|Publication number||US20070162133 A1|
|Application number||US 11/668,577|
|Publication date||12 Jul 2007|
|Filing date||30 Jan 2007|
|Priority date||2 Mar 2004|
|Also published as||US7195644, US20060142862, WO2008073064A1|
|Publication number||11668577, 668577, US 2007/0162133 A1, US 2007/162133 A1, US 20070162133 A1, US 20070162133A1, US 2007162133 A1, US 2007162133A1, US-A1-20070162133, US-A1-2007162133, US2007/0162133A1, US2007/162133A1, US20070162133 A1, US20070162133A1, US2007162133 A1, US2007162133A1|
|Inventors||Robert Doubler, John Hammill, Robert Diaz|
|Original Assignee||Robert Doubler, John Hammill, Diaz Robert L|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (15), Classifications (39), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is continuation in part of U.S patent application Ser. No. 11/207,683 filed Aug. 18, 2005 which is a continuation in part of U.S. patent application Ser. No. 11/060,206 filed Feb. 15, 2005 which is a continuation-in-part of a U.S. patent application Ser. No. 11/025,656, filed Dec. 28, 2004 which is a continuation-in-part of U.S. application Ser. No. 10/793,433 now 7,083,651 which is a continuation-in-part of U.S. application Ser. No. 10/792,399 now U.S. Pat. No. 7,115,144; the contents of which is incorporated herein by reference.
This invention relates to orthopedic surgery and, in particular, constrained spinal implants for replacement of ruptured or excised spinal disks.
Several attempts have been made to design a spinal prosthesis for replacement of missing or excised disk material that replicates the functions of the missing tissue. U.S. Pat. No. 4,759,769 to Hedman et al discloses an artificial disk device in which two plates are attached to the adjacent vertebrae by bone screws inserted through flanges on the plates. A spring biasing mechanism is captured between the plates to simulate the actions of the natural disk material. U.S. Pat. No. 5,246,458 to Graham and U.S. Pat. No. 6,228,118 to Gordon disclose other intervertebral implants with spherical flanges used to connect the device to adjacent vertebra. Graham also teaches a resilient structure.
The patents to Marnay, U.S. Pat. No. 5,314,477, Buttner-Janz et al, U.S. Pat. No. 5,401,269, Yuan et al, U.S. Pat. No. 5,676,701, and Shelokov, U.S. Pat. No. 6,039,763, all are directed to the design of the opposing faces of the adjacent plates of an implant to provide a limited universal joint to simulate the natural movement of the spine.
U.S. Pat. No. 5,683,465 to Shinn et al teaches two plates with bow shaped skirts which are interlocked.
The invention is directed to a constrained spinal implant for insertion between adjacent vertebrae to function as a disk prosthesis. The prosthesis is formed from two plates fastened to adjacent vertebrae facing each other. The facing sides of the plates have an interacting, depending skirt. The skirts are range limiting wherein the skirt on a superior endplate can be shaped to limit lateral, flexion and extension motion.
A depression is centrally located between the arcs of both plates. A sphere or ball is placed in the central depression of one of the plates. The plates are oriented to each other at 90 degrees and the ball is engaged in the depression of the other plate. The plates are then rotated about 90 degrees and the skirt of one plate interlocks with an opposed arcs of the other plate to prevent separation in the axial direction.
Therefore, it is an objective of this invention to provide a constrained spinal implant for axial support of the spinal column which replicates the dimensions and function of an intervertebral disk.
It is another objective of this invention to provide a kit including all the components for assembly and surgical placement of an artificial spinal disk.
It is a further objective of this invention to provide a method of assembly of the components of the kit which results in an axially interlocked constrained spinal implant. Specifically, one plate forms a receptacle for a dynamic socket to be inserted and fixed in place internally.
It is yet another objective of this invention to provide a ball and socket joint between two plates attached to adjacent vertebrae permitting axial rotation, lateral bending, vertical tilting and axial compression.
It is a still further objective of this invention to provide shaped interrupted skirts on two plates which act as stop limits for tilting and bending.
It is another objective of this invention is to provide an axially resilient ball and socket joint, compressive load bearing poly-axial motion joint.
