Facet joint implants and delivery tools

• US 20090306671A1
• Filed: 12/23/2008
• Published: 12/10/2009
• Est. Priority Date: 06/06/2008
• Status: Active Grant

• Current Assignee: Providence Medical Technology, Inc.
• Original Assignee: Providence Medical Technology, Inc.
• Inventors: McCormack, Bruce M., Smith, Jeffrey D.
• Granted Patent: US 8,267,966 B2
• Time in Patent Office: Days
• US Class Current: 606/90
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/0642 for bones, e.g. for osteosynthesis or connecting tendon to bone
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1735 for rasps or chisels
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/7044 also having plates, staples or washers bearing on the vertebrae
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/8004 with means for distracting or compressing the bone or bones
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61B 2090/037 with a frangible part, e.g. by reduced diameter

Abstract

A spinal joint distraction system is disclosed and may include a driver assembly with a tubular shaft, a pair of implant holder arms, an implant distractor, an internal actuator, and a distractor knob, the system also including a delivery device with a tubular shaft, a receiving assembly, and a pair of forks, where the delivery device is adapted for slidable insertion of the driver assembly, the system also including an implant, a chisel, and an injector. Several embodiments of an implant are disclosed as well a method of placing an implant.

Claims

1. A spinal joint distraction system comprising:

a driver assembly including;

a tubular shaft having a longitudinal axis; and

a pair of implant holder arms positioned on a distal end of the tubular shaft, the arms configured to hold a spinal implant.

2. The system of claim 1, wherein the arms include an engagement feature for engaging a lateral portion of an implant.

3. The system of claim 2, wherein the engagement feature includes a tab structure.

4. The system of claim 2, wherein the engagement feature includes a bull nose feature adapted to engage a U-shaped slot.

5. The system of claim 1, wherein the driver assembly further comprises:

an implant distractor positioned along the longitudinal axis near the distal end of the tubular shaft;

an internal actuator positioned within the tubular shaft and adapted to advance the implant distractor; and

a distractor knob adapted to control the internal actuator.

6. The system of claim 5, wherein the distractor knob is rotatably engaged with the internal actuator and the internal actuator is free to move longitudinally relative to the distractor knob.

7. The system of claim 6, wherein the internal actuator is rotatably engaged with the implant distractor.

8. The system of claim 7, wherein the implant distractor is a threaded screw adapted for insertion into a proximal end of an implant.

9. The system of claim 5, further comprising:

a delivery device including;

a tubular shaft;

a receiving assembly positioned on a proximal end of the tubular shaft; and

a pair of forks extending from a distal end of the tubular shaft, the forks adapted to penetrate a facet joint;

wherein, the delivery device is adapted to slidably receive the driver assembly.

10. The system of claim 9, wherein the receiving assembly is adapted to allow the distractor knob of the driver assembly to nest within it when inserted.

11. The system of claim 10, wherein the receiving assembly includes an offset annular ring and the distractor knob is rotatable by accessing the knob through an access opening.

12. The system of claim 9, wherein the distal end of the tubular shaft of the delivery device includes opposing copes defining the forks.

13. The system of claim 12, wherein the forks include a V-shaped distal tip and further include serrations on a superior and an inferior surface.

14. The system of claim 9, further comprising an implant adapted for holding by the implant holding arms of the driver assembly, the implant comprising:

upper and lower members with an inner surface and an outer surface, the members connected to each other at respective distal ends; and

teeth protruding from the outer surface of at least one of the upper or lower arms;

wherein, the upper and lower members are adapted to be expanded by the implant distractor.

15. The system of claim 14, further comprising threaded slots in at least one of the members, the slots adapted to be engaged by the implant distractor.

16. The system of claim 14, further comprising a guide feature positioned at a proximal edge of at least one of the upper and lower members, the guide feature adapted to guide the implant distractor between the upper and lower members.

17. The system of claim 14, further comprising a U-member connecting the distal ends of the upper and lower member.

18. The system of claim 14, further comprising a chisel, the chisel including:

a shaft portion;

a tip at a distal end of the shaft; and

a head at a proximal end of the shaft;

wherein;

the delivery device is adapted to receive the chisel; and

the head of the chisel is adapted to be tapped by a driving member to insert the tip of the chisel into a facet joint.

19. The system of claim 18, wherein the chisel includes a longitudinal lumen.

20. The system of claim 18, wherein the tip is a chamfered tip.

21. The system of claim 18, wherein the tip is a coped tip.

22. The system of claim 18, further comprising an injector, the injector including:

a cannula with a closed distal end and two exit doors positioned on opposite sides of the distal end;

a plunger with a seal positioned within the cannula;

a stop disc at a proximal end of the cannula; and

a handle positioned on a proximal end of the plunger;

wherein the delivery device is further adapted to receive an injector.

