Search

Objectives: To investigate migration and other electrode-related complications in cochlear implant surgery. Methods: Retrospective review of all patients (adult and paediatric) undergoing cochlear implantation at a tertiary referral centre in England, between April 2019 and December 2021. Split arrays and patients who did not have post-op imaging were excluded. Results: Two hundred and ninety-nine cochlear implants were performed including 90% primary and 10% revision surgeries. Two hundred and forty-eight (86%) of electrodes implanted were straight arrays. Twenty-seven (9%) demonstrated suboptimal position on post-operative imaging. Three (11%) were true migration, 4 (15%) possible migration, 15 (56%) had two or less extra-cochlear electrodes, 3 (11%) expected partial insertion and 2 (7%) demonstrated tip fold-overs. Twenty (74%) of arrays within the suboptimal insertion group were in primary surgeries. Six patients required re-implantation. The most common reason for re-implantation was migration. Discussion: Electrode migration after cochlear implantation may be more common than previously thought. We demonstrate rates of migration congruous with current literature; this is despite robust and varied fixation techniques. Notable in our series is that all true captured migrations were seen exclusively in straight arrays. The majority of patients in the possible and confirmed migration group had normal inner ear anatomy. Conclusion: Suboptimal electrode position following cochlear implant surgery is a recognized complication and can affect implant performance. Reporting may increase with more widespread use of sophisticated post-operative imaging. Use of a pre-curved electrode and routine use of appropriate fixation techniques may reduce migration rates. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the predictive value of intracochlear electrocochleography (ECochG) for identifying tip fold‐over during cochlear implantation (CI) using the slim modiolar electrode (SME) array. Study Design: Prospective cohort study. Setting: Tertiary referral center. Methods: From July 2022 to June 2023, 142 patients, including adults and children, underwent intracochlear ECochG monitoring during and after SME placement. Tone‐bursts were presented from 250 Hz to 2 kHz at 108 to 114 dB HL. A fast Fourier transform (FFT) allowed for frequency‐specific evaluation of ECochG response. ECochG patterns during insertion and postinsertion were evaluated using sensitivity and specificity analysis to predict tip fold‐over. Intraoperative plain radiographs served as a reference standard. Results: Fifteen tip fold‐over cases occurred (10.6%) with significant ECochG response (>2 µV). Sixty‐one cases without tip fold‐over occurred (43.0%) with significant ECochG response. All tip fold‐overs had both a nontonotopic postinsertion sweep and nonrobust active insertion pattern. No patients with robust insertion or tonotopic sweep patterns had tip fold‐over. Sensitivity of detecting tip fold‐over when having both nonrobust insertion and nontonotopic sweep patterns was 100% (95% confidence inteval [CI] 78.2%‐100%), specificity was 68.9% (95% CI 55.7%‐80.1%), and the overall accuracy was 72.0% (95% CI 60.5%‐81.7%). Conclusion: Intracochlear ECochG monitoring during cochlear implantation with the SME can be a valuable tool for identifying properly positioned electrode arrays. In cases where ECochG patterns are nonrobust on insertion and nontonotopic for electrode sweeps, there may be a concern for tip fold‐over, and intraoperative imaging is necessary to confirm proper insertion. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the role of intraoperative radiographs to confirm electrode position following pediatric cochlear implantation (CI). Study Design: Retrospective chart review. Setting: Single tertiary care pediatric center. Methods: A retrospective chart review was conducted, including all pediatric patients undergoing CI at UPMC Children's Hospital of Pittsburgh over a 13‐year period. Results: We identified 326 patients undergoing 492 procedures. Across the cohort, there were 7 cases that required intraoperative electrode reinsertion due to malposition or presumed malposition. For 6 of the 7 cases, intraoperative X‐ray identified electrode malposition. Neural response telemetry (NRT) testing was