Background: Navigation systems have become essential tools in neurosurgery. Precise registration is indispensable for the accuracy of navigation. The rapid and precise registration by surface matching on the facial skin is possible using the landmarks of the face in the supine position. On the other hand, incomplete registration often occurs in the lateral or prone position due to the direction of the face and displacement of the skin by headpins and obscuring of the skin by the bispectral index monitor and many electrodes on the forehead as well as the eye patch. Surface matching on the occipital scalp is not suitable for registration because the shape of the occipital scalp is flat and it is compressed in the supine position when obtaining preoperative neuroimaging. To overcome this problem, the authors have developed a new method of registration designated as "bony surface registration" in which surface matching is achieved using the bony surface of the skull after exposure.
Methods: Between June and December 2014, this technique was used in 23 patients and its effectiveness was examined.
Results: Registration time was markedly shortened and useful navigation was achieved due to accurate registration in all patients.
Conclusions: This is the first report of a registration methodology for a navigation system in the lateral or prone position. This bony surface registration method is useful for navigation system image-guided surgery in the lateral or prone position.
Keywords: Bony surface registration; Image-guided neurosurgery; Navigation system; Prone or lateral position.