Expandable implant for inter-bone stabilization and adapted to extrude osteogenic material, and a method of stabilizing bones while extruding osteogenic material

• US 6,214,050 B1
• Filed: 05/11/1999
• Issued: 04/10/2001
• Est. Priority Date: 05/11/1999
• Status: Expired due to Fees

• Current Assignee: Donald R. Huene
• Original Assignee: Donald R. Huene
• Inventors: Huene, Donald R.
• Primary Examiner(s): Isabella, David J.
• Application Number:
  US09/309,918
• Time in Patent Office: 700 Days
• Field of Search: 623/17.11, 623/17.12, 623/17.13, 623/17.14, 623/17.15, 623/17.16, 606/61
• US Class Current: 623/17.15
• CPC Class Codes: A61F 2/30721 Accessories
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4601 for introducing bone substitute, for implanting bone graft implants or for compacting them in the bone cavity
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• 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 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30481 using a locking clip
• CPC Class Codes: A61F 2002/30495 using a locking ring
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30537 adjustable
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/30886 : externally-threaded
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2002/4638 : Tools for performing screwing, e.g. nut or screwdrivers, or particular adaptations therefor
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0004 : adjustable
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

An expandable implant is capable of extruding material during expansion. The expandable implant comprises an anchor structure and a movable structure. The anchor structure is adapted to be inserted at least partially into a bone or between two bones, and is adapted to be secured thereto by expansion. The movable structure is operatively connected to the anchor structure so that movement of the movable structure with respect to the anchor structure causes expansion of the implant and at least partial extrusion of material contained within the implant. Preferably, the implant also includes an actuation device which connects the anchor structure to the movable structure, and the material which is at least partially extruded is an osteogenic material. In response to mechanical manipulation, the actuation device can move the movable structure with respect to the anchor structure in a first predetermined direction which causes expansion of the implant and reduces the volume of a cavity within the implant. As a result of the reduction in volume, the osteogenic material is extruded at least partially out from the cavity. Also provided is a method of stabilizing first and second bones with respect to one another. The method comprises the steps of: inserting at least one expandable implant between the bones; expanding the implant; and extruding an osteogenic material from the implant during expansion thereof.

Claims

1. An expandable intervertebral implant comprising:

an anchor structure adapted to be inserted at least partially into vertebrae or between two vertebrae, and adapted to be secured thereto by expansion, said anchor structure having interiorly disposed surfaces and a plurality of radially movable fingers extending axially along said intervertebral implant;

a moveable structure having interiorly disposed surfaces and exteriorly disposed surfaces, said exteriorly disposed surfaces engageable with vertebrae, said movable structure being operatively connected to said anchor structure so that movement of said movable structure with respect to said anchor structure causes expansion of the implant and at least partial extrusion of material contained within the implant;

said anchor structure cooperating with said movable structure and defining a cavity delimited by said interiorly disposed surfaces of said anchor structure, said interiorly disposed surfaces of said movable structure, and said plurality of fingers; and

at least one of said anchor structure and movable structure having an extrusion opening through which said at least partial extrusion of material in said cavity occurs.

2. The expandable intervertebral implant of claim 1, wherein said anchor structure and said movable structure have shapes which cooperate to form a cavity within said intervertebral implant, said cavity having a volume which varies depending upon positioning of said movable structure with respect to said anchor structure.

3. The expandable intervertebral implant of claim 2, wherein at least one of said movable structure and said anchor structure has at least one extrusion opening which provides access from said cavity to an exterior of said intervertebral implant.

4. The expandable intervertebral implant of claim 1, further comprising an actuation device adapted to move said movable structure with respect to said anchor structure, said actuation device having a first end threadedly connected to at least one of said anchor structure and said movable structure, said actuation device being responsive to torque applied in a first predetermined direction to cause said movable structure to move toward said anchor structure to produce radial expansion of the intervertebral implant and thereby at least partially extrude material contained within the implant.

5. The expandable intervertebral implant of claim 4, wherein said cavity has a volume which varies depending upon positioning of said movable structure with respect to said anchor structure.

6. The expandable intervertebral implant of claim 5, wherein said actuation device is responsive to torque in a second predetermined direction to cause said movable structure to move away from said anchor structure and provide radial contraction of said intervertebral implant.

7. The expandable intervertebral implant of claim 1, wherein an osteogenic material is contained in said cavity and is at least partially extruded during expansion.

8. The expandable intervertebral implant of claim 1, wherein said anchor structure includes a cap portion, said plurality of fingers extending axially from said cap portion;

and

wherein said movable structure is movable at least partially through said cavity to effect increases or reductions in a volume of said cavity depending on a direction of movement of said movable structure.

9. The expandable intervertebral implant of claim 8, wherein said movable structure includes bearing surfaces which engage respective ones of said plurality of fingers and urge said fingers radially outwardly to effect expansion of said intervertebral implant when said movable structure is moved in the direction which effects reductions in the volume of said cavity.

10. The expandable intervertebral implant of claim 8, wherein said movable structure also includes a plurality of fingers interposed between the plurality of fingers of said anchor structure, said anchor structure including bearing surfaces which engage respective ones of said plurality of fingers of the movable structure and urge said fingers of the movable structure radially outwardly to effect further expansion of said intervertebral implant when said movable structure is moved in the direction which effects reductions in the volume of said cavity.

11. The expandable intervertebral implant of claim 1, wherein said movable structure includes a plurality of fingers extending axially along said intervertebral implant, said plurality of fingers being arranged with respect to one another and with respect to said anchor structure such that a cavity is delimited by inside surfaces of said anchor structure and said plurality of fingers;

and

wherein said movable structure is movable at least partially through said cavity to effect increases or reductions in a volume of said cavity depending on a direction of movement of said movable structure.

