734232.fig.004a
(a)
734232.fig.004b
(b)
734232.fig.004c
(c)
Figure 4: (a) The microscope is first positioned vertically (right picture). The drilling begins vertically, up to the posterior cortical bone, at that time the microscope has to be repositioned to get an oblique view (left picture). The drilling is then continued horizontally up to the contralateral side. (b)-(c) Postoperative axial CT scan showing the directions (white arrows) and final area of drilling.