Laterally insertable artificial vertebral disk replacement implant with translating pivot point
An implant that can be placed between two vertebrae using a lateral insertion method is described. The implant is characterized by having a first end plate and a second end plate with a hemi-cylindrical spacer extending from the second end plate. The hemi-cylindrical spacer fits within a socket on the first end plate and allows for pivotal or rotational motion and also for twisting motion.
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This application claims priority under 35 USC 119 to U.S. Patent Application No. 60/526,724, filed on Dec. 2, 2003 and entitled “ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH TRANSLATING PIVOT POINT AND LATERAL IMPLANT METHOD,” which is hereby incorporated by reference.
CROSS-REFERENCE TO RELATED APPLICATIONSThis application is related to U.S. Provisional Application No. 60/422,039, filed Oct. 29, 2002, entitled “ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH TRANSLATING PIVOT POINT AND METHOD,” U.S. patent application Ser. No. 10/684,668, filed Oct. 14, 2003, entitled “ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH CROSSBAR SPACER AND METHOD,” U.S. patent application Ser. No. 10/684,669, filed Oct. 14, 2003, entitled “ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH TRANSLATING PIVOT POINT AND METHOD,” U.S. Provisional Application No. 60/422,011, filed Oct. 29, 2002, entitled “TOOLS FOR IMPLANTING AN ARTIFICIAL VERTEBRAL DISK AND METHOD,” U.S. patent application Ser. No. 10/685,134, filed Oct. 14, 2003, entitled “TOOLS FOR IMPLANTING AN ARTIFICIAL VERTEBRAL DISK AND METHOD,” U.S. Provisional Application No. 60/422,022, filed Oct. 29, 2002, entitled “ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH A SPACER AND METHOD,” U.S. Provisional Application No. 60/422,021, filed Oct. 29, 2002, entitled “ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH CROSSBAR SPACER AND METHOD,” U.S. patent application Ser. No. 10/685,011, filed Oct. 14, 2003, entitled “ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH SPACER AND METHOD,” U.S. patent application Ser. No. ______, filed ______, entitled “METHOD OF LATERALLY INSERTING AN ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH TRANSLATING PIVOT POINT,” (KLYCD-05007US6), U.S. patent application Ser. No. ______, filed ______, entitled “LATERALLY INSERTABLE ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH A CROSSBAR SPACER,” (KLYCD-05008US6), U.S. patent application Ser. No. ______, filed ______, entitled “METHOD OF LATERALLY INSERTING AN ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH A CROSSBAR SPACER,” (KLYCD-05008US7), U.S. patent application Ser. No. ______, filed ______, entitled “LATERALLY INSERTABLE ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH A SPACER,” (KLYCD-05010US4), U.S. patent application Ser. No. ______, filed ______, entitled “METHOD OF LATERALLY INSERTING AN ARTIFICIAL VERTEBRAL DISK REPLACEMENT IMPLANT WITH A SPACER,” (KLYCD-05010US5), all of which are incorporated herein by reference.
FIELD OF ARTThis field of art of this disclosure is directed to an artificial vertebral disk replacement and method.
BACKGROUNDThe spinal column is a biomechanical structure composed primarily of ligaments, muscles, vertebrae and intervertebral disks. The biomechanical functions of the spine include: (1) support of the body, which involves the transfer of the weight and the bending movements of the head, trunk and arms to the pelvis and legs, (2) complex physiological motion between these parts, and (3) protection of the spinal cord and nerve roots.
As the present society ages, it is anticipated that there will be an increase in adverse spinal conditions which are characteristic of aging. For example, with aging comes an increase in spinal stenosis (including, but not limited to, central canal and lateral stenosis), and facet joint degeneration. Spinal stenosis typically results from the thickening of the bones that make up the spinal column and is characterized by a reduction in the available space for the passage of blood vessels and nerves. Facet joint degeneration results from the constant load borne by the facet joints, and the eventual wear that results. Pain associated with both conditions can be relieved by medication and/or surgery.
