Expanding Vertebral Body Implant

• US 20080114467A1
• Filed: 11/09/2006
• Published: 05/15/2008
• Est. Priority Date: 11/09/2006
• Status: Active Grant

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Karahalios, Dean G., Miller, Keith E., Potts, Eric A., Capote, Marco D.
• Granted Patent: US 8,328,871 B2
• Time in Patent Office: Days
• US Class Current: 623/23.47
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• 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 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30505 spring biased
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30828 parallel
• 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 2230/0019 rectangular
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0069 : cylindrical

Abstract

An expandable medical implant for supporting bone structures is disclosed. The implant may include an outer member and an inner member receivable in the outer member. One of the outer and inner members includes a tapered surface and the other of the outer and inner members includes a scalloped surface. The implant may also include a locking element disposed between the tapered surface and the scalloped surface. The tapered surface may be movable relative to the locking element to transversely shift the locking element into engagement with the scalloped surface to inhibit a decrease in the overall implant height.

Claims

1. An expandable medical implant for supporting bone structures, the implant having an overall implant height adjustable along a longitudinal axis, the implant comprising:

an outer member being configured to cooperatively engage a first bone structure;

an inner member receivable in the outer member and movable relative to the outer member to increase and decrease the overall implant height, the inner member being configured to cooperatively engage a second bone structure,

wherein one of the outer and inner members includes a tapered surface and the other of the outer and inner members includes a roughened locking surface; and

a locking element disposed between the tapered surface and the roughened locking surface, the tapered surface being movable relative to the locking element to transversely shift the locking element into engagement with the roughened locking surface to inhibit a decrease in the overall implant height.

2. The expandable implant of claim 1, wherein the outer member includes an inner surface forming the tapered surface and wherein the inner member includes the roughened locking surface.

3. The expandable implant of claim 1, further including a locker member disposed between the inner and outer member, the locker member including a receiving aperture containing the locking element.

4. The expandable implant of claim 3, wherein the locker member is configured to act on the locking element to affect the position of the locking element relative to the tapered surface, and wherein the tapered surface is configured to affect the position of the locking element relative to the roughened locking surface.

5. The expandable implant of claim 3, wherein the locker member and the locking element are movable relative to the tapered surface between a locked condition and a free condition.

6. The expandable implant of claim 5, further including a biasing member configured to bias the locker member toward the locked condition.

7. The expandable implant of claim 6, wherein the biasing member is a leaf spring.

8. The expandable implant of claim 1, wherein the locking element is substantially cylindrical.

9. The expandable implant of claim 8, wherein the locking element contacts the roughened locking surface along a line extending transverse to the longitudinal axis of the implant.

10. The expandable implant of claim 1, including two locking elements disposed between the inner and outer members at opposing sides of the inner member.

11. The expandable implant of claim 1, wherein the roughened locking surface of the inner member is a scalloped surface.

12. The expandable implant of claim 11, wherein the scalloped surface is formed of increments less than 1 mm apart.

13. The expandable implant of claim 1, wherein the inner member has a substantially rectangular cross section, and the roughened locking surface is formed on at least one side of the rectangle.

14. The expandable implant of claim 1, wherein at least one of the inner and outer members includes vascularization openings formed on opposing sides of the implant.

15. The expandable implant of claim 14, wherein the vascularization openings on one opposing side are larger than the vascularization openings on the other opposing side.

16. The expandable implant of claim 1, wherein the roughened locking surface includes at least one vascularization opening formed therein.

17. An expandable medical implant for supporting bone structures, the implant having an overall implant height adjustable along a longitudinal axis, the implant comprising:

an outer member having an inner surface and being configured to cooperatively engage a first bone structure;

an inner member receivable in the outer member and movable relative to the outer member to increase and decrease the overall implant height, the inner member having a roughened locking surface and being configured to cooperatively engage a second bone structure;

a locking element disposed between the inner surface of the outer member and the roughened locking surface of the inner member, the locking element being movable between a locked condition and an unlocked condition, and being biased toward the locked condition, the locking element being disposed to selectively engage the roughened locking surface to inhibit a decrease in the overall implant height.

18. The expandable implant of claim 17, further including a locker member disposed between the inner and outer member, the locker member including a receiving aperture containing the locking element.

19. The expandable implant of claim 18, wherein the locker member is configured to act on the locking element to affect the position of the locking element relative to the outer member, and wherein the tapered surface of the outer member is configured to affect the position of the locking element relative to the roughened locking surface of the inner member.

20. The expandable implant of claim 17, further including a leaf spring biasing member configured to bias the locker member toward the locked condition.

21. The expandable implant of claim 17, wherein the locking element is substantially cylindrical.

22. The expandable implant of claim 21, wherein the locking element contacts the roughened locking surface along a line extending transverse to the longitudinal axis of the implant.

23. The expandable implant of claim 17, including two locking elements disposed between the inner and outer members at opposing sides of the inner member.

24. The expandable implant of claim 17, wherein the roughened locking surface of the inner member is a scalloped surface.

