System and method for registering a bone of a patient with a computer assisted orthopaedic surgery system

• US 20070161888A1
• Filed: 12/30/2005
• Published: 07/12/2007
• Est. Priority Date: 12/30/2005
• Status: Abandoned Application

• Current Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Inventors: Popovic, Radivoje, Ashby, Alan, Sherman, Jason, DiSilvestro, Mark
• Application Number:
  US11/323,963
• Publication Number:
  US 20070161888A1
• Time in Patent Office: Days
• US Class Current: 600/409
• CPC Class Codes: A61B 17/15 Guides therefor arrangements for guiding straight saw blades in general B23D51/025
• CPC Class Codes: A61B 17/1703 using imaging means, e.g. by X-rays
• CPC Class Codes: A61B 17/1725 for applying transverse screws or pins through intramedullary nails or pins
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/252 indicating steps of a surgical procedure
• CPC Class Codes: A61B 2034/256 having a database of accessory information, e.g. including context sensitive help or scientific articles
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems

Abstract

A computer assisted orthopaedic surgery system includes a controller, a display device, and a magnetic sensor array. The magnetic sensor array includes one or more magnetic sensors configured to sense a magnetic field of a magnetic source coupled to a bone of a patient. The magnetic sensor array is configured to determine a position of the magnetic source and transmit data indicative of such position to the controller. The controller retrieves an image of the bone from an electronic file, determines a position of the bone, and displays a graphically rendered image of the bone on the display screen.

Claims

1. A method for operating a computer assisted orthopaedic surgery system, the method comprising:

determining a position of a magnetic source coupled to a bone of a patient based on a magnetic field generated by the magnetic source;

retrieving an image of the bone including indicia of the position of the magnetic source relative to the bone from a database; and

creating a graphically rendered image of the bone based on the determining and retrieving steps.

2. The method of claim 1, wherein the determining step comprises measuring a magnetic flux density of the magnetic field at a plurality of points in space.

3. The method of claim 2, wherein the measuring step comprises positioning a magnetic sensor array in the magnetic field.

4. The method of claim 3, wherein positioning a magnetic sensor array comprises positioning a magnetic sensor selected from the group consisting of:

a superconducting quantum interference (SQUID) magnetic sensor, an anisotropic magnetoresistive (AMR) magnetic sensor, a giant magnetoresistive (GMR) magnetic sensor, and a Hall-effect magnetic sensor.

5. The method of claim 3, further comprising activating an indicator of the magnetic sensor array when the measured magnetic flux density is greater than a predetermined threshold value.

6. The method of claim 3, wherein the determining step comprises determining a position of the magnetic source relative to the magnetic sensor array.

7. The method of claim 6, wherein the determining step comprises determining a position of the magnetic sensor array relative to the computer assisted orthopaedic surgery system.

8. The method of claim 7, wherein determining the position of the magnetic sensor array comprises determining a position of the magnetic sensor array using a reflective sensor array coupled to the magnetic sensor array.

9. The method of claim 7, wherein determining the position of the magnetic sensor array comprises determining a position of the magnetic sensor array using a wireless transmitter coupled to the magnetic sensor array.

10. The method of claim 2, wherein the measuring step comprises measuring at least one component of the three-dimensional magnetic flux density of the magnetic source at a plurality of points in space.

11. The method of claim 1, wherein the determining step comprises

measuring a first magnetic field generated by a first magnet;

measuring a second magnetic field generated by a second magnet; and

determining a position of the magnetic source based on the first and second magnetic fields.

12. The method of claim 11, wherein the determining step comprises determining values of the six degrees of freedom of the magnetic source based on the first and second magnetic fields.

13. The method of claim 11, wherein the determining step comprises determining a value of at least one of the six degrees of freedom of the magnetic source based on the position of the first and second magnets in the retrieved image.

14. The method of claim 1, wherein the determining step comprises determining a values of at least five degrees of freedom of a cylindrical, dipole magnet coupled to the bone of the patient.