In addition, to spinal stenosis, and facet joint degeneration, the incidence of damage to the intervertebral disks is also common. The primary purpose of the intervertebral disk is to act as a shock absorber. The disk is constructed of an inner gel-like structure, the nucleus pulposus (the nucleus), and an outer rigid structure comprised of collagen fibers, the annulus fibrosus (the annulus). At birth, the disk is 80% water, and then gradually diminishes with time, becoming stiff. With age, disks may degenerate, and bulge, thin, herniate, or ossify. Additionally, damage to disks may occur as a result disease, trauma or injury to the spine.
The damage to disks may call for a range of restorative procedures. If the damage is not extensive, repair may be indicated, while extensive damage may indicate full replacement. Regarding the evolution of restoration of damage to intervertebral disks, rigid fixation procedures resulting in fusion are still the most commonly performed surgical intervention. However, trends suggest a move away from such procedures. Currently, areas evolving to address the shortcomings of fusion for remediation of disk damage include technologies and procedures that preserve or repair the annulus, that replace or repair the nucleus, and that advance implants for total disk replacement. The trend away from fusion is driven both by issues concerning the quality of life for those suffering from damaged intervertebral disks, as well as responsible health care management. These issues drive the desire for procedures that are minimally invasive, can be tolerated by patients of all ages, especially seniors, and can be performed preferably on an out patient basis.
Most recently, there has been an increased interest in total disk replacement technology. A number of artificial disks are beginning to appear in the medical device marketplace. These artificial disks vary greatly in shape, design and functionality. With these devices go tools and methods for insertion between vertebrae thereof.
Accordingly, there is a need in the art for innovation in technologies and methods that advance the art in the area of minimally invasive intervertebral disk replacement. This not only enhances the quality of life for those suffering from the condition, but is responsive to the current needs of health care management.
BRIEF DESCRIPTION OF THE DRAWINGS
The following description is presented to enable any person skilled in the art to make and use what is disclosed. Various modifications to the embodiments described will be readily apparent to those skilled in the art, and the principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of what is disclosed and defined by the appended claims. Thus, what is disclosed is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. To the extent necessary to achieve a complete understanding of what is disclosed herein, the specification and drawings of all patents and patent applications cited in this application are incorporated herein by reference.
Several configurations of implant 100 are contemplated. For instance,
The upper end plate 610 of implant 600 has a first outer surface 612 from which a first keel 614 extends with a first set of teeth 615. In one embodiment, when implant 600 is inserted between vertebrae, the first keel 614 extends longitudinally across the first outer surface 612, about perpendicular to the sagittal plane of the spine. In another embodiment, the first keel 614 extends longitudinally only partially across the first outer surface 612, about perpendicular to the sagittal plane of the spine. The teeth 615 in the two embodiments with complete or partial extension of the keel 614 across the first outer surface 612 of the upper end plate 610 point towards the left lateral face of implant 600 when the embodiment is meant to be put into a slot in a vertebral body from the left lateral approach to the spine. This orientation is shown in the figures, and is particularly evident where the keel 614 is fully displayed, as in
The first outer surface 612 abuts the vertebral body when the implant 600 is implanted. The first keel 614 extends into the vertebral body to anchor implant 600 into position, and is perpendicular to the median sagittal plane of the spine, in which extension and flexion occur. The first keel 614 in this orientation offers substantial stability during extension and flexion for the implant 600 inserted between the vertebrae of a patient. Additionally, the first keel 614 in this embodiment is preferably aligned with and supports the articulation of implant 600. The first inner surface 616 with socket 636 at least partially engages the spacer 630 of the implant and opposes the second end plate 620. The first inner surface 616 can form a planar surface that is parallel to the first outer surface 612, or can form a planar surface that is not parallel to the first outer surface 612.