also abnormal for 4 of these cases prior to reinsertion. Implantation of Cochlear's Slim Modiolar electrode was associated with an abnormal perioperative X‐ray (odds ratio [OR]: 9.2, p = 0.03) and increased change in management (OR: 9.2, p = 0.03) compared to Cochlear's Contour Advance (CA). Incidence of abnormal X‐rays was 1.24% overall, 4% in the Slim Modiolar group, and 0.3% in the CA group. The Slim Modiolar electrode accounted for 4 of 7 cases requiring reinsertion, and in all 4 of these cases, electrode fold‐over was identified on the X‐ray. NRT was normal in 1 of these 4 cases. Conclusion: The use of Cochlear's Slim Modiolar electrode was associated with a significantly increased risk of abnormal intraoperative X‐ray compared to the CA electrode. Given the risk of fold‐over with routine insertion and normal electrical testing using the Slim Modiolar electrode, we recommend routine use of intraoperative skull X‐ray to confirm electrode position. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the importance of mobile cone‐beam computed tomography in detecting tip fold‐over of a slim modiolar electrode within the cochlea during surgery. Study Design: Retrospective case review. Setting: Tertiary medical center. Methods: From January 2020 to June 2022, 33 ears of 30 patients with normal cochlear morphology underwent cochlear implantation with slim modiolar electrodes and intraoperative mobile cone‐beam computed tomography imaging. Furthermore, we retrospectively reviewed the medical records and images. Results: The tip fold‐over of the electrodes was detected using mobile cone‐beam computed tomography in 3 out of 33 ears (9.1%). We could not identify the tip fold‐over by scouting plain X‐ray images in 2 out of 3 cases before taking the cone‐beam computed tomography images. Electrode removal and reinsertion were performed before wound closure and the successful reinsertion was confirmed by mobile cone‐beam computed tomography. The folded electrode tips were located at 238.8°, 152°, and 185.8°. Conclusion: Intraoperative mobile cone‐beam computed tomography is useful in detecting the tip fold‐over of the slim modiolar electrodes during surgery. Therefore, it was possible to reinsert the electrodes in all cases before closing the wound, eliminating the need for revision surgeries. Moreover, the analysis of mobile cone‐beam computed tomography images may help to elucidate the mechanisms of electrode tip fold‐over. [ABSTRACT FROM AUTHOR]

Objectives: Cochlear implant array malpositioning is associated with impaired speech perception, vertigo, and facial nerve stimulation. Tip fold-over is a subset of malpositioning that occurs more often with perimodiolar electrodes, but historically it has not been characterized due to lack of knowledge regarding electrode movements of the electrode within the cochlea. The aim of this study was to characterize the mechanics of tip fold-over events and their associated insertion pressure profiles., Methods: Cadaveric human heads were surgically prepared with a mastoidectomy and facial recess. Fiberoptic pressure sensors were inserted into the scala vestibuli and tympani to measure intracochlear pressures. Perimodiolar CI electrodes (Cochlear Slim-Modiolar, CI532) were inserted via round window under fluoroscopy., Results: Three types of tip fold-over events were observed: anterior-posterior C-shaped, medial-lateral C-shaped, and S-shaped roll-overs. The largest transient pressures occurred with anterior-posterior and S-type roll-over, and were associated with rotation or twisting inside the cochlea., Conclusions: Results demonstrate at least three subtypes of tip fold-overs. Elevated pressure transients were noted before and during the tip fold-over event related to electrode twisting. The characterization of tip fold-over into subtypes is novel and may aid identification of tip fold-over events intraoperatively in the future. It remains important to identify tip fold-over events, and they should be recognized early using a multimodal verification system. Further investigation is still required to determine the significance of these changes and other possible patterns of intracochlear electrode movement., Level of Evidence: N/A: Cadaver study Laryngoscope, 2024., (© 2024 The American Laryngological, Rhinological and Otological Society, Inc.)

