Spinal stabilization device

• US 20050203517A1
• Filed: 03/03/2005
• Published: 09/15/2005
• Est. Priority Date: 09/24/2003
• Status: Active Grant

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: N Spine Incorporated (Johnson & Johnson)
• Inventors: Yim, Jason, Bowman, Brian, Jahng, Tae-ahn
• Granted Patent: US 7,326,210 B2
• Time in Patent Office: Days
• US Class Current: 606/254
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/3421 Cannulas
• CPC Class Codes: A61B 17/3423 Access ports, e.g. toroid shape introducers for instruments or hands access sites for liquids A61M39/0247
• CPC Class Codes: A61B 17/3439 with means for changing the inner diameter of the cannula, e.g. expandable A61B17/3423, A61B17/3431 take precedence; catheters A61M25/0662
• CPC Class Codes: A61B 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• CPC Class Codes: A61B 17/3472 for bones, e.g. intraosseus injections
• CPC Class Codes: A61B 17/7007 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit around the screw or hook heads
• CPC Class Codes: A61B 17/702 having a core or insert, and a sleeve, whereby a screw or hook can move along the core or in the sleeve
• CPC Class Codes: A61B 17/7026 with a part that is flexible due to its form
• CPC Class Codes: A61B 17/7028 the flexible part being a coil spring
• CPC Class Codes: A61B 17/7029 the entire longitudinal element being flexible
• CPC Class Codes: A61B 17/7031 made wholly or partly of flexible material
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/705 for linking adjacent ends of longitudinal elements
• CPC Class Codes: A61B 17/8897 Guide wires or guide pins
• CPC Class Codes: A61B 2017/00004 (bio)absorbable, (bio)resorbable or resorptive
• CPC Class Codes: A61B 2017/00862 elastic or resilient
• CPC Class Codes: A61B 2090/363 Use of fiducial points
• CPC Class Codes: A61B 2090/3916 Bone tissue
• CPC Class Codes: A61B 2090/3987 Applicators for implanting markers
• CPC Class Codes: A61B 90/39 : Markers, e.g. radio-opaque or breast lesions markers

Abstract

A flexible connection unit for use in a spinal fixation device, includes: a longitudinal member having first and second ends; at least one spacer located between the first and second ends, wherein the at least one spacer comprises a first portion made from a first material and a second portion made from a second material; and at least one flexible member located in a longitudinal axial channel of the at least one spacer, wherein the first and second ends substantially limit motion of the at least one spacer in the longitudinal axial direction with respect to the at least one flexible member.

Claims

1. A flexible connection unit for use in a spinal fixation device, comprising:

a longitudinal member having first and second ends;

at least one spacer located between the first and second ends, wherein the at least one spacer comprises a first portion made from a first material and a second portion made from a second material; and

at least one flexible member located in a longitudinal axial channel of the at least one spacer, wherein the at least one flexible member comprises a biocompatible metal material and the first and second ends substantially limit motion of the at least one spacer in the longitudinal axial direction.

2. The flexible connection unit of claim 1 wherein the first material comprises at least one material selected from a group of biocompatible materials consisting of:

metals, metal alloys, polymers, resins, plastics and composites thereof.

3. The flexible connection unit of claim 1 wherein the second material comprises at least one material selected from a group of biocompatible materials consisting of:

elastomers, polymers, resins, plastics, and composites thereof.

4. The flexible connection unit of claim 1 wherein the first portion comprises a metal spacer and the second portion comprises a non-metal cladding surrounding the metal spacer.

5. The flexible connection unit of claim 4 wherein the non-metal cladding comprises an elastomer.

6. The flexible connection unit of claim 1 wherein the first portion comprises a metal material and the second portion comprises a non-metal material, wherein the metal material surrounds at least a portion of the non-metal material.

