Method and system for computer assisted surgery

1. A method for computer assisted orthopedic feedback of at least one surgical instrument relative a pre-operative plan, wherein the surgical instrument is moveable relative to a patient structure during surgery; the pre-operative plan including a virtual structure, which is a virtual representation of the patient structure; comprising:

providing the pre-operative plan including planned position and orientation of an implant relative to the virtual structure;

obtaining a position of the patient structure using a surgical navigation system;

obtaining a position of at least one surgical instrument using the surgical navigation system;

registering the patient structure to the virtual structure;

tracking a current position and orientation of the at least one surgical instrument relative said patient structure using the surgical navigation system; and

providing feedback of the current position and orientation of the at least one surgical instrument relative to the planned position and orientation of the implant based on the tracked current position and orientation of the at least one surgical instrument.

2. The method according to claim 1 , wherein obtaining the position of the at least one surgical instrument comprises calibrating at least one position of the surgical instrument relative a calibration unit within the surgical navigation system.

3. The method according to claim 2 , further comprising calibrating an end-effector of the surgical instrument relative the calibration unit.

4. The method according to claim 2 , wherein calibrating the at least one position of the surgical object comprises calibrating a position of a navigation unit at the surgical instrument relative a surface of the calibration unit, said surface having a predetermined position at the calibration unit.

5. The method according to claim 4 , wherein calibrating the position of the navigation unit at the surgical instrument comprises:

determining a position of a navigation unit at the calibration unit, the navigation unit at the calibration unit having a fixed positional relationship relative the surface having the predetermined position.

6. The method according to claim 4 , wherein calibrating the position of the navigation unit at the surgical instrument comprises:

registering multiple positions of the navigation unit at the surgical instrument while it is moved and a position of an end-effector of the surgical instrument is substantially fixed at the surface having the predetermined position, and

determining the position of the end-effector based on the registered multiple positions of the navigation unit at the surgical instrument.

7. The method according to claim 1 , wherein providing the feedback comprises providing at least one of:

visual feedback of a current position and orientation of the surgical instrument relative to the planned orientation and position of the implant on a display in response to the tracked current position and orientation of the surgical instrument;

visual indication of a deviation of a current position and orientation of the surgical instrument relative the planned position and orientation of the implant on a display in response to the tracked current position and orientation of the surgical implant; and

visual indication of the deviation of the current position and orientation of the surgical instrument relative the planned position and orientation of the implant in response to the tracked current position and orientation of the surgical instrument, wherein the visual indication is indicated at the surgical instrument.

8. The method according to claim 1 , wherein tracking the current position and orientation of the patient structure comprises tracking a position of a navigation unit, which is attached to the patient structure, using the surgical navigation system.

9. The method according to claim 1 , further comprising obtaining a position of at least one implant for implantation into the patient structure.

10. The method according to claim 1 , wherein obtaining the position of the patient structure comprises obtaining a position and orientation of a bony anatomy of the patient.

11. The method according to claim 1 , wherein providing the pre-operative plan comprises:

accessing volumetric scan data, wherein the scan data comprises patient structure scan data;

converting the patient structure scan data into the virtual structure, which comprises a three dimensional representation of the patient structure;

planning at least one position and orientation of the implant relative to the virtual structure; and

including at least one of the scan data and the three dimensional representation of the virtual structure together with the planned position and orientation of the implant in the pre-operative plan.

12. The method according to claim 1 , further comprising attaching a tracking unit, which is detachable and attachable, to the surgical instrument; and

calibrating at least one position of the surgical instrument relative a calibration unit within the surgical navigation system.

13. The method according to claim 12 , further comprising attaching a tracking unit, which is detachable and attachable, to the calibration unit prior to calibrating said at least one position of the surgical instrument relative the calibration unit.

14. The method according to claim 13 , further comprising calibrating at least one position of the calibration unit within the surgical navigation system after attaching the tracking unit to said calibration unit.

15. The method according to claim 12 , wherein attaching said tracking unit to said surgical instrument comprises mating a connection interface, which has at least one projection or recess, with a connection interface at the surgical instrument, said connection interface at said surgical instrument having a shape that is complementary to a shape of the connection interface of the navigation unit.

16. The method according to claim 15 , wherein attaching said tracking unit comprises mating the connection interface, which has multiple projections or recesses, with the connection interface at the surgical instrument.