Rotating, locking, middle-expanded intervertebral disk stabilizer

• US 5,658,336 A
• Filed: 06/07/1995
• Issued: 08/19/1997
• Est. Priority Date: 03/18/1994
• Status: Expired due to Term

• Current Assignee: Perumala Corporation
• Original Assignee: Perumala Corporation
• Inventors: Pisharodi, Madhavan
• Primary Examiner(s): Prebilic, Paul B.
• Application Number:
  US08/475,211
• Time in Patent Office: 804 Days
• Field of Search: 606/61, 606/62, 606/63, 606/60, 606/53, 606/66, 606/73, 623/17, 623/66
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 2017/0256 for the spine
• 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 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• 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 2002/30169 Pi-shaped
• CPC Class Codes: A61F 2002/30214 having tapered sections of different conicities
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30253 ellipsoidal or ovoid
• CPC Class Codes: A61F 2002/30286 barrel-shaped
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30398 Sliding
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30426 Bayonet coupling
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• 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 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30873 : Threadings machined on non-cylindrical external surfaces
• CPC Class Codes: A61F 2002/30879 : Ribs
• 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 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• 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 2230/0047 : Pi-shaped
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0067 : conical
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0076 : ellipsoidal or ovoid
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

A middle expanded, removable disk implant for stabilizing adjacent vertebrae. The implant is substantially rectangular in cross-sectional shape with a minimal height and a width greater than the height. The implant is detachably mounted to an applicator for insertion into the anatomical region between two adjacent vertebrae from which a portion of the intervertebral disk has been removed, and once inserted, is positioned by anterior-posterior movement in the disk space to the position in which both the expanded, larger width middle portion and the smaller diameter end portions of the implant will engage the bodies of the adjacent vertebrae and the implant is then rotated to bring the sides of the rectangularly-shaped implant defining the width of the implant, with its larger dimension, into engagement with the bodies of the adjacent vertebrae. A lock is then secured to the implant to prevent further rotation thereof.

Claims

1. A vertebral disk stabilizer comprising:

an elongate implant having a substantially rectangular cross-sectional shape perpendicular to the elongate length thereof, comprised of first, second, third, and forth sides providing a minimal height defined by the first and second sides and maximal width defined by the third and forth sides, the third and forth sides being arched from one end of said implant to the other end of said implant to provide the middle portion of said implant with a bi-convex shape having a width larger than the width of the ends of said implant, the height being less than the width;

a lock having a bearing surface formed thereon, and

means detachably mounting said lock to one end of said implant to prevent rotation of said lock relative said implant with the bearing surface oriented at approximately 90°

with respect to the height of said implant.

2. The stabilizer of claim 1 wherein the third and fourth sides of said implant are provided with teeth.

3. The stabilizer of claim 1 wherein said lock is provided With a substantially flat surface for contacting either the first or the second side of said implant to prevent rotation of said lock relative to said implant.

4. The stabilizer of claim 1 wherein the corners of said implant between the first, second, third, and fourth sides are rounded.

5. The stabilizer of claim 1 wherein the end of said implant opposite the end to which said lock is mounted is rounded.

6. The stabilizer of claim 1 additionally comprising an applicator for detachably mounting to said implant after removing said lock therefrom.

7. Apparatus for inserting between adjacent vertebrae after removal of a portion of the intervertebral disk from therebetween with an elongate applicator comprising:

an elongate implant having a substantially rectangular cross-sectional shape perpendicular to the elongate length thereof, comprised of first and second substantially flat sides defining the height of said implant and third and fourth sides defining the width of said implant, the third and fourth sides being arched to provide said implant with a bi-convex shape having a width greater in the middle portion than at the ends thereof, the height of said implant being less in dimension than the width of said implant;

means formed in one end of said implant for detachably mounting an applicator to said implant; and

a lock detachably secured to said implant to prevent rotation of said implant in the space between the adjacent vertebrae after (a) inserting said implant when mounted to said applicator into the space between the adjacent vertebrae with the first and second sides of said implant contacting the adjacent vertebrae, (b) rotating said applicator having said implant mounted to the applicator approximately 90°

to cause the third and fourth sides of said implant to contact the adjacent vertebrae, and (c) detaching said applicator from said implant.

8. The apparatus of claim 7 wherein said lock is provided with a surface for bearing against the adjacent vertebrae to prevent rotation of said lock relative to the adjacent vertebrae.

9. The apparatus of claim 8 wherein said bearing surface is oriented at an angle of approximately 90°

to the first and second sides of said implant when secured thereto.

10. The apparatus of claim 7 wherein said lock is provided with a flat surface for contacting either the first or second surface of said implant when secured thereto.

11. The apparatus of claim 7 wherein the third and fourth sides of said implant are provided with teeth for biting into the adjacent vertebrae when said implant is rotated.