7. The flexible connection unit of claim 6 wherein the non-metal material comprises an elastomer.

8. The flexible connection unit of claim 1 wherein the first portion comprises a metal spacer and the second portion comprises a first non-metal cladding surrounding a first portion of the at least one flexible member between the metal spacer and the first end, and a second non-metal cladding surrounding a second portion of the at least one flexible member between the metal spacer and the second end.

9. The flexible connection unit of claim 8 wherein the metal spacer is configured to be secured by a first securing member to a patient'"'"'s spine and the second end is configured to be secured by a second securing member to the patient'"'"'s spine.

10. The flexible connection unit of claim 9 wherein the location of the metal spacer substantially corresponds to a location of a joint between adjacent superior and inferior vertebrae of the patient'"'"'s spine when the first securing member is fixed to the inferior vertebra and the second securing member is fixed to the superior vertebra.

11. The flexible connection unit of claim 1 wherein:

the first material comprises at least one material selected from a group of biocompatible materials consisting of;

metals, metal alloys, polymers, resins, plastics and composites thereof;

the second material comprises at least one materials selected from a group of biocompatible materials consisting of;

elastomers, polymers, resins, plastics, and composites thereof; and

the at least one spacer further comprises a third portion made from a third material comprising a bio-absorbable material.

12. The connection unit of claim 11 wherein the bio-absorbable material comprises at least one material selected from a group consisting of:

polylactic acid, polyglycolic acid, polyglactic acid, polydioxanone, polyglyconate, calcium sulfate, calcium phosphate and combinations thereof.

13. The flexible connection unit of claim 1 wherein:

the first material comprises at least one material selected from a group of biocompatible materials consisting of;

metals, metal alloys, polymers, resins, plastics and composites thereof; and

the second material comprises a bio-absorbable material.

14. The connection unit of claim 13 wherein the bio-absorbable material comprises at least one material selected from a group consisting of:

polylactic acid, polyglycolic acid, polyglactic acid, polydioxanone, polyglyconate, calcium sulfate, calcium phosphate and combinations thereof.

15. The flexible connection unit of claim 1 wherein the at least one flexible member comprises a single shaft.

16. The flexible connection unit of claim 1 wherein the at least one flexible member comprises at least one wire having a plurality of yarns.

17. The flexible connection unit of claim 16 wherein the at least one wire comprises a braided wire comprising a plurality of interwoven wires.

18. The flexible connection unit of claim 1 wherein the at least one flexible member is integrally formed with the first and second ends.

19. The flexible connection unit of claim 1 wherein at least one end of the at least one flexible member is not directly connected to a respective one of the first and second ends.

20. A flexible connection unit for use in spinal stabilization, comprising:

a longitudinal member having first and second ends;

a spacer located between the first and second ends;

a flexible member located in a longitudinal axial channel of the spacer; and

a flexible cladding configured to limit motion of the spacer.

21. The flexible connection unit of claim 20 wherein the flexible cladding encapsulates the spacer and the flexible member between the first and second ends.

22. The flexible connection unit of claim 20 wherein the flexible cladding fills one or more spaces between the spacer and the flexible member and the first and second ends so as to limit motion of the spacer relative to the flexible member and the first and second ends.

23. The flexible connection unit of claim 20 wherein:

the spacer comprises a material selected from a group of biocompatible materials consisting of;

metals, metal alloys, polymers, resins, plastics and composites thereof; and

the flexible cladding comprises a material selected from a group of biocompatible materials consisting of;

elastomers, polymers, resins, plastics, and composites thereof.

24. The flexible connection unit of claim 20 wherein the flexible cladding comprises a first segment surrounding a first portion of the flexible member between the spacer and the first end, and a second segment surrounding a second portion of the flexible member between the one spacer and the second end.

25. The flexible connection unit of claim 24 wherein the spacer is configured to be secured by a first securing member to a patient'"'"'s spine and the second end is configured to be secured by a second securing member to the patient'"'"'s spine.

