Disc and facet replacement
An artificial disc for replacement of a spinal three-joint complex of a mammal includes a generally spinal disc-shaped upper plate having an anterior section and a posterior section and a generally spinal disc-shaped lower plate also having an anterior section and a posterior section. The anterior section of the upper plate is selectively separable from the posterior section of the upper plate and the anterior section of the lower plate is likewise selectively separable from the posterior section of the lower plate. A ball is interposed the lower face of the upper plate and the upper face of the lower plate and a plurality of posts, each projecting from one of the faces toward the other of the faces corresponds to a plurality of detents provided on the one of the faces opposite the face from which the corresponding post projects for engaging the posts.
This present application claims all available benefit under 35 U.S.C. § 119(e) of co-pending U.S. provisional patent application Ser. No. 60/720,414 filed Sep. 26, 2005. By this reference, the entire disclosure of U.S. provisional patent application Ser. No. 60/720,414, including the drawings, is incorporated herein as though now set forth in its entirety.
FIELD OF THE INVENTIONThe present invention relates to medical devices. More particularly, the invention relates to an artificial intervertebral disc and facet replacement that very closely approximates the function of a natural three-joint disc and facet complex and that may be placed or extracted from or to either the anterior or posterior of a patient under treatment as may be medically determined to be appropriate and, in the case of extraction, without regard for whether the disc and facet replacement was placed from the anterior or posterior.
BACKGROUND OF THE INVENTIONDeterioration through disease or damage from injury often necessitates that a patient undergo surgical intervention for the removal of his or her natural three-joint disc and facet complex and replacement thereof with an artificial disc. Unfortunately, the available artificial discs do not generally well approximate the function of a natural three-joint disc and facet complex. Still further, the available artificial discs cannot generally be placed or extracted from or to either the anterior or posterior of a patient under treatment as may be medically determined to be appropriate and, in the case of extraction, without regard for whether the artificial disc was placed from the anterior or posterior.
With the shortcomings of the prior art in mind, it is therefore an principal object of the present invention to improve over the prior art by providing an artificial disc and facet replacement that may be placed or extracted from or to either the anterior or posterior of a patient under treatment as may be medically determined to be appropriate and, in the case of extraction, without regard for whether the disc and facet replacement was placed from the anterior or posterior. Additionally, it is an object of the present invention to provide such an artificial disc and facet replacement that also very closely approximates the function of a natural three-joint disc and facet complex.
SUMMARY OF THE INVENTIONIn accordance with the foregoing objects, the present invention—an artificial disc for replacement of a spinal three-joint complex of a mammal—generally comprises a generally spinal disc-shaped upper plate comprising an anterior section and a posterior section and a generally spinal disc-shaped lower plate also comprising an anterior section and a posterior section. The anterior section of the upper plate is selectively separable from the posterior section of the upper plate and the anterior section of the lower plate is likewise selectively separable from the posterior section of the lower plate. A ball is interposed the lower face of the upper plate and the upper face of the lower plate and a plurality of posts, each projecting from one of the faces toward the other of the faces corresponds to a plurality of detents provided on the one of the faces opposite the face from which the corresponding post projects for engaging the posts.
Finally, many other features, objects and advantages of the present invention will be apparent to those of ordinary skill in the relevant arts, especially in light of the foregoing discussions and the following drawings, exemplary detailed description and appended claims.
Although the scope of the present invention is much broader than any particular embodiment, a detailed description of the preferred embodiment follows together with illustrative figures, wherein like reference numerals refer to like components, and wherein:
Although those of ordinary skill in the art will readily recognize many alternative embodiments, especially in light of the illustrations provided herein, this detailed description is exemplary of the preferred embodiment of the present invention, the scope of which is limited only by the claims appended hereto. As used herein, reference to an anatomical coordinate such as, for example, anterior, posterior, superior, inferior, sagittal plane, axial plane and the like, should be given its ordinary meaning with respect to human anatomy and, when applied to the disc and facet replacement 20 of the present invention and/or components thereof should be considered as describing the disc and facet replacement 20 as operably positioned as particularly shown in
Referring now to the figures, and to
As particularly shown in
A critical aspect of the present invention is the selective separability of the anterior section 22 and the posterior section 34 of the upper plate 21 and the selective separability of the anterior section 48 and the posterior section 61 of the lower plate 47. While not critical to the present invention, it is nonetheless highly desirable that the upper plate 21 and the lower plate 47 be provided with means for facilitating alignment of the anterior section 22 and the posterior section 34 of the upper plate 21 when joining together the anterior section 22 and the posterior section 34 to form the unitary upper plate 21 and means for facilitating alignment of the anterior section 48 and the posterior section 61 of the lower plate 47 when joining together the anterior section 48 and the posterior section 61 to form the unitary lower plate 47. To this end, as particularly shown in at least
As previously mentioned, the selective separability of the anterior sections 22, 48 and the posterior sections 34, 61 of the upper plate 21 and the lower plate 47, respectively, is implemented in the preferred embodiment of the present invention by the provision of a plurality of section connection assemblies 79. As particularly shown in
In the case of an anterior placement of the disc and facet replacement 20 of the present invention, the component parts of the disc and facet replacement 20 are assembled ex vivo prior to placement. In the case of an anterior extraction of a previously placed disc and facet replacement 20 of the present invention, the disc and facet replacement 20 may be extracted in tact or, if necessary to free it from surrounding structures, the disc and facet replacement 20 may be disassembled in situ and the components thereof removed from the intervertebral disc space 113 piecemeal. In the case of a posterior placement of the disc and facet replacement 20 of the present invention, the disc and facet replacement 20 must, in order to avoid injury to the patient's spinal cord 119 due to the limited distance that the spinal cord 119 may be extracted from within the vertebral canal 118, be placed piecemeal and assembled in situ. Likewise, in the case of a posterior extraction of a previously placed disc and facet replacement of the present invention, the disc and facet replacement 20 must be disassembled in situ and the components thereof removed from the intervertebral disc space 113 piecemeal.
