3D reconstruction of the temporal bone in cochlear implant surgery

Abstract

In the preoperative evaluation of prospective cochlear implant patients high resolution computed tomography (CT) is routinely performed. Sectional images of the temporal bones in the axial or coronal plane can give essential information about cochlear or mastoid pathology that will enable the surgeon to select a side for operation and alert him to surgical obstacles he might encounter. Even with the help of serial CTs it has always been very difficult to visualize the complicated anatomy of the normal temporal bone. In particular, in a patient with a malformation or a previous operation, even an experienced otologic surgeon cannot always avoid unwelcome surprises. In analyzing the CT films he must still try to form a 3-dimensional image in his mindby looking through a large number of different pictures s. Consequently, to make it easier to understand, a lot of effort has been put into the development of 3-dimensional (3D) imagingof the object. A variety of 3D graphics systems that provide multi-angled surface renderings from serial CT images have become available in recent years and proved to be useful in craniofacialreconstructive, orthopedic and neurosurgical planning. We applied our own image analysis technique to produce three-dimensional reconstructions of temporal bones in patients and in isolation on a personal computer9 We focused on the use of this method for the preoperative examination and surgical planning for cochlear implantation as well as for our research purposes. This system and the results are presented here.