Background and ObjectiveThe cochlear implant (CI) electrode insertion process is a key step in CI surgery. One of the aims of advances in robotic-assisted CI surgery (RACIS) is to realize better cochlear structure preservation and to precisely control insertion. The aim of this literature review is to gain insight into electrode selection for RACIS by acquiring a thorough knowledge of electrode insertion and related complications from classic CI surgery involving a manual electrode insertion process.MethodsA systematic electronic search of the literature was carried out using PubMed, Scopus, Cochrane, and Web of Science to find relevant literature on electrode tip fold over (ETFO), electrode scalar deviation (ESD), and electrode migration (EM) from both pre-shaped and straight electrode types.ResultsA total of 82 studies that include 8,603 ears implanted with a CI, i.e., pre-shaped (4,869) and straight electrodes (3,734), were evaluated. The rate of ETFO (25 studies, 2,335 ears), ESD (39 studies, 3,073 ears), and EM (18 studies, 3,195 ears) was determined. An incidence rate (±95% CI) of 5.38% (4.4–6.6%) of ETFO, 28.6% (26.6–30.6%) of ESD, and 0.53% (0.2–1.1%) of EM is associated with pre-shaped electrodes, whereas with straight electrodes it was 0.51% (0.1–1.3%), 11% (9.2–13.0%), and 3.2% (2.5–3.95%), respectively. The differences between the pre-shaped and straight electrode types are highly significant (p < 0.001). Laboratory experiments show evidence that robotic insertions of electrodes are less traumatic than manual insertions. The influence of round window (RW) vs. cochleostomy (Coch) was not assessed.ConclusionConsidering the current electrode designs available and the reported incidence of insertion complications, the use of straight electrodes in RACIS and conventional CI surgery (and manual insertion) appears to be less traumatic to intracochlear structures compared with pre-shaped electrodes. However, EM of straight electrodes should be anticipated. RACIS has the potential to reduce these complications.

In seltenen Fällen kann es bei einer Cochlea-Implantation während der Elektrodenträgerinsertion zu einem sogenannten Tip-Foldover kommen. Um eine solche Fehllage zu erkennen oder sicher auszuschließen, wird intra- oder oftmals erst postoperativ eine radiologische Kontrolle des Cochlea-Implantat(CI)-Elektrodenträgers durchgeführt (Goldstandard). Der Patient ist dabei einer zusätzlichen Strahlenbelastung ausgesetzt. Alternativ kann die Lagekontrolle auch mit einer Messung der Spread of Excitation (SOE) durchgeführt werden. Die Deutung der Testergebnisse setzt jedoch Expertenwissen voraus. Zudem sind einheitliche Messkonzepte und Vergleichswerte wesentlich. Ziel der Studie ist daher die Evaluierung eines automatisierten Screening-Verfahrens, um intraoperativ und mit möglichst geringem Aufwand eine sichere Aussage über die regelrechte tonotope Lage des implantierten CI-Elektrodenträgers zu erhalten. Bei CI-Versorgungen mit Cochlear™ Nucleus® Implantaten wurde in einer bi-zentrischen Studie an über 100 erwachsenen Patienten ein intraoperatives Tip-Foldover(TFO)-Screening durchgeführt: Zuerst erfolgten Schwellenmessungen mit elektrisch ausgelösten Summenaktionspotentialen (ECAP) mittels AutoNRT™. Anschließend wurden SOE-Messungen an den Elektroden 13 und 22 durchgeführt. Die automatisierte Analyse der vollständigen SOE-Profile ermöglichte dann eine dichotome Entscheidung über ein unauffälliges oder nicht unauffälliges Testergebnis. Die korrekte bzw. nicht korrekte Lage des Elektrodenträgers wurde intra- oder postoperativ mit einer transorbitalen Röntgenaufnahme überprüft und definiert (Referenzverfahren). Das intraoperative TFO-Screening mittels SOE-Messungen konnte in rund 80% der Fälle angewendet werden. Die Treffergenauigkeit des Screenings lag für SOE-Messungen an der aktiven Stimulationselektrode 13 bei 63,9% und an der Elektrode 22 bei 95,4%. Der Klassifikationsfehler ergab sich zu 36,1% bzw. 4,6% und der Phi-Koeffizient zu 0,27 bzw. 0,69. Die radiologisch nachgewiesenen Tip-Foldover wurden mit dem intraoperativen Screening sicher erkannt (Sensitivität = 100%). Eine hinreichende Spezifität (>95%) konnte nur mit SOE-Messungen an der Stimulationselektrode 22 erreicht werden. Das TFO-Screening an der Elektrode 22 ermöglicht eine hinreichend genaue Trennung zwischen unauffälligen und nicht unauffälligen Elektrodenträgerlagen, wobei letztere weiterer radiologischer Untersuchungen zur Verifikation eines Tip-Foldover bedürfen. In rare cases, a cochlear implantation can lead to a so-called tip fold-over during insertion of the electrode array. In order to detect or exclude such a misalignment a radiological check of the cochlear implant (CI) electrode array is carried out intra- or often post-operatively (gold standard), thereby exposing the patient to additional radiation. Alternatively, successful electrode insertion can be verified by measuring the spread of excitation (SOE). However, interpretation of the test results requires considerable expertise, and standardized measurement protocols and reference values are also essential. Therefore, the aim of the study is to evaluate an automated screening procedure in order to obtain a reliable statement about the normal tonotopic position of the implanted CI electrode array intraoperatively and with as little effort as possible. For CI surgery with Cochlear™ Nucleus® implants, an intraoperative tip-fold-over (TFO) screening was performed in a bi-centric study in over 100 adult patients: Firstly, threshold measurements for electrically evoked compound action potential (ECAP) using AutoNRT™ were recorded. Subsequently, SOE measurements were carried out on electrodes 13 and 22. The automated evaluation of the SOE data sets then made it possible to make a dichotomous decision about a normal or abnormal test result. The position of the electrode array was checked intra- or post-operatively using conventional transorbital X-ray (reference method). The intraoperative TFO screening procedure is applicable in around 80% of cases. The accuracy of the screening for measurements via the active stimulation electrodes 13 / 22 is 63.9% / 95.4%. The classification error is 36.1% / 4.6% and the phi coefficient is 0.27 / 0.69. All radiologically proven tip-fold-overs were reliably identified with the intraoperative screening (sensitivity = 100%). A higher specificity (>95%) can be achieved only with measurements via electrode 22. The TFO Screening via measurement at electrode 22 can successfully distinguish between a correct and incorrect position of the electrode array due to a tip-fold-over, and the remaining cases would require further imaging. [ABSTRACT FROM AUTHOR]

Copyright of Hungarian Medical Journal / Orvosi Hetilap is the property of Akademiai Kiado and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives/Hypothesis: Two types of electrode arrays for cochlear implants (CIs) are distinguished: lateral wall and perimodiolar. Scalar translocation of the array can lead to intracochlear trauma by penetrating from the scala tympani into the scala vestibuli or scala media, potentially negatively affecting hearing performance of CI users. This systematic review compares the lateral wall and perimodiolar arrays with respect to scalar translocation. Study Design: Systematic review. Methods: PubMed, Embase, and Cochrane databases were reviewed for studies published within the last 11 years. No other limitations were set. All studies with original data that evaluated the occurrence of scalar translocation or tip fold‐over (TF) with postoperative computed tomography (CT) following primary cochlear implantation in bilateral sensorineuronal hearing loss patients were considered to be eligible. Data were extracted independently by two reviewers. Results: We included 33 studies, of which none were randomized controlled trials. Meta‐analysis of five cohort studies comparing scalar translocation between lateral wall and perimodiolar arrays showed that lateral wall arrays have significantly lower translocation rates (7% vs. 43%; pooled odds ratio = 0.12). Translocation was negatively associated with speech perception scores (weighted mean 41% vs. 55%). Tip fold‐over of the array was more