23. A spinal distraction implant comprising:

an upper member and a lower member, the upper and lower member being generally rectangular and each having a distal edge, a proximal edge, and two parallel lateral edges, the upper and lower member positioned adjacent and substantially parallel to each other and having an inner surface and an outer surface, the distal edges of the upper and lower member connected to each other and the proximal edges adapted to receive an implant distractor; and

teeth positioned along the lateral edges of at least one of the upper or lower member and extending outwardly.

24. The implant of claim 23, further comprising a receiving feature on a lateral edge of the implant, the receiving feature adapted to receive an engagement feature of a driver assembly.

25. The implant of claim 24, further comprising a pair of guide features, each positioned near the proximal edge of the upper and lower members, the guide features adapted to guide an implant distractor between the upper and lower member.

26. The implant of claim 25, wherein the upper and lower members include threaded slots for receiving threads of the implant distractor.

27. The implant of claim 26, wherein the guide feature is a segment of a cone.

28. The implant of claim 23, wherein the lateral edges of the upper and lower members follow a first radiused curve from the inner surface to the outer surface, wherein the extension of the first radiused curve beyond the outer surface of the upper or lower member defines an outside face of the teeth.

29. The implant of claim 28, wherein an inside face of the teeth is defined by a second radiused curve offset from the first radiused curve.

30. The implant of claim 29, wherein the teeth have a sloping distal face and a proximal face orthogonal to the upper or lower surface.

31. The implant of claim 30, wherein the teeth are equally spaced.

32. The implant of claim 31, wherein the distal edges are coupled together via a weld.

33. The implant of claim 23, further comprising a U-member positioned along the distal edge of each of the upper and lower member and coupling the distal edges together.

34. The implant of claim 33, wherein the U-member is a relatively thin rectangular piece of material formed into the shape of a U.

35. The implant of claim 34, wherein the U-member overlaps and is secured to the outer surface of the upper and lower members.

36. The implant of claim 35, wherein the U-member abuts and is secured to the distal edges of the upper and lower members.

97. The implant of claim 23, further comprising flanges extending substantially orthogonally from a proximal end of the upper and lower members, the flanges including openings for receiving anchors to anchor the implant to a lateral mass of a facet joint.

37. A method of distracting a facet joint of the spine comprising:

inserting a delivery device to access the facet joint of a patient;

inserting a driver assembly holding an implant into the delivery device; and

actuating the driver assembly thereby distracting the implant.

38. The method of claim 37, wherein inserting the delivery device includes:

inserting a chisel through the delivery device; and

tapping on the proximal end of the chisel to advance the chisel and the delivery device into the facet joint.

39. The method of claim 38, wherein actuating the driver assembly includes turning a distractor knob on the driver assembly thereby rotating an internal actuator and advancing an implant distractor.

40. The method of claim 37, further comprising inserting an injector in the delivery device and delivering a bone paste to the implantation site.

41. A spinal distraction implant comprising:

an upper member, a lower member and a proximal member, the upper and lower members being generally rectangular and each having a distal edge and two parallel lateral edges, the upper and lower members extending generally continuously into each other to form the proximal member, the upper and lower member positioned adjacent and substantially parallel to each other and having an inner surface and an outer surface, the proximal member being generally perpendicular relative to the upper and lower members, at least one of the upper and lower members further including threaded slots adapted to receive threads of an implant distractor and outwardly extending teeth positioned along the lateral edges of at least one of the upper or lower members.

42. The implant of claim 41, wherein the proximal member includes a penetration for receiving an implant distractor.

43. A spinal distraction implant comprising:

a threaded bolt with a proximal end terminating in a head;

a proximal non-threaded block positioned along the bolt and abutting the head of the bolt;

a distal threaded block positioned a distance away from the proximal threaded block; and

a plurality of expansion members positioned between the proximal and the distal threaded blocks.

44. The implant of claim 43, wherein the plurality of expansion members are V-shaped members.

45. The implant of claim 44, wherein, the plurality of V-shaped members are adapted to deformably flatten out and expand laterally when compressed between the distal and proximal blocks.

46. The implant of claim 43, wherein the plurality of expansion members are planar plates with slotted holes such that when freely positioned on the bolt, the plates are positioned in a skewed position relative to a longitudinal axis of the bolt.

47. The implant of claim 46, wherein the planar plates are adapted to engage one another and thus position themselves perpendicular to the bolt when compressed between the distal and proximal blocks.

