Fig. 5

Geometrical demonstration of SafA and OSIC width calculations. a Method of SafA calculation; (b) Method of OSIC width calculation. In the schematics, the IE segment represents the optimal implant position (in pink) and the S point is the safety margin identified on CT images by rotating the axis of the implant around its insertion point until the position is considered unsafe. The insertion point (I), exit point (E), safety margin (S), and radius of the implant (r) are all known entities