frequent with perimodiolar arrays (X2 = 6.8, P <.01). Conclusions: Scalar translocation and tip fold‐overs occurred more frequently with perimodiolar arrays than with lateral wall arrays. In addition, translocation of the array negatively affects hearing with the cochlear implant. Therefore, if one aims to minimize clinically relevant intracochlear trauma, lateral wall arrays would be the preferred option for cochlear implantation. Laryngoscope, 131:1358–1368, 2021 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: To explore the immediate and 1-year outcomes of patients who underwent implantation with the slim modiolar electrode (SME).Study Design: Consecutive case series with chart review.Setting: Tertiary referral academic center.Subject and Methods: Between May 2016 and August 2018, a total of 326 cochlear implantations (CIs) were performed. Intraoperative x-rays were performed in all cases to identify tip rollovers. Scalar location was identified for 76 CIs that had postoperative computed tomography reconstructions. Speech outcomes were measured at 3, 6, and 12 months with consonant-nucleus-consonant word and AzBio sentences in quiet and noise (+10-dB signal-to-noise ratio). Preservation of hearing was defined as maintaining a low-frequency pure tone average ≤80 dB at 250 and 500 Hz.Results: Among 326 CIs, 23 (7%) had tip rollovers. Postoperative reconstructions revealed 5 of 76 (6.6%) scalar translocations. A subset of 177 cases met criteria for evaluation of speech perception scores. The marginal mean differences between presurgery and 12 months for speech tests were as follows: consonant-nucleus-consonant, 43.7 (95% CI, 39.8-47.6); AzBio in quiet, 49.7 (95% CI, 44.9-54.4); and AzBio in noise, 29.9 (95% CI, 25.2-34.7). Sixty-one patients were identified with preservable hearing (low-frequency pure tone average ≤80 dB), and 12 of 61 (20%) preserved hearing at 1 year.Conclusion: CI with SME provides reliable scala tympani insertion in a consistent perimodiolar position. An initially increased tip rollover rate improved with case volume and sheath design improvement. For long-term outcomes, speech performance was comparable to that of other cochlear implants. While hearing preservation for the SME may be better than prior perimodiolar electrodes, consistent outcomes are unlikely. [ABSTRACT FROM AUTHOR]

Copyright of Clinical Neuroscience / Ideggyógyászati Szemle is the property of LifeTime Media Kft. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: It is important for the surgeon to determine the position of the CI electrode array during and after its placement within the cochlea. Most preferably, this should be within the scala tympani to obtain the best audiological outcome. Thus, misplacement into the scala vestibuli or tip fold-over should be prevented. Since there are different ways to ensure proper positioning of the electrode array within the scala tympani (e.g., intraoperative radiography, electrophysiological recordings), our study was aimed at detecting intraoperative electrophysiologic characteristics to better understand the mechanisms of those electrode tip fold-overs. Material and methods: In a multi-centric, retrospective case–control series, patients with a postoperatively by radiography detected tip fold-over in perimodiolar electrodes were included. The point of fold-over (i.e., the electrode position) was determined and the intraoperative Auto-NRT recordings were analysed and evaluated. Results: Four patients were found to have an electrode tip fold-over (out of 85 implantees). Significant changes of the Auto-NRT recordings were not detected. All tip fold-overs occurred in the most apical part of the electrodes. Discussion: Cochlear implantation for hearing impaired patients plays a decisive role in modern auditory rehabilitation. Perimodiolar electrode arrays may fold over during the insertion and, hence, could have a negative impact on audiological outcome. Characteristic electrophysiologic changes to possibly predict this were not found in our series. [ABSTRACT FROM AUTHOR]

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.

