Middle expandable intervertebral disk implant

• US 5,693,100 A
• Filed: 03/15/1996
• Issued: 12/02/1997
• Est. Priority Date: 02/22/1991
• Status: Expired due to Fees

• Current Assignee: Madhavan Pisharodi
• Original Assignee: Madhavan Pisharodi
• Inventors: Pisharodi, Madhavan
• Primary Examiner(s): Willse, David H.
• Application Number:
  US08/617,490
• Time in Patent Office: 627 Days
• Field of Search: 623/17, 606/60, 606/61, 606/63, 269/48.1, 269/48.3
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• 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 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 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30146 octagonal
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/3028 polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30293 Cylindrical body made by spirally rolling up a sheet or a strip around itself
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• 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 2002/30471 : connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30556 : for adjusting thickness
• CPC Class Codes: A61F 2002/30573 : 2-D spiral springs
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• 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 2002/30599 : stackable
• CPC Class Codes: A61F 2002/30624 : Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• 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 2220/0091 : connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

Artificial disk implant and methods for implanting same, the implant, in one embodiment, having a member for adapting in size and shape to the anatomical space between vertebrae, and apparatus for expanding the member to conform to the space. In one preferred embodiment, there is provided an artificial intervertebral disk implant having a cylindrical body comprised of cylindrical subunits capable of expansion. In another preferred embodiment, rectangular subunits capable of expansion are provided. The implant can be used alone or in various combinations for the purpose of spinal fusion.

Claims

1. An implant for disposition in the space between two adjacent vertebrae after removal of a portion of the intervertebral disk therefrom comprising:

an elongate, threaded rod;

a first end cap mounted to said rod;

a second end cap threadedly engaging said rod for moving along said rod relative to said first end cap when said rod is rotated along the threads on said rod; and

a plurality of hinged subunits mounted between said first and second end caps and hingedly connected thereto, said hinged subunits comprising hinges which are movable from a first position surrounding and in close proximity to said rod so as to minimize the vertical dimension of the implant to facilitate insertion into the opening of the disk space to a second position with maximal vertical dimension by radially outward expansion of the hinges of said hinged subunits upon rotation of said rod after insertion into the disk space from which a portion of the disk has been removed to conform the shape of the implant to the shape of the anatomical region of the space from which the disk has been removed.

2. The implant of claim 1 additionally comprising a lock nut for engaging said rod to prevent rotation of said rod after expansion of the hinges of said subunits to said second position.

3. The implant of claim 1 wherein said second end cap receives said rod in a threaded hole, said rod being inlaid in said second end cap.

4. The implant of claim 1 additionally comprising means for preventing rotation of said rod after expansion of the hinges of said hinged subunits from said first position to said second position.

5. The implant of claim 4 wherein said rotation preventing means is inlaid in said second end cap.

6. The implant of claim 4 wherein said rotation preventing means comprises a screw threadably engaging the threads in said second end cap.

7. The implant of claim 1 wherein said hinged subunits are angled.

8. The implant of claim 1 wherein said hinged subunits are provided with bearing surfaces which cause the hinges of said hinged subunits to tend to move radially outwardly from said first position to said second position upon rotation of said rod.

9. The implant of claim 1 wherein said hinged subunits are provided with beveled sides to minimize the vertical dimension of the implant when said hinged subunits are in said first position.