Computer-aided three-dimensional reconstruction and measurement for multiple-electrode cochlear implant.

To assist surgeons in performing multiple-electrode cochlear implant operations, the spatial relations between middle and inner ear structures in six normal temporal bones were studied using the computer-aided 3-D reconstruction method. When viewed through the external auditory canal, the approach used for electrode insertion, and the relation of the malleus to the helicotrema or the scala vestibuli in the second turn of the cochlea were found to vary considerably. In contrast, when viewed from the same transmeatal approach, both the direction and the distance from the stapes footplate to the scala vestibuli of the second turn of the cochlea and helicotrema were found to be quite stable. We concluded that the stapes footplate was a better landmark than the malleus when approaching the helicotrema and scala vestibuli of the second turn of the cochlea during multiple-electrode cochlear implant surgery.