Computer-implemented technique for defining a bone cut

Patent metadata

Field	Value
Publication number	US-9659152-B2
Application number	US-201414249695-A
Country	US
Kind code	B2
Filing date	Apr 10, 2014
Priority date	Apr 12, 2013
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A technique for generating a data set that geometrically defines a bone cut configuration for transverse maxillary distraction is using a computer-implemented method. An aspect of the technique comprises creating a numeric model of a maxilla based on patient-specific data of the maxilla. The numeric model is representative of mechanical properties of the maxilla. Based on the numeric model thus generated, one or more cut configurations for one or more bone cuts on at least one of a left hand side and a right hand side of the maxilla are determined. Each cut configuration has been determined to compensate for asymmetric mechanical properties of the maxilla. In a further step, a data set indicative of the one or more cut configurations thus determined is generated. The data set may be used to create a surgical template or jig, for computer-assisted surgery or a surgical navigation system.

First claim

The invention claimed is:

1. A computer-implemented method of generating a data set that geometrically defines at least one bone cut configuration for transverse maxillary distraction, the method comprising:
creating, based on patient-specific data of a maxilla, a numeric model representative of mechanic properties of the maxilla;
determining, based on the numeric model thus generated, one or more cut configurations for one or more first bone cuts on at least one of a left hand side and a right hand side of the maxilla, wherein the one or more cut configurations are determined so as to compensate for asymmetric mechanic properties of the maxilla upon distraction; and
generating a data set indicative of the one or more cut configurations.

2. The method of claim 1 , wherein the one or more first bone cuts are defined to at least partially extend in a lateral midfacial area.

3. The method of claim 1 , wherein each cut configuration comprises data indicative of at least one of a cutting plane, a cutting line, a cutting direction, a cutting length and at least one bone cut boundary point.

4. The method of claim 1 , wherein determining the one or more cut configurations comprises introducing the one or more first bone cuts in the numeric model and analyzing the resulting numeric model as to its mechanic properties upon distraction.

5. The method of claim 1 , wherein determining the one or more cut configurations comprises introducing one or more second bone cuts in the numeric model and analyzing the resulting numeric model as to its mechanic properties upon distraction, wherein the one or more second bone cuts at least partially separate in the numeric model regions moved apart upon distraction from regions essentially not affected by distraction.

6. The method of claim 1 , wherein creating the numeric model comprises:
processing the patient specific data to determine at least one of contour data and stiffness data for the maxilla;
and calculating the numeric model from at least one of the contour data and the stiffness data.

7. The method of claim 1 , wherein the numeric model is indicative of at least one of a stiffness of the maxilla, a reaction force upon distraction of the maxilla and a displacement upon distraction of the maxilla.

8. The method of claim 1 , wherein the one or more cut configurations are determined, based on the numeric model, so as to balance at least one of a stiffness asymmetry of the maxilla, asymmetric reaction forces upon distraction and asymmetric displacements upon distraction.

9. The method of claim 1 , wherein determining the one or more cut configurations comprises one of:
applying a distraction force on each of a first side and a second side of the numeric model that correspond to the left hand side and the right hand side of the maxilla, respectively, and determining the resulting displacements of the first side and the second side of the numeric model, respectively; and
applying a displacement on each of the first side and the second side of the of the numeric model and determining the resulting reaction forces on the first side and the second side of the numeric model, respectively.

10. The method of claim 9 , wherein the distraction forces or displacements are applied in at least one of a region of the molars and a region of the canines.

11. The method of claim 1 , wherein determining the one or more cut configurations based on the numeric model comprises applying an iterative calculation procedure based on one or more optimization parameters.

12. The method of claim 11 , wherein in each iteration at least one new cut configuration is calculated and a new numeric model is created based thereon for the next iteration.

13. The method of claim 11 , wherein the one or more optimization parameters include at least one of a minimum cut length, equalization of stiffnesses on a first side and a second side of the numeric model that correspond to the left hand side and the right hand side of the maxilla, respectively, equalization of displacements on the first side and the second side, equalization of distraction or reaction forces on the first side and the second side, and minimum distraction or reaction forces.

14. The method of claim 1 , wherein initially multiple cut configurations are defined for which associated numeric models are determined and analyzed as to one or more quality parameters.

15. The method of claim 14 , wherein the one or more quality parameters include at least one of a minimum cut length, equalization of stiffnesses on a first side and a second side of the of the numeric model that correspond to the left hand side and the right hand side of the maxilla, respectively, equalization of displacements on the first side and the second side, equalization of distraction or reaction forces on the first side and the second side, and minimum distraction or reaction forces.

16. A computer program comprising: program code portions for performing the steps of claim 1 when the computer program is executed by a computing device.

17. The computer program of claim 16 , stored on a computer readable recording medium.

18. The method of claim 1 , wherein the data set generated is for at least one of manufacturing a surgical template or jig for bone cutting, controlling a computer-assisted surgery system for bone cutting and controlling a surgical navigation system for bone cutting.

19. A surgical template or jig for bone cutting, manufactured on the basis of the data set generated according to claim 1 .

20. A computer-assisted surgery system, controlled on the basis of the data set generated according to claim 1 .

21. A surgical navigation system, controlled on the basis of the data set generated according to claim 1 .

22. A computer-implemented method of generating a data set that geometrically defines at least one bone cut configuration for transverse maxillary distraction, the method comprising:
creating, based on patient-specific data of a maxilla, a numeric model representative of mechanic properties of the maxilla;
determining, based on the numeric model thus generated, one or more cut configurations for one or more first bone cuts on at least one of a left hand side and a right hand side of the maxilla, wherein the one or more cut configurations are determined so as to compensate for asymmetric mechanic properties of the maxilla upon performing the transverse maxillary distraction, and wherein determining the one or more cut configurations comprises introducing the one or more first bone cuts in the numeric model, analyzing the resulting numeric model as to its mechanic properties upon distraction, and applying an iterative calculation procedure based on one or more optimization parameters, wherein, in each iteration, at least one new cut configuration is calculated, and a new numeric model is created based thereon for the next iteration; and
generating a data set indicative of the one or more cut configurations.

Assignees

• Cadfem Gmbh
• Stryker European Holdings I Llc

Inventors

• Mueller Christoph

Classifications

• A61B34/10

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

• A61B34/20 Primary

  Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis · CPC title

• A61B2034/107

  Visualisation of planned trajectories or target regions · CPC title

• A61B2034/105

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

• G16H50/50

  for simulation or modelling of medical disorders · CPC title