Fig. 1: Experimental setup.

a ARNS using HoloLens 2 with virtual twin representations of the block (blue) and drill (yellow) are displayed next to the phantom. b ARNS presented a virtual block with a blue boundary, accompanied by a drill and guidance. The guidance consisted of two tori for the translational deviation of the drill tip (tip indicator) and tail (tail indicator) from the planned trajectory, while a middle torus in ellipse shows the angular deviation. The colors of all indicators turn green if the translational and angular errors are within 1mm and 1°. The virtual drill turns green from yellow when it reaches the planned depth and red if deeper (>1 mm). c The CNS setting displayed drilling navigation on an external 2D monitor (right). The optical tracker is not shown. d The graphical user interface of CNS displays three sub-windows with orthogonal CT planes of the phantom block, illustrating the spatial alignment of the drill with the trajectory. A compensatory view in the lower right sub-window provided a transverse trajectory perspective that enhanced the accuracy of the drill alignment. The circle (represents drill tip) and middle ring (tail) change from yellow to green when translational error is ≤ 1 mm. A depth slider to the left visualizes the current depth (yellow) relative to the planned depth (purple). The slider and the outer ring change from yellow to green at the planned depth (0–1 mm) and turn red if it exceeds that depth by >1 mm.