System and method for facet joint replacement

• US 8,252,027 B2
• Filed: 08/29/2008
• Issued: 08/28/2012
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: Globus Medical, Inc.
• Original Assignee: Gmedelaware 2 LLC (Globus Medical, Inc.)
• Inventors: Helgerson, Joel R.
• Primary Examiner(s): Robert, Eduardo C
• Assistant Examiner(s): PALMER, JAMES W
• Application Number:
  US12/201,128
• Publication Number:
  US 20080319488A1
• Time in Patent Office: 1,460 Days
• Field of Search: 606/246, 606/60, 606/247, 623 1711- 1716
• US Class Current: 606/247
• CPC Class Codes: A61B 17/7005 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit in the screw or hook heads
• CPC Class Codes: A61B 17/7035 Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• CPC Class Codes: A61B 17/704 the longitudinal element passing through a ball-joint in the screw head
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/7067 Devices bearing against one or more spinous processes and also attached to another part of the spine; Tools therefor
• CPC Class Codes: A61B 17/707 Devices acting on, or attached to, a transverse process or rib; Tools therefor
• CPC Class Codes: A61B 2017/7073 with intervertebral connecting element crossing an imaginary spinal median surface
• CPC Class Codes: A61F 2/0095 Packages or dispensers for prostheses or other implants for intraocular lenses A61F2/1691; for dental surgery A61C19/02
• CPC Class Codes: A61F 2/4405 for apophyseal or facet joints, i.e. between adjacent spinous or transverse processes devices implanted between spinous or transverse processes A61B17/7062
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30471 connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2002/30481 using a locking clip
• CPC Class Codes: A61F 2002/30495 using a locking ring
• CPC Class Codes: A61F 2002/305 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 2002/30522 releasable, e.g. using a releasable ratchet
• CPC Class Codes: A61F 2002/30537 adjustable
• 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 2002/30604 : modular
• CPC Class Codes: A61F 2002/30649 : Ball-and-socket joints
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30845 : with cutting edges
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30884 : Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• 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 2002/449 : comprising multiple spinal implants located in different intervertebral spaces or in different vertebrae
• 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 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/0091 : connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2250/0004 : adjustable
• CPC Class Codes: A61F 2250/0007 : for adjusting length
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

A facet joint replacement system includes an inferior implant with an inferior articular surface, a superior implant with a superior articular surface and may include a crosslink extending across a vertebral sagittal plane. The inferior implant may comprise an inferior strut, and a polyaxially adjustable, lockable mechanism which may couple the inferior articular surface with a first end of the inferior strut, and couple the inferior articular surface with the crosslink. A second end of the inferior strut may be secured to a polyaxially adjustable, lockable fixation assembly securable in a vertebra. The superior implant may be secured to a polyaxially adjustable lockable fixation assembly securable in a vertebra. The positions of the inferior articular surface and the first end of the inferior strut are independently translatable along a medial-lateral axis of the vertebra prior to lockout by the lockable mechanism. The crosslink may be placed into the lockable mechanism from a posterior approach.

Claims

1. A system for replacing at least a portion of a natural facet joint that controls motion between a first vertebra and a second vertebra, the system comprising:

a left fixation member implantable in a left pedicle of the second vertebra;

a right fixation member implantable in a right pedicle of the second vertebra;

a crosslink, wherein the crosslink comprises a half-pipe body;

a left inferior facet joint implant comprising;

a left inferior articular surface shaped to replace a natural left inferior articular surface of the second vertebra;

a left inferior strut comprising a first end and a second end, wherein the first end is securable to the left fixation member and the second end is connectable to the crosslink; and

a left attachment mechanism; and

a right inferior facet joint implant comprising;

a right inferior articular surface shaped to replace a natural right inferior articular surface of the second vertebra;

a right inferior strut comprising a first end and a second end, wherein the first end is securable to the right fixation member and the second end is connectable to the crosslink; and

a right attachment mechanism;

wherein each attachment mechanism comprises a saddle oriented posteriorly to permit insertion of the crosslink into the saddle from a posterior approach;

wherein each attachment mechanism is actuatable from an adjustable configuration, in which the position and/or orientation of the corresponding inferior articular surface and/or the second end of the corresponding inferior strut is adjustable relative to the crosslink, and a locked configuration in which the second end, the corresponding inferior articular surface, and the crosslink are rigidly secured to each other.

2. The system of claim 1, wherein the first end of each inferior strut comprises a first post securable to the corresponding fixation member through the use of a second attachment mechanism coupled to the corresponding fixation member, wherein the second attachment mechanism is configured to adjustably receive the first end in a manner that permits cephalad-caudal translation of a position of the first end relative to the corresponding fixation member prior to securement of the first end to the corresponding fixation member.

3. The system of claim 1, wherein each second end comprises a second post, wherein the crosslink is hollow and comprises an interior within which each second end may be retained.

4. The system of claim 1, wherein each second end comprises a second post, wherein the first and second posts of each inferior strut are formed monolithically with each other and are oriented nonparallel to each other.

