ABSTRACT
OBJECTIVE: To describe our newly devised method of viewing intracochlear ossification for the purpose of minimizing bone drilling during cochlear implantation for partially ossified cochleas and to evaluate its usefulness. STUDY DESIGN: Descriptive study that compares 1) conventional computed tomographic (CT) films with the newly devised CT movie and 2) preoperative evaluation using the CT movie with the findings during surgery. SETTING: University Hospital. PATIENTS: Four cochlear implantees with partial ossification of cochlea due to meningitis. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURES: Reconstruction of high-resolution CT images of the temporal bone was performed using a multiplanar reformat software. By rotating the cochlear cross plane from the round window niche in the direction of the inferior segment by 5 degrees, 72 images were obtained for 360-degree rotation, which were converted to a movie using QuickTime Pro software. The preoperative evaluation and intraoperative findings were compared. RESULTS: The advantage of CT movie over sequential CT films was facility in understanding the 3-dimensional space in the cochlea. Evaluation of the extent of the ossified region on CT movie corresponded to the intraoperative findings in all 4 patients. In 1 patient, the CT movie corrected an erroneous evaluation based on conventional CT films. However, additional drilling over the extent of ossification was necessitated in another patient because of scar tissue development. CONCLUSION: Computed tomographic movie is considered an innovative new method for preoperative evaluation of ossified cochleas and is able to reduce human errors. However, additional drilling beyond ossified part can become necessary during surgery.