The lower end plate 620 has a second outer surface 622 from which a keel 624 extends with a second set of teeth 625. In one embodiment, when implant 600 is inserted between vertebrae, the second keel 624 is about perpendicular to the sagittal plane of the spine. As described above for the first upper end plate 610, in one embodiment, the second keel 624 extends longitudinally across the second outer surface 622, while in another embodiment, the second keel 624 extends longitudinally partially across the second outer surface 622. The teeth 625 in the two embodiments with complete or partial extension of the second keel 624 across the second outer surface 622 of the lower end plate 620 point towards the left lateral face of implant 600 when the embodiment is meant to be put into a slot in a vertebral body from the left lateral approach to the spine. This orientation is shown in the figures, and is particularly evident where the second keel 624 is fully displayed, as in
The second outer surface 622 abuts the vertebral body when the implant 600 is implanted. The second keel 624 extends into the vertebral body to anchor implant 600 into position, and is perpendicular to the median sagittal plane of the spine, in which extension and flexion occur. The second keel 624 in this orientation offers substantial stability during extension and flexion for the implant 600 inserted between the vertebrae of a patient. Additionally, the second keel 624 in this embodiment is aligned with and supports the articulation of implant 600. The second end plate 620 with second inner surface 626 having the spacer 630 opposes the first end plate 610 with first inner surface 616 having socket 636. The spacer 630 of second inner surface 626 at least partially engages socket 636 of first upper surface. The second inner surface 626 can form a planar surface that is parallel to the second outer surface 622, or can form a planar surface that is not parallel to the second outer surface 622.
The first inner surface 616 of the first end plate 610 can be parallel to the second inner surface 626 of the second end plate 620 when the implant 600 is assembled and is in a neutral position (i.e., the position where the first end plate 610 has not rotated relative to the second end plate 620). Alternatively, the first inner surface 616 of the first end plate 610 can be non-parallel to the planar surface of the second inner surface 626 of the second end plate 620 when the implant 600 is assembled and in a neutral position. This non-parallel orientation of the first end plate 610 and the second end plate 620 allows the plates to pivot to a greater degree with respect to each other. Additionally, factors such as the height and position of the spacer 630, and the, can also be adjusted in order to increase the degree that the first end plate 610 and the second end plate 620 can pivot relative to each other. Other factors that effect the degree of movement of the first end plates 110 or 610 relative to the second end plates 120 or 620 for implant 100 or implant 600 will discussed below.
When implant 600 is inserted between vertebrae the planar surfaces corresponding to the first and second outer surfaces 612, 622 and the first and second inner surfaces 616, 626 of the first and second end plates 610, 620 lie within, or substantially within, the axial plane of the body. Similarly, the first and second keels 614, 624 are aligned in the axial plane, or perpendicular to the sagittal plane of the vertebrae. The first and second keels 614,624 extend into the vertebral bodies to anchor implant 600 into position, and are perpendicular to the median sagittal plane of the spine, in which extension and flexion occur. The first and second keels 614,624 in this orientation offer substantial stability during extension and flexion for implant 600 inserted between the vertebrae of a patient. Additionally, the first and second keels 614,624 in this embodiment are aligned with and support the axis of articulation of implant 600 defined by an RL to LL orientation.
The lateral orientation of the keels allow the implants to be inserted into the spine using a lateral approach as opposed to an anterior or posterior approach. The lateral approach is advantageous, because the spinal nerves in the spinal cavity are minimally undisturbed when the implants are inserted laterally into the spine. In comparison to a posterior insertion approach in which the spinal nerves can be substantially disturbed, the spinal nerves are bypassed and relatively undisturbed when the implant is inserted laterally between the vertebral bodies from the side of the spine. Although an anterior insertion approach has its benefits, the lateral insertion approach can allow the present implant and associated implantation tools, to be inserted into the spine with less disturbance of the patient's internal organs. This can translate into less time and risk associated with preparing the spine for insertion as well as inserting the implant itself into the spine. Further, the laterally oriented keels offer substantial stability to the vertebral bodies during extension, flexion and lateral bending of the spine.
In the embodiment shown in
Further, a combination of the two embodiments shown in
In
As shown in
In
Turning now to
In the embodiments shown in
The embodiments of implants 100, 600 can be made of medical grade titanium, stainless steel or cobalt chrome. Other materials that have appropriate structural strength and that are suitable for implantation into a patient can also be used.
