Intervertebral disk arthroplasty device

• US 5,562,738 A
• Filed: 01/12/1995
• Issued: 10/08/1996
• Est. Priority Date: 01/06/1992
• Status: Expired due to Term

• Current Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Original Assignee: Danek Medical, Inc.
• Inventors: Pettine, Kenneth A., Boyd, Lawrence M., Salib, Richard M.
• Primary Examiner(s): Milano, Michael J.
• Application Number:
  US08/371,754
• Time in Patent Office: 635 Days
• Field of Search: 623/16, 623/17, 623/18, 606/61
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30123 with two diametrically opposed lobes
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30232 Half-cylinders
• CPC Class Codes: A61F 2002/30245 Partial spheres
• CPC Class Codes: A61F 2002/30253 ellipsoidal or ovoid
• CPC Class Codes: A61F 2002/30327 differing in diameter
• CPC Class Codes: A61F 2002/30359 Pyramidally- or frustopyramidally-shaped protrusion and recess
• 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 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30481 using a locking clip
• 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 2002/30578 : having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/3065 : Details of the ball-shaped head
• CPC Class Codes: A61F 2002/30662 : with rotation-limiting means
• CPC Class Codes: A61F 2002/30663 : multiaxial, e.g. biaxial; multipolar, e.g. bipolar or having an intermediate shell articulating between the ball and the socket
• CPC Class Codes: A61F 2002/30685 : Means for reducing or preventing the generation of wear particulates
• CPC Class Codes: A61F 2002/3079 : Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30828 : parallel
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30879 : Ribs
• CPC Class Codes: A61F 2002/30884 : Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/30894 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30968 : Sintering
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• 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 2220/005 : using adhesives
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0071 : spherical
• CPC Class Codes: A61F 2230/0076 : ellipsoidal or ovoid
• CPC Class Codes: A61F 2250/0039 : differing in diameter
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00407 : Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00976 : Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF

Abstract

A disk arthroplasty device (310) is provided for replacement of a spinal disk. The device is implantable into a resected disk space and is formed with ball (346) and socket (326) members and shaped to provide lateral bending and backward extension of up to about 5° and forward flexion of up to about 15°. Four embodiments (10), (110), (210) and (310) permit up to about 5° axial rotation and a fifth embodiment (410) permits unrestricted axial rotation. Metal insert cups (70) and (170) are provided for attaching to the device surfaces and are convexly shaped along one axis to conform to the natural contours of the top and bottom vertebra surfaces. The metal insert cups (70) and (170) provide tensile support to the structure and provide for the attachment of additional structures for retaining the device in position after implantation into a disk space.

Claims

1. An intervertebral disk arthroplasty device adapted to replace a disk between a first vertebra and a second vertebra in a spine, said arthroplasty device comprising:

a first member having a first joint surface, a top surface opposite said first joint surface, a first posterior end and a first anterior end;

a second member having a second joint surface facing said first joint surface, a bottom surface opposite said second joint surface, and second posterior and anterior ends juxtaposed with corresponding ones of said first posterior and anterior ends;

a first insert cup having a first receiving surface for receiving said top surface therein, and a first engaging surface opposite said first receiving surface for engaging the first vertebra; and

a second insert cup having a second receiving surface for receiving said bottom surface therein, and a second engaging surface opposite said second receiving surface for engaging the second vertebra, wherein said first and second engaging surfaces are convex about the sagittal plane of the spine.

2. The intervertebral disk arthroplasty device of claim 1, further including:

means for restrainably retaining said top and bottom surfaces within said first and second receiving surfaces respectively.

3. The intervertebral disk arthroplasty device of claim 2, wherein said means for restrainably retaining comprises a press fit.

4. The intervertebral disk arthroplasty device of claim 2, wherein said top, bottom, first receiving and second receiving surfaces are configured to permit said first and second members to be slidably received within said first and second insert cups respectively.