48. A spinal distraction implant comprising:

a pair of stacked structures separated by a sloping plane, the structures having an engagement surface along the plane including ratchet teeth.

49. The implant of claim 48, wherein a first structure of the pair of stacked structures increases in thickness in a proximal direction and a second structure of the pair of stacked structures increases in thickness in a distal direction.

92. The implant of claim 48 further comprising flaps extending from the head of the shaft and including teeth for engaging a lateral mass of a facet joint.

50. A spinal distraction implant comprising:

a generally tapered shaft in the form of a screw, the shaft defining a longitudinal axis and having a length, the shaft having threads along an outer surface for engaging articular surfaces of a facet joint.

51. The implant of claim 50, wherein the threads are notched along the length of the implant creating serrations for cutting into the articular surfaces of a facet joint.

52. The implant of claim 50, wherein the threads include leaf springs for preventing backing out of the implant.

53. The implant of claim 50, wherein the threads have a T-shaped cross-section.

54. The implant of claim 50, wherein the implant includes a relatively broad head with a decorticating feature on a distal surface thereof.

55. The implant of claim 54, wherein the decorticating feature includes tabs projecting distally from the head.

56. The implant of claim 54, wherein the decorticating feature includes spurs.

57. The implant of claim 54, wherein the head is in the form of a floating collar and is free to pivot about the longitudinal axis of the implant in a ball and socket type fashion.

58. The implant of claim 50, wherein the implant includes a torque limiting mechanism.

59. The implant of claim 50, wherein the shaft includes a hollow cavity and thus takes the form of a cone, the cone being made from a relatively malleable material, the implant further comprising an inner core support member for use when inserting the implant and for removal once the implant is in place.

60. The implant of claim 50, wherein the generally tapered shaft is a first tapered shaft, the implant further comprising a second generally tapered shaft in the form of a screw, the second generally tapered shaft positioned adjacent to the first generally tapered shaft and having communicative threaded serrations such that when one shaft is rotated, the other shaft rotates in the opposite direction.

86. The implant of claim 50 further comprising an arm type locking mechanism, the arm being biased in a distal direction such that when implanted the arm provides a biasing force to maintain friction on the threads.

61. A spinal distraction implant comprising a plate and a orthogonally positioned bumper, the superior aspect of the bumper having a rounded surface for opposing the lateral mass of a superior vertebra, the implant including an anchoring screw for securing the implant to a lateral mass of a facet joint.

62. A spinal distraction implant comprising a wedge insertable between facet surfaces, the wedge having teeth on at least one of an anterior and inferior surface thereof.

63. The implant of claim 62, further comprising a diagonally placed anchor screw positioned through the implant for advancing into the surface of a facet joint.

64. A spinal distraction implant comprising:

an anterior hook;

a posterior hook; and

a bolt joining the anterior and posterior hook.

65. The implant of claim 64, wherein the anterior hook is C-shaped with a lip and the posterior hook is S-shaped with a lip, the anterior hook adapted to engage the anterior aspect of the inferior facet and the posterior hook is adapted to engage the posterior aspect of the posterior facet.

67. The implant of claim 64 wherein the insert is rectangular and the tabs have holes for receiving an anchor.

66. A spinal distraction implant comprising:

an insert; and

tabs positioned to extend orthogonally from a proximal end of the insert.

68. A spinal distraction implant comprising:

a collapsible diamond shaped structure including;

two opposing threaded corners; and

two opposing non-threaded corners including pads; and

a bolt threaded through the threaded corners of the diamond shaped structure;

wherein, actuating the bolt draws the threaded corners together and extends the non-threaded corners.

69. A spinal distraction implant comprising:

an upper member;

a lower member;

a hinge connecting the upper member to the lower member; and

a brace member for maintaining the implant in an open position.

70. A spinal distraction implant comprising a generally cylindrically shaped member including at least two sections separated by a slot, the sections connected together at distal ends to form a tip, the member adapted to receive a screw to cause it to expand, the outer surface of the sections including teeth for engaging articular surfaces of a facet joint.

71. A method of securing a superior verterbra comprising:

applying a force to the superior vertebra to increase the foraminal area between the superior vertebra and an inferior vertebra; and

placing an angled screw through a superior facet, through a facet capsule, and into an inferior facet.

72. A spinal distraction implant comprising:

a collapsible triangular shaped implant including;

a central shaft; and

at least two springing leaves connected to the distal end of the shaft, extending proximally along the shaft, and biased in a direction to form an arrow shape;

wherein, the implant may be collapsed within a tube and delivered to a site where the tube is removed and the implant is allowed to expand.

