Generation of a mating surface model for patient specific cutting guide based on anatomical model segmentation

Patent metadata

Field	Value
Publication number	US-10912571-B2
Application number	US-201414776660-A
Country	US
Kind code	B2
Filing date	Mar 17, 2014
Priority date	Mar 15, 2013
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

A smooth mating surface model defining a mating surface of a customized arthroplasty jig is generated. For example, sagittal slices of a volumetric image of a patient bone are segmented with segmentation splines. An anatomically accurate model of the patient bone is generated from the segmentation splines. The anatomically accurate model includes anatomically accurate segmentation splines. The anatomically accurate segmentation splines are transformed into mating surface contours. Any inadequate segments of the mating surface contours are modified to obtain modified mating surface contours. A mating surface model of the patient bone is generated based on the mating surface contours and the modified mating surface contours. Three-dimensional cross-sections of the mating surface model are smoothed to generate the smooth mating surface model.

First claim

What is claimed is:

1. A method for generating a smooth mating surface model the method comprising:
segmenting sagittal slices of a volumetric image of a patient bone with segmentation splines;
generating an anatomically accurate model of the patient bone from the segmentation splines using at least one processor, the anatomically accurate model including anatomically accurate segmentation splines;
transforming the anatomically accurate segmentation splines into mating surface contours;
modifying any inadequate segments of the mating surface contours to obtain modified mating surface contours;
generating a mating surface model of the patient bone using the at least one processor based on the mating surface contours and the modified mating surface contours; and
smoothing three-dimensional cross-sections of the mating surface model by removing one or more peaks and valleys in at least one curve of the three-dimensional cross-sections without encroaching into a region corresponding to inside the patient bone to generate the smooth mating surface model, wherein smoothing the three-dimensional cross-sections of the mating surface model comprises:
identifying a group of points extending along one of the mating surface contours, the group of points being part of points defining the mating surface contour;
identifying an extreme outward point of the points defining the mating surface contour;
defining an outer boundary extending through the extreme outward point;
identifying a middle point of the group of points; and
determining whether the middle point is inward relative to the outward boundary, the middle point being translated along a path generally perpendicular to the outward boundary to reside on the outward boundary where the middle point is inward relative to the outward boundary and the middle point being left in place where the middle point is on the outward boundary.

2. The method of claim 1 , wherein the mating surface contours extend along at least one of an outer bone surface or an outer cartilage surface of the patient bone.

3. The method of claim 1 , wherein the group of points includes three points.

4. The method of claim 1 , wherein the inadequate segments include segments having at least one of: an imaging deficiency, a manufacturability constraint, or a surgical constraint.

5. The method of claim 1 , wherein the inadequate segments include segments corresponding to portions of a mating surface of a customized arthroplasty jig configured such that the portions would not contact a corresponding surface of the patient bone when the mating surface of the customized arthroplasty jig matingly receives and contacts the surface of the patient bone.

6. The method of claim 1 , wherein the patient bone is at least one of: a femur or a tibia.

7. The method of claim 1 , further comprising:
outputting the smooth mating surface model to a machining system configured to produce a customized arthroplasty jig based on the smooth mating surface model.

8. One or more non-transitory tangible computer readable storage media storing computer-executable instructions for performing a computer process on a computing system, the computer process comprising:
segmenting sagittal slices of a volumetric image of a patient bone with segmentation splines;
generating an anatomically accurate model of the patient bone from the segmentation splines, the anatomically accurate model including anatomically accurate segmentation splines;
transforming the anatomically accurate segmentation splines into mating surface contours;
modifying any inadequate segments of the mating surface contours to obtain modified mating surface contours;
generating a mating surface model of the patient bone based on the mating surface contours and the modified mating surface contours; and
smoothing three-dimensional cross-sections of the mating surface model by removing one or more peaks and valleys in at least one curve of the three-dimensional cross-sections without encroaching into a region corresponding to inside the patient bone to generate a smooth mating surface model, wherein smoothing the three-dimensional cross-sections of the mating surface model comprises:
identifying a group of points extending along one of the mating surface contours, the group of points being part of points defining the mating surface contour;
identifying an extreme outward point of the points defining the mating surface contour;
defining an outer boundary extending through the extreme outward point;
identifying a middle point of the group of points; and
determining whether the middle point is inward relative to the outward boundary, the middle point being translated along a path generally perpendicular to the outward boundary to reside on the outward boundary where the middle point is inward relative to the outward boundary and the middle point being left in place where the middle point is on the outward boundary.

9. The one or more non-transitory tangible computer readable storage media of claim 8 , wherein the mating surface contours extend along at least one of an outer bone surface or an outer cartilage surface of the patient bone.

10. The one or more non-transitory tangible computer readable storage media of claim 8 , wherein the group of points includes three points.

11. A system comprising:
a computing device having at least one processor;
the computing device generating a smooth mating surface model having smoothed three-dimensional cross-sections of a mating surface model by removing one or more peaks and valleys in at least one curve of three-dimensional cross-sections without encroaching into a region corresponding to inside a patient bone, the mating surface model generated based on an anatomically accurate model of a patient bone, the anatomically accurate model generated from segmentation splines segmenting sagittal slices of a volumetric image of the patient bone;
the anatomically accurate model including anatomically accurate segmentation splines;
the at least one processor transforming the anatomically accurate segmentation splines into mating surface contours;
the at least one processor modifying any inadequate segments of the mating surface contours to obtain modified mating surface contours;
the at least one processor generating a mating surface model of the patient bone based on the mating surface contours and the modified mating surface contours; and
wherein the computing device smoothes the three-dimensional cross-sections of the mating surface model by:
identifying a group of points extending along one of the mating surface contours, the group of points being part of points defining the mating surface contour;
identifying an extreme outward point of the points defining the mating surface contour;
defining an outer boundary extending through the extreme outward point;
identifying a middle point of the group of points; and
determining whether the middle point is inward relative to the outward boundary, the middle point being translated along a path generally perpendicular to the outward boundary to reside on the outward boundary where the middle point is inward relative to the outward boundary and the middle point being left in place where the middle point is on the outward boundary.

12. The system of claim 11 , further comprising:
a machining system producing the customized arthroplasty jig based on the smooth mating surface model.

13. The system of claim 11 , wherein the patient bone is at least one of: a femur or a tibia.

Assignees

• Howmedica Osteonics Corp

Inventors

• Pavlovskaia Elena I
• Shpungin Boris E
• Mishin Oleg
• Sominskaya Olga

Classifications

• A61B17/155 Primary

  Cutting femur · CPC title

• A61F2/38

  for elbows or knees · CPC title

• A61B2034/105

  Modelling of the patient, e.g. for ligaments or bones · CPC title

• A61B34/10

  Computer-aided planning, simulation or modelling of surgical operations · CPC title

• A61B2034/108

  Computer aided selection or customisation of medical implants or cutting guides · CPC title