The present invention relates generally to an implantable inter-vertebral disk for placement between opposing body portions of succeeding vertebra, such as associated with but not limited to a human spine. More specifically, the present invention disclose an artificial disk which replaces a previously existing and damaged or otherwise degraded inter-vertebral fibro cartilage, the artificial disk exhibiting outer layers of metal exhibiting bone fusing characteristics which sandwich therebetween a soft plastic cushioning layer which, upon being implanted, mimics the characteristics of natural fibro cartilage.
The prior art is documented with examples of inter-vertebral body implants, such as disks or cushions. A first example of this is the flanged interbody spinal fusion implant of Michelson, U.S. Pat. No. 6,730,127. The flange body exhibits bone screw receiving holes adapted to overly each of the adjacent vertebral bodies. The implant has at least one locking element to lock one or more of the bone screws inserted into the receiving holes.
McLeod, US 2009/0105826 teaches disc prosthesis for use in the lumbar spine region and including a core consisting of one or more filling elements provided within an inner component of fabric. The inner component is provided within an outer component of fabric. A smooth inner contacting surface between the inner component and the core filling facilitates movement between the inner component and the core.
Seifert 2011/0251689 teaches an intervertebral implant in which a spacer portion includes inferior and superior surfaces, each of which have a contact area capable of engaging with the anatomy in the treated intervertebral space. A through hole extends through the spacer body. Screw holes extend from a side portion to the inferior and superior surfaces of the spacer portion and plate portion containing screw receiving holes is rigidly coupled to the spacer portion through a coupling means. A screw back out prevention mechanism on the plate portion prevents back out of screws from the holes and to secure the spacer portion to the plat portion of the implant.
Finally, US 2011/0106262 teaches a prosthetic intervertebral disc and method in which upper and lower endplates are separated by a compressible core member. A series of one, two, three and four piece structures are provided and exhibit stiffness in the vertical direction, torsional stiffness, bending stiffness in the sagittal plane, and bending stiffness in the front plane, and in which the degree of these features can be controlled independently by adjusting the components of the discs. An interface mechanism between the endplates and the core members across the several embodiments facilitates surgical implantation.
The present invention discloses an inter-vertebral and implantable disk substituting for a fibro cartilage and including first and second hard outer layers between which is sandwiched a softer inner cushioning layer. Each of the outer layers includes an exterior texturized pattern for promoting bone in-growth subsequent to implantation.
Each of the outer layers may also include an exteriorly integrally formed and angled mounting portion including an interiorly positioned aperture. The mounting portions are adapted to being applied against reconditioned side exterior locations of first and second succeeding intervertebral bodies and mounted to the bodies with a screw or clip.
Other features include the outer layers being constructed of any of titanium, medical grade stainless steel, other metal, composite metal/polymer, or composite polymer material. The inner cushioning layer may also include a material with a lower/softer durometer rating less than that associated with a harder/higher rating of the hard outer layers.
An inner surface associated with each of the hard outer layers may also integrate an arrangement of keyed inward projections in a staggered or offset fashion relative to the inner sandwiched cushioning layer to provide better bond line maintenance along boundary interfaces established between the inner surfaces and the cushioning layer and to further provide a degree of anti-shear support relative to the boundary interfaces in order to prevent inadvertent separation of the cushioning material from either of the hard outer layers.
Other features include the exterior texturized pattern exhibiting a plurality of laser cut and intersecting grid lines establishing an angle relative to a perpendicular established with a face of the layer. The exterior texturized pattern may also incorporate any of a repetitive wave pattern combined with iteratively located apertures for further promoting bone in-growth, multiple spiral patterns, or an irregular and cavitation surface pattern.
Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which:
As previously described, the present invention disclose an artificial disk assembly, which is generally depicted at 10 in each of
In this manner, the nucleus of the disk acts as a shock absorber in order to absorb the impact of the body's daily activities along with keeping the opposing vertebrae separated. As further depicted in each of
Without embarking upon a detailed physiological description of the human anatomy, suffice it to say that the human spine includes twenty three disks, including six in the neck (cervical) region, twelve in the middle back (thoracic) region, and an additional five in the lower back (lumbar) region. As again shown in
Rear spinous processes are further shown in the rotated and partially sectioned view of
For purposes of ease of illustration, also not depicted are a collection of ligament structures surrounding the spinal column, these including such as the anterior longitudinal ligaments which overlay the bodies 1 and 2 and inter-disposed disk assembly 10 (this again in substitution of the inter-vertebral fibro-cartilage), the posterior longitudinal ligaments (this located on the opposite rear side of the bodies 1 and 2 proximate the interconnecting pedicle 9 and the vertebral foramen, the capsulary ligaments extending between the superior articular facets or processes 3 and 4, as well as related inter-vertebral fibro cartilage and anterior costo-transverse ligaments, the inter-spinal ligaments associated with the spinous processes 7 and 8, and the supra-spinal ligaments extending from the rear of the column. Also not shown is the spinal nerve cord and individual branches associated with the column and which is outside of the scope of this description.
Having undertaken a general description of the associated anatomy with which the present invention cooperates, the artificial disk 10 as generally depicted exhibits a pair of outer layers 12 and 14 of a hard material, such as including but not limited to any of a titanium, other medical grade stainless steel, other metal or any hard composite material not limited to plastic/metal or various polymeric compositions exhibiting a hard outer consistency including such as medical grade nylon or other material. As shown collectively in
Each of the angled end brackets includes one or more interiorly positioned apertures, such as depicted by closed perimeter defining surface 20 for angled end bracket 16 associated with layer 12, further by closed perimeter surface 22 for angled end bracket 18 associated with layer 14. One or more screws, clips or other suitable fastener, such as generally depicted at 21 and 23, can be provided and in order to mount to reconditioned side disposed and exterior facing locations 24 and 26 respectively of the vertebral bodies 1 and 2.
Sandwiched between the hard outer layers 12 and 14 is a soft plastic cushioning layer 28 (such as including any lower durometer rated polymer or like material) and which, upon being implanted, mimics the characteristics of natural inner nucleus pulposus (such as including exhibiting an equivalent durometer rating as associated with the original cartilage material), with the hard outer layers 12 and 14 likewise mimicking that of natural fibro cartilage. Each of
The keyed projections 34 & 36 and 38 & 40 are depicted in a staggered or offset fashion relative to the inner sandwiched cushioning layer 28, such as in order to provide better bond line maintenance along boundary interfaces 42 and 44 established between the inner surfaces of the outer layers 12 and 14 and the intermediate cushioning layer 28, this further providing a degree of anti-shear support relative to the boundary interfaces 42 and 44 and in order to prevent inadvertent separation of the cushioning material 28 from either of the hardened upper 12 and lower 14 layers.
Referring now to
Having described my invention, other and additional preferred embodiments will become apparent to those skilled in the art to which it pertains, and without deviating from the scope of the appended claims.
This Application claims the benefit of U.S. Provisional Application 61/616,651 filed on Mar. 28, 2012, the contents of which are incorporated herein in its entirety.
Number | Date | Country | |
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61616651 | Mar 2012 | US |