Use of anatomic or invasive markers in association with skin surface registration in image-guided surgery of the temporal bone

Conclusion: The use of an invasive marker in the ipsilateral temporal bone with mid-facial skin contouring for registration improved the position accuracy (PA) to levels required for otological and neuro-otological procedures. Objective: The aim of this study was to compare the PA after skin contouring with the combination of anatomic landmarks or a local invasive marker and skin surface registration for intratemporal computer-assisted navigation. Patients and methods: Thirty-three patients undergoing a lateral skull base procedure with the Digipointeur® system (Collin, Bagneux, France) based on CT scan were included in this study. Registration was obtained by a mid-facial skin contouring. In the first protocol (n=8), PA was evaluated and the position corrected for three intratemporal landmarks before evaluation of the target (round window). In a second protocol (n=25), a titanium screw was placed in the ipsilateral mastoid region before imaging. PA was measured before and after screw registration for five intratemporal landmarks. Results: In the first protocol, PA did not improve after the registration of the landmarks, and PA of the target was evaluated as 4.9±0.64 mm. In the second protocol, PA was reduced after screw registration for all landmarks with a mean PA ranging from 0 to 2.3 mm.