It is another objective of this invention is to provide use of a true roller-ball bearing which reduces radial friction forces and the entire spherical ball surface area can be utilized for low wear characteristics.
Still another objective of this invention is to provide the use of an endplate that can be shaped to limit lateral, flexion and extension motion.
Still another objective of this invention is to provide a constrained construct implant.
Still another objective of this invention is to provide an inserter instrument.
Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.
Referring to the Figures, the constrained spinal implant 10, shown in
The upper plate 11 has a planar surface 14 for contact with the end wall of a vertebra and an opposite disk surface 15. Depending from the disk surface is a continuous skirt 16 with opposed internal spherical bearing surfaces 17 and 18. The spherical bearing surfaces are approximately 180 degrees apart at their centers and extend about 90 degrees around the continuous skirt. However, it should be noted that smaller or larger spherical bearing surfaces spaced to provide axial guidance and load bearing may be utilized without departing from the scope of the invention. In the preferred embodiment, the diameter of the arcs is less than the periphery of the plate 11 leaving a horizontal flange 19. Centrally located within the spherical bearing surfaces formed within the continuous skirt is a receptacle 13. A sleeve 51 is inserted in the receptacle 13 and telescopes in the plate 11. The sleeve 51 has a spherical depression 52.
The lower plate 12 has a planar surface 20 for contact with the end wall of a vertebra and an opposite disk surface 21. Upstanding from the disk surface is an continuous skirt 22 with opposed external spherical bearing surfaces 23 and 24. The spherical bearing surfaces are approximately 180 degrees apart at their centers and extend about 90 degrees around the skirt. However, it should be noted that smaller or larger spherical bearing surfaces spaced to provide axial guidance and load bearing may be utilized without departing from the scope of the invention. The diameter of the arcs is less than the periphery of the plate 12 leaving a horizontal flange 25. Centrally located within the semi-circular arcs is a receptacle 26. A sleeve 53 is inserted in the receptacle and reciprocates in the plate 12. The sleeve 53 has a depression 54 that is rounded and shaped to closely mirror the contours of the depression 52. The depressions 52 and 54, as well as the diameter of the ball 50, are of such dimensions construction to provide bearing surfaces suitable to support the weight of the spinal column.
As shown, though the relationship could be reversed, the opposed spherical bearing surfaces 17 and 18 of the depending skirt 16 are concentric with the opposed spherical bearing surfaces 23 and 24 of the upstanding skirt and of larger diameter allowing rotation of the plates relative to each other with surface contact between the outer spherical bearing surface(s) of the upstanding skirt and the inner bearing surface(s) 29 of the depending skirt to define an outer ball and socket 85.
The constrained spinal implant provides support and range of motion similar to the natural joint in that the plates 11 and 12 may rotate axially limited by natural anatomical structures, such as tendons, ligaments and muscles. To simulate the compression of the natural disk during normal activities, such as walking, an alternative embodiment as shown in
In the manufacturing step, the o-ring 61 is inserted and covered by the sleeve 53. A retainer ring 58 is placed between the upper circumference of the sleeve 53 and is preferably laser welded to the plate. Other suitable permanent attachment methods well known in the art may also be used without departing from the scope of the invention. Similarly, an o-ring 60 may be used in the upper plate 11 with the sleeve 51 inserted and held in position by a retainer ring 55, the retainer ring can then be laser welded to the plate or other permanent attachment methods may be used. By absorbing some of the longitudinal loads, the prosthesis lessens the stresses on the adjacent natural disks. Further, during placement of the prosthesis, the springs may be compressed to lessen the overall height of the prosthesis.
The spine may bend laterally and tilt medially in flexion/extension in a range comparable to the normal range of motion. The implant of the instant invention provides limitation of these movements through interaction of the depending skirt and the upstanding skirt. As shown in
In the preferred embodiment, fastening to the vertebra can be enhanced by the use of spikes 34 attached or formed on flanges 19 and 25 which are to be driven into the end walls of the adjacent vertebra.
Alternatively, or in conjunction with spikes, each of flanges 19 and 25 of the constrained spinal implant may include a vertical extension, not shown, which cooperate with bone screws to mount the constrained spinal implant on the vertebra. The vertical extension is illustrated in the inventors prior application(s) which are incorporated by reference. The vertical extensions can be on opposite lateral sides of the flanges 19 and 25 permitting fastening of each plate on the opposite side of adjacent vertebrae. The fasteners may be used together, e.g., the spikes may be on one plate and the vertical extensions on the other plate of the same constrained spinal implant.
