System and method for image segmentation in generating computer models of a joint to undergo arthroplasty

• US 8,160,345 B2
• Filed: 04/18/2011
• Issued: 04/17/2012
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Otismed Corporation (Stryker Corporation)
• Inventors: Pavlovskaia, Elena, Mishin, Oleg, Shpungin, Boris E.
• Primary Examiner(s): FULLER, RODNEY EVAN
• Application Number:
  US13/066,568
• Publication Number:
  US 20110282473A1
• Time in Patent Office: 365 Days
• Field of Search: 385/131
• US Class Current: 382/131
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61B 17/1703 using imaging means, e.g. by X-rays
• CPC Class Codes: A61B 17/7013 the shape of the element being adjustable before use adjustable length plates A61B17/7014
• CPC Class Codes: A61B 2017/1602 Mills
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/107 Visualisation of planned trajectories or target regions
• CPC Class Codes: A61B 2034/108 Computer aided selection or customisation of medical implants or cutting guides
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 2090/3762 using computed tomography systems [CT]
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 90/37 Surgical systems with images on a monitor during operation
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: G06F 30/20 : Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06T 17/00 : Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 17/20 : Finite element generation, e.g. wire-frame surface description, tesselation
• CPC Class Codes: G06T 2200/08 : involving all processing steps from image acquisition to 3D model generation
• CPC Class Codes: G06T 2207/30008 : Bone
• CPC Class Codes: G06T 7/0012 : Biomedical image inspection
• CPC Class Codes: G06T 7/12 : Edge-based segmentation
• CPC Class Codes: G06T 7/13 : Edge detection
• CPC Class Codes: G06T 7/70 : Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06V 10/46 : Descriptors for shape, contour or point-related descriptors, e.g. scale invariant feature transform [SIFT] or bags of words [BoW]; Salient regional features colour feature extraction G06V10/56
• CPC Class Codes: G06V 10/471 : using approximation functions
• CPC Class Codes: G06V 2201/033 : of skeletal patterns
• CPC Class Codes: G16H 50/50 : for simulation or modelling of medical disorders
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

A custom arthroplasty guide and a method of manufacturing such a guide are disclosed herein. The guide manufactured includes a mating region configured to matingly receive a portion of a patient bone associated with an arthroplasty procedure for which the custom arthroplasty guide is to be employed. The mating region includes a surface contour that is generally a negative of a surface contour of the portion of the patient bone. The surface contour of the mating region is configured to mate with the surface contour of the portion of the patient bone in a generally matching or interdigitating manner when the portion of the patient bone is matingly received by the mating region. The method of manufacturing the custom arthroplasty guide includes: a) generating medical imaging slices of the portion of the patient bone; b) identifying landmarks on bone boundaries in the medical imaging slices; c) providing model data including image data associated with a bone other than the patient bone; d) adjusting the model data to match the landmarks; e) using the adjusted model data to generate a three dimensional computer model of the portion of the patient bone; f) using the three dimensional computer model to generate design data associated with the custom arthroplasty guide; and g) using the design data in manufacturing the custom arthroplasty guide.

Claims

1. A method of manufacturing a custom arthroplasty guide, the guide including a mating region configured to matingly receive a portion of a patient bone associated with an arthroplasty procedure for which the custom arthroplasty guide is to be employed, the mating region including a surface contour that is generally a negative of a surface contour of the portion of the patient bone, the surface contour of the mating region being configured to mate with the surface contour of the portion of the patient bone in a generally matching or interdigitating manner when the portion of the patient bone is matingly received by the mating region, the method of manufacture comprising:

a) generating medical imaging slices of the portion of the patient bone;

b) identifying landmarks on bone boundaries in the medical imaging slices;

c) providing model data including image data associated with a bone other than the patient bone;

d) adjusting the model data to match the landmarks;

e) using the adjusted model data to generate a three dimensional computer model of the portion of the patient bone;

f) using the three dimensional computer model to generate design data associated with the custom arthroplasty guide; and

g) using the design data in manufacturing the custom arthroplasty guide.

2. The method of claim 1, wherein operation a) includes generating at least one of MRI slices or CT slices of the portion of the patient bone.

3. The method of claim 1, wherein operation b) includes placing landmark points on the bone boundaries in the medical imaging slices.

4. The method of claim 3, wherein placing the landmark points includes a user at a user interface employing at least one of a mouse, keyboard, pen-and-tablet system, touch screen system, or spatial input device to place landmark points.

5. The method of claim 3, wherein the bone boundaries include lines representative in the medical imaging slices of cortical bone boundaries.

6. The method of claim 1, wherein the image data associated with a bone other than the patient bone includes a golden bone model.

7. The method of claim 1, wherein the image data of operation c) includes a model of a bone that is the same bone type as the patient bone, but representative of what is considered to be generally normal with respect to the bone type for at least one of size, condition, shape, weight, age, height, race, gender or diagnosed disease condition.

8. The method of claim 1, wherein operation d) includes deforming a mesh to match the landmarks, wherein the mesh is associated with the model data.

9. The method of claim 8, wherein deforming the mesh to match the landmarks includes registering the mesh to the landmarks using at least one of translation transforms, similarity transforms or affine transforms.

10. The method of claim 9, wherein deforming the mesh to match the landmarks further includes detecting image edges near the mesh.

11. The method of claim 10, wherein detecting image edges near the mesh includes computing a signed distance image for the mesh.

12. The method of claim 11, wherein detecting the image edges near the mesh further includes computing a gradient of the signed distance image.

