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Intervertebral disc implantRelated Patent Categories: Prosthesis (i.e., Artificial Body Members), Parts Thereof, Or Aids And Accessories Therefor, Implantable Prosthesis, Bone, Spine Bone, Having A Fluid Filled ChamberIntervertebral disc implant description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060282165, Intervertebral disc implant. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application in a continuation-in-part of co-pending applications Ser. No. 11/246,961, filed Oct. 7, 2005, entitled TOTAL ARTIFICIAL INTERVERTEBRAL DISC, Ser. No. 11/195,890, filed Aug. 2, 2005, entitled TOTAL ARTIFICIAL DISC, International Application No. PCT/US2005/009323, filed Mar. 19, 2005, entitled ROTATING, LOCKING, SPRING-LOADED ARTIFICIAL DISK, and Ser. No. 10/804,895, filed Mar. 19, 2004, entitled ROTATING, LOCKING, SPRING-LOADED ARTIFICIAL DISK. BACKGROUND OF THE INVENTION [0002] The present invention relates to an intervertebral disc implant for stabilizing two adjacent vertebrae that maintains the functions of the normal, healthy disc. More specifically, the present invention relates to a rectangularly-shaped disc implant that is expanded in the middle portion that is used as an alternative to spinal fusion. [0003] Treatment of the damaged intervertebral disc, especially in the cervical and/or lumbar region of the spine, continues to be a challenging field of medicine. The classic treatment for a ruptured disc is diskectomy, i.e., removal of the disc from between the vertebrae. In this process, all or a portion of the intervertebral disc is removed, leaving a defect that may bother the patient throughout the rest of their life and compromising the normal interaction between disc and adjacent vertebrae. A procedure that is sometimes used as an alternative to diskectomy is to remove some or all of the disc and then fill the disc space with a bone graft, usually bone chips cut from the patient's iliac crest, or bone plug, bringing about fusion of the vertebrae above and below the disc, eliminating the empty space between the vertebrae. [0004] Diskectomy with fusion is not ideal because the replaced bone does not have the function of the cartilaginous tissue of the disc, i.e. no cushioning effect, and has complications because of several factors. First, conventional bone plugs used to pack the disc space do not conform to the space of the disc because the disc bulges maximally in the center while the bone plug is generally cylindrically shaped and the disc space is wider in the middle and narrower at its anterior and posterior ends. For this reason, many commercially available bone plugs have just four points at which they contact the bodies of the adjacent vertebrae, i.e. two points at each of the front and back of the disc space. Second, access to the disc is from the side of the dorsal spine of the adjacent vertebrae, leaving a space that is "off-center" relative to the bodies of the adjacent vertebrae such that the stability of the implant is even more problematical than might be apparent from the limited contact resulting from the shape of the intervertebral space. Another complication is the possibility of infection or other conditions that may require removal of the implant. Also, if the bone pieces do not fuse, they may eventually extrude out of the disc space, pressuring the nerve roots. The most significant disadvantages of fusion, however, is that it eliminates all motion at the joint between the two vertebrae as well as the shock-absorbing/cushioning function of the disc. [0005] Various prosthetic disc plugs, or implants, are disclosed in the art, but all are characterized by limitations of not conforming to the shape of the disc space, lack of stability when inserted off-center, inability to be removed, or other disadvantages. For instance, U.S. Pat. No. 4,863,476 (and its European counterpart, EP-A-0260044) describes an elongate, generally cylindrically-shaped body divided longitudinally into two portions having a cam device between the two portions for increasing the space between the two body portions once inserted into the disc space. However, because that device is cylindrical in shape such that the only contact points between the device and the vertebral bodies are at the front and back of the disc space, creating increased likelihood of instability, that device is generally unsuitable for use after partial diskectomy. [0006] The art also discloses intervertebral disc prostheses such as are shown in U.S. Pat. Nos. 3,867,728, 4,309,777, 4,863,477, 4,932,969, Applicant's own Pat. No. 5,123,926, and French Patent Application No. 8816184 that may have more general contact with the adjacent discs, and spinal joint prostheses as described in U.S. Pat. No. 4,759,769, but which are not intended for use in fusion of the discs. The utility of such devices is also limited by a number of disadvantages, in particular, the same lack of cushioning described above in connection with prior art disc plugs and implants. Further, those implants and prostheses that attempt to address this cushioning problem have generally failed because they are not capable of supporting the load imposed upon them by the active post-surgical patient. Further, many prior implants and prostheses require removal of the disc. Removing the disc is not totally undesirable because removing the intervertebral disc does help prevent problems from recurrent disc herniation through the opening into the intervertebral disc space. However, as with all surgical procedures, it is desirable to utilize as much existing structure as possible and to minimize invasiveness. One reason it is desirable to retain as much of the original disc as possible is that if an implant subsequently fails, or if further surgical intervention is indicated for reasons such as infection, the only alternative that is generally available after removal of the intervertebral disc is fusion. [0007] There is, therefore, a need for a device capable of stabilizing the vertebrae adjacent an intervertebral disc that overcomes the various disadvantages and limitations of known spinal fusion procedures and the disc plugs and implants that are used in such procedures, and it is an object of the present invention to provide apparatus and methods for meeting that need. [0008] There is also a need for a device that can be implanted into the disc space in a procedure that decreases the likelihood of recurrent disc herniation and it is also an object of the present invention to provide apparatus and methods for meeting that need. [0009] There is also a need for a device that mimics the function of the disc, in part by retaining as much of the undamaged