Image guided surgery of the lateral skull base: Testing a new dental splint registration device

Objective: The widespread use of image guided surgery in the frontolateral skull base region has been limited by the need for a reliable and non-invasive registration procedure that provides sub-millimetric accuracy. We developed and validated preclinically a non-invasive, easy-to-use registration device based on a dental splint with a laterally mounted fiducial carrier. Methods: Repeated accuracy measurements were performed on six titanium target fiducials which were screwed into the lateral skull base region of a cadaver head and could be unequivocally identified both on the CT image and in reality. The system accuracy was evaluated by determining the deviation of the real target position from the position indicated in the CT scan. The accuracy of the dental splint-based registration was compared to that of two standard registration procedures: contour-based laser surface registration and fixed marker registration. Results: The mean accuracy of 0.55 +/- 0.28 mm obtained when using the maxillary splint device was similar to that obtained with the "gold standard" registration using bone-implanted markers (0.33 +/- 0.26 mm), while being clearly superior to that obtained with contour-based laser surface registration (1.91 +/- 0.74 mm). Conclusions: Registration using the non-invasively fixed maxillary fiducial platform can provide sub-millimetric accuracy in the lateral skull base region. In vivo validation may prove dental splint-based registration to be an accurate and non-invasive alternative option for image guided surgery of the lateral skull base, and may facilitate the application of navigation systems in this delicate region.