12. The expandable intervertebral implant of claim 1, wherein each of said anchor structure and said movable structure has at least one extrusion opening.

13. The expanded intervertebral implant of claim 12, wherein an osteogenic material is contained within said cavity.

14. The expandable intervertebral implant of claim 1, wherein each of said anchor structure and said movable structure includes a plurality of extrusion openings.

15. The expandable intervertebral implant of claim 1, wherein said anchor structure and said movable structure have dimensions which permit insertion of said expandable intervertebral implant between two vertebrae and expansion of the anchor structure to provide stabilization of said two vertebrae with respect to one another.

16. An expandable intervertebral implant comprising:

an anchor structure adapted to be inserted at least partially into vertebrae or between two vertebrae, and adapted to be secured thereto by expansion, said anchor structure having interiorly disposed surfaces and a plurality of radially movable fingers extending axially along said intervertebral implant;

a movable structure having interiorly disposed surfaces and exteriorly disposed surfaces, said exteriorly disposed surfaces engageable with vertebrae, said movable structure operatively connected to said anchor structure so that movement of said movable structure with respect to said anchor structure causes expansion of the intervertebral implant and at least partial extrusion of osteogenic material from the implant;

said anchor structure cooperating with said movable structure and defining a cavity delimited by said interiorly disposed surfaces of said anchor structure, said interiorly disposed surfaces of said movable structure, and said plurality of fingers;

osteogenic material contained within said cavity;

an actuation device threadedly connected to at least one of said anchor structure and said movable structure and adapted to move, in response to torque, said movable structure with respect to said anchor structure in a first predetermined direction which reduces a volume of said cavity to thereby extrude said osteogenic material at least partially from said cavity and which causes expansion of said intervertebral implant; and

at least one extrusion opening in at least one of said movable structure and anchor structure, through which said at least partial extrusion occurs.

17. The expandable intervertebral implant of claim 16, wherein said actuation device is responsive to torque in a second predetermined direction to cause said movable structure to move away from said anchor structure and provide radial contraction of said intervertebral implant.

18. The expandable intervertebral implant of claim 16, wherein each of said movable structure and said anchor structure has at least one extrusion opening which provides access from said cavity to an exterior of said intervertebral implant.

19. The expandable intervertebral implant of claim 16, wherein said anchor structure includes a cap portion, said plurality of fingers extending axially from said cap portion;

and

wherein said movable structure is movable at least partially through said cavity to effect increases or reductions in said volume depending on a direction of movement of said moveable structure.

20. The expandable intervertebral implant of claim 19, wherein said movable structure includes bearing surfaces which engage respective ones of said plurality of fingers and urge said fingers radially outwardly to effect expansion of said intervertebral implant when said movable structure is moved in the direction which effects reductions in the volume of said cavity.

21. The expandable intervertebral implant of claim 19, wherein said movable structure also includes a plurality of fingers interposed between the plurality of fingers of said anchor structure, said anchor structure including bearing surfaces which engage respective ones of said plurality of fingers of the movable structure and urge said fingers of the movable structure radially outwardly to effect further expansion of said intervertebral implant when said movable structure is moved in the direction which effects reductions in the volume of said cavity.

22. The expandable intervertebral implant of claim 16,

wherein said movable structure is movable at least partially through said cavity to effect increases or reductions in a volume of said cavity depending on a direction of movement of said movable structure.

23. The expandable intervertebral implant of claim 16, wherein each of said anchor structure and said movable structure includes a plurality of extrusion openings.

24. The expandable intervertebral implant of claim 16, wherein said anchor structure and said movable structure have dimensions which permit insertion of said expandable intervertebral implant between two vertebrae and expansion of the anchor structure to provide stabilization of said two vertebrae with respect to one another.

25. A method of stabilizing first and second bones with respect to one another, said method comprising the steps of:

inserting at least one expandable implant between the bones, the implant having an anchor structure and a movable structure in operative connection and at least one extrusion opening, the anchor structure including an interiorly disposed surface and a plurality of radially movable fingers extending axially from the implant, the movable structure including an interiorly disposed surface, the anchor structure and the movable structure cooperating to form an internal cavity containing osteogenic material, the internal cavity delimited by the plurality of fingers and the interiorly disposed surfaces of the anchor structure and the interiorly disposed surfaces of the movable structure;

expanding the implant; and

extruding the osteogenic material from the implant during expansion thereof.

26. The method of claim 25, wherein said step of inserting at least one expandable implant includes insertion of two expandable implants.

27. The method of claim 25, wherein said osteogenic material includes bone material.

28. The method of claim 25, wherein said steps of inserting, expanding, and extruding are performed between two vertebrae.

29. The method of claim 25, wherein said step of extruding is performed through the at least one extrusion opening(s) in said at least one expandable implant, by reducing a volume of the internal cavity.

30. The method of claim 25, further comprising the steps of:

determining whether a desired relative alignment of the first and second bones has been achieved after said step of expanding; and

if said step of determining indicates that the desired relative alignment was not achieved, radially compressing said at least one expandable implant, repositioning said at least one expandable implant, reexpanding said at least one expandable implant, verifying whether the desired relative alignment has been achieved after repositioning and reexpansion, and if verification indicates that the desired relative alignment has not been achieved, repeating said steps of radially compressing, repositioning, reexpanding, and verifying until said desired relative alignment is achieved.