Accuracy analysis of cavities for cochlea implants milled conventionally and manually with navigated control

A new experimental support system for milling cavities for cochlear implants is proposed. In contrast to assisting the milling task by drilling jigs, image-based navigation systems or robots, the approach of "Navigated Control" features a supervision of the power of the user controlled instrument. The main feature is the decrease of the power of an active instrument depending on the location of this instrument relative to a planned volume. A first experiment to determine the accuracy of the system in contrast to conventional manual milling is presented. The accuracy of the manual milling with "Navigated Control" was at 0.2 ± 0.2 mm compared to the lower accuracy of the conventional manual milling without "Navigated Control" at 0.8 ± 0.2 mm. The results are discussed.