Implants and Related Devices for Monitoring Bony Fusion

• US 20080177387A1
• Filed: 11/01/2006
• Published: 07/24/2008
• Est. Priority Date: 11/01/2006
• Status: Abandoned Application

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Parimore, Dianna, Hutton, Scott, Melkent, Anthony J.
• Application Number:
  US11/555,339
• Publication Number:
  US 20080177387A1
• Time in Patent Office: Days
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30171 rosette- or star-shaped
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/3023 wedge-shaped cylinders
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/30372 with additional means for limiting said translation
• CPC Class Codes: A61F 2002/30476 locked by an additional locking mechanism
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/3052 unrestrained in only one direction, e.g. moving unidirectionally
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/3054 about a connection axis or implantation axis for selecting any one of a plurality of radial orientations between two modular parts, e.g. Morse taper connections, at discrete positions, angular positions or continuous positions
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30736 : Augments or augmentation pieces, e.g. wedges or blocks for bridging a bone defect
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/005 : Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00359 : Bone or bony tissue
• CPC Class Codes: A61F 2310/00365 : Proteins; Polypeptides; Degradation products thereof

Abstract

A medical implant for supporting skeletal structures is disclosed. The implant includes an expandable central portion formed of a first material that at least partially inhibits the monitoring of bone in-growth using a medical diagnostic technique. The implant further includes end caps for mating with the central portion and the skeletal structure. The end caps are made of a second material different than the first material that inhibits the monitoring of bone in-growth using the medical diagnostic technique to a lesser degree than the first material. In another aspect, a polymer end member for use with a metallic implant for supporting a skeletal structure is disclosed. The polymer end member facilitates the monitoring of fusion or bone in-growth using fluoroscopy. In another aspect, a spinal implant is disclosed. The implant includes a central portion made of a first material and an end cap made of a different material.

Claims

1. A spinal implant for positioning between a superior vertebra and an inferior vertebra, the device comprising:

a central portion having a superior section, an inferior section, and a longitudinal axis extending therebetween, the central portion made of a first material;

a superior end cap having an inferior surface for engagement with the superior section of the central portion and having a superior surface for engagement with the superior vertebra, the superior end cap made of a second material adapted to facilitate the monitoring of bone in-growth between the superior vertebra and the superior surface, the second material being different than the first material; and

an inferior end cap having an upper surface for engagement with the inferior section of the central portion and having a lower surface for engagement with the inferior vertebra, the inferior end cap made of a third material adapted to facilitate the monitoring of bone in-growth between the inferior vertebra and the lower surface, the third material being different than the first material.

2. The implant of claim 1 wherein the first material is substantially radiopaque and the second and third materials are substantially radiolucent.

3. The implant of claim 2 wherein the first material is a metal and the second material is a polymer.

4. The implant of claim 3 wherein the first material is titanium and the second material is PEEK.

5. The implant of claim 4 wherein the central portion is expandable.

6. The implant of claim 1 wherein the first material substantially reflects energy from an imaging apparatus and the second and third materials are substantially transmissive to the energy from the imaging apparatus.

7. The implant of claim 1 wherein the second and third materials are the same.

8. The implant of claim 6 wherein the superior end cap has a thickness between 0.5 and 10 mm.

9. The implant of claim 8 wherein the thickness of the superior end cap varies so that the superior surface is not perpendicular to the longitudinal axis of the central portion.

10. The implant of claim 9 wherein the inferior end cap has a thickness between 0.5 and 10 mm.

11. The implant of claim 10 wherein the thickness of the inferior end cap varies so that the lower surface is not perpendicular to the longitudinal axis of the central portion.

12. The implant of claim 1 wherein the spinal implant is a corpectomy device.

13. The implant of claim 1 wherein the spinal implant is an interbody device.

14. An expandable medical implant for supporting skeletal structures comprising:

an expandable central portion having a first end section, an opposing second end section, and a longitudinal axis extending therebetween, the central portion formed of a first material that at least partially inhibits the monitoring of bone in-growth using a medical diagnostic technique;

a first end cap having a first mating surface for mating with the first end section of the central portion and having a first engagement surface for engagement with a first portion of the skeletal structure, the first end cap made of a second material different than the first material, the second material inhibiting the monitoring of bone in-growth using the medical diagnostic technique to a lesser degree than the first material; and

a second end cap having a second mating surface for mating with the second end section of the central portion and having a second engagement surface for engagement with a second portion of the skeletal structure, the second end cap made of the second material.

15. The implant of claim 14 wherein the medical diagnostic technique is fluoroscopy.

16. The implant of claim 15 wherein the first material is substantially radiopaque and the second material is substantially radiolucent.

17. The implant of claim 16 wherein the first material is a metal and the second material is a polymer.

18. The implant of claim 17 wherein the first and second end caps each have a thickness between 0.5 and 10 mm.

19. The implant of claim 18 wherein the thicknesses of the first and second caps are non-uniform.

20. The implant of claim 17 wherein the first engagement surface includes a plurality of projections for at least partially penetrating into the first portion of the skeletal structure.

21. The implant of claim 20 wherein the second engagement surface includes a plurality of projections for at least partially penetrating into the second portion of the skeletal structure.

22. An end member for use with a metallic implant for supporting a skeletal structure, the end member comprising:

a body portion having a thickness;

an implant engagement surface extending from the body portion for securely engaging the metallic implant; and

a skeletal engagement surface extending from the body portion opposite the implant engagement surface, the skeletal engagement surface for securely engaging the skeletal structure and promoting bony in-growth between the skeletal structure and the end member;

wherein the end member is formed of a polymer.

23. The member of claim 22 wherein the implant engagement surface includes a plurality of radially spaced projections.

24. The member of claim 23 wherein the skeletal engagement surface includes a plurality of projections for at least partially penetrating the skeletal structure.

25. The member of claim 24 wherein the thickness of the body portion is substantially uniform.

26. The member of claim 24 wherein the thickness of the body portion is variable.

27. The member of claim 26 wherein the variable thickness of the body portion is linear.

28. The member of claim 27 wherein the skeletal structure includes a portion of the spine and the variable linear thickness of the body portion is adapted to substantially match a curvature of the spine.

29. The member of claim 28 wherein the curvature of the spine is lordotic.

30. The member of claim 28 wherein the curvature of the spine is kyphotic.

31. The member of claim 22 wherein the body portion includes a central opening extending therethrough.

32. The member of claim 31 further comprising a shoe for attachment to the end cap, the shoe spanning at least a portion of the central opening and providing at least in part an interface with the skeletal structure

33. The member of claim 32 wherein the shoe includes a concave recess for receiving bone growth material.

34. The member of claim 33 wherein the shoe further includes a plurality of openings to facilitate bony in-growth.

35. The member of claim 34 wherein the shoe is formed from a bioresorbable material.

36. The member of claim 34 wherein the shoe is formed from a polymer.

37. The member of claim 32 wherein the shoe includes a convex projection to substantially match a concave recess of the skeletal structure.

38. The member of claim 22 wherein the skeletal structure is the spine.

39. The member of claim 22 wherein the skeletal structure is a long bone.