5. The system of claim 1, wherein each attachment mechanism comprises:

a coupling body comprising opposing sidewalls that extend posteriorly to define the corresponding saddle;

a compressible member positionable at least partially within the coupling body; and

a locking member configured to be actuated relative to the compressible member to secure the crosslink within the saddle and urge compression of the compressible member;

wherein, in response to compression of the compressible member, an interior wall of a cavity of the compressible member exerts force against a rounded surface fixedly connected to the corresponding inferior articular surface to restrict rotation of the inferior articular surface relative to the second end of the corresponding inferior strut to provide the locked configuration.

6. The system of claim 5, wherein each rounded surface comprises a spherical member, wherein the coupling body of each attachment mechanism comprises a threaded wall and the compressible member of each attachment mechanism comprises a plurality of fingers, wherein the locking member of each attachment mechanism comprises a screw configured to threadably engage the threaded wall such that tightening of the nut on the threaded wall urges the fingers together within the coupling body to cause compression of the fingers around the spherical member.

7. The system of claim 1, wherein in the adjustable configuration, the position of the each inferior articular surface is adjustable medial-laterally relative to the second end of the corresponding inferior strut.

8. The system of claim 1, further comprising:

a left superior facet joint implant securable to a left pedicle of the first vertebra, the left superior facet joint implant comprising a left superior articular surface;

a right superior facet joint implant securable to a right pedicle of the first vertebra, the right superior facet joint implant comprising a right superior articular surface;

wherein, when all of the facet joint implants are secured to the corresponding pedicles, the left superior articular surface is positioned to articulate with the left inferior articular surface and the right superior articular surface is positioned to articulate with the right inferior articular surface.

9. A system for replacing at least a portion of a natural facet joint that controls motion between a first vertebra and a second vertebra, the system comprising:

a left fixation member implantable in a left pedicle of the second vertebra;

a right fixation member implantable in a right pedicle of the second vertebra;

a crosslink;

a left inferior facet joint implant comprising;

a left inferior articular surface shaped to replace a natural left inferior articular surface of the second vertebra;

a left inferior strut comprising a first end and a second end, wherein the first end is securable to the left fixation member and the second end is connectable to the crosslink; and

a left attachment mechanism; and

a right inferior facet joint implant comprising;

a right inferior articular surface shaped to replace a natural right inferior articular surface of the second vertebra;

a right inferior strut comprising a first end and a second end, wherein the first end is securable to the right fixation member and the second end is connectable to the crosslink; and

a right attachment mechanism;

wherein each attachment mechanism comprises a single element that is actuatable to move the attachment mechanism from an adjustable configuration, in which the position of the corresponding inferior articular surface is adjustable medial-laterally relative to the second end of the corresponding inferior strut, and a locked configuration in which the corresponding second end and the corresponding inferior articular surface are rigidly secured to each other; and

wherein each second end comprises a second post, wherein the crosslink is hollow and comprises an interior within which each second end may be retained.

10. The system of claim 9, wherein the first end of each inferior strut comprises a first post securable to the corresponding fixation member through the use of a second attachment mechanism coupled to the corresponding fixation member, wherein the second attachment mechanism is configured to adjustably receive the first end in a manner that permits cephalad-caudal translation of a position of the first end relative to the corresponding fixation member prior to securement of the first end to the corresponding fixation member.

11. The system of claim 9, wherein each second end comprises a second post, wherein the first and second posts of each inferior strut are formed monolithically with each other and are oriented nonparallel to each other.

12. The system of claim 9, wherein each attachment mechanism comprises:

a coupling body comprising opposing sidewalls that extend posteriorly to define a saddle;

a compressible member positionable at least partially within the coupling body; and

a locking member configured to be actuated relative to the compressible member to retain the crosslink within the saddle and urge compression of the compressible member;

wherein, in response to compression of the compressible member, an interior wall of a cavity of the compressible member exerts force against a rounded surface fixedly connected to the corresponding inferior articular surface to restrict rotation of the inferior articular surface relative to the second end of the corresponding inferior strut to provide the locked configuration.

13. The system of claim 12, wherein each rounded surface comprises a spherical member, wherein the coupling body of each attachment mechanism comprises a threaded wall and the compressible member of each attachment mechanism comprises a plurality of fingers, wherein the locking member of each attachment mechanism comprises a screw configured to threadably engage the threaded wall such that tightening of the nut on the threaded wall urges the fingers together within the coupling body to cause compression of the fingers around the spherical member.

14. The system of claim 9, further comprising:

a left superior facet joint implant securable to a left pedicle of the first vertebra, the left superior facet joint implant comprising a left superior articular surface;

a right superior facet joint implant securable to a right pedicle of the first vertebra, the right superior facet joint implant comprising a right superior articular surface;

wherein, when all of the facet joint implants are secured to the corresponding pedicles, the left superior articular surface is positioned to articulate with the left inferior articular surface and the right superior articular surface is positioned to articulate with the right inferior articular surface.