One class of materials contemplated for use in implant 100 is the class of biocompatible polymers. Copolymers, blends and composites of polymers are also contemplated for fabrication of parts of the disclosed device. A copolymer is a polymer derived from more than one species of monomer. A polymer composite is a heterogeneous combination of two or more materials, wherein the constituents are not miscible, and therefore exhibit an interface between one another. A polymer blend is a macroscopically homogeneous mixture of two or more different species of polymer.
One group of biocompatible polymers are the polyaryl ester ketones which has several members, which include polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). PEEK has proven as a durable material for implants, as well as meeting criteria of biocompatibility. Medical grade PEEK is available from Victrex Corporation under the product name PEEK-OPTIMA. Medical grade PEKK is available from Oxford Performance Materials under the name OXPEKK, and also from CoorsTek under the name BioPEKK. Still another interesting group of biocompatible polymers are polyalkyl biocompatible polymers, such as polyethylenes, polypropylenes, and the like.
These medical grade biocompatible polymers are also available as reinforced polymer materials. To reinforce a polymeric material, fillers, are added to a polymer, copolymer, polymer blend, or polymer composite. Fillers are added to modify properties, such as mechanical, optical, and thermal properties. In this case, fillers, such as carbon fibers, are added to reinforce the polymers mechanically to enhance strength for certain uses, such as load bearing devices.
In addition to disclosure of embodiments of an intervertebral implant, tools for preparing and inserting an intervertebral implant are also disclosed.
As will be appreciated by those of skill in the art, the tool shown in
A variety of kits can be assembled that include an implant 100 (or 600) sized for a particular patient. The kit could also include several cutting tools 700 and several implanting tools 800 or a single handle that cooperates with cutting ends 702 and implantation ends 820.
What has been disclosed herein has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit what is disclosed to the precise forms described. Many modifications and variations will be apparent to the practitioner skilled in the art. What is disclosed was chosen and described in order to best explain the principles and practical application of the embodiments described herein, thereby enabling others skilled in the art to understand the various embodiments and various modifications that are suited to the particular use contemplated. It is intended that the scope of what is disclosed be defined by the following claims and their equivalence.
Claims
1. An intervertebral implant comprising:
- a first end plate with a first inner surface;
- a second end plate with a second inner surface opposing the first inner surface, where the second inner surface has an articulating element formed thereon; and
- an attachment mechanism adapted to engage a vertebral body, wherein the attachment mechanism is adapted to extend, when implanted, along a lateral direction with respect to the vertebral body.
2. The implant of claim 1 wherein the articulating element allows movement of the vertebral body in between flexion to extension directions.
3. The implant of claim 1 wherein the attachment mechanism is aligned with and supports the articulating element.
4. The implant of claim 1 wherein the articulating element further comprises an elongated hemi-cylindrical structure protruding from the second inner surface and an elongated cavity in the first inner surface adapted to receive the hemi-cylindrical structure.
5. The implant of claim 1 wherein the attachment mechanism is a keel upstanding from at least one of the first end plate and the second end plate.
6. An intervertebral implant comprising:
- a first end plate adapted to mate with a first vertebral body further comprising: a first inner surface; a first outer surface; and at least one keel on the first outer surface, wherein the keel is adapted to be perpendicular to a sagittal plane of the first vertebral body when implanted thereto;
- a second end plate adapted to mate with a second vertebral body further comprising; a second inner surface opposing the first inner surface, wherein the second inner surface has a spacer coupled thereto; and a second outer surface.
7. The implant of claim 6 wherein the spacer allows bending from flexion to extension.
8. The implant of claim 6, where the keel is aligned with and supports the spacer.
9. The implant of claim 6, further comprising at least one keel on the second outer surface, wherein the keel is oriented perpendicular to the sagittal plane when implanted to a second vertebral body.
10. The implant of claim 9 wherein the keel is supports the spacer.
11. An intervertebral implant comprising:
- a first end plate adapted to mate with a first vertebral body further comprising: a first inner surface; a first outer surface; and at least one keel on the first outer surface, where the keel is adapted to be perpendicular to the sagittal plane of the vertebrae when implanted thereto;
- a second end plate adapted to mate a second vertebrae, comprising: a second inner surface opposing the first inner surface, where the second inner surface has extending spacer therefrom; a second outer surface; and at least one keel on the second outer surface, where the keel is adapted to be perpendicular to the sagittal plane of the vertebral body when implanted thereto.
