Adjustable vertebral body replacement

• US 5,702,453 A
• Filed: 05/13/1996
• Issued: 12/30/1997
• Est. Priority Date: 12/09/1994
• Status: Expired due to Term

• Current Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Original Assignee: Sofamor Danek Group, Inc. (Medtronic Plc)
• Inventors: Boyd, Lawrence M., Chevalier, Jean-Louis, Moreau, Jean-Charles, Rabbe, Louis-Marie
• Primary Examiner(s): Milano, Michael J.
• Application Number:
  US08/647,272
• Time in Patent Office: 596 Days
• Field of Search: 623/17, 623/22, 606/61, 606/71
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/70 Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/8061 specially adapted for particular bones A61B17/70 and A61B17/74 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• 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 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 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30166 H-shaped or I-shaped
• CPC Class Codes: A61F 2002/3023 wedge-shaped cylinders
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• 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 2002/30383 made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30411 having two threaded end parts connected by a threaded central part with opposite threads at its opposite ends, i.e. for adjusting the distance between both end parts by rotating the central part
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30494 Cooperating protrusions and recesses, e.g. radial serrations, located on abutting end surfaces of a longitudinal 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 2002/3055 : for adjusting length
• CPC Class Codes: A61F 2002/30561 : breakable or frangible
• CPC Class Codes: A61F 2002/30574 : with an integral complete or partial collar or flange
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30601 : telescopic
• 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 2002/30774 : 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 2002/30841 : 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 2002/30892 : parallel
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• 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 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0071 : breakable or frangible
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys

Abstract

An adjustable vertebral body replacement implant and assembly includes a thin-walled cylindrical body configured to span over most of the length between intact vertebrae when damaged or diseased vertebrae have been removed. The cylindrical body defines a hollow interior with a plurality of bone-ingrowth apertures communicating with the interior. The replacement assembly further includes endplates configured to contact the adjacent vertebra and to engage the cylindrical body therebetween. The cylindrical body and the endplates include mating threads to permit adjustment of the overall height of the implant. A means for fixing the cylindrical body to the endplates is contemplated, which in one embodiment is a set screw for locking the components in place. In another embodiment, the means for fixing includes a crimping channel and notch defined in the endplates to be crimped onto the cylindrical body. A means for connecting the replacement implant to a longitudinal member is provided, which in one embodiment contemplates a clamp and screw assembly. In another embodiment, the means for connecting includes an arm projecting from the endplates with an opening to receive the longitudinal member therethrough.

Claims

1. A vertebral replacement implant for interposition in a space left by one or more removed vertebrae between adjacent intact vertebrae, comprising:

a replacement body with opposite ends sized to span a portion of the space between the intact vertebrae, said replacement body having first threads defined thereon at each of said opposite ends;

a pair of endplates each having an end surface for contacting a respective one of the intact vertebrae when the implant is interposed in the space, each of said endplates having a cylindrical portion integrally extending from said end surface, said cylindrical portion having second threads defined thereon configured to threadedly engage the first threads on said replacement body, and each of said endplates defining a bore therethrough opening at said end surface and at said cylindrical portion; and

an end cap for closing said bore of one of salad endplates at said end surface thereof, said end cap including;

a plate shaped to correspond to said bore opening in said endplate; and

a support bar attached to said plate;

wherein said endplate includes a slot defined at said end surface for receiving said support bar so that said plate of said end cap resides flush with said end surface of said endplate.

2. The vertebral replacement implant according to claim 1, wherein said replacement body includes a wall defining a hollow interior, said wall further defining a plurality of apertures therethrough, said apertures being in communication with said hollow interior.

3. The vertebral replacement implant according to claim 2, wherein said hollow interior of said replacement body is open at said opposite ends.

4. The vertebral replacement implant according to claim 2, wherein said first threads on said replacement body are external threads and said second threads on said cylindrical portion of said pair of endplates are internal threads.

5. The vertebral replacement implant according to claim 2, further comprising means for fixing said replacement body to each of said endplates to prevent unthreading of said first and second threads.

6. The vertebral replacement implant according to claim 5, wherein said means for fixing includes:

a number of openings defined in said cylindrical portion of each of said pair of endplates; and

a member extendable through one of said number of openings into contact with said replacement body.

7. The vertebral replacement implant according to claim 6, wherein:

said member is a set screw; and

said number of openings is threaded to receive said set set screw in threaded engagement.

8. The vertebral replacement implant according to claim 6, wherein said number of openings are defined in said endplates at said second threads.

9. The vertebral replacement implant according to claim 2, wherein each of said endplates includes a flange defining said end surface, said flange extending radially outwardly from said cylindrical portion and defining a shape generally corresponding to the shape of a portion of the intact vertebra against which the endplate is in contact.

10. The vertebral replacement implant according to claim 9, wherein said flange defines a number of vascularization apertures therethrough.