Cochlear implantation has been performed safely for over two decades but still has various minor and major complications. We report two cases of an unusual complication of electrode implantation: tip fold-over of the electrode array within the cochlea. Both cases required undergoing explantation and re-implantation. The frequent use of fine and pre-curved electrodes particularly with the use of an insertion tool necessitates routine postoperative radiological evaluation of the electrode array. Our cases demonstrate the benefit of systematic imaging including the possible use of the Cone Beam CT intraoperatively. [ABSTRACT FROM AUTHOR]

Background: One of the mechanisms that cause tip fold-over is a misalignment between the electrode array's coiling direction and the cochlea's curving direction., Objectives: We reviewed surgical videos and computed tomography (CT) datasets of the patients who underwent cochlear implantation procedures from January 2010 to December 2021, paying particular attention to the cochlea's orientation in the surgeon's microscopic view., Methods: CT dataset and video recordings were analyzed to measure the "slope angle," which is the angle between the cochlea's coiling plane and the horizontal plane., Results: There were 220 cases that met the criteria and completed the analysis. The mean slope angle was 12.1° ± 9.5°, with a minimum of -9.4° and maximum of 44.6°. However, each surgeon had a favored slope angle range., Conclusion: Understanding the slope angle and making an effort to reduce the chance of misalignment during electrode insertion may help prevent tip fold-over of slim perimodiolar electrode arrays., Competing Interests: T. Nakagawa and his entire team including all the authors hold a contracted research project funded by Cochlear Japan, and we declare this fact as a potential conflict of interest., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of Otology & Neurotology, Inc.)

Electrode tip fold-over is a rare complication of cochlear implantation (CI), especially in lateral wall (LW) electrodes. We describe a case of LW electrode tip fold-over in a patient with incomplete partition type-1 (IP–I). Preoperative measurement of cochlear length is important for optimal CI electrode selection. In cochlear malformation, Stenvers x-ray is superior to spread of excitation in detecting tip fold-over. Despite tip fold-over, hearing threshold, speech reception threshold, and word recognition score were almost symmetrical bilaterally. Therefore, revision surgery should be reserved for patients with persistent symptoms or markedly affected speech performance, in whom deactivation did not suffice. • Tip fold-over is a rare complication of CI, especially in lateral wall electrodes. • Preoperative measurement of cochlear length is important for optimal CI electrode selection. • In cochlear malformation, Stenvers x-ray is superior to spread of excitation in detecting tip fold-over. • Revision surgery is reserved for persistent symptoms or markedly affected performance, after attempting deactivation. [ABSTRACT FROM AUTHOR]

Összefoglaló. Bevezetés: Az elmúlt években a cochlearis implantátum a súlyos halláskárosodás vagy a teljes siketség rutinszerű és hatékony kezelési eszközévé vált. Korunk egyik leggyakrabban használt és leghatékonyabb újítása a cochlearis implantációban a perimodiolaris vékony elektródasorok alkalmazása. A cochlea középtengelyét, a modiolust szorosan ölelő atraumatikus elektródasor igen meggyőző eredménnyel bizonyítja népszerűségét, mind az elektrofiziológiai mérések során, mind az akusztikus hallás megőrzése terén nyújtott teljesítményével. Ugyanakkor igen kevés publikáció írja le az elektródasor nem megfelelő helyzetének előfordulási gyakoriságát, pontosabban a visszatekeredését a csúcsi szakaszon. Célkitűzés: Tanulmányunk célja olyan szoftveres technika, a transzimpedancia-mátrix (TIM) beillesztése a rutin intraoperatív elektrofiziológiai mérési metodikák közé, amely képes objektív diagnosztikai lehetőséget biztosítani ahhoz, hogy korán felismerhessük a cochlearis implantátum elektródasorán keletkezett hurkot. Módszer: Hároméves kisgyermek kétoldali cochlearis implantációját követően, posztoperatív röntgenfelvételen a bal oldalon az elektródasor megfelelő pozíciója figyelhető meg, míg a jobb oldalon az intracochlearis elektródasor végének visszatekeredése igazolódott. Képalkotó vizsgálatot követően elektrofiziológiai metódusként TIM-vizsgálatot végeztünk. Az eljárás során a mérőeszköz a kijelölt stimuláló elektródákon 1 V nagyságrendű feszültséget közöl állandó áramerősség mellett a cochlea közel eső struktúrái felé. Mérőelektródák segítségével regisztráljuk a szöveteken mérhető feszültséget, majd transzimpedancia-mátrixszá alakítjuk a mért értékeket. Eredmények: Az elektródasor visszatekeredése, amelyet korábban radiológiai vizsgálattal igazoltunk, az objektív elektrofiziológiai mérések segítségével is jól azonosítható, és a vizsgálatok szoros párhuzamot mutatnak. Következtetés: Az elektródák helyzetének megjelenítésére szolgáló standard radiológiai képalkotási technikák kiegészíthetők, illetve kiválthatók egyszerűen elvégezhető, hatékony, objektív elektrofiziológiai vizsgálatokkal. Intraoperatíven, még a sebzárás előtt kimutatható, ha az elektródasor nem megfelelő helyzetbe került, így csökkenthetjük a radiológiai vizsgálatokkal járó sugárterhelés és annak finanszírozási problémáját. Orv Hetil. 