5. The intervertebral disk arthroplasty device of claim 4, wherein said means for restrainably retaining includes:

a first screw oriented in a direction perpendicular to said top surface from said first insert cup toward said first member, and engaging said first insert cup to said first member; and

a second screw oriented in a direction perpendicular to said bottom surface from said second insert cup toward said second member, and engaging said second insert cup to said second member.

6. The intervertebral disk arthroplasty device of claim 1, further including:

a plurality of resisting means for resisting axial rotation of said intervertebral disk arthroplasty device, said resisting means extending from the anterior ends of said first and second engaging surfaces, and perpendicular to said top and bottom surfaces.

7. The intervertebral disk arthroplasty device of claim 6, further including:

a coating disposed on said first and second engaging surfaces wherein said coating is a biologically acceptable material suitable for promoting bony ingrowth fixation.

8. The intervertebral disk arthroplasty device of claim 7, wherein said material is composed of titanium beads.

12. The intervertebral disk arthroplasty device of claim 1, wherein said first and second insert cups are made of titanium

9. An intervertebral disk arthroplasty device adapted to replace a disk between a first vertebra and a second vertebra in a spine, said arthroplasty device comprising:

a first member having a first joint surface, a top surface opposite said first joint surface, a first posterior end and a first anterior end;

a second member having a second joint surface facing said first joint surface, a bottom surface opposite said second joint surface, and second posterior and anterior ends juxtaposed with corresponding ones of said first posterior and anterior ends;

a first insert cup having a first receiving surface for receiving said top surface therein, and a first engaging surface opposite said first receiving surface for engaging the first vertebra;

a second insert cup having a second receiving surface for receiving said bottom surface therein, and a second engaging surface opposite said second receiving surface for engaging the second vertebra; and

retaining ribs formed within said top and bottom surfaces and extending parallel with the anterior and posterior ends of said first and second insert cups along a substantial portion of said top and bottom surfaces, said retaining ribs being configured to permit movement of said disk arthroplasty device in the first direction and to resist movement of said disk arthroplasty device in an opposite direction.

10. The intervertebral disk arthroplasty device of claim 9, further including:

a first recessed channel in said top surface, said first channel extending parallel with said retaining ribs along said top surface, said first channel having a first predetermined width centered equidistant from the anterior and posterior ends of said first insert cup; and

a second recessed channel in said bottom surface, said second channel extending parallel with said retaining ribs along said bottom surface, said second channel having a second predetermined width centered equidistant from the anterior and posterior ends of said second insert cup.

11. The intervertebral disk arthroplasty device of claim 10, further including:

a coating disposed within said first and second recessed channels, wherein said coating is a biologically acceptable material suitable for promoting bony ingrowth fixation.

13. An intervertebral disk arthroplasty adapted to replace a disk between a first vertebra and a second vertebra in a spine, said arthroplasty comprising:

a first member having a first surface for engaging the first vertebra, an opposite first joint surface, a posterior end and a first anterior end, said ends defining a transverse midline therebetween, said midline being equidistant from said first posterior end and said first anterior end;

a second member having a second surface for engaging the second vertebra, an opposite second joint surface facing said first joint surface, and second posterior and anterior ends juxtaposed with corresponding ones of said first posterior and anterior ends;

a joint between said first and second members to permit relative rotation between said first member and said second member about a first axis parallel to said transverse midline and a second axis perpendicular to said first axis, said joint including;

a first, second and third ball portion defined in said first joint surface of said first member, said ball portions having circular cross sections along an axis parallel to said transverse midline, said first ball portion having a larger radius than said second and third ball portions, said second and third ball portions having equal radii and being disposed on opposite sides of said first ball portion, said ball portions being disposed radially about said firsts axis; and

a socket portion defined in said second joint surface substantially complementary to said ball portions in said first joint surface and configured to receive said ball portions therein;

a first insert cup for inserting the surface opposite said first joint surface of said first member therein; and

a second insert cup for inserting the surface opposite said second joint surface of said second member therein;

each of said insert cups having a surface for engaging a respective vertebra of the first and second vertebra; and

said engaging surfaces being disposed convexly about said second axis.