Systems and methods for performing spine surgery

Abstract

The present application includes a position tracking system for tracking the location of surgical objects within the surgical field, a neuromonitoring system for detecting the existence of (and optionally the distance and/or direction to) neural structures during a surgical procedure, and a processing system communicatively linked to both the position tracking system and the neuromonitoring system.

What is claimed is: 
     
       1. A method for tracking a position of an instrument relative to a surgical target site, said method comprising the steps of:
 using an imaging device to take a first image of a patient's body in a first anatomical view, wherein said imaging device displays a virtual center location when taking said first image and said first image has a user defined first point location at said virtual center location, and wherein said imaging device is in a first position; 
 obtaining three-dimensional positional data of the location of said imaging device in said first position while taking said first image; 
 using said imaging device to take a second image of said patient's body in said first anatomical view, wherein said imaging device displays a second virtual center location when taking said second image and said second image has a user defined second point location at said second virtual center location, and wherein said imaging device is in a second position, and wherein movement between said first and second positions of said imaging device is constrained to one axis; 
 obtaining three-dimensional positional data of the location of said imaging device in said second position while taking said second image; 
 scaling the first and second images to create a virtual backdrop image in said first anatomical view for viewing on a display unit, wherein said scaling comprises selecting the user defined first and second point locations to calculate a physical distance between said user defined first and second point locations and selecting at least one said user defined first and second point locations from at least one of said first and second images to correlate said physical distance between said user defined first and second point locations on said patient's body and a number of pixels between said user defined first and second point locations as represented on said display unit; and 
 monitoring three-dimensional position data of at least one surgical instrument via said display unit as said surgical instrument is moved within said patient's body by tracking a virtual representation of said surgical instrument overlaid onto said virtual backdrop image. 
 
     
     
       2. The method of  claim 1 , wherein said imaging device is a c-arm fluoroscope. 
     
     
       3. The method of  claim 1 , wherein said user defined first point location is on the spine of said patient. 
     
     
       4. The method of  claim 1 , wherein said first anatomical view is at least one of a lateral view and an anterior-posterior view. 
     
     
       5. The method of  claim 1 , wherein said three-dimensional positional data of the first and second positions of the imaging device is registered using an infrared position tracking system. 
     
     
       6. The method of  claim 1 , wherein said user defined second point location is on the spine of said patient. 
     
     
       7. The method of  claim 1 , wherein the scaling is accomplished manually. 
     
     
       8. The method of  claim 1 , wherein the at least one surgical instrument comprises at least one of a cannula, a dilator, a retractor blade, a k-wire, a cobb, a rasp, a drill, a tap, and a screw driver. 
     
     
       9. The method of  claim 1 , wherein the position of said at least one surgical instrument is monitored during a spine surgery procedure. 
     
     
       10. The method of  claim 9 , wherein the spinal surgery procedure is a lateral lumbar spinal surgery procedure. 
     
     
       11. A method for tracking a position of a surgical instrument during a surgical procedure, said method comprising the steps of:
 using an intraoperative imaging device in a first position to generate a first radiographic image of a patient's body in a first anatomical view, wherein said first radiographic image displays a first user defined point location in the center of the first image; 
 using said intraoperative imaging device in a second position to generate a second radiographic image of the patient's body in said first anatomical view, wherein said second radiographic image displays a second user defined point location in the center of the second image; 
 obtaining three-dimensional positional data of said first position of said imaging device during generation of said first image and said second position of said imaging device during generation of said second image; 
 scaling the first and second images to create a first virtual backdrop image in said first anatomical view for viewing on a display unit, said scaling step comprising correlating a physical distance between the first and second user defined point locations on said patient's body and a number of pixels between said first and second user defined point locations as represented on said display unit; 
 using said imaging device in a third position to generate a third radiographic image of the patient's body in a second anatomical view, wherein said third radiographic image displays a third user defined point location in the center of the third image; 
 using said imaging device in a fourth position to generate a fourth radiographic image of the patient's body in said second anatomical view, wherein said fourth radiographic image displays a fourth user defined point location in the center of the fourth image; 
 obtaining three-dimensional positional data of said third position of said imaging device during generation of said third image and said fourth position of said imaging device during generation of said fourth image; 
 scaling the third and fourth images to create a second virtual backdrop image in said second anatomical view for viewing on said display unit, said scaling the third and fourth images step comprising correlating a physical distance between the third and fourth user defined point locations on said patient's body and a number of pixels between said third and fourth user defined point locations as represented on said display unit; and 
 tracking a virtual representation of a surgical instrument against said first and second virtual backdrop images as the actual surgical instrument is moved within said patient's body. 
 
