Enhanced graphics features for computer assisted surgery system

Abstract

A computer assisted surgery system with is enhanced graphics features is described for assisting a surgeon in orthopaedic procedures. A system is described for use in inserting multiple guide pins in hip fracture surgery using a single bore drill guide that has a graphical representation comprising its real trajectory and one or more virtual trajectories, the virtual trajectories representing potential positions of other guide pins to be placed during the procedure. Additionally, representations of inserted guide pins and virtual trajectories may be retained on the display at their inserted positions for use in aligning subsequent guide pins. A system is also described for orientation of an acetabular cup in a total hip replacement surgery. During cup insertion, the surgeon is provided with information regarding the orientation of the cup with respect to a pelvic reference frame that is based on accepted pelvic landmarks. The positions of each landmark is calculated by the system when a probe with a virtual tip, separate from its physical tip, is overlaid on the landmark in roughly orthogonal images of the pelvis.

1 . A computer assisted surgery system with enhanced graphic capabilities for insertion of guide pins into a body part, the system comprising: 
 an x-ray imaging device for generating at least one 2-D image of a body part;    a surgical instrument with a physical feature defining a real trajectory;    a localizing device for measuring the pose of the surgical instrument; and    a computer comprising:    means for displaying the at least one 2-D image of the body part;    means for generating a graphic representation of the real trajectory;    means for determining the location of one or more virtual trajectories relative to the real trajectory, wherein the one or more virtual trajectories represent possible positions of components used during a surgical operation; and    means for superimposing graphic representations of the real and virtual trajectories over the at least one 2-D image of the body part; wherein the virtual trajectories may be used for assisting the surgeon in aligning the surgical instrument relative to the body part or guide pins and said virtual trajectories need not represent a real feature of the surgical instrument.    
   
   
       2 . The computer assisted surgery system of  claim 1  wherein the surgical instrument is a drill guide, the real trajectory represents the bore of the drill guide and the virtual trajectories represent future possible drill guide trajectories.  
   
   
       3 . The computer assisted surgery system of  claim 2  further comprising: 
 means for recording the pose of the drill guide at a signal from the surgeon; and    means for retaining graphic representations of the real and virtual trajectories superimposed on the 2-D image of the body part corresponding to the recorded pose;    wherein the retained virtual trajectories serve as guide lines for subsequent pin insertions.    
   
   
       4 . In a computer assisted surgery system with enhanced graphic capabilities for insertion of guide pins into a body part, the system comprising an x-ray imaging device for generating at least one 2-D image of a body part, a surgical instrument with a physical feature defining a real trajectory, a localizing device for measuring the pose of the surgical instrument, and a computer comprising instructions for: 
 displaying the at least one 2-D image of the body part;    generating a graphic representation of the real trajectory;    determining the location of one or more virtual trajectories relative to the real trajectory, wherein the one or more virtual trajectories represent possible positions of components used during a surgical operation; and    superimposing graphic representations of the real and virtual trajectories over the at least one 2-D image of the body part; wherein the virtual trajectories may be used for assisting the surgeon in aligning the surgical instrument relative to the body part or guide pins and said virtual trajectories need not represent a real feature of the surgical instrument.    
   
   
       5 . The computer assisted surgery system of  claim 4  wherein the surgical instrument is a drill guide, the real trajectory represents the bore of the drill guide and the virtual trajectories represent future possible drill guide trajectories.  
   
   
       6 . The computer assisted surgery system of  claim 4 , wherein said computer further comprises instructions for recording the pose of the drill guide at a signal from the surgeon; and retaining graphic representations of the real and virtual trajectories superimposed on the 2-D image of the body part corresponding to the recorded pose, wherein the retained virtual trajectories serve as guide lines for subsequent pin insertions.  
   
   
       7 . A computer assisted surgery system with enhanced graphic capabilities for insertion of guide pins into a body part, the system comprising: 
 an x-ray imaging device that generates an image of a body part;    a surgical instrument with a physical feature defining a real trajectory;    a localizing device for measuring the pose of the surgical instrument; and    a computer that (a) displays the image of the body part; (b) generates a graphic representation of the real trajectory; (c) determines the location of one or more virtual trajectories relative to the real trajectory, wherein the one or more virtual trajectories represent possible positions of components used during a surgical operation; and (d) superimposes graphic representations of the real and virtual trajectories over the image of the body part; wherein the virtual trajectories may be used for assisting the surgeon in aligning the surgical instrument relative to the body part or guide pins.    
   
   
       8 . The computer assisted surgery system of  claim 7 , wherein said virtual trajectories need not represent a real feature of the surgical instrument.  
   
   
       9 . The computer assisted surgery system of  claim 7 , wherein the surgical instrument is a drill guide, the real trajectory represents the bore of the drill guide and the virtual trajectories represent future possible drill guide trajectories.  
   
   
       10 . The computer assisted surgery system of  claim 7 , wherein said computer also records the pose of the drill guide at a signal from the surgeon; and retains graphic representations of the real and virtual trajectories superimposed on the image of the body part corresponding to the recorded pose, wherein the retained virtual trajectories serve as guide lines for subsequent pin insertions.