The Usefulness of Reconstructed 3D Images in Surgical Planning for Cochlear Implantation in a Malformed Ear with an Abnormal Course of the Facial Nerve

OBJECTIVES: It is not unusual for a cochlear implantation (CI) candidate to have some type of ear malformation, in particular an abnormal course of the facial nerve (FN). In this study, we attempted to reconstruct a three-dimensional (3D) image of temporal bone structures with malformation using computed tomography (CT) imaging and examined its usefulness in the surgical planning of CI in a malformed ear. METHODS: We prepared 3D images for 6 separate CI cases before surgery. First, we manually colored preoperative CT images using Photoshop CS Extended. We then converted the colored CT images to 3D images using Delta Viewer, free-ware for Macintosh. Before surgery, we discussed any problems anticipated based on the 3D images and plans for surgery with those who would be performing the CI. RESULTS: Case 1: The subject was a 3-year-old boy with malformed ossicles, semicircular canal (SC) hypoplasia, internal auditory canal stenosis, and an abnormal course of the FN. 3D image indicated that the stapes were absent, and the FN was more anteriorly displaced, so that it was difficult to perform cochleostomy. The surgical findings were similar to those depicted on the 3D image, so we could insert an electrode based on the preoperative image simulation without complications. Case 2: The subject was a 7-year-old boy with malformed stapes, atresia of the round window, cochlear and SC aplasia, and an abnormal course of the FN with bifurcation. CI was performed with no problems, in the same manner as in Case 1. CONCLUSION: We were able to successfully depict the structures of the inner ear, ossicles, and FN as 3D images, which are very easy to understand visually and intuitively. These 3D images of the malformed ear are useful in preoperative image simulation and in surgical planning for those performing a CI procedure.

Surgical Experiences of Congenital Aural Atresia Analysis of 53 Cases / 대한이비인후과학회지

Congenital aural atresia requires reconstructive surgery because of its negative effect against hearing and cosmetic problem. Two surgical methods, anterior and transmastoid approaches, have been designed for the surgery and many surgeons have advocated any techniques depending on their surgical experiences and advantages of each method. We analyzed retrospectively 53 cases of congenital aural atresia operated with the use of one of both approaches, and got the clinical, audiological and surgical results as follows. 1) Postoperative dressing period was shorter in the anterior approach(34.5 days) than in the posterior one(44.2 days). 2) Hearing results are better in the anterior approach. 3) Postoperative complications include granulation tissue formation, drum lateralization, external auditory canal stenosis and temporary facial nerve weakness. And it happened more frequently in the anterior approach than the posterior one. 4) Facial nerve anormaly was noted in 16 cases(30.2%) and cholesteatoma in 5 cases(9.4%).