The method includes the steps of: a) providing a surgical template (10) having a bushing (12) positioned and orientated so as to define the axis of the hole, the bushing (12) being adapted to receive drill guide sleeves with which drills of progressively increasing diameter are to be guided for the making of the hole b) performing a CT scan of the portion of the patients cranium in which the hole is to be made, with the surgical template (10) positioned thereon c) removing the surgical template (10) from the patients mouth d) performing a CT scan on the surgical template (10) only and e) generating, from the CT scan obtained in steps b) and d), a three-dimensional model of the aforesaid portion of the patients cranium, in which the surgical template (10), and therefore the axis of the aforesaid hole, are placed in the same position as that in which they were placed in step b).