26. The flexible connection unit of claim 25 wherein the location of the spacer substantially corresponds to a location of a joint between adjacent superior and inferior vertebrae of the patient'"'"'s spine when the first securing member is fixed to the inferior vertebra and the second securing member is fixed to the superior vertebra.

27. The flexible connection unit of claim 20 further comprising a bio-absorbable cladding configured to provide an increased stiffness to the connection unit upon initial implantation into a patient, wherein the connection unit decreases in stiffness as a result of in vivo biodegradation of the bio-absorbable cladding.

28. The connection unit of claim 27 wherein the bio-absorbable material comprises at least one material selected from a group consisting of:

polylactic acid, polyglycolic acid, polyglactic acid, polydioxanone, polyglyconate, calcium sulfate, calcium phosphate and combinations thereof.

29. The flexible connection unit of claim 20 wherein the at least one flexible member comprises a single shaft.

30. The flexible connection unit of claim 20 wherein the at least one flexible member comprises at least one wire having a plurality of yarns.

31. The flexible connection unit of claim 20 wherein the at least one wire comprises a braided wire comprising a plurality of interwoven wires.

32. The flexible connection unit of claim 20 wherein the at least one flexible member is integrally formed with the first and second ends.

33. The flexible connection unit of claim 20 wherein at least one end of the at least one flexible member is not directly connected to a respective one of the first and second ends.

34. The flexible connection unit of claim 20 wherein the thickness of cladding on at least one side of the connection unit is altered to provide a first level of stiffness when the connection unit is bent in a first direction and a second level of stiffness, different from the first level of stiffness, when the connection unit is bent in a second direction.

35. The flexible connection unit of claim 20 wherein the flexible member is located eccentric from the longitudinal axis so as to provide a first level of stiffness when the connection unit is bent in a first direction and a second level of stiffness, different from the first level of stiffness, when the connection unit is bent in a second direction.

36. The flexible connection unit of claim 20 further comprising at least one capture and retention element for maintaining a physical connection between the flexible cladding and respective surfaces of the first and second ends.

37. The flexible connection unit of claim 36 wherein the at least one capture and retention element comprises an undercut region filled by the flexible cladding.

38. The flexible connection unit of claim 36 wherein the at least one capture and retention element comprises through holes filled by the flexible cladding.

39. The flexible connection unit of claim 36 wherein the at least one capture and retention element comprises a roughened surface.

40. The flexible connection unit of claim 36 wherein the at least one capture and retention element comprises an intermediate surface treatment to improve bonding between the flexible cladding and the respective surfaces.

41. A spinal fixation device comprising:

first and second securing members configured to be secured to two respective and adjacent vertebrae consisting of a superior vertebra and a inferior vertebra, each securing member having a coupling assembly;

a longitudinal member having a first portion configured to be received and secured by the coupling assembly of the first securing member and a second portion configured to be received and secured by the coupling assembly of the second securing member, wherein the longitudinal member further comprises a flexible portion located off-center with respect to the first and second portions so as to provide flexibility at or near an intervertebral disc between the superior and inferior vertebrae when the first and second securing members are secured to respective ones of the superior and inferior vertebrae.

42. The spinal fixation device in claim 41 wherein said flexible portion comprises a metal-hybrid spacer, the metal hybrid spacer comprising a metal portion and a non-metal portion.

43. The spinal fixation device of claim 41 wherein the metal portion comprises a metal spacer and the non-metal portion comprises an elastomer cladding.

44. The spinal fixation device of claim 43 wherein second portion comprises the metal spacer and the metal spacer is configured to be received and secured by a respective one of the coupling assemblies of the first and second securing members.

45. A flexible connection unit for use in a spinal fixation device comprising:

a longitudinal member configured to be secured to a patient'"'"'s spine using at least three securing members;

wherein a first portion of the longitudinal member is configured to be located between a first pair of securing members and a second portion of the longitudinal member is configured to be located between a second pair of securing members; and

wherein at least the first portion of the longitudinal member comprises at least one spacer interposed between two end portions and at least one flexible member located in a longitudinal axial channel of the at least one spacer, wherein the at least one spacer is substantially fixed in position with respect to at least one flexible member.