13. The method of claim 12, wherein detecting the image edges near the mesh yet further includes computing a gradient of at least one of the medical imaging slices.

14. The method of claim 13, wherein detecting the image edges near the mesh still further includes computing an edges image by correcting the gradient of at least one of the medical imaging slices with the gradient of the signed distance image.

15. The method of claim 10, wherein deforming the mesh to match the landmarks yet further includes registering simultaneously the mesh to the landmarks and the image edges using B-spline deformable transforms.

16. The method of claim 8, wherein operation d) further includes generating segmentation curves from the deformed mesh.

17. The method of claim 16, wherein operation d) yet further includes approximating the segmentation curves with spline curves.

18. The method of claim 17, wherein operation d) still further includes modifying the spline curves to match the landmarks.

19. The method of claim 18, wherein modifying the spline curves to match the landmarks includes identifying a landmark from the landmarks and computing a distance of the spline curve to the indentified landmark.

20. The method of claim 19, wherein modifying the spline curves to match the landmarks further includes identifying a closest arc of the spline curve to the identified landmark and modifying the closest arc to include the identified landmark, resulting in a modified spline curve.

21. The method of claim 20, wherein modifying the spline curves to match the landmarks yet further includes computing distances from other landmarks to the modified spline curve and, if the distances are worse, disregarding the modification to the closest arc that resulted in the modified spline curve.

22. The method of claim 21, wherein modifying the spline curves to match the landmarks still further includes identifying a point in the closest arc that is closest to the identified landmark and inserting a spline vertex at the indentified point.

23. The method of claim 22, wherein modifying the spline curves to match the landmarks still further includes adjusting the closest arc to fit the spline curve.

24. The method of claim 23, wherein modifying the spline curves to match the landmarks still further includes moving the identified point to the identified landmark.

25. The method of claim 1, wherein in operation e) the three dimensional computer model of the portion of the patient bone includes:

a bone only model that represents bone surfaces but no cartilage surfaces;

or a restored bone model that represents bone surfaces but no cartilage surfaces.

26. The method of claim 1, wherein in operation e) the three dimensional computer model of the portion of the patient bone includes an arthritic model that represents both bone and cartilage surfaces.

27. The method of claim 1, wherein in operation f) the data associated with the custom arthroplasty guide includes at least one of data associated with the design of the surface contour of the mating region or a resection plane associated with a resection guide surface of the custom arthroplasty guide.

28. The method of claim 1, wherein in operation f) the data associated with the custom arthroplasty guide includes manufacturing instructions for manufacturing the custom arthroplasty guide.

29. The method of claim 1, wherein operation g) includes using the design data to guide a CNC machine or SLA machine in manufacturing the custom arthroplasty guide.

30. A method of manufacturing a custom arthroplasty guide, the guide including a mating region configured to matingly receive a portion of a patient bone associated with an arthroplasty procedure for which the custom arthroplasty guide is to be employed, the mating region including a surface contour that is generally a negative of a surface contour of the portion of the patient bone, the surface contour of the mating region being configured to mate with the surface contour of the portion of the patient bone in a generally matching or interdigitating manner when the portion of the patient bone is matingly received by the mating region, the method of manufacture comprising:

a) generating medical imaging data of the portion of the patient bone;

b) identifying landmarks associated with bone boundaries in the medical imaging data;

c) providing a geometrical representation of an exemplary bone that is not the patient bone but is the same bone type as the patient bone and is representative of what is considered to be generally normal with respect to the bone type for at least one of size, condition, shape, weight, age, height, race, gender or diagnosed disease condition;

d) adjusting the geometrical representation of the exemplary bone to match the landmarks;

e) using the adjusted geometrical representation of the exemplary bone to generate a three dimensional computer model of the portion of the patient bone;

f) using the three dimensional computer model to generate design data associated with the custom arthroplasty guide; and

g) using the design data in manufacturing the custom arthroplasty guide.

31. The method of claim 30, wherein the geometrical representation includes at least one of a golden femur mesh or a golden tibia mesh.

32. A method of manufacturing a custom arthroplasty guide, the guide including a mating region configured to matingly receive a portion of a patient bone associated with an arthroplasty procedure for which the custom arthroplasty guide is to be employed, the mating region including a surface contour that is generally a negative of a surface contour of the portion of the patient bone, the surface contour of the mating region being configured to mate with the surface contour of the portion of the patient bone in a generally matching or interdigitating manner when the portion of the patient bone is matingly received by the mating region, the method of manufacture comprising:

a) generating medical imaging slices of the portion of the patient bone;

b) identifying landmarks on cortical bone boundaries in the medical imaging data;

c) providing golden bone image data that is not of the patient bone but is of the same bone type as the patient bone and is representative of what is considered to be generally typical with respect to a characteristic of bones such as the patient bone;

d) segmenting the golden bone image data and generating a golden bone mesh from the segmented golden bone image data;

e) deforming the golden bone mesh to match the landmarks;

f) generating at least one of segmentation curves or spline curves from the deformed golden bone mesh;

g) modify the at least one of segmentation curves or spline curves to match the landmarks;

h) using the modified at least one of segmentation curves or spline curves to generate a three dimensional computer model generally representative of the portion of the patient bone;

i) using the three dimensional computer model to generate design data associated with the custom arthroplasty guide; and

j) using the design data in manufacturing the custom arthroplasty guide.

33. The method of claim 32, wherein, with respect to operation c), the characteristic includes at least one of size, condition, shape, weight, age, height, race, gender or diagnosed disease condition.