AOS006 - Predictive Value of Trans-Impedance Matrix Measurements to Detect Electrode Tip Foldovers
Friday, April 29, 2022
2:34 PM – 2:41 PM CT
Location: Landmark A
Emily Kay-Rivest MD, MSc
Sean O. McMenomey, MD
Daniel Jethanamest, MD, MSc
William H. Shapiro, AuD
David R. Friedmann MD, MSc
Susan B. Waltzman PhD
J. Thomas Roland Jr. MD
Objective:To evaluate the ability of the trans-impedance matrix (TIM) measurement to detect cochlear implant electrode tip foldover by comparing results to a gold standard, the intraoperative plain film radiograph.
Study design: Retrospective case series.
Setting: Tertiary referral hospital.
Patients: 103 patients who underwent cochlear implantation between June 2020 and August 2021.
Interventions: Intraoperative electrophysiologic monitoring (electrode impedances, Neural Response Telemetry, and TIM measurement) and modified Stenver’s view plain film radiographs.
Main outcome measures: Identification of tip foldover on both TIM and plain films.
Results: In total, 103 patients (117 ears) had both a TIM measurement and intraoperative -ray available for review, including 68 adults and 35 children. 100 (85%) received the Cochlear Slim Modiolar electrode. Tip foldovers were noted in three of 117 implants (2.5%). In all cases, TIM was able to detect the foldover, and the electrode arrays were reinserted with repeat X-ray demonstrating a normal configuration. Two other abnormal TIM patterns were identified. One was in a patient with an obstructed cochlea in whom only 10 electrodes could be inserted, the other was in a patient with a common cavity abnormality. One additional patient required electrode revision intraoperatively, due to overinsertion. In this patient, the TIM appeared to be within normal limits but the overinsertion was apparent only on X-ray. Overall, the sensitivity of TIM measurements in detecting tip foldover was 100%.
Conclusions: TIM measurements were able to accurately identify tip foldovers but were not sensitive to overinsertion of the array. More research is needed to define the adjunctive role of TIM as an intraoperative measure.
*Professional Practice Gap & Educational Need: In certain cochlear implant centres, routine intraoperative X-ray may not always be readily available. We explore the TIM and its ability to detect tip foldovers, which may represent a feasible alternative for position placement check in the context of normal cochleovestibular anatomy.
*Learning Objective: TIM measurements were able to detect tip foldovers in all cases.
*Desired Result: To provide the attendee with the knowledge of an additional tool for intraoperative monitoring and explore other possible benefits of the transimpedance matrix.
*Level of Evidence: Level III
*Indicate IRB or IACUC: NYU School of Medicine Institutional Review Board i21-01186.