73. A spinal distraction implant comprising a facet spacer plate and screw, wherein the screw may be inserted diagonally through a facet surface to engage the facet spacer plate thereby forcing separation of a facet joint.

74. The implant of claim 73, wherein the screw passes through the spacer plate prior to entering the spinal structure.

75. A spinal distraction implant comprising:

a first bracket;

a second bracket; and

a bolt extending between the brackets;

wherein, the brackets are adapted to separate when the bolt is turned.

76. The implant of claim 75, wherein the first and second brackets are adapted to be attached to a lateral mass of a facet joint.

77. The implant of claim 75, wherein the first and second brackets include a leg adapted to be inserted into a facet joint.

78. A spinal distraction implant comprising:

a triangular shaped wedge;

an anchor screw positioned diagonally through the wedge; and

a malleable flap extending from the wedge including teeth for engaging a lateral mass of a facet joint.

79. A spinal distraction implant comprising:

an anchoring plug;

an expandable plate; and

two external plates;

wherein securing the external plates to a lateral mass of a facet joint and inserting the expandable plug causes the facet joint to separate.

80. A spinal distraction implant comprising:

a delivery system; and

at least two nitinol hooks;

wherein the hooks may be flattened and inserted with the delivery system; and

once in place may be allowed to assume their pre-flattened shape.

81. A spinal distraction implant comprising:

a hollow screw sleeve having barbs adapted to be ejected from a retracted position; and

a wedge adapted to be inserted in the hollow screw sleeve to eject the barbs.

82. A spinal distraction implant comprising a collapsible nut positioned over a bolt, the bolt defining a longitudinal axis, wherein advancing the bolt causes the nut to collapse along the longitudinal axis in an accordion shape, thereby expanding laterally.

83. A spinal distraction implant comprising a collapsible plate positioned over a bolt, the bolt defining a longitudinal axis, wherein advancing the bolt causes the plate to collapse along the longitudinal axis in an accordion shape, thereby expanding laterally.

84. A spinal distraction implant comprising a wire surrounding a block in a helical fashion, the wire adapted to contract and expand laterally when pulled taught or released respectively.

85. A spinal distraction implant comprising:

an outer housing; and

an internal spring;

wherein, the housing is biased to be in a laterally broad position when the spring is in a neutral position.

87. A spinal distraction implant comprising:

a pair of stacked structures separated by a sloping plane; and

a fastener positioned at an angle through the pair of structures thereby preventing relative movement along the plane.

88. A spinal distraction implant comprising a collapsible cylinder with side cutouts, the cylinder made from a resilient elastic material.

89. A spinal distraction implant comprising a distal tip of a delivery tool, wherein the tip is adapted to distract a facet joint and detach from the delivery tool.

90. A spinal distraction implant comprising:

a housing;

a central gear rotatably positioned within the housing;

two plates slidably positioned in the housing and positioned opposite one another adjacent to the central gear and including teeth for engaging the gear;

wherein, rotating the gear slidably extends the plates beyond an outer surface of the housing in opposite directions.

91. A spinal distraction implant comprising a triangularly bent plate with a first and second bracket on each side, the first bracket adapted to receive an anchor screw and the second bracket including teeth for biting into a lateral mass of a facet joint.

93. A spinal distraction implant comprising:

a rotatable cone with a longitudinal axis including a shoulder with a ledge defining a cam surface; and

an anchor screw;

wherein the shoulder is adapted to be inserted into a facet joint and the implant rotated to cause a superior facet to ride upward along the facet surface and distract the joint, wherein the screw may be advanced to secure the implant.

94. A spinal distraction implant comprising:

a housing with penetrations for ejection of spikes;

internal spikes positioned with the housing and in alignment with the penetrations; and

an internal wire routed through the spike positions;

wherein, pulling the wire taught forces the spikes from housing to engage articular surfaces of a facet joint.

95. A spinal distraction implant comprising:

a housing;

a cavity within the housing;

penetrations on lateral surfaces of the housing extending from the cavity through the wall of the housing;

spikes positioned to be ejected through the penetrations, the spikes having a beveled inner surface; and

a piston having a torpedo shaped distal end positioned within the cavity;

wherein advancing the piston engages the torpedo shaped distal end with the beveled inner surface of the spikes causing them to eject through the penetrations and engage articular surfaces of a facet joint.

96. A spinal distraction implant comprising:

two parallel equal length side bars; and

at least two struts pivotably positioned between the side bars at each end, the struts having textured surfaces on each end thereof;

wherein, the struts may be pivoted to lie in plane with and parallel side bars and once in position in a facet joint, may be pivoted substantially perpendicular to the side bars to distract the facet joint.