128-multidetector CT: For assessment of optimal depth of electrode array insertion in cochlear implant operations

Abstract

Objective: To assess the diagnostic reliability of MDCT in pre-operative evaluation of cochlear implant candidates and post-operative, estimation of depth of insertion. Material and methods: The study includes 40 patients (18 males and 22, females); classified into 2 groups: group A (20 patients): cochlear, implant device was Nucleus-22. Group B (20 patients): device was MED-EL.Cochlear length (CL) and cochlear height (CH) were measured pre-operatively by 128-multidetector CT. Electrode length (EL) and insertion, depth angle (α) were measured post-operatively by MDCT. Results: Group A: mean CL was 9.1 mm ± 0.4 SD; mean CH was 4.1 ± 0.3 SD; mean EL was 18 ± 2.7 SD; mean α angle was 299.05 ± 37 SD. Significant, statistical correlation (P < 0.05) was found between preoperative CL and, post-operative EL. Significant statistical correlation was found between, EL and α angle (r2 = 0.7). Group B: mean CL was 9.1 mm ± 0.3 SD; mean CH, was 4.1 ± 0.4 SD; mean EL was 27 ± 2.1 SD; mean α angle was 287.6 ± 41.7, SD. Significant statistical correlation was found between CL and EL & α angle. Conclusion: Cochlear length is a reliable prognostic parameter in, prediction of the depth of electrode array insertion. Keywords: Multidetector CT (MDCT), Cochlear implant (CI), Cochlear length (CL), Angle of insertion (α angle)