     
     
       12. The method of  claim 11 , wherein said imaging device is a c-arm fluoroscope. 
     
     
       13. The method of  claim 11 , wherein said three-dimensional positional data of the first, second, third, and fourth positions of the imaging device is registered using an infrared position tracking system. 
     
     
       14. The method of  claim 11 , wherein said first and second anatomical views are anterior-posterior and lateral views. 
     
     
       15. The method of  claim 11 , wherein the surgical instrument is at least one of an intervertebral implant, an intervertebral trial, a rasp, a cobb, a retractor, a dilator, a cannula, a k-wire, a drill, a tap, and a screw driver. 
     
     
       16. The method of  claim 11 , wherein each said scaling step is accomplished manually. 
     
     
       17. The method of  claim 11 , wherein the position of said surgical instrument is monitored during a spine surgery procedure. 
     
     
       18. The method of  claim 17 , wherein the spinal surgery procedure is a lateral lumbar spinal surgery procedure. 
     
     
       19. A method comprising, with one or more processors:
 receiving movement data of an instrument as the instrument is advanced to a surgical target site;   receiving neurophysiological data, wherein the neurophysiological data corresponds to the movement data;   determining a virtual location on an image of the surgical target site corresponding to a location of the instrument relative to the surgical target site when a neurophysiological response was elicited by the instrument, the determining being based on the movement data and the neurophysiological data; and   overlaying a graphic representative of the neurophysiological data onto the image of the surgical target site in association with the determined virtual location.    
     
     
       20. The method of claim 19, wherein the neurophysiological data comprises one or more electromyography responses received at a distal end of the instrument.  
     
     
       21. The method of claim 20, further comprising:
 determining one or more threshold ranges based on a plurality of predetermined electromyography responses; and   based on an electromyography response of the neurophysiological data being within a range of the one or more threshold ranges, determining at least one or more visual effects associated with the graphic to be displayed on the image of the surgical target site.    
     
     
       22. The method of claim 19, further comprising:
 overlaying a virtual representation of the instrument onto the image of the surgical target site as the instrument is advanced to the surgical target site.    
     
     
       23. The method of claim 19, wherein the image of the surgical target site comprises at least one of an anterior-posterior view and a lateral view.  
     
     
       24. The method of claim 19, wherein the instrument comprises at least one of a cannula, a dilator, a retractor blade, a k-wire, a cobb, a rasp, a drill, a tap, and a screw driver.  
     
     
       25. The method of claim 19, wherein the instrument is advanced through the psoas muscle to the surgical target site.  
     
     
       26. The method of claim 19, wherein overlaying the graphic representative of the neurophysiological data at the determined virtual location includes:
 providing, as part of the graphic representation, a number based on a threshold intensity required to elicit the neurophysiological response.    
     
     
       27. The method of claim 19, wherein overlaying the graphic representative of the neurophysiological data at the determined virtual location includes:
 providing, as part of the graphic, a color associated with a relative distance to nearby nerve tissue.    
     
     
       28. The method of claim 19, wherein overlaying the graphic representative of the neurophysiological data at the determined virtual location includes:
 providing, as part of the graphic, an indication of a radial position of the instrument corresponding to the neurophysiological response.    
     
     
       29. The method of claim 19, further comprising:
 causing a neuromonitoring system to provide an electrical stimulation signal to tissue of a patient having the surgical target site via at least one electrode of the initial dilator.    
     
     
       30. The method of claim 19, further comprising:
 simultaneously displaying onto the image each respective graphic of a plurality of graphics at a respective virtual location of where a respective neurophysiological response was detected while the instrument was at that respective virtual location.    
     
     
       31. The method of claim 30, further comprising:
 as the instrument is retreated or repositioned, modifying one or more of the plurality of graphics.    
     
     
       32. A method comprising:
 receiving movement data of a dilator as the dilator is advanced through a patient's psoas muscle to a surgical target site;   overlaying a virtual representation of the dilator onto an image of the surgical target site as the dilator is advanced to the surgical target site;   receiving neurophysiological data, wherein the neurophysiological data corresponds to the movement data;   determining a virtual location on an image of the surgical target site corresponding to a location of the instrument relative to the surgical target site when a neurophysiological response was elicited by the instrument, the determining being based on the movement data and the neurophysiological data; and   overlaying a graphic representative of the neurophysiological data onto the image of the surgical target site in association with the determined virtual location,   wherein overlaying the graphic representative of the neurophysiological data at the determined virtual location includes:   providing, as part of the graphic representation, a number based on a threshold intensity required to elicit the neurophysiological response;   providing, as part of the graphic, a color associated with a relative distance to nearby nerve tissue; or   providing, as part of the graphic, an indication of a radial position of the instrument corresponding to the neurophysiological response.    
     
