Dynamic Intraoperative Interpretation of TIM Heatmaps: Fluoroscopic Correlation of Skip and Central Heat TIM Patterns in Cochlear Malformation

Objective: To describe intraoperative fluoroscopic and transimpedance matrix (TIM) findings during cochlear implantation in a patient with bilateral cochlear malformations, highlighting the dynamic relationship between electrode position and evolving TIM heatmap patterns. Study design: Case report. Methods: Retrospective review of patient medical and radiographic records, intraoperative fluoroscopy, and TIM data. Results: Initial insertion produced a previously characterized TIM skip heat pattern seen in patients with incomplete partition type II and deficient interscalar septal width. This prompted partial electrode withdrawal under fluoroscopy, which subsequently resulted in a TIM central heat pattern, representing a symmetric voltage concentration around the mid-array region. Advancing the array slightly resulted in a skip heat pattern with a more defined current delineation and a more favorable x-ray profile. Interestingly, SmartNav analysis interpreted the TIM data as a tip fold over, despite good positioning. Conclusion: This case visually demonstrates which small positional changes of electrodes within malformed cochleae can transform TIM morphology, helping to elucidate why certain patterns occur, and the next steps to study clinical relevance.