BONE SCREW INCORPORATING A POROUS SURFACE FORMED BY AN ADDITIVE MANUFACTURING PROCESS

• US 20160157908A1
• Filed: 02/16/2016
• Published: 06/09/2016
• Est. Priority Date: 07/24/2014
• Status: Active Grant

• Current Assignee: Kyocera Medical Technologies, Inc.
• Original Assignee: Renovis Surgical Technologies, Inc.
• Inventors: Cawley, Trace, Ross, Thomas
• Granted Patent: US 10,561,456 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/7035 Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2002/0081 directly machined on the prosthetic surface, e.g. holes, grooves A61F2/30771 takes precedence
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/3093 for promoting ingrowth of bone tissue
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/66 by mechanical means
• CPC Class Codes: B22F 2003/247 Removing material: carving, cleaning, grinding, hobbing, honing, lapping, polishing, milling, shaving, skiving, turning the surface
• CPC Class Codes: B22F 2005/005 Article surface comprising protrusions
• CPC Class Codes: B22F 3/11 Making porous workpieces or articles
• CPC Class Codes: B22F 5/06 of threaded articles, e.g. nuts
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

The present invention provides a bone screw or bone anchor, such as a threaded pedicle screw or the like, incorporating a porous surface for enhancing bony fixation, ingrowth, and purchase when implanted in bone. Preferably, this porous surface covers at least a portion of the threads of the bone screw or bone anchor. The porous surface is formed by a conventional or novel additive manufacturing process, such as three-dimensional (3D) printing or the like, optionally as well as a prior and/or subsequent machining process. The porous surface may include novel needle-like protrusions and/or lattice structures, and/or any other protruding/depressed features, whether regular or irregular.

Claims

1. A bone screw, comprising:

a threaded shaft portion;

a head portion coupled to the threaded shaft portion;

a tip portion coupled to the threaded shaft portion opposite the head portion; and

one or more threads disposed concentrically about the threaded shaft portion, wherein at least some of the one or more threads comprise a porous surface.

2. The bone screw of claim 1, wherein intermediate spaces disposed between the one or more threads also comprise the porous surface.

3. The bone screw of claim 1, wherein at least a portion of the head portion also comprises a porous surface.

4. The bone screw of claim 1, wherein at least a portion of the tip portion also comprises a porous surface.

5. The bone screw of claim 1, wherein the porous surface is additively manufactured by building up raised areas of the porous surface that protrude relative to depressed areas of the porous surface that are not built up.

6. The bone screw of claim 1, wherein one or more of the threaded shaft portion, the head portion, and the tip portion are additively manufactured.

7. The bone screw of claim 1, wherein the porous surface comprises regular raised portions.

8. The bone screw of claim 1, wherein the porous surface comprises irregular raised portions.

9. A method for manufacturing a bone screw, comprising:

one or more of subtractively and additively forming a shaft;

one or more of subtractively and additively forming one or more threads disposed concentrically about the shaft; and

additively manufacturing a porous surface on at least a portion of at least some of the one or more threads.

10. The method of claim 9, further comprising one or more of subtractively and additively forming a head coupled to the shaft.

11. The method of claim 9, further comprising one or more of subtractively and additively forming a tip coupled to the shaft.

12. The method of claim 9, further comprising subtractively modifying one or more of the shaft, the one or more threads, and the porous surface.

13. The method of claim 9, wherein the porous surface comprises regular raised portions.

14. The method of claim 9, wherein the porous surface comprises irregular raised portions.

15. The method of claim 9, wherein the porous surface is additively manufactured by building up raised areas of the porous surface that protrude relative to depressed areas of the porous surface that are not built up.