Geometrical positioning of drilling in medical applications

A method for positioning a drill for drilling a subsequent hole in a bone at a predetermined distance from, and in a predetermined orientation in respect to, a reference hole, the drill having a drill bit with a central axis, the method comprising the steps of:

• (a) inserting a reference insert into the reference hole, said reference insert being adapted to establish a reference guideline, said reference guideline being of the predetermined orientation;
• (b) providing an alignment mechanism, attached to the drill, said alignment mechanism adapted to be fixed at the predetermined distance from and parallel to the central axis of the drill bit, said alignment mechanism including an optical device for colinearly aligning an alignment axis of said alignment mechanism with said reference guideline;
• (c) fixing said alignment mechanism at the predetermined distance;
• and,
• (d) aligning said alignment axis of said optical device of said alignment mechanism with said reference guideline, thereby positioning the drill at the predetermined distance from and in the predetermined orientation in respect to the reference hole.