The present invention relates to spinal corrective surgery and, more particularly to plate with a spinal stabilization device to inhibit disc degeneration and adjacent disc degeneration.
The vertebrae of the human spine are arranged in a column with one vertebra on top of the next. Between each vertebra exists an intervertebral disc that transmits force between adjacent vertebrae and provides a cushion between the adjacent vertebrae.
Sometimes, back pain is caused by degeneration or other deformity of the intervertebral disc (“diseased disc”). Conventionally, surgeons treat diseased discs by surgically removing the diseased disc and inserting an implant in the space vacated by the diseased disc, which implant may be bone or other biocompatible implants. The adjacent vertebrae are then immobilized relative to one another. Eventually, the adjacent vertebrae grow into one solid piece of bone.
For example, a conventional method to fuse vertebrae together includes a bone graft and a plate to stabilize the device. The current process of inserting a bone graft and fusing the adjacent vertebrae will be explained with referring to
To immobilize the vertebrae 102 and 104 with the implant 108 in place, the surgeon next applies a plate 202 over the adjacent vertebrae 102 and 104. Plate 202 may have a central viewing window 204 and one or more screw holes 206, in this example four screw holes 206a-206d are shown. Four bone screws (which will be identified by reference numerals 208a-208d) would be screwed into the vertebrae using the screw holes 206 to anchor the cervical plate to the vertebrae and immobilize the vertebrae with respect to one another.
Immobilizing the superior and inferior vertebrae with a bone graft in the intervertebral disc space prompts fusion of the superior and inferior vertebrae into one solid bone. As can be appreciated, fusing vertebral bodies like this limits the range of motion of the spine. Moreover, fusing vertebral bodies together may accelerate or contribute to the degeneration of adjacent discs. Sometimes adjacent discs may already have some disc degeneration, but the degeneration is not sufficient to justify additional fusing.
Against this background, it would be desirous to develop a fusion technology that provided some support for adjacent discs to inhibit any or additional degeneration of those discs.
The present invention provides a dynamic spinal stabilization system. The dynamic spinal stabilization system comprises a spinal fusion plate to fuse a vertebral segment. An artificial disc is implanted into a intervertebral disc space proximate the vertebral segment being fused. A movable member couples the spinal fusion plate and the artificial disc to provide support in relate to flexion and extension of the spine.
The present invention also provides a dynamic spinal stabilization system comprising a spinal plate to fuse adjacent vertebral bodies. The plate has an extension that traverses the spinal column to provide support to a superior or inferior vertebral body. The extension is pivotally connected to the plate.
The present invention also provides a dynamic spinal stabilization system comprising a spinal plate to promote fusing adjacent vertebral bodies into a single bone mass. An anchor is coupled to a vertebral body proximate the fused adjacent vertebral bodies. A movable member couples the anchor to the plate.
The present invention also provides an intervertebral disc support clip. The support clip includes a first surface adjacent an inferior surface of a superior vertebral disc and a second surface adjacent a superior surface of an inferior vertebral disc. The first surface and second surface are connected by a wall traversing intervertebral disc space of an intervertebral disc to be supported. The support clip is formed of a biased material so first surface and second surface tend away from each other and distract the intervertebral disc space.
The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention, and together with the description, serve to explain the principles thereof. Like items in the drawings are referred to using the same numerical reference.
The present invention will now be described with reference to the figures. Referring first to
Further shown in
The fusion of second vertebral body 304 to third vertebral body 306 operates to alleviate pain, but frequently adjacent discs, such disc 318 associated with intervertebral disc space 308, are experiencing some degeneration. Fusing second vertebral body 304 and third vertebral body 306 may provide additional stress on disc 318 because of the increased load and motion intervertebral disc 318 must support due to the fusing that accelerates or initiates degeneration of disc 318, a.k.a adjacent disc disease. While possible to fuse first vertebral body 302 and second vertebral body 304, it is a less than desirable solution because of the decreased range of motion and the additional stress placed on intervertebral discs not shown in
Still with reference to
Artificial member 320 would provide resistance to further degeneration, but fusion of second vertebral body 304 and third vertebral body 306 still provides additional stress. To reduce the stress, a member 324 (or several members 324) may be provided extending from plate 314 to artificial member 320. Member 324 should have some elasticity to allow flexion, extension, and preferably rotation to allow range of motion for the spinal segment 300. For example, member 324 may be provided, in part, as a shaped memory alloy (SMA), an elastic biocompatible polymer, a ball and socket joint, a hinge style connection, other modular connection, or the like.