Although, especially in light of this exemplary description, those of ordinary skill in the art will recognize that some steps may be performed in different order and/or differing manner, assembly ex vivo of the disc and facet replacement 20 of the present invention is generally carried out by first inserting an end plug 91 into the anterior end 56 of each of the orifices 55 of the anterior section 48 of the lower plate 47 and, likewise, inserting an end plug 91 into the anterior end 30 of each of the orifices 29 of the anterior section 22 of the upper plate 21. As particularly shown in
With the end plugs 91 generally positioned as shown in
With the connecting rods 80 inserted as previously described into the orifices 55 through the anterior section 48 of the lower plate 47, the anterior edge 72 of posterior section 61 of the lower plate 47 is abutted against the posterior edge 53 of the anterior section 48 of the lower plate 47, the posterior sections 87 of the connecting rods 80 being received from the anterior into the orifices 74 through the posterior section 61 of the lower plate 47. A sleeve 96 of a section connection assembly 79 is then inserted from the posterior side of the posterior section 61 of the lower plate 47 into one of the orifices 74 through the posterior section 61 of the lower plate 47. As particularly shown in
Temporarily setting aside the integral lower plate 47, assembly ex vivo of the disc and facet replacement 20 of the present invention continues by inserting the anterior section 81 of a connecting rod 80 into the posterior end of one of the orifices 29 through the anterior section 22 of the upper plate 21, whereafter the connecting rod 80 is rotated about its longitudinal axis to engage the threaded shaft 82 (conforming to the internally threaded diameter 33 of the corresponding orifice 29 through the anterior section 22 of the upper plate 21) with the interiorly threaded bore 33 of the orifice 29 through the anterior section 22 of the upper plate 21. Rotation of the connecting rod 80 is continued until the anterior section 81 of the connecting rod 80 abuts against the interior face of the previously inserted end plug 91. As was the case with the lower plate 47, it is noted that the threaded shaft 82 of the anterior section 81 comprises a thread pitch reverse of that forming the threaded shaft 88 of the posterior section 87 of the connecting rod 80. Likewise, the thread pitch of the internally threaded bore 33 of the orifice 29 through the anterior section 22 of the upper plate 21 is reverse that of the internal threading 98 of the barrel 97 of each of the sleeves 96 of the section connection assemblies 79. As a result, the section connection assemblies 79 operate as turnbuckles to draw together or push apart the anterior section 22 of the upper plate 21 and the posterior section 34 of the upper plate 21. While it is necessary that opposite pitches be provided in the anterior and posterior components as discussed, it is not critical that one or the other of the anterior or posterior components be given left or right threading, the particular selection being wholly arbitrary. In any case, and as the threading is shown in the figures, the connecting rod 80 is rotated counterclockwise to effect insertion of the anterior section 81 of the connecting rod 80 fully into the orifice 29 through the anterior section 22 of the upper plate 21 and into abutment with the interior face of the end plug 91. Upon completion of this step for the first orifice 29 through the anterior section 22 of the upper plate 21, a second connecting rod 80 is inserted in identical manner into the remaining orifice 29 through the anterior section 22 of the upper plate 21.
