A method for automated opening of craniotomies includes, under the control of a computer processor, drilling into a skull for a predetermined distance and determining when there is a conductance drop near the drilling tip that indicates skull breakthrough. If the conductance is not below a predetermined threshold, drilling continues iteratively manner until conductance is below the threshold. A craniotomy pattern may be predetermined and automatically drilled under control of the processor. A cranial window may be created by drilling along a path that interpolates between holes to form the circumference of the window. An automated craniotomy opening apparatus includes a drilling apparatus with a drilling tip, at least one drilling apparatus positioning device, a detection device, and a computer processor that controls the drilling apparatus, the positioning device, and the detection device according to the method. Determining conductance may include use of an impedance detection circuit.
