Surgical guide system for assisting a user controlling a surgical tool

A surgical guide system for assisting a user controlling a surgical tool, comprising:

• (a) a first reference guide member which includes a QR code and which can be coupled to a selected surgical device for implantation in a patient having at least one mounting hole formed in it, the first reference guide member defining a first reference frame within a three-dimensional space that is fixed relative to the implanted surgical device and thereby defines a reference coordinate system internal to the patient;
• (b) a control unit which includes a database containing a library of pre-stored geometric models of surgical devices, each model defining spatial relationships between the location of the marker and predetermined mounting hole geometries of the corresponding surgical devices,
• (c) a camera which can be accessed by the control unit for capturing an image of the said QR code;
• and
• (d) a mixed reality headset;
• in which the control unit (i) uses the image of the QR code to identify the selected surgical device from the said plurality of surgical devices, (ii) provides an identification signal indicative of the selected surgical device, (iii) determines, without requiring intraoperative imaging or patient specific reconstruction, the position and orientation of said at least one mounting hole relative to said first reference frame based on the geometric model, and (iv) provides a first output signal to the mixed reality headset which causes a visual marker to be displayed on the headset that projects and extrapolates the central axis of the at least one mounting hole onto an exterior surface of the patient, superimposed on a mixed-reality view of the patient in alignment with the internal mounting hole.