Radiologically assisted navigation in cochlear implantation for X-linked deafness malformation.

The X-linked deafness syndrome is characterised by a complex labyrinth malformation with a shortened cochlea with missing bony separation between the cochlea and internal auditory canal and a deviant route of the facial nerve. Cochlear implant surgery in this malformation may be complicated by an unintended electrode insertion into the internal auditory canal. The authors report a new surgical approach: intraoperative three dimensional-volume tomography (3D-VT)-based navigation and direct intraoperative control by 3D-VT. The navigation dataset was based on intraoperative 3D-VT after performing the mastoidectomy and posterior tympanotomy. The cochleostomy was then performed under navigation control. After insertion, the electrode position was directly visualised by 3D-VT. On the basis of the reconstruction results, the electrode position was corrected and an intracochlear insertion resulted. Cochlear implantation in X-linked deafness malformation can be facilitated using intraoperative 3D-VT-assisted navigation and intraoperative 3D-VT control of the electrode position. This approach enhances the precision of navigation and reduces the risk of improper electrode placement and additional surgery in complex malformations. Copyright 2009 John Wiley & Sons, Ltd.