The components are made from materials that are suitable for implantation in the living body and have the requisite strength to perform the described functions without deformation, e.g., the opposed bearing surfaces of the depressions and ball may be made of metal or ceramic or a suitable combination thereof, respectively, the ceramic material is implant grade alumina ceramic or a silicon nitride or carbide and the metal may be a nitrogen alloyed chromium stainless steel or cobalt chrome alloy, or titanium, and alloys of each, coated metals, ceramics, ceramic coatings, and polymer coatings.
The plates may be made entirely of cobalt chrome alloy or only the inserts. In the high wear areas, such as the depressions, coatings or inserts may be used to prevent galling and permit repair. In this modular concept, the end plates may be titanium, titanium alloy, or stainless steel among other materials as discussed above.
The prosthetic ball 50 is preferably made from an implant grade alumina ceramic or a silicon nitride or silicon carbide material. The ball 50 may be formed entirely of the ceramic material or a ceramic coating on another matrix. The alumina ceramic or silicon nitride or silicon carbide material can be manufactured by isostatic pressing or any other suitable method well known in the art. The ball 50 is then machined to shape and the surface polished to a mirror-like finish. The ceramic ball is completely corrosion resistant and is non-abrasive. The solid matrix eliminates the wear particles, such as those liberated from metal, other coated metals and polyethylene implants. The ball 50 has excellent thermal conductivity thereby reducing patient discomfort associated with exposure to cold weather. Further, the alumina ceramic or silicon nitride implant will react well with x-ray and MRI (magnetic resonance imaging) diagnostic procedures.
The kit contains plates with protrusions and skirts of varying lengths to allow selection of components for an implant with the axial dimension substantially the same as the thickness of the disk the implant will replace. The kit may also contain upper and lower plate components of varying sizes.
Referring now to
A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiment but only by the scope of the appended claims.
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|US8771355||29 May 2007||8 Jul 2014||M. S. Abdou||Inter-vertebral disc motion devices and methods of use|
|US9107762||3 Nov 2011||18 Aug 2015||Spinalmotion, Inc.||Intervertebral prosthetic disc with metallic core|
|US20110054618 *||22 Aug 2006||3 Mar 2011||Beat Lechmann||Total disc replacement device|
|WO2010003119A2 *||2 Jul 2009||7 Jan 2010||Spinalmotion, Inc.||Limited motion prosthetic intervertebral disc|
|WO2012170826A2 *||8 Jun 2012||13 Dec 2012||Doty Keith L||Devices for providing up to six-degrees of motion having kinematically-linked components and methods of use|
|Cooperative Classification||A61F2/30742, A61F2220/0033, A61F2002/3097, A61F2310/00017, A61F2310/00281, A61F2002/443, A61F2002/30462, A61F2002/30616, A61F2310/00317, A61F2002/30662, A61F2002/30578, A61F2002/30331, A61F2002/30574, A61F2002/30563, A61F2002/30426, A61F2/4611, A61F2220/0075, A61F2002/30242, A61F2220/0025, A61F2002/30495, A61F2002/30649, A61F2002/30451, A61F2002/30841, A61F2310/00592, A61F2310/00029, A61F2220/0058, A61F2002/30014, A61F2310/00203, A61F2310/00023, A61F2002/30663, A61F2230/0071, A61F2/4425, A61F2002/30904, A61F2310/00395, A61F2250/0018|
|European Classification||A61F2/46B7, A61F2/44D2|
|16 Feb 2007||AS||Assignment|
Owner name: SPINAL, LLC, FLORIDA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:DOUBLER, ROBERT L.;HAMMILL, JOHN E.;DIAZ, ROBERT L.;REEL/FRAME:018910/0932;SIGNING DATES FROM 20070121 TO 20070123
|14 Aug 2009||AS||Assignment|
Owner name: JOINT SYNERGY, LLC, FLORIDA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SPINAL, LLC;REEL/FRAME:023100/0255
Effective date: 20090813