12. The intervertebral implant of claim 11 wherein the spacer allows bending from flexion to extension.
13. The intervertebral implant of claim 11 wherein the keels on the first outer surface and the second outer surface support the spacer.
14. The intervertebral implant of claim 11 wherein the first end plate and second end plate have a lateral dimension longer than an anterior-posterior dimension.
15. An interspinous disk replacement implant adatped to be inserted between adjacent vertebral bodies, the implant having a first end plate, a second end plate, and an articulating element formed on the second end plate, the improvement comprising the implant having at least one keel that is about perpendicular to the sagittal plane of a vertebral body.
16. The implant of claim 15 wherein the articulating element is hemi-cylindrical.
17. An interspinous disk replacement implant adapted to be inserted between adjacent vertebral bodies, the implant having an articulating unit with a first end plate having a first inner surface with a first socket therein, a second end plate having a second inner surface opposing the first inner surface, the second inner surface with an articulating element formed thereon, where the articulating element is at least partially received in the first socket, the improvement of the implant comprising the implant having at least one keel extending from the articulating unit that is about perpendicular to the sagittal plane of a vertebral body.
18. The implant of claim 17 wherein the articulating element is hemi-cylindrical.
19. An interspinous disk replacement implant having a first end plate, a second end plate, and an articulating element between formed on the second end plate, the improvement comprising the implant having an attachment mechanism that supports the articulating element, the attachment mechanism adapted to laterally engage an adjacent vertebrae.
20. The implant of claim 19 wherein the attachment mechanism is at least one keel.
21. The implant of claim 19 wherein the articulating element is hemi-cylindrical.
22. An interspinous disk replacement implant having an articulating unit with a first end plate having a first inner surface with a first socket therein, a second end plate having a second inner surface opposing the first inner surface, the second inner surface with an articulating element formed thereon, where the articulating element is at least partially received in the first socket, the improvement of the implant comprising the implant having an attachment mechanism is aligned with and supports the articulating element, the attachment mechanism adapted to laterally engage an adjacent vertebrae.
23. The implant of claim 22 wherein the attachment mechanism is at least one keel.
24. The implant of claim 22 wherein the articulating element is hemi-cylindrical.
25. A kit to insert an interspinous disk replacement implant in a spine, the kit comprising:
- an interspinous disk replacement implant adapted for lateral insertion into the spine; and
- at least one tool for preparing the spine to receive the implant.
26. An interspinious implant comprising:
- a first end plate having a first anterior end, a first posterior end and two first lateral ends extending between the first anterior and posterior ends;
- a second end plate having a second anterior end, a second posterior end and two second lateral ends extending between the second anterior and posterior ends;
- a spacer extending from the second end plate, the spacer having an elongated hemi-cylindrical configuration;
- a first keel protruding from a first outer surface of the first end plate, wherein the first keel is oriented lengthwise between the two first lateral ends; and
- a second keel protruding from a second outer surface of the second end plate, wherein the second keel is oriented lengthweise between the two second lateral ends.
27. An interspinous implant adapted to be inserted between adjacent vertebral bodies comprising:
- an implant body having a first outer surface adapted to mate with a first vertebral body and a second outer surface adapted to mate with a second vertebral body;
- an articulating element within the implant body, the articulating element having an elongated spacer and corresponding elongated socket;
- a first keel protruding from the first outer surface and oriented generally parallel to the articulating element.
Type: Application
Filed: Nov 5, 2004
Publication Date: Jul 14, 2005
Applicant: St. Francis Medical Technologies, Inc. (Alameda, CA)
Inventors: James Zucherman (San Francisco, CA), Ken Hsu (San Francisco, CA), Charles Winslow (Walnut Creek, CA), Scott Yerby (Montara, CA), Steven Mitchell (Pleasant Hill, CA), John Flynn (Concord, CA)
Application Number: 10/981,863