Reliability of Measuring Insertion Depth in Cochlear Implanted Infants and Children Using Cochlear View Radiography

Objectives Cochlear implant depth of insertion affects audiologic outcomes and can be measured in adults using plain films obtained in the "cochlear view." The objective of this study was to assess interrater and intrarater reliability of measuring depth of insertion using cochlear view radiography. Study Design Prospective, observational. Setting Tertiary referral pediatric hospital. Subjects and Methods Patients aged 11 months to 20 years (median, 4 years; interquartile range [IQR], 1-8 years) undergoing cochlear implantation at our institution were studied over 1 year. Children underwent cochlear view imaging on postoperative day 1. Films were deidentified and 1 image per ear was selected. Two cochlear implant surgeons and 2 radiologists evaluated each image and determined angular depth of insertion. Images were re-reviewed 6 weeks later by all raters. Inter- and intrarater reliability were calculated with intraclass correlation coefficients (ICCs). Results Fifty-seven ears were imaged from 42 children. Forty-nine ears (86%) had successful cochlear view x-rays. Median angular depth of insertion was 381 degrees (minimum, 272 degrees; maximum, 450 degrees; IQR, 360 degrees-395 degrees) during the first round of measurement. Measurements of the same images reviewed 6 weeks later showed median depth of insertion of 382 degrees (minimum, 272 degrees; maximum, 449 degrees; IQR, 360 degrees-397 degrees). Interrater and intrarater reliability ICCs ranged between 0.81 and 0.96, indicating excellent reliability. Conclusions Postoperative cochlear view radiography is a reliable tool for measurement of cochlear implant depth of insertion in infants and children. Further studies are needed to determine reliability of intraoperatively obtained cochlear view radiographs in this population.