15. The method of claim 1, wherein the determining step comprises determining the six degrees of freedom of the magnetic source based on the magnetic field at a plurality of points in space.

16. The method of claim 1, wherein the determining step comprises determining at lest one of the six degrees of freedom of the magnetic source based on the retrieved image.

17. The method of claim 1, wherein the retrieving step comprises retrieving an image selected from the group consisting of a computed tomography (CT) image of the bone, a fluoroscopy image of the bone, and an X-ray image of the bone.

18. The method of claim 1, wherein the retrieving step comprises retrieving the image based on the identity of the patient.

19. The method of claim 1, wherein the retrieving step comprises retrieving a three-dimensional image.

20. The method of claim 1, wherein the creating step comprises displaying the graphically rendered image of the bone in a location and orientation based on the determining step.

21. The method of claim 1, wherein the creating step comprises creating a graphically rendered image of the bone having surface contours determined based on the retrieved image.

22. The method of claim 1, further comprising wirelessly transmitting the position of the magnetic source to a computer.

23. The method of claim 3, further comprising locating the magnetic source with the magnetic sensor array subsequent to the creating step and decoupling the magnetic source from the bone.

24. The method of claim 3, further comprising compensating measurements of the magnetic sensor array based on at least one of an offset voltage of a magnetic sensor and a measurement value of the Earth'"'"'s magnetic field.

25. A computer assisted orthopaedic surgery system comprising:

a display device;

a processor electrically coupled to the display device; and

a memory device electrically coupled to the processor, the memory device having stored therein a plurality of instructions, which when executed by the processor, cause the processor to;

receive position data indicative of a position of a magnetic source coupled to a bone of a patient;

retrieve an image of the bone including indicia of the position of the magnetic source relative to the bone from a database; and

display a graphically rendered image of the bone on the display device in a location and orientation based on the retrieved image and the position data.

26. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive position data from a magnetic sensor array positioned in a magnetic field of the magnetic source.

27. The computer assisted orthopaedic surgery system of claim 26, further comprising determining a position of the magnetic sensor array relative to a reference point.

28. The computer assisted orthopaedic surgery system of claim 27, further comprising determining a position of the bone based on the position data and the position of the magnetic sensor array.

29. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to wirelessly receive position data from a magnetic sensor array.

30. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive position data from a magnetic sensor array of a wired connection.

31. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive position data indicative of a position of a cylindrical, dipole magnet.

32. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive position data that has been determined based on a magnetic field generated by the magnetic source.

33. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive position data that has been determined based on a first magnetic field generated by a first magnet and a second magnetic field generated by a second magnet.

34. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive data indicative of five degrees of freedom of the magnetic source.

35. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive data indicative of at least one component of the three-dimensional magnetic flux density of the magnetic source at a point in space.

36. The computer assisted orthopaedic surgery system of claim 25, wherein to receive position data comprises to receive position data indicative of a three dimensional location and orientation of the magnetic source relative to a magnetic sensor array.

37. The computer assisted orthopaedic surgery system of claim 25, wherein to retrieve an image of the bone comprises to retrieve an image selected from the group consisting of a computed tomography (CT) image of the bone, a fluoroscopy image of the bone, and an X-ray image of the bone.

38. The computer assisted orthopaedic surgery system of claim 25, wherein the retrieving step is based on the identity of the patient.

39. The computer assisted orthopaedic surgery system of claim 25, wherein to display a graphically rendered image of the bone comprises to display a graphically rendered image of the bone having surface contours determined based on the retrieved image.

40. A method of registering a bone of a patient with a computer assisted orthopaedic surgery system, the method comprising:

coupling a magnetic source to the bone of the patient;

generating an image of the bone and the magnetic source subsequent to the coupling step;

determining a position of the magnetic source based on a magnetic field generated by the magnetic source; and

creating a graphically rendered image of the bone based on the generating and determining steps.