46. The flexible connection unit of claim 45 wherein the first portion further comprises a non-metal cladding that limits motion of the at least one spacer with respect to the at least one flexible member and the end portions.

47. The flexible connection unit of claim 46 wherein the first portion further comprises a bio-absorbable cladding configured to provide an increased stiffness to the first portion upon initial implantation into a patient, wherein the first portion decreases in stiffness as a result of in vivo biodegradation of the bio-absorbable cladding.

48. The flexible connection unit of claim 47 wherein the bio-absorbable material comprises at least one material selected from a group consisting of:

polylactic acid, polyglycolic acid, polyglactic acid, polydioxanone, polyglyconate, calcium sulfate, calcium phosphate and combinations thereof.

49. The flexible connection unit of claim 45 wherein the first portion further comprises a bio-absorbable cladding configured to provide an increased stiffness to the first portion upon initial implantation into a patient, wherein the first portion decreases in stiffness as a result of in vivo biodegradation of the bio-absorbable cladding.

50. The flexible connection unit of claim 49 wherein the bio-absorbable material comprises at least one material selected from a group consisting of:

polylactic acid, polyglycolic acid, polyglactic acid, polydioxanone, polyglyconate, calcium sulfate, calcium phosphate and combinations thereof.

51. A flexible connection unit for use in spinal stabilization, comprising:

a longitudinal member having first and second ends;

a spacer located between the first and second ends and having a longitudinal axial channel therein;

a flexible member located in the longitudinal axial channel of the spacer between the first and second ends;

a first cladding surrounding a first portion of the flexible member disposed between the spacer and the first end; and

a second cladding surrounding a second portion of the flexible member disposed between the spacer and the second end.

52. The flexible connection unit of claim 51 wherein the first end is configured to be coupled to a first securing member and the spacer is configured to be coupled to a second securing member.

53. The flexible connection unit of claim 52 wherein the first securing member is configured to be fixed to a pedicle bone of a superior vertebra and the second securing member is configured to be fixed to a pedicle bone of an inferior vertebra such that stabilized mobility is provided to the pedicle bone of the inferior vertebra entirely by the movement of the spacer with respect to the first and second ends and the flexible member, and not by movement of the spacer within a coupling assembly of the second securing member.

54. The flexible connection unit of claim 51 wherein the spacer is capable of movement in six degrees of freedom while experiencing resistance to such movement in each of the six degrees of freedom.

55. The flexible connection unit of claim 51 wherein the thickness of the cladding on at least one side of at least one of the first and second claddings is altered to provide a first level of stiffness when the connection unit is bent in a first direction and a second level of stiffness, different from the first level of stiffness, when the connection unit is bent in a second direction.

56. The flexible connection unit of claim 51 wherein the thickness of the first cladding is different from the thickness of the second cladding.

57. The flexible connection unit of claim 51 wherein the first cladding comprises a different material than the second cladding.

58. The flexible connection unit of claim 51 wherein the first and second cladding are integrally formed and connected by a middle portion of cladding material located between an internal surface of the spacer and the flexible member.

59. The flexible connection unit of claim 51 wherein the flexible member is located eccentric from the longitudinal axis so as to provide a first level of stiffness when the connection unit is bent in a first direction and a second level of stiffness, different from the first level of stiffness, when the connection unit is bent in a second direction.

60. The flexible connection unit of claim 51 further comprising a bio-absorbable material surrounding at least the first cladding and second claddings.

61. A flexible connection unit configured to be fixed to respective pedicle bones of a superior vertebra and an inferior vertebra, wherein the flexible connection unit provides stabilized mobility to the pedicle bone of the inferior vertebra entirely by the flexion of a flexible portion of the connection unit located at or near the pedicle bone of the inferior vertebra.