Semi-automatic customization of plates for internal fracture fixation
View Patent ↗A method on a processor customizes a fixation plate for repairing a bone fracture. A digital CAD model of an implant contains smooth analytic geometry representations including NURBS. The CAD geometry is directly manipulated to generate a customized implant CAD model that conforms to the desired region of the bone surface of a patient. Direct manipulation of NURBS geometry is computationally fast and suitable for interactive planning. The patient specific customized implant is produced directly from the generated customized CAD model with a standard CNC machine before surgery. The patient customized implant is implanted in the patient.
1. A method for creating a customized medical implant, comprising a processor:
receiving a Computer Aided Design (CAD) model of a medical implant;
converting a three dimensional medical image of a bone of patient, to an image of polygonal meshes;
computing a guide curve on the image of polygonal meshes of the bone;
registering the CAD model to an initial location on the image of the polygonal meshes of the bone;
deforming the CAD model in accordance with the guide curve to a customized CAD model; and
outputting the customized CAD model.
2. The method of claim 1 , wherein the customized CAD model is output to a manufacturing machine that manufactures the customized medical implant.
3. The method of claim 2 , further comprising installing the customized medical implant on the bone of the patient.
4. The method of claim 1 , further comprising:
interactively selecting a set of points on a path in the image of polygonal meshes of the bone that defines the guide curve.
5. The method of claim 4 , wherein a set of mesh edges connecting the set of points is computed by the processor and a deformation curve is computed as a B-Spline curve approximation of mesh vertices on a connecting path.
6. The method of claim 5 , wherein the processor processes the deformation curve to remove a wiggle.
7. The method of claim 1 , further comprising the processor converting all curves and surfaces in the CAD model to Non Uniform Rational B-Spline (NURBS) representations in the CAD model.
8. The method of claim 1 , further comprising the processor interpolating in a plurality of steps an interpolated deformation curve located between an axis defined by the initial location and the guide curve.
9. The method of claim 8 , further comprising testing for a collision between the interpolated deformation curve and the image of the polygonal meshes of the bone.
10. The method of claim 1 , further comprising increasing a degree of freedom that is associated with a maximum curvature of the guide curve.
11. The method of claim 1 , wherein the CAD model is selected from a library containing a plurality of predetermined CAD models.
12. A system to create a customized implant, comprising:
a memory enabled to store and retrieve data, including instructions;
a processor enabled to execute instructions to perform the steps:
receiving a Computer Aided Design (CAD) model of an implant;
converting a three dimensional medical image of a bone of patient to an image of polygonal meshes;
computing a guide curve on the image of polygonal meshes of the bone;
registering the CAD model to an initial location on the image of the polygonal meshes of the bone;
deforming the CAD model in accordance with the guide curve to a customized CAD model; and
outputting the customized CAD model on an output.
13. The system of claim 12 , further comprising a manufacturing machine that receives the customized CAD model and manufactures the customized implant based on the customized CAD model.
14. The system of claim 13 , wherein the manufacturing machine is a Computer Numerical Controlled (CNC) machine.
15. The system of claim 12 , wherein the processor:
selects a set of points on a path in the image of polygonal meshes of the bone that defines the guide curve;
computes a set of mesh edges connecting the set of points; and
computes a deformation curve as a B-Spline curve approximation of mesh vertices on a connecting path.
16. The system of claim 12 , wherein the processor:
converts all curves and surfaces in the CAD model to Non Uniform Rational B-Spline (NURBS) representations in the CAD model.
17. The system of claim 12 , wherein the processor:
interpolates a plurality of interpolated deformation curves located between an axis defined by the initial location and the guide curve.
18. The system of claim 12 , wherein the processor:
increases a degree of freedom that is associated with a maximum curvature of the guide curve.
19. The system of claim 12 , wherein the CAD model is provided from a storage device containing a library of at least two CAD models for medical implants.
20. The system of claim 12 , comprising a library of predetermined CAD models from which the CAD model of the implant is selected.