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  Intervertebral prosthesisUSPTO Application #: 20060293754Title: Intervertebral prosthesis Abstract: An intervertebral prosthesis for insertion between adjacent vertebrae includes a first prosthesis plate and a second prosthesis plate. The first and second prosthesis plates each comprise a midline, an engagement surface to engage a first vertebra and a bearing surface disposed opposite the engagement surface. The bearing surfaces of the first and second plates are arranged to cooperate to form an articulate joint. A first region of serrations is disposed on the engagement surface of the first plate on one side of the midline of the first plate, and a second region of serrations is disposed on the engagement surface of the first plate on an opposite side of the first plate midline. Each region comprises at least several serrations, and each serration comprises a base attached to one of the plates and tapers from the base to a tip. (end of abstract) Agent: Townsend And Townsend And Crew, LLP - San Francisco, CA, US Inventors: Malan deVilliers, Ulrich R. Hahnle USPTO Applicaton #: 20060293754 - Class: 623017140 (USPTO) Related Patent Categories: Prosthesis (i.e., Artificial Body Members), Parts Thereof, Or Aids And Accessories Therefor, Implantable Prosthesis, Bone, Spine Bone, Having Ball And Socket Means The Patent Description & Claims data below is from USPTO Patent Application 20060293754. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCES TO RELATED APPLICATIONS [0001] The present application is a continuation of U.S. patent application Ser. No. 11/084,224 (Atty. Docket No. 022031-001710US), filed on Mar. 18, 2005, which is a continuation-in-part of PCT/IB2003/001529 (Atty. Docket No. 022031-001700PC), filed on Apr. 24, 2003, designating the United States, which claimed priority from South African Application No. 2002/7517, filed on Sep. 19, 2002; the full disclosures of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to an intervertebral prosthesis. [0004] In the event of damage to a spinal disc it is known practice to implant an intervertebral prosthesis surgically to replace the damaged organ. Several types of prosthesis for this purpose are known and in common use. [0005] One type of known intervertebral prosthesis is sold by Waldemar Link GmbH & Co under the trademark LINK.RTM. SB Charite. This prosthesis includes upper and lower prosthesis plates which locate against and engage the adjacent vertebral bodies, and a low friction core between the plates. The core has upper and lower convexly curved surfaces and the plates have corresponding, concavely curved recesses which cooperate with the curved surfaces of the core. This allows the plates to slide over the core to allow required spinal movements to take place. The curved recesses in the plates are surrounded by annular ridges which locate, at the limit of sliding movement of the plates over the core, in opposing peripheral channels surrounding the curved surfaces of the core. [0006] This type of configuration is also described in European Patent Publication Nos. EP 0 560 140 and EP 0 560 141 (both Waldemar Link GmbH & Co). However a drawback of such configurations is that the provision of the peripheral ribs and channels limits the areas available for bearing and sliding contact between the plates and core, and accordingly the loads which can be transmitted by the prosthesis. As a result of the relatively small bearing areas, it is believed that at least the core will be subject to rapid wear and have a relatively short life-span. [0007] EP 0 560 141 also describes one alternative arrangement in which the curved surfaces of the core carry opposing, elongate keys that locate in elongate grooves in the plates and another alternative arrangement in which the plates have opposing elongate keys that locate in elongate grooves in the opposite curved surfaces of the core. These key and groove arrangements allow the plates to slide freely over the core, within the limits of the length of the grooves, in one plane only. Although allowance is made for some lateral play of the keys in the grooves, very little sliding movement of the plates over the core can take place in the orthogonal vertical plane, and this is considered to be a serious drawback of this design. [0008] 2. Description of the Background Art [0009] European Patent Publication Nos. EP 0 560 140 and EP 0 560 141 have been discussed above. U.S. Patent Publication Nos. US2002/0035400 and US2002/0128715 describe intervertebral prostheses with center-posts received in passages in a core. The core possesses an annular flange structure engaged by extensions on the plates. BRIEF SUMMARY OF THE INVENTION [0010] According to the invention there is provided an intervertebral prosthesis for insertion between adjacent vertebrae, the prosthesis comprising upper and lower prosthesis plates locatable against the respective vertebrae and having opposing, concavely curved recesses therein and a core located between the plates, the core having opposed, convexly curved surfaces received in the recesses of the plates to allow the plates to slide in articulated manner over the core, characterized in that: [0011] the opposed surfaces of the core and the recesses of the plates have cooperating spherical curvatures, [0012] the recess of a plate surrounds a locating peg projecting centrally from the base of the recess, and [0013] the peg locates loosely in an opening located centrally in a curved surface of the core, whereby the plates can slide over the core in all directions while the peg holds the core captive. [0014] In some embodiments, only one of the plates, typically the operatively lower plate, includes a peg. In other embodiments, both plates include pegs, the pegs opposing one another and locating loosely in respective openings located centrally in the opposed curved surfaces of the core. In each embodiment it is preferred that each peg and the opening in which it locates are conical in shape. [0015] According to another aspect of the invention there is provided a prosthesis plate for use in a prosthesis as summarized above, the prosthesis plate having a coarse surface locatable against a vertebra, an oppositely facing concavely curved surface which is complemental in shape to a convexly curved surface of a core of the prosthesis, characterized in the concavely curved surface of the plate has a spherical curvature and in that the plate includes a conical locating peg extending centrally from the concavely curved surface, the peg being locatable loosely in a central opening in the convexly curved surface of the core. [0016] According to yet another aspect of the invention there is provided a core for use in the prosthesis, the core comprising a one piece plastics body having operatively upper and lower curved surfaces, characterized in that the curved surfaces of the body are spherically curved and at least one of the surfaces has a central, conical opening therein dimensioned to receive a conical locating peg of a prosthesis plate loosely. [0017] Other features of the invention are set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0018] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: [0019] FIG. 1 shows a cross-sectional view of a prosthesis plate used in a prosthesis according to the invention; [0020] FIG. 2 shows a plan view of the prosthesis plate seen in FIG. 1; [0021] FIG. 3 shows a cross-sectional view of a core used in a prosthesis according to the invention; [0022] FIG. 4 shows a plan view of the core seen in FIG. 3; [0023] FIG. 5 shows a cross-sectional view of an intervertebral prosthesis according to a first embodiment of the invention in a neutral condition before articulation has taken place; Continue reading... Full patent description for Intervertebral prosthesis Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Intervertebral prosthesis 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 prosthesis or other areas of interest. ### Previous Patent Application: Intervertebral disc prosthesis and associated methods Next Patent Application: Vertebral body replacement implant Industry Class: Prosthesis (i.e., artificial body members), parts thereof, or aids and accessories therefor ### FreshPatents.com Support Thank you for viewing the Intervertebral prosthesis patent info. 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