Objectives: The aim of this study is to report on our preliminary experience with Transimpedance Matrix (TIM)measurement for the detection of cochlear implant electrode tip foldovers compared with intraoperative imaging in patients implanted with the slim modiolar electrode (SME). Study Design: Proof of concept study. Setting: Tertiary university referral center. Patients: Twenty five ears (in 22 patients) implanted consecutively with the SME. Intervention(s): Following cochlear implantation, intraoperative TIM-measurement and fluoroscopy were performed. One week postoperatively, the electrode position was evaluated using Computed Tomography (CT)-imaging. Main Outcome Measures: Electrode array tip foldover.Results: Electrode array tip foldover occurred in three of the 25 cochlear implantations performed (12%). In each case, the foldover was detected by both TIM and fluoroscopy, leading to reposition and correct intracochlear placement of the array. Conclusions: TIM-measurement is a promising method for the intraoperative detection of an electrode array tip foldover. The TIM-tool with intuitive heatmap display is easy to use, fast, and readily available to clinics using TIM-software in the operating theatre.
Objective: The aim of this study was to compare Transimpedance Matrix (TIM-) measurement and X-ray fluoroscopy for the intraoperative detection of electrode array tip foldover in cochlear implant recipients. Study design: Retrospective agreement study. Setting: Tertiary referral hospital. Patients: Forty-two patients (47 ears) consecutively implanted with the Slim Modiolar Electrode. Interventions: Five raters, with different levels of clinical experience, individually retrospectively evaluated the TIMheatmaps and X-ray fluoroscopy images of all patients included in this study for electrode array tip fold-over. Main Outcome Measures: Agreement between raters' individual evaluation and the diagnosis given during clinical intraoperative evaluation for both modalities, as well as the inter-method agreement between TIM-measurement and fluoroscopy, and the inter-rater agreement for both modalities. Results: A tip fold-over was found in three of the fortyseven implantations (6.4%) included in this study. The average agreement between raters' evaluation and the intraoperative evaluation was 88% (Cohens k ¼ 0.378) for fluoroscopy and 99% (Cohens k ¼ 0.915) for TIM-measurement. Two raters misdiagnosed at least one tip fold-over as being correctly positioned when evaluating the fluoroscopy images (1/3 and 3/3, respectively). Each of the raters correctly detected all three tip fold-overs using the TIMheatmaps. The inter-rater agreement for fluoroscopy was classified as ''fair'' (Fleiss' k ¼ 0.286), while the inter-rater agreement for TIM-measurement was classified as ''nearperfect'' (Fleiss' k ¼ 0.850). Conclusions: TIM-measurement has a high potential to replace X-ray fluoroscopy for intraoperatively detecting electrode array tip fold-over in cochlear implantation, especially in patients implanted with flexible, precurved arrays.
Background: Histopathologic studies reported that cochlear implantation, a well-established means to treat severe-to-profound sensorineural hearing loss, may induce inflammation, fibrosis, and new bone formation (NBF) with possible impact on loss of residual hearing and hearing outcome. Purpose:To assess NBF in vivo after cochlear implantation with ultra-high-spatial-resolution (UHSR) CT and its implication on long-term residual hearing outcome. Materials and Methods:In a secondary analysis of a prospective single-center cross-sectional study, conducted between December 2016 and January 2018, patients with at least 1 year of cochlear implantation experience underwent temporal bone UHSR CT and residual hearing assessment. Two observers evaluated the presence and location of NBF independently, and tetrachoric correlations were used to assess interobserver reliability. In addition, the scalar location of each electrode was assessed. After consensus agreement, participants were classified into two groups: those with NBF (n = 83) and those without NBF (n = 40). The association between NBF and clinical parameters, including electrode design, surgical approach, and long-term residual hearing loss, was tested using the x 2 and Student t tests.Results: A total of 123 participants (mean age 6 standard deviation, 63 years 6 13; 63 women) were enrolled. NBF was found in 83 of the 123 participants (68%) at 466 of 2706 electrode contacts (17%). Most NBFs (428 of 466, 92%) were found around the 10 most basal contacts, with an interobserver agreement of 86% (2297 of 2683 contacts). Associations between electrode types and surgical approaches were significant (58 of 79 participants with NBF and a precurved electrode vs 24 of 43 with NBF and a straight electrode, P = .04; 64 of 88 participants with NBF and a cochleostomy approach vs 18 of 34 with NBF and a round window approach, P = .03). NBF was least often seen in full scala tympani insertions, but there was no significant association between scalar position and NBF (P = .15). Long-term residual hearing loss was significantly larger in the group with NBF compared with the group without NBF (mean, 22.9 dB 6 14 vs 8.6 dB 6 18, respectively; P = .04). Conclusion:In vivo detection of new bone formation (NBF) after cochlear implantation is possible by using ultra-high-spatial-resolution CT. Most cochlear implant recipients develop NBF, predominately located at the base of the cochlea. NBF adversely affects long-term residual hearing preservation.
Purpose The aim of this study was to evaluate the intracochlear position of the Slim Modiolar Electrode (SME) after insertion via the extended Round Window (eRW) approach, and to correlate this with residual hearing preservation and speech perception outcomes. Methods Twenty-three adult participants, consecutively implanted with the SME via the eRW approach, were included in this prospective, single-center, observational study. Electrode position was evaluated intra-operatively using X-ray fluoroscopy and TIM measurement, and post-operatively using ultra-high resolution CT. Residual hearing [threshold shift in PTA between pre- and post-operative measurement, relative hearing preservation (RHP%)] and speech perception were evaluated at 2 and 12 months after surgery. Results In each of the 23 participants, complete scala tympani positioning of the electrode array could be achieved. In one participant, an initial tip fold-over was corrected during surgery. Average age at implantation was 63.3 years (SD 13.3, range 28–76) and mean preoperative residual hearing was 81.5 dB. The average post-operative PTA threshold shift was 16.2 dB (SD 10.8) at 2 months post-operatively, corresponding with a RHP% score of 44% (SD 34.9). At 12 months, the average RHP% score decreased to 37%. Postoperative phoneme scores improved from 27.1% preoperatively, to 72.1% and 82.1% at 2 and 12 months after surgery, respectively. Conclusion Use of the eRW approach results in an increased likelihood of complete scala tympani insertion when inserting the SME, with subsequent excellent levels of speech perception. However, residual hearing preservation was found to be moderate, possibly as a result of the extended round window approach, emphasizing that it is not an all-purpose approach for inserting this particular electrode array.
Figure 2 contained an error and has been changed to "Precurved electrode 1 cochleostomy approach (n=80)."This copy is for personal use only. To order printed copies, contact
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