     
       33. The method of claim 30, wherein overlaying the graphic representative of the neurophysiological response at the determined virtual location includes:
 providing, as part of the graphic representation, a number based on a threshold intensity required to elicit the neurophysiological response;   providing, as part of the graphic, a color associated with a relative distance to nearby nerve tissue; and   providing, as part of the graphic, an indication of a radial position of the instrument corresponding to the neurophysiological response.    
     
     
       34. A system comprising:
 a position tracking system capable of tracking one or more movements of an instrument during a surgical procedure;   a display unit; and   a control unit in communication with the position tracking system and the display unit, wherein the control unit is configured to:
 receive, from the position tracking system, movement data of the instrument as the instrument is advanced to a surgical target site; 
 receive neurophysiological data, wherein the neurophysiological data corresponds to the movement data; 
 determine a virtual location on an image of the surgical target site corresponding to a location of the instrument when a neurophysiological response was elicited, the determining being based on the neurophysiological data and the movement data; 
 overlay a graphic representative of the neurophysiological response onto the image of the surgical target site in association with the determined virtual location; and 
 display the overlaid graphic via the display unit.  
   
     
     
       35. The system of claim 34, wherein the neurophysiological data comprises one or more electromyography responses received at a distal end of the instrument.  
     
     
       36. The system of claim 35, wherein the control unit is further configured to:
 determine one or more threshold ranges based on a plurality of predetermined electromyography responses; and   based on an electromyography response of the neurophysiological data being within a range of the one or more threshold ranges, determine at least one or more visual effects associated with the graphic to be displayed on the image of the surgical target site.    
     
     
       37. The system of claim 34, wherein the control unit is further configured to:
 overlay a virtual representation of the instrument onto the image of the surgical target site as the instrument is advanced to the surgical target site; and   display the overlaid virtual representation onto the image via the display unit.    
     
     
       38. The system of claim 34, wherein the image of the surgical target site comprises at least one of an anterior-posterior view and a lateral view.  
     
     
       39. The system of claim 34, wherein the instrument comprises at least one of a cannula, a dilator, a retractor blade, a k-wire, a cobb, a rasp, a drill, a tap, and a screw driver.  
     
     
       40. The system of claim 34, wherein the instrument is advanced through the psoas muscle to the surgical target site.  
     
     
       41. A computer-implemented method comprising:
 receiving a first neurophysiological response associated with an instrument being in a first position at a surgical target site;   receiving a second neurophysiological response associated with the instrument being in a second position at the surgical target site;   determining first and second virtual locations corresponding to the first and second positions; and   overlaying a first graphic representative of the first neurophysiological response at the first virtual location onto the image of the surgical target site;   overlaying a second graphic representative of the second neurophysiological response at the second virtual location onto the image of the surgical target site; and   displaying the overlaid first and second graphics.    
     
     
       42. The method of claim 41, wherein the second position is based on a given rotational movement of the instrument.  
     
     
       43. The method of claim 41, wherein the first and second neurophysiological responses comprise electromyography responses, the method further comprising:
 determining one or more threshold ranges based on a plurality of predetermined electromyography responses; and   based on a given electromyography response being within a given range of the one or more threshold ranges, determining at least one or more visual effects associated with at least one of the first or second graphic to be displayed on the image of the surgical target site.    
     
     
       44. The method of claim 41, further comprising:
 overlaying a virtual representation of the instrument onto the image of the surgical target site.    
     
     
       45. The method of claim 41, wherein the image of the surgical target site comprises at least one of an anterior-posterior view and a lateral view.  
     
     
       46. The method of claim 41, wherein the instrument comprises at least one of a cannula, a dilator, a retractor blade, a k-wire, a cobb, a rasp, a drill, a tap, and a screw driver.  
     
     
       47. The method of claim 41, wherein the overlaying includes:
 providing, as part of the first graphic, a first number based on a threshold intensity required to elicit the first neurophysiological response; and   providing, as part of the second graphic, a second number based on a threshold intensity required to elicit the second neurophysiological response.    
     
     
       48. The method of claim 41, wherein the overlaying includes:
 providing, as part of the first graphic, a color associated with a relative distance to nearby nerve tissue.    
     
     
       49. The method of claim 41, wherein the overlaying includes:
 providing, as part of the first graphic, a first indication of a radial position of the instrument corresponding to the first neurophysiological response; and   providing, as part of the second graphic, a second indication of a radial position of the instrument corresponding to the second neurophysiological response.