title: Radiological and NRT-Ratio-Based Estimation of Slim Straight Cochlear Implant Electrode Positions: A Multicenter Study.
abstract: OBJECTIVE
  An intraoperative neural response telemetry-ratio (NRT-ratio) was established, which can provide information about the intraoperative intracochlear electrode array position for perimodiolar electrodes.
  
  
  METHODS
  In a retrospective controlled study in 2 tertiary referral centers, the electrophysiological data sets of 50 patients with measured intraoperative auto-NRTs and postoperative radiological examinations were evaluated. All patients were implanted with Nucleus slim straight electrodes. The NRT-ratio was calculated by dividing the average auto-NRT data from electrodes 16 to 18 with the average from electrodes 5 to 7. Using a flat panel tomography system or a computed tomography, the position of the electrode array was certified radiological.
  
  
  RESULTS
  Radiologically, 2 out of 50 patients were identified with an electrode translocated from the scala tympani into the scala vestibuli. The radiologically estimated electrodes indicating a scalar change showed a regular NRT-ratio but nonspecific NRT-level changes at the localization of translocation.
authors: Department of Otolaryngology, ukb Berlin, Germany philipp.mittmann@googlemail.com.
authors: Philipp
authors: P
authors: Mittmann
authors: Department of Otolaryngology, ukb Berlin, Germany.
authors: Ingo
authors: I
authors: Todt
authors: Department of Otolaryngology, ukb Berlin, Germany.
authors: Arneborg
authors: A
authors: Ernst
authors: Radiology at ukb Berlin, Germany.
authors: Grit
authors: G
authors: Rademacher
authors: Radiology at ukb Berlin, Germany.
authors: Sven
authors: S
authors: Mutze
authors: Department of Neuroradiology and Radiology, University Hospital of Essen, University Duisburg-Essen, Essen, Nordrhein-Westfalen, Germany.
authors: Sophia
authors: S
authors: Göricke
authors: Department of Neuroradiology and Radiology, University Hospital Giessen and Marburg GmbH, Germany.
authors: Marc
authors: M
authors: Schlamann
authors: Department of Otolaryngology, Head and Neck Surgery, University Hospital of Essen, University Duisburg-Essen, Germany.
authors: Stephan
authors: S
authors: Lang
authors: Department of Otolaryngology, Head and Neck Surgery, University Hospital of Essen, University Duisburg-Essen, Germany.
authors: Diana
authors: D
authors: Arweiler-Harbeck
authors: Department of Otolaryngology, Head and Neck Surgery, University Hospital of Essen, University Duisburg-Essen, Germany.
authors: Florian
authors: F
authors: Christov
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003051:Cochlea / Q000000981:diagnostic imaging*; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014054:Tomography; D055815:Young Adult
keywords: NRT; cochlear implants; electrode design; hearing loss; neurophysiology