25. The expandable implant of claim 24, wherein the scalloped surface is formed of increments less than 1 mm apart.

26. The expandable implant of claim 17, wherein the inner member has a substantially rectangular cross section, and the roughened locking surface is formed on at least one side of the rectangle.

27. The expandable implant of claim 17, wherein at least one of the inner and outer members includes vascularization openings formed on opposing sides of the implant, and wherein the vascularization openings on one opposing side are larger than the vascularization openings on the other opposing side.

35. The expandable implant of claim 23, wherein at least one of the inner and outer members includes vascularization openings formed on opposing sides of the implant, and wherein the vascularization openings on one opposing side are larger than the vascularization openings on the other opposing side.

28. An expandable medical implant for supporting bone structures, the implant having an overall implant height adjustable along a longitudinal axis, the implant comprising:

an outer member having a tapered inner surface and being configured to cooperatively engage a first bone structure;

a locker member receivable in the outer member and movable relative to the outer member, the locker member including a receiving aperture;

an inner member receivable in the locker member and movable relative to the locker member and the outer member to increase and decrease the overall implant height, the inner member having a scalloped surface and being configured to cooperatively engage a second bone structure; and

a locking element disposed within the receiving aperture of the locker member, the locking element being associated with the tapered inner surface of the outer member and the scalloped surface of the inner member, the tapered surface being movable relative to the locking element to transversely shift the locking element into engagement with the scalloped surface to inhibit a decrease in the overall implant height.

29. The expandable implant of claim 28, wherein the locker member and the locking element are movable relative the outer member between a locked condition and a free condition.

30. The expandable implant of claim 29, further including a biasing member configured to bias the locker member toward the locked condition.

31. The expandable implant of claim 30, wherein the biasing member is a leaf spring.

32. The expandable implant of claim 28, wherein the locking element is substantially cylindrical.

33. The expandable implant of claim 32, wherein the locking element contacts the scalloped surface along a line extending transverse to the longitudinal axis.

34. The expandable implant of claim 28, including two locking elements disposed between the inner and outer members at opposing sides of the inner member.

36. A method of supporting bone structures with an expandable medical implant, the implant having an overall implant height adjustable along a longitudinal axis, the method comprising:

placing the implant between bone structures to be supported;

displacing an inner member having a scalloped surface relative to an outer member having a tapered inner surface in order to increase the overall implant height, the outer member being configured to cooperatively engage a first bone structure and the inner member being configured to cooperatively engage a second bone structure, wherein displacing the inner member allows a locking element to disengage the scalloped surface; and

supporting a compressive load from the bone structures on the inner and outer members, wherein the compressive load causes the tapered surface to shift the locking element into engagement with the scalloped surface and to inhibit a decrease in the overall implant height.

37. The method of claim 36, wherein the implant includes two locking elements disposed at opposite sides of the inner member, and wherein displacing the inner member allows the two locking elements to disengage the scalloped surface, and wherein supporting the compressive load shifts the two locking elements into engagement with scalloped surfaces.

38. The method of claim 36, including at least two locking elements disposed between the inner and outer members at opposing sides of the inner member, wherein the locking elements are cylindrical rollers.

39. The method of claim 36, further including decreasing the overall height of the implant by displacing a locker member containing the locking element so that the locking element is allowed to move along the tapered surface of the outer member and is allowed to move away from the scalloped surface of the inner member.

40. The method of claim 36, wherein the locking element is a cylinder, and the shifting the locking element into engagement with the scalloped surface includes contacting the scalloped surface along at least a line of contact transverse to the longitudinal axis of the implant.

41. The method of claim 36, wherein at least one of the inner and outer members includes vascularization openings formed on opposing sides of the implant, and wherein the vascularization openings on one opposing side are larger than the vascularization openings on the other opposing side, the method including the step of placing a bone growth material through the larger vascularization openings.

42. An expandable medical implant for supporting bone structures, the implant having an overall implant height adjustable along a longitudinal axis, the implant comprising:

an outer member being configured to cooperatively engage a first bone structure;

an inner member receivable in the outer member and movable relative to the outer member to increase and decrease the overall implant height, the inner member being configured to cooperatively engage a second bone structure,

wherein at least one of the inner and outer members includes vascularization openings formed on first and second opposing sides of the implant, and wherein the vascularization openings on the first opposing side are larger than the vascularization openings on the second opposing side.

43. The expandable implant of claim 42, wherein said at least one of the inner and outer members includes vascularization openings formed at sides of the implant extending between the first and second opposing sides, and wherein the sides include vascularization openings that are smaller than the larger vascularization openings on the first opposing side.

44. The expandable implant of claim 43, wherein the vascularization openings on the sides are smaller than the vascularization openings on the second opposing side.

45. An expandable medical implant for supporting bone structures, the implant comprising:

an outer member being configured to cooperatively engage a first bone structure; and

an inner member receivable in the outer member and movable relative to the outer member to increase and decrease the overall implant height, the inner member being configured to cooperatively engage a second bone structure,

wherein at least one of the inner and outer members includes vascularization openings formed on opposing sides of the implant, and wherein the vascularization openings on one opposing side are larger than the vascularization openings on the other opposing side.