Figure 2 (a) Dry skull model. Right frontal in situ mini osteoplastic flap (blue star) with horizontal limb (white arrow), three ports (green, black and yellow arrows). Left frontal sinus open showing septum a supraorbital cell (blue arrow). (b) Same dry skull model. Right frontal multiportal approach with two instruments (right curved suction tip and left 45 degrees angled Bleksely forceps).