Method for modeling an implant and an implant manufactured by the method

• US 7,050,877 B2
• Filed: 07/25/2003
• Issued: 05/23/2006
• Est. Priority Date: 08/30/2001
• Status: Expired due to Fees

• Current Assignee: Hiroshi Iseki, Pentax Corporation (Hoya Corporation)
• Original Assignee: Hiroshi Iseki, Pentax Corporation (Hoya Corporation)
• Inventors: Abe, Keita, Ogawara, Yoshiyuki, Iseki, Hiroshi
• Primary Examiner(s): Picard, Leo
• Assistant Examiner(s): KOSOWSKI, ALEXANDER J
• Application Number:
  US10/626,533
• Publication Number:
  US 20040138591A1
• Time in Patent Office: 1,033 Days
• Field of Search: 700/95, 700/97, 700/118, 700/182, 623/17.19, 623/901, 623/11.11, 623/16.11, 128/897, 128/898
• US Class Current: 700/118
• CPC Class Codes: A61F 2/2875 Skull or cranium A61F2/2803 and A61F2/3099 take precedence
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30948 using computerized tomography, i.e. CT scans
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: B29C 64/165 using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber
• CPC Class Codes: B29L 2031/7532 Artificial members, protheses
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G05B 19/4097 characterised by using design data to control NC machines, e.g. CAD/CAM G05B19/4093 takes precedence
• CPC Class Codes: G05B 2219/35062 Derive mating, complementary, mirror part from computer model data
• CPC Class Codes: G05B 2219/35069 Derive missing surface from mirror part of computer model
• CPC Class Codes: G05B 2219/45168 Bone prosthesis
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

A method for modeling an implant to be applied to a defect of a bone comprises the steps of obtaining a plurality of tomographic image data of the bone based on measurement data by MRI, producing three-dimensional image data of the bone based on the plurality of tomographic image data, and estimating a shape of a missing born that was previously present or should have been present in the defect of the bone to obtain three-dimensional data of the implant. The estimating step comprises the steps of estimating a provisional shape of the implant which has a contour conformable with the shape of a contour of periphery of the side walls of the defect at the distal surface of the bone and has a predetermined thickness; and deleting data of portions of the provisional shape of the implant that overlap the bone from the data of the provisional shape of the implant so that the three-dimensional data of the implant has an outer peripheral shape that is conformable with the shape of the side walls of the defect.

Claims

1. A method for modeling an implant to be applied to a defect of a bone, the defect having side walls, comprising:

obtaining a plurality of tomographic image data of the bone based on magnetic resonance imaging (MRI) measurement data, the tomographic image data being obtained by inverting a threshold value of the MRI measurement data to obtain threshold value inverting data, and extracting a bone region from the threshold value inverting data;

producing three-dimensional image data of the bone based on the plurality of tomographic image data; and

estimating a shape of a missing bone that was previously present or should have been present in the defect of the bone to obtain three-dimensional data of the implant, wherein the three-dimensional data of the implant is modeled such that at least a part of an outer periphery of the implant is conformable with a shape of the side walls of the defect of the bone.

2. The method as claimed in claim 1, wherein estimating comprises:

estimating a provisional shape of the implant which has a contour conformable with the shape of a contour of a periphery of the side walls of the defect at a distal surface of the bone and has a predetermined thickness; and

deleting data of portions of the provisional shape of the implant that overlap the bone from the data of the provisional shape of the implant so that the three-dimensional data of the implant has an outer peripheral shape that is conformable with the shape of the side walls of the defect.

3. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 2.

4. The method as claimed in claim 1, wherein estimating comprises:

producing data of a contour of a distal surface of the implant so that the contour is conformable with the shape of a contour of a periphery of the side walls at a distal surface of the bone;

estimating a provisional shape of the implant which has a predetermined thickness and has a substantially predetermined shape in the thickness direction thereof using the data of the contour of the distal surface of the implant; and

deleting data of portions of the provisional shape that overlap the bone from the data of the provisional shape of the implant so that the three-dimensional data of the implant has an outer peripheral shape that is conformable with the shape of the side walls of the defect.

5. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 4.

6. The method as claimed in claim 1, wherein the estimating comprises:

producing data of a contour of a distal surface of the implant so that the contour is conformable with the shape of a contour of a periphery of the side walls at a distal surface of the bone;

estimating a provisional shape of the implant which has a predetermined thickness and has a substantially predetermined shape in the thickness direction thereof using the data of the contour of the distal surface of the implant; and

correcting the data of the provisional shape so that the three-dimensional data of the implant has an outer peripheral shape that is conformable with the shape of the side walls of the defect by comparing the estimated data of the provisional shape of the implant with the data of the side walls of the three-dimensional image data.

7. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 6.

8. The method as claimed in claim 1, wherein when the implant is applied to the defect of the bone, and a distal surface of the implant forms a continuous surface with the distal surface of the bone.

9. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 8.

10. The method as claimed in claim 1, wherein the bone substantially has plane symmetry, in which the estimation of the shape of the missing bone is carried out by utilizing data of a portion of the three-dimensional image data which is plane-symmetrical with the defect in the three-dimensional image data.

11. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 10.

12. The method as claimed in claim 1, wherein the bone is a cranium bone.

13. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 12.

14. The method as claimed in claim 1, wherein the plurality of tomographic images for producing the three-dimensional image data are taken with a predetermined slice interval between the adjacent images, in which the slice interval is in the range of 0.1 to 5 mm.

15. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 14.

16. An implant which is manufactured based on a model prepared in accordance with the modeling method as defined in claim 1.

17. The implant as claimed in claim 16, wherein the implant is manufactured through a manufacturing process which comprises:

forming a layer made of material powder; and

hardening the material powder by making at least a part of the layer contact with a reaction liquid,

wherein the forming and hardening are carried out repeatedly to obtain a laminate comprised of a plurality of layers, thereby manufacturing an implant having a shape corresponding to the three-dimensional data of the implant provided by the modeling method.

18. The implant as claimed in claim 16, wherein the implant has a porosity of 10 to 90 vol %.