Positioning aid for surgical procedures

A positioning aid for a surgical procedure on a patient, comprising

• a carrier system;
• and
• a template;
• wherein the carrier system comprises a carrier plate with an opening or a recess and with supports to fixate the carrier system to a cranial bone over an operating field for surgical intervention;
• wherein the carrier plate has first and second ends with the opening or the recess disposed between the first and second ends;
• wherein the template comprises a template plate connected in a play-free manner to the carrier plate so as to extend beyond at least one of the first and second ends of the carrier plate, said template plate having a guiding aperture, which can be created and oriented by means of removal of material from a blank template plate, said guiding aperture being configured at a location and orientation relative to the patient and to an attachment location of the carrier system in accordance with predetermined coordinates based on calculations from planning data for the surgical procedure on the patient;
• wherein the longitudinal central axis of the guiding aperture, when the carrier system and template are in the assembled state and the carrier system is fixed to the cranial bone, corresponds to a trajectory for an access to the operating field for the surgical intervention;
• and
• wherein the longitudinal central axis of the guiding aperture is arranged eccentrically relative to the template plate and offset from a center point of the recess or the opening of the carrier plate, said longitudinal central axis of the guiding aperture having an incline which deviates from the vertical of the surface of the template plate, the recess or the opening in the carrier plate being dimensioned to be of such a size that the guiding aperture in the template plate is not covered by the carrier plate even in a case of maximum eccentric arrangement.