41. The method of claim 40, wherein the coupling step comprises implanting the magnetic source in the bone.

42. The method of claim 40, wherein the coupling step comprises coupling a cylindrical, dipole magnet to the bone.

43. The method of claim 40, wherein the coupling step comprises coupling the magnetic source to the bone using a jig.

44. The method of claim 40, wherein the coupling step comprises (i) coupling a first magnet generating a first magnetic field to the bone and (ii) coupling a second magnet generating a second magnetic field to the bone, wherein the first and second magnets are separated by a distance such that the first and second magnetic fields do not substantially interfere with each other.

45. The method of claim 44, wherein the first and second magnets are coupled to the bone using a jig.

46. The method of claim 44, wherein the determining step comprises sensing the first and second magnetic fields and determining the position of the magnetic source based on the first and second magnetic fields.

47. The method of claim 40, wherein the generating step comprises generating an image selected from the group consisting of a computed tomography (CT) image of the bone, a fluoroscopy image of the bone, a magnetic resonance image (MRI) of the bone, and an X-ray image of the bone.

48. The method of claim 40, wherein the generating step comprises generating a three-dimensional image.

49. The method of claim 40, wherein the determining step comprises determining data indicative of the six degrees of freedom of the magnetic source.

50. The method of claim 40, wherein the creating step comprises creating a graphically rendered image of the bone having surface contours determined based on the generated image.

51. The method of claim 40, further comprising displaying the graphically rendered image of the bone in a location and orientation based on the position data.

52. The method of claim 40, wherein the determining step comprises determining the position of the magnetic source using a magnetic sensor.

53. The method of claim 52, further comprising compensating measurements of the magnetic sensor based on an offset voltage of the magnetic sensor.

54. The method of claim 52, further comprising compensating measurements of the magnetic sensor based on the Earth'"'"'s magnetic field.

55. The method of claim 40, further comprising locating the magnetic source with a magnetic sensor array subsequent to the creating step and decoupling the magnetic source from the bone.

56. The method of claim 40, further comprising storing the generated image in a database.

57. The method of claim 40, wherein the generating step comprises generating an image of the bone having a first magnet coupled thereto in a first position and a second magnet coupled thereto in a second position;

and further comprising determining a matrix of values that defines an amount of translation and rotation relating the position of the first magnet to the position of the second magnet.

58. The method of claim 40 further comprising determining data indicative of a positional relationship between the bone and the magnetic source based on the generated image.

59. The method of claim 58, wherein the data comprises a three-dimensional vector.

60. An apparatus for registering a bone of a patient with a computer assisted orthopaedic surgery system, the apparatus comprising:

a housing;

a magnetic sensor positioned in the housing and configured to measure a magnetic field of a magnetic source;

a processing circuit located in the housing and electrically coupled to the magnetic sensor, the processing circuit configured to determine position data indicative of a position of the magnetic source relative to the apparatus based on an output signal of the magnetic source; and

a transmitter located in the housing and electrically coupled with the processing circuit, the transmitter configured to transmit the position data to the computer assisted orthopaedic surgery system.

61. The apparatus of claim 60, wherein the processing circuit comprises a processor configured to determine a number of coefficients indicative of at least a portion of the six degrees of freedom of the magnetic source.

62. The apparatus of claim 60, wherein the transmitter comprises a wireless transmitter.

63. The apparatus of claim 60, further comprising an indicator coupled to the processing circuit, the processing circuit being configured to activate the indicator while the output of the magnetic sensor is greater than a predetermined threshold.

64. The apparatus of claim 63, wherein the indicator is a visual indicator.

65. A method of registering a bone of a patient with a computer assisted orthopaedic surgery system, the method comprising:

coupling a magnetic source to a bone of the patient;

retrieving an image of the bone having indicia of a position of the magnetic source relative to the bone from a database;

determining the six degrees of freedom of the magnetic source based on the retrieving step; and

creating a graphically rendered image of the bone based on the retrieved image and the determined values.