Measurement of Cochlear Implant Electrode Position From Intraoperative Post-insertion Skull Radiographs. Issue 9 (October 2015)

• Record Type: Journal Article
• Authors: Svrakic, Maja; Friedmann, David R.; Berman, Phillip M.; Davis, Adam J.; Roland, J. Thomas; Svirsky, Mario A.
• Is Part Of: Otology & neurotology. Volume 36:Issue 9(2015)
• Publication Date: 2015-10
• Subjects: Otology -- Periodicals; Ear -- Diseases -- Periodicals; Skull base -- Surgery -- Periodicals; 617.8005
• DOI: 10.1097/MAO.0000000000000852
• Languages: English
• ISSNs: 1531-7129

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>Objective:</title> <p>To validate a method of measuring angular depth of insertion (aDOI) as well as positional depth of each electrode contact in a cochlear implant by using intraoperative postinsertion skull radiographs.</p> </sec> <sec> <title>Study Design:</title> <p>Retrospective review.</p> </sec> <sec> <title>Setting:</title> <p>Tertiary referral center.</p> </sec> <sec> <title>Patients:</title> <p>Intraoperative postinsertion radiographs obtained from 18 cochlear implant recipients were chosen for analysis. One high-resolution computer tomography scan of the head with the electrode in place was also analyzed. One cadaveric temporal bone with an inserted electrode provided additional data for analysis.</p> </sec> <sec> <title>Intervention:</title> <p>aDOI and position of each electrode contact were measured from the radiographs using readily available software. High-resolution computer tomography imaging of the cochlea and electrode were reconstructed in three dimensions and used to simulate head rotation during intraoperative radiographs. The cadaveric temporal bone was imaged by x-ray at various acquisition angles.</p> </sec> <sec> <title>Main Outcome Measures:</title> <p>We evaluated the error introduced in measuring aDOI by assessing intra- and inter-rater variability. We also evaluated the error introduced by x-ray acquisition at nonstandardized angles by analyzing the three-dimensional construct and the cadaveric temporal bone.</p> </sec> <sec> <title>Results:</title> <p>The concordance correlation coefficients for intrarater (0.991) and inter-rater (0.996) variability in aDOI measurement were excellent. The error introduced by nonstandardized x-ray acquisition angles was only −12.5 degrees to +15.8 degrees even at the limits of clinically relevant head rotation.</p> </sec> <sec> <title>Conclusions:</title> <p>The intraoperative postinsertion radiograph is sufficient for estimating positional depth of electrode contacts and the aDOI. This measure is robust in the face of nonstandardized x-ray acquisition angles, and shows good intra- and inter-rater variability</p> </sec> </abstract>