disc as possible, that cooperates with the remaining portion of the disc to function in a manner similar to the normal, intact disc to provide the cushioning effect of the disc, and it is an object of the present invention to provide apparatus and methods for meeting that need. [0010] There is also a need for a device that not only functions to provide the cushioning effect of the intervertebral disc but that also provides the opportunity for repairing the remaining portion of the disc, and it is an object of the present invention to provide apparatus and methods for meeting that need. [0011] Another need that is apparent from the limitations and disadvantages of prior procedures, disc plugs, and prostheses is the need for a device that maintains the function of the healthy, intact intervertebral disc when implanted between adjacent vertebrae, is capable of being implanted in a surgical procedure that is minimally invasive, and that does not require removal of the entire intervertebral disc, and it is therefore also an object of the present invention to provide apparatus and methods for meeting that need. [0012] Another need that is apparent from the limitations and disadvantages of prior procedures, disc plugs, and prostheses is the need for a device that works with the structure of the intervertebral disc space to maintain as much of the normal function of the disc as possible, and it is also an object of the present invention to provide apparatus and methods that combine the properties of cushioning (by utilizing the remaining portion of the disc), stability (by utilizing a monolithic, biconvex implant), shock absorption (by providing different cushioning characteristics in different portions of the disc space), and provide the opportunity to help reconstruct and/or prevent recurrent herniation of the remaining portion of the disc (by utilizing a hydrogel to fill gaps in the disc space and using known surgical repair techniques) thereby meeting that need. [0013] Another need that is apparent is the need for a device that is capable of supporting the load imposed upon it when implanted in the disc space while also providing the cushioning function of the natural intervertebral disc and it is also an object of the present invention to provide apparatus and methods for meeting that need. [0014] Another need that is apparent is a need for a frame for an intervertebral disc implant comprised of two spaced apart, substantially parallel arms, a bridge connecting the arms at one end, a "U"-shaped ear extending at approximately a right angle from the end of one of the arms opposite the bridge and having a hole formed therein for receiving a screw, and a "Y"-shaped ear extending at approximately a right angle from the end of one of the arms opposite the bridge having holes formed in both forks of the Y-shaped ear for receiving screws, the frame being comprised of a material that tends to return to its original shape after the frame is subjected to either a compression or tension load object of the present invention is to provide a frame for meeting that need. [0015] Other objects, and the many advantages of the present invention, will be made clear to those skilled in the art in the following detailed description of several preferred embodiments of the present invention and the drawings appended hereto. Those skilled in the art will recognize, however, that the embodiments of the invention described herein are only examples provided for the purpose of describing the making and using of the present invention and that they are not the only embodiments of artificial discs that are constructed in accordance with the teachings of the present invention. SUMMARY OF THE INVENTION [0016] The present invention addresses the above-described problem by providing an intervertebral disc implant comprising an elongate body comprised of a resilient material having a cavity extending longitudinally into the body, the height of the body being greater than the width of the body, and a frame received within the cavity in the body comprised of two spaced apart, substantially parallel arms and a bridge connecting the arms at one end, the frame being comprised of a material that tends to return to its original shape after the frame is subjected to either a compression or tension load, the frame extending only part way into the cavity of the body in which it is received. [0017] In another aspect, the present invention provides a method of mimicking the function of the intervertebral disc of the intact spinal column after removal of a portion or all of the intervertebral disc from between the two adjacent vertebrae comprising the steps of inserting a resilient body having a height greater than its width and a cavity formed therein with a key received in the cavity into the intervertebral disc space with the height of the body oriented substantially parallel to the longitudinal axis of the spinal column, removing the key from the cavity in the body after the body is inserted into the intervertebral disc space, and inserting a frame part way into the cavity in the body, the frame comprising first and second arms arms connected by a bridge at one end for providing resistance to flexion and/or extension of the spinal column, and filling the portion of the cavity in the body into which the frame does not extend with a hydrogel. BRIEF DESCRIPTION OF THE DRAWINGS [0018] Referring now to the figures, FIG. 1 shows a side elevational view of a presently preferred embodiment of an intervertebral disc implant constructed in accordance with the teachings of the present invention showing the key assembled to the implant for implantation in the intervertebral disc space. [0019] FIG. 2 is an end view of the intervertebral disc implant of FIG. 1. [0020] FIG. 3 is a perspective view of the intervertebral disc implant of FIG. 1 after removal of the key from the cavity in the body of the implant and insertion of the frame into the cavity. [0021] FIG. 4 is a side elevational view of the invertebral disc implant of FIG. 3. Continue reading about Intervertebral disc implant... Full patent description for Intervertebral disc implant Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Intervertebral disc implant patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Intervertebral disc implant or other areas of interest. ### Previous Patent Application: Implant shell and filler apparatus Next Patent Application: Compliant porous coating Industry Class: Prosthesis (i.e., artificial body members), parts thereof, or aids and accessories therefor ### FreshPatents.com Support Thank you for viewing the Intervertebral disc implant patent info. 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