Anterior expandable spinal fusion cage system

• US 6,821,298 B1
• Filed: 04/18/2000
• Issued: 11/23/2004
• Est. Priority Date: 04/18/2000
• Status: Expired due to Fees

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Telect Incorporated (Amphenol Corporation)
• Inventors: Jackson, Roger P.
• Primary Examiner(s): Pellegrino, Brian E
• Application Number:
  US09/552,743
• Time in Patent Office: 1,680 Days
• Field of Search: 623/17.11, 623/17.15, 623/17.16, 606/61
• US Class Current: 623/17.15
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• 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 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• 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 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• 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 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30515 using a locking wedge or block
• CPC Class Codes: A61F 2002/30517 using a locking plate
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• 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 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/30779 : arcuate
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3079 : Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30904 : 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 2002/4627 : 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 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• 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
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: Y10S 623/908 : Bone

Abstract

A fenestrated, hollow intervertebral cage containing a packed, harvested bone graft for fusing adjacent vertebrae together while maintaining or correcting the angular alignment and balance of the spine. Use of the device for an anterior interbody fusion results in a fused bone segment having a predetermined fixed angular orientation. The apparatus has a cage unit adjustably coupled to an expansion cap, and an adjustable wedge to support the adjacent vertebrae with facing surfaces at a predetermined angle relative to each other. A connecting bolt may be threaded or fixed to the rear of the cage unit. In certain embodiments, the cage unit and expansion cap are interlocking. Also in certain embodiments, especially utilizing round cages, the expansion cap may also include upper and lower horizontal bone-supporting surfaces and an anterior recess for receiving fasteners. A pair of independently adjustable cage units can be fixedly intercoupled by a link.

Claims

1. An apparatus for positionally stabilizing adjacent vertebrae of a spine by promotion of bone fusion between the adjacent vertebrae, said apparatus comprising:

a) an anteriorly expandable implant adapted to promote bone growth between the adjacent vertebrae;

said implant having upper and lower walls extending between anterior and posterior ends of the implant and a posterior wall connecting the upper and lower walls;

b) a post mounted in said posterior wall and extending to near the anterior end of said implant;

c) an expansion member operably coupled with said post and engaging said upper and lower walls for operably expanding a spacing between said anterior ends of said upper and lower walls, so as to operably urge said implant upper and lower walls into a predetermined non parallel angle relative to one another and so as produce a desired alignment of the adjacent vertebrae;

d) a cover assembly having upper and lower elongate support surfaces sized and shaped to contact and support an anterior region of the adjacent vertebrae; and

e) a fastener mechanism operably securing said cover assembly and said expansion member to said implant during use.

2. The apparatus according to claim 1 wherein:

a) said implant includes an interior chamber for receiving bone fragments; and

b) said implant has a plurality of radially positioned apertures for permitting bone fragments in said chamber to join and fuse with bone in the adjacent vertebrae.

3. An apparatus for stabilizing adjacent vertebrae of a spine by promotion of bone fusion between the adjacent vertebrae, said apparatus comprising:

a) an implant for implanting between a pair of adjacent vertebrae, said implant adapted to promote bone growth between the adjacent vertebrae;

b) an expansion cap coupled with said implant for expanding opposite sides of an anterior end of said implant to a predetermined spacing between the sides to provide a desired alignment of the adjacent vertebrae; and

c) an implant end cover that is non integral to said expansion cap and that is operably positioned anterior of said implant and operably secured to said implant;

said cover including upper and lower support surfaces that are elongate and generally linear and that are sized and shaped to engage and operably support along a substantial anterior region of both of said adjacent vertebrae.

4. The apparatus according to claim 3 wherein:

a) said expansion cap includes a recess for receiving a fastener to secure said cap to said implant.

5. The apparatus according to claim 3 wherein:

a) said implant includes an interior chamber for receiving bone fragments; and

b) said implant has a plurality of radially positioned apertures for permitting bone fragments in said chamber to join and fuse with bone in the adjacent vertebrae.

6. The apparatus according to claim 3 wherein:

a) said expansion cap and said implant include structure for cooperatively locking together said cap and said implant when fully joined.

7. In an implant that in use is located between adjacent vertebrae for stabilizing such vertebrae and wherein the implant has upper and lower walls joined by a posterior wall, the improvement comprising:

a) a post mounted in said posterior wall and extending to near an interior end of said implant; and

b) an anterior expansion member coupled to said post and adapted to operably expand an anterior spacing between said upper and lower walls, as said expansion member moves posteriorly along said post during installation;

said expansion member being anteriorly accessible and operably moved along said post by rotation of at least one of said expansion member and said post at said anterior end of said implant;

said expansion member being sized and shaped to remain in contact with said upper and lower walls at the anterior ends of said upper and lower walls, so as to provide support to said anterior ends during usage.

8. The implant according to claim 7 including:

a) a fastener for positioning said expansion member relative to said post and securing said expansion member to said post.