Member 324 will have a plate extension 326 traversing a portion of spinal segment 300 in along the vertical axis. Plate extension 326 extends from plate 314 to first intervertebral disc space 308. Plate Extension 326 may be flush with spinal segment 300 to provide additional support or a gap G may be provided between spinal segment 300 and extension 326. Member 324 also includes a disc extension 328, which extends perpendicular or somewhat perpendicular depending on anatomical conditions from vertical axis V. Disc extension 328 extends from artificial member 320 through annulus 322 (unless annulus 322 has been removed) to a pivotal connection 330 connecting disc extension 328 and plate extension 326. Pivotal connection 330 allows for movement between disc extension 328 and plate extension 326. Pivotal connection 330 may be similar to a hinge, an elastic polymer, a ball and socket joint, a shaped memory alloy such as NiTi, a resin or the like to allow some rotational movement. Moreover, if member 324 is sufficiently flexible, pivotal member 330 may be removed.
As mentioned above, member 324 should have some elasticity to allow for flexion, extension, and rotation of spinal segment 300. The elasticity may be provided only in pivotal connection 330. Alternatively or in combination, plate extension 326 or disc extension 328 may be made of an elastic biocompatible material. Member 324 should be sufficiently elastic to allow movement, which inhibits bone growth and fusion of first vertebral body 302 and second vertebral body 304, by sufficiently rigid to provide support to artificial disc 320, which inhibits further degeneration. For example, if spinal segment 300 was associated with the cervical region of the spine, and the plate 314 was implanted on the anterior side of the spine, flexion of the neck area would cause distraction 332 of the posterior disc space in first intervertebral disc space 308 and compression 334 of the anterior disc space. In this case, member 324 would provide support and inhibit the stress on artificial disc 320. Further, extension of the neck would cause the opposite reaction and member 324 would provide support to artificial disc 320 by resisting over extension.
In some instances, biological disc 318 may not have sufficiently degenerated to justify using artificial member 320. But, it would still be desirable to provide support to biological disc 318 to inhibit degeneration of that disc. As shown in
Referring now to
Referring now to
As mentioned above, fusing second vertebral body 304 and third vertebral body 306 causes disc 318 to support more stress, due to increased movement, rotation, or load across the disc space. To assist disc 318 support the increased stress, an extension plate 604 may be coupled to plate 314. Extension plate 604 is attached to plate 314 with a flexible/pivotal connection 606. Extension plate 604 may be a flat plate, shaped similar to plate 314, or shaped to cradle vertebral body 302. If shaped to cradle vertebral body 302, extension plate 604 may be provided with an inner surface 608 made of a low friction material to accommodate relative movement between vertebral body 302 and extension plate 604. Flexible/pivotal connection 606 may be, for example, a hinge, ball (or rod) and socket joint, shaped memory alloy such as NiTi, a gel, resin, or the like to support pivotal movement. Flexible/pivotal connection 606, however, may comprise an elastic polymer to support both pivotal movement between first vertebral body 302 and second vertebral body 304 as well as rotational movement. Given the example is an anterior cervical view of stabilization device 600, when a patient bends the neck towards the chest, extension plate 604 would contact first vertebral body 302 and provide some support so some of the additional stress is diverted from disc 318. Notice, while shown a separate parts for convenience, extension plate 604, flexible/pivotal connection 606, and plate 314 can be incorporated into a single unit. Stabilization device 600 could be used on the posterior side of the spinal segment 300, but would have to be designed to accommodate other spinal features, such as, for example, the spinous process.
Referring now to
Referring now to
Referring to
Referring to
While the above figures show a plate extending over one level, one of ordinary skill in the art will recognize on reading the disclosure that the present invention would be useful for multiple level fusions. Moreover, although the stabilization device is depicted extending from a single end of the plate, one of ordinary skill in the art on reading the disclosure would understand that the present invention could have stabilization devices extending from multiple connection points, i.e, the superior and inferior direction.
While the invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made without departing from the spirit and scope of the invention.
The present invention claims priority to U.S. Provisional Patent Application Ser. No. 60/711,352, filed Aug. 25, 2005, titled Plate with Stabilization, the disclosure of which is incorporated herein by reference as if set out in full.
Number | Date | Country | |
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60711352 | Aug 2005 | US |