Intervertebral spacer device utilizing a spirally slotted belleville washer having radially spaced concentric grooves

• US 6,863,688 B2
• Filed: 10/11/2001
• Issued: 03/08/2005
• Est. Priority Date: 02/15/2001
• Status: Expired due to Fees

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Spinecore, Inc. (Stryker Corporation)
• Inventors: Ralph, James D., Tatar, Stephen
• Primary Examiner(s): Pellegrino, Brian E
• Application Number:
  US09/975,471
• Publication Number:
  US 20020111685A1
• Time in Patent Office: 1,244 Days
• Field of Search: 623/17.11, 623/17.13, 623/17.14, 623/17.15, 411/155, 411/156, 411/261, 411/544, 411/545
• US Class Current: 623/17.13
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/30171 rosette- or star-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• 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 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30492 using a locking pin
• 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 2002/30518 with possibility of relative movement between the prosthetic parts
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30565 having spring elements
• CPC Class Codes: A61F 2002/30571 Leaf springs
• 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 2002/30649 Ball-and-socket joints
• CPC Class Codes: A61F 2002/30769 : madreporic
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30909 : Nets
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30975 : made of two halves
• 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 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/005 : Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• 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 2310/00365 : Proteins; Polypeptides; Degradation products thereof

Abstract

An intervertebral spacer device having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by at least one spring mechanism. The preferred spring mechanism is at least one spirally slotted belleville washer having radially spaced concentric grooves. In a preferred embodiment there is a single such belleville washer which is modified to mount onto a ball-shaped head. The lower plate of this embodiment includes a post extending upwardly from the inner surface of the plate, the post including a ball-shaped head. The modified belleville washer can be rotatably mounted to the head such that the wider portion of the washer seats against the upper plate.

Claims

1. An intervertebral spacer device comprising:

first and second plate members, each having first and second plate surfaces thereof, said plates being disposed in a spaced apart relationship such that first ones of said plate surfaces oppose one another, and second ones of said plate surfaces face in opposite directions; and

at least one restoring force providing element disposed between said first surfaces of said first and second plate members, and disposed such that a compressive load applied to said second surfaces of said first and second plate members is counteracted by said at least one restoring force providing element, said at least one restoring force providing element including at least one belleville washer having at least one radially spaced concentric groove and at least one spiral slot;

wherein said at least one radially spaced concentric groove in said at least one belleville washer comprises a plurality of radially spaced concentric grooves, and wherein at least one of said plurality of radially spaced concentric grooves in said at least one belleville washer has a length;

wherein said length forms a closed loop.

2. The device as set forth in claim 1, further comprising disposed on at least one of said first and second plate members a retaining wall in which said at least one restoring force providing element is contained.

3. The device as set forth in claim 1, wherein said at least one belleville washer has a narrow end and a wide end and being oriented such that said wide end is in contact with said first surface of one of said first and second plate members.

4. The device as set forth in claim 1, wherein said at least one of said plurality of radially spaced concentric grooves in said at least one belleville washer has a depth and a width, and at least one of said width and said depth is uniform along said length.

5. The device as set forth in claim 1, wherein the radial spacing of said plurality of radially spaced concentric grooves is uniform.

6. The device as set forth in claim 1, wherein each of said plurality of radially spaced concentric grooves in said at least one belleville washer has a respective length, a respective depth along said respective length, and a respective width along said respective length, and wherein at least one of said depths is different than at least one other of said depths, and wherein at least one of said widths is different than at least one other of said widths.

7. The device as set forth in claim 6, wherein each of said plurality of radially spaced concentric grooves in said at least one belleville washer is at a respective distance from an outer edge of said at least one belleville washer, wherein said depths increase incrementally with decreasing said distances, and said widths increase incrementally with decreasing said distances.

8. The device as set forth in claim 1, wherein said at least one spiral slot in said at least one belleville washer comprises a plurality of spaced apart spiral slots, each of which extends from a locus on a peripheral edge of said at least one belleville washer to a locus which is radially in from said peripheral edge.

9. The device as set forth in claim 1, wherein one of said first and second plate members further comprises a post structure extending outwardly from said first surface of said one of said first and second plate members, and which post structure includes a ball-shaped head.

10. The device as set forth in claim 9, wherein said post structure further includes a threaded bore which extends axially from said ball-shaped head toward said first surface of said one of said first and second plate members, and which bore receives therein a threaded set screw such that prior to an insertion of the set screw therein, said bore permits the ball-shaped head to compress radially inwardly, and such that after the insertion of said set screw said ball-shaped head is not readily radially compressible.

11. The device as set forth in claim 10, wherein said at least one belleville washer further comprises a central opening which includes a curvate volume for receiving and holding therein said ball-shaped head.

12. The device as set forth in claim 11, wherein a tightening of said set screw locks said curvate volume with respect to said ball-shaped head.