for clinical translation.

scholarly journals The Importance of Intraoperative Plain Radiographs during Cochlear Implant Surgery in Patients with Normal Anatomy

2021 ◽  
Vol 11 (9) ◽  
pp. 4144
Author(s):  
Ohad Cohen ◽  
Jean-Yves Sichel ◽  
Chanan Shaul ◽  
Itay Chen ◽  
J. Thomas Roland ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Electrode Array ◽  
Cost Effective ◽  
X Rays ◽  
Normal Anatomy ◽  
Electrode Arrays ◽  
Plain Radiographs ◽  
Hearing Function ◽  
Tertiary Center ◽  
Cochlear Implant Surgery

Although malpositioning of the cochlear implant (CI) electrode array is rare in patients with normal anatomy, when occurring it may result in reduced hearing outcome. In addition to intraoperative electrophysiologic tests, imaging is an important modality to assess correct electrode array placement. The purpose of this report was to assess the incidence and describe cases in which intraoperative plain radiographs detected a malpositioned array. Intraoperative anti-Stenver’s view plain X-rays are conducted routinely in all CI surgeries in our tertiary center before awakening the patient and breaking the sterile field. Data of patients undergoing 399 CI surgeries were retrospectively analyzed. A total of 355 had normal inner ear and temporal bone anatomy. Patients with intra or extracochlear malpositioned electrode arrays demonstrated in the intraoperative X-ray were described. There were four cases of electrode array malposition out of 355 implantations with normal anatomy (1.1%): two tip fold-overs, one extracochlear placement and one partial insertion. All electrodes were reinserted immediately; repeated radiographs were normal and the patients achieved good hearing function. Intraoperative plain anti-Stenver’s view X-rays are valuable to confirm electrode array location, allowing correction before the conclusion of surgery. These radiographs are cheaper, faster, and emit much less radiation than other imaging options, making them a viable cost-effective tool in patients with normal anatomy.

scholarly journals A cadaveric study of the location and morphology of the central patellar ridge for bone-patellar tendon-bone graft

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Thanathep Tanpowpong ◽  
Thun Itthipanichpong ◽  
Thanasil Huanmanop ◽  
Nonn Jaruthien ◽  
Nattapat Tangchitcharoen
Keyword(s):  
Patellar Tendon ◽  
Cancellous Bone ◽  
Average Distance ◽  
Cadaveric Study ◽  
Anterior Cortex ◽  
Length Width ◽  
Central Ridge ◽  
The Mean ◽  
Bone Patellar Tendon ◽  
And Cartilage

Abstract Introduction The central ridge of the patella is the thickest area of patella and varies among patients. This cadaveric study identified the location and thickness of the bone at the central patella ridge for bone-patellar tendon-bone (BPTB) harvesting. Materials and methods Fifty cadaveric knees were assessed. First, the morphology, length, width, and location of the central patellar ridge were recorded. Then, we transversely cut the patella 25 mm from the lower pole and measured the thickness of the anterior cortex, cancellous bone, and cartilage from both the mid-patella and the central ridge location. Finally, the depth of the remaining cancellous bone at the mid-patella was compared to the bone at the central ridge. Results The location of the central-patellar ridge deviated medially from the mid-patella in 46 samples with an average distance of 4.36 ± 1 mm. Only 4 samples deviated laterally. The mean patella length was 41.19 ± 4.73 mm, and the width was 42.8 ± 5.25 mm. After a transverse cut, the remaining cancellous bone was significantly thicker at the central ridge compared to the bone at the mid-patella. Conclusions Most of the central patellar ridge deviated medially, approximately 4 mm from the mid-patella. Harvesting the graft from the central ridge would have more remaining bone compared to the mid-patella.

Pituitary dimensions and volume measurements in pregnancy and post partum

1998 ◽  
Vol 39 (1) ◽  
pp. 64-69 ◽  
Author(s):  
H. Dinç ◽  
F. Esen ◽  
A. Demirci ◽  
A. Sari ◽  
H. Resit Gümele
Keyword(s):  
Pituitary Gland ◽  
Matched Control ◽  
Post Partum ◽  
Three Dimensions ◽  
Maximum Height ◽  
Third Trimester ◽  
Normal Pituitary Gland ◽  
Volume Measurements ◽  
Length Width ◽  
The Mean

Purpose: Our purpose was to clarify and further characterize the changes in height, length, width, volume, and shape in the normal pituitary gland and in width in the infundibulum during pregnancy and the first 6 months post partum. Material and Methods: Cranial MR imaging was performed in 78 women who were pregnant in the second or third trimester or who were post partum, and in 18 age-matched control subjects who were not pregnant. Volume measurements were performed in 2 ways; volume 1=1/2xheightxlengthxwidth; and volume 2=area (measured by trackball)xslice thickness Results: Gland volume, height, width, length, and convexity, and infundibular width increased during pregnancy. the highest values were seen during the 3 days immediately post partum. When compared with volunteers, volumes 1 and 2 showed the largest increase (120%) among the parameters. Gland height showed the best correlation (r=0.94, p>0.00001) with gestational age. the mean height of the gland was 8.76 mm in the third trimester. None of the pregnant women had a gland height of above 10 mm during pregnancy. Only 2 subjects had gland heights of 10.04 and 10.2 mm during the 0–3 days post partum. After this first post-partum period of 3 days, the gland size, shape, and volume and the infundibular width returned to normal within 6 months Conclusion: the pituitary gland enlarges in three dimensions throughout pregnancy. During pregnancy, the volume of the gland shows the highest percentage of increase compared to its length, height, and width. the maximum height of the gland does not exceed 10 mm during pregnancy but it may exceed 10 mm during the 3 days immediately post partum.

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