2021; 162(25): 988-996., Introduction: In recent years, the cochlear implant has become a routine and effective treatment tool for severe hearing loss and total deafness. One of the commonly used and effective innovations of our time in cochlear implantation is the perimodiolar thin electrode array. The atraumatic electrode array, which closely embraces the central axis of the cochlea (modiolus), has served its popularity with very convincing results, with its performance in both electrophysiological measurements and acoustic hearing preservation. However, very few publications describe the frequency of improper positioning of the electrode array, which is known as 'tip fold-over'., Objective: The aim of our study is to incorporate a software technique, the transimpedance matrix (TIM), into routine intraoperative electrophysiological measurement methodologies to provide a potential objective diagnostic opportunity for early detection of tip fold-over of the electrode array., Method: Following bilateral cochlear implantation of a three-year-old child, postoperative radiography showed the correct position of the electrode array on the left side, while tip fold-over of the intracochlear electrode array was detected on the right side. Following imaging, a TIM study was performed as an electrophysiological method. During the procedure, the measuring device transmits a voltage of the order of 1 V to the nearby structures of the cochlea at a constant current at the designated stimulus electrodes. Measuring electrodes were used to register the voltage measured on the tissues, and then converted into a TIM., Results: Electrode tip fold-over was previously diagnosed by radiological examination, while it can also be diagnosed by objective electrophysiological measurements now, and these two tests correlate well., Conclusion: Standard radiological imaging techniques for electrode positioning can be supplemented or replaced by easy-to-perform, effective objective electrophysiological studies. Tip fold-over can be detected intraoperatively, even before wound closure, if the electrode array is in the wrong position, thus reducing the radiation exposure associated with radiological examinations as well as reducing relevant costs. Orv Hetil. 2021; 162(25): 988-996.

Background - Several cochlear implant recipients experience functionality loss due to electrode array mal-positioning. The application of delicate perimodiolar electrodes has many electrophysiological advantages, however, these profiles may be more susceptible to tip fold-over. Purpose - The prompt realization of such complication following electrode insertion would be auspicious, thus the electrode could be possibly repositioned during the same surgical procedure. Methods - The authors present three tip fold-over cases, experienced throughout their work with Slim Modiolar Electrode implants. Implantations were performed through the round window approach, by a skilled surgeon. Standard intraoperative measurements (electric integrity, neural response telemetry, and electrical stapedial reflex threshold tests) were successfully completed. The electrode position was controlled by conventional radiography on the first postoperative day. Results - Tip fold-over was not tactilely sensated by the surgeon. Our subjects revealed normal intraoperative telemetry measurements, only the postoperative imaging showed the tip fold-over. Due to the emerging adverse perception of constant beeping noise, the device was replaced by a CI512 implant after 6 months in one case. In the two remaining cases, the electrode array was reloaded into a back-up sheath, and reinserted into the scala tympani successfully through an extended round window approach. Discussion - Future additional studies using the spread of excitation or electric field imaging may improve test reliability. As all of these measurements are still carried out following electrode insertion, real-time identification, unfortunately, remains questionable. Conclusion - Tip fold-over could be reliably identified by conventional X-ray imaging. By contrast, intraoperative electrophysiology was not sufficiently sensitive to reveal it.