With the connecting rods 80 inserted as previously described into the orifices 29 through the anterior section 22 of the upper plate 21, the anterior edge 40 of posterior section 34 of the upper plate 21 is abutted against the posterior edge 27 of the anterior section 22 of the upper plate 21, the posterior sections 87 of the connecting rods 80 being received from the anterior into the orifices 42 through the posterior section 34 of the upper plate 21. A sleeve 96 of a section connection assembly 79 is then inserted from the posterior side of the posterior section 34 of the upper plate 21 into one of the orifices 42 through the posterior section 34 of the upper plate 21. As was the case with the lower plate 47, the barrel 97 of each sleeve 96 is sized to fit snuggly in the space between the threaded shaft 88 of the posterior section 87 of a connecting rod 80 and a smooth bore 45 forming the orifice 42 through the posterior section 34 of the upper plate 21. Utilizing the provided drive arrangement 104 as previously described (and assuming the choice of thread direction previously discussed and as shown in the figures), the sleeve 96 is rotated clockwise to engage its internal threading 98 with the threaded shaft 88 of the posterior section 87 of the respective connecting rod 80, thereby seating the integral cap 101 of the sleeve 96 into a shoulder 44 provided about the posterior end 43 of the orifice 42 through the posterior section 34 of the upper plate 21 and drawing the posterior section 34 of the upper plate 21 tightly against the anterior section 22 of the upper plate 21. Upon completion of this step for the first orifice 42 through the posterior section 42 of the upper plate 21, a second sleeve 96 is inserted in identical manner into the remaining orifice 42 through the posterior section 34 of the upper plate 21. Finally, in order to stabilize each sleeve 96 in place, a locking screw 107 is inserted into each of a plurality of threaded holes 46 provided parallel to and slightly radially offset from each orifice 42 through the posterior section 34 of the upper plate 21, thereby completing the assembly of the upper plate 21, the anterior section 22 and the posterior section 34 being completely and securely adjoined to form a unitary upper plate 21.
As previously discussed, the provided posts 26, 39 and slots 50, 69 cooperate with the ball 109 interposed the unitary upper plate 21 and the unitary lower plate 47 to allow limited rotation and flotation between the upper plate 21 and the lower plate 47 such that the assembled disc and facet replacement 20 very closely approximates the function of a natural three-joint disc and facet complex. In a first preferred embodiment of the present invention as particularly shown in
In a second preferred embodiment of the present invention as particularly shown in
With the ball 109 sandwiched in place between the unitary upper plate 21 and the unitary lower plate 47 with or without implementation of one or both of the inserts 58, 60, the disc and facet replacement 20 as assembled ex vivo is fully prepared for anterior side placement into the intervertebral disc space 113 of a patient under treatment. The surgeon need only first prepare the intervertebral disc space 113 by surgically removing the affected intervertebral disc 114 from between the superior and inferior vertebral bodies 112.
Assembly in situ for a posterior insertion of the disc and facet replacement 20 of the present invention is preceded by preparation of the surgical site by first excising portions of the superior articular process 115 from the inferior vertebra and portions of the inferior articular process 116 and lamina 117 from the superior vertebra as necessary to access the intervertebral disc space 113 as shown in
Finally, as previously discussed, the present invention contemplates that it may under some circumstances be necessary to disassemble in situ a previously placed disc and facet replacement 20 for removal of the disc and facet replacement 20 from the anterior side. In this case (still assuming the threading adopted previously herein), the disc and facet replacement 20 is disassembled by first removing the end plugs 91 by clockwise rotation. The connecting rods 80 are then removed to the anterior by clockwise rotation of the rods 80 from their respective anterior ends 83 until the anterior sections 22, 28 pull away and separate from their respective posterior sections 34, 61. Upon separation, the component parts of the disc and facet replacement 20 may be extracted piecemeal.
While the foregoing description is exemplary of the preferred embodiment of the present invention, those of ordinary skill in the relevant arts will recognize the many variations, alterations, modifications, substitutions and the like as are readily possible, especially in light of this description, the accompanying drawings and claims drawn thereto. For example, stabilizing spikes 24, 36, 52, 71 may be provided on the outer faces 23, 35, 51, 70 of the disc and facet replacement 20 to promote stability of the disc and facet replacement 20 post-placement. Additionally, those of ordinary skill in the art will recognize that the midsection 85 of the connecting rods 80 may comprise a smooth shaft 86 in order to limit threading about the rods 80 as may be necessary to ensure separation of the anterior sections 22, 28 and posterior sections 34, 61 during disassembly of the disc and facet replacement 20. Still further, those of ordinary skill in the art will recognize that while the present invention is preferably constructed of polyetheretherketone other materials such carbon fiber, titanium or any substantial equivalent of any of these materials may be utilized. In any case, because the scope of the present invention is much broader than any particular embodiment, the foregoing detailed description should not be construed as a limitation of the scope of the present invention, which is limited only by the claims appended hereto.
Claims
1. An artificial disc for replacement of a spinal three-joint complex of a mammal, said artificial disc comprising:
- a generally spinal disc-shaped upper plate comprising an anterior section and a posterior section, said anterior section of said upper plate being selectively separable from said posterior section of said upper plate;
- a generally spinal disc-shaped lower plate comprising an anterior section and a posterior section, said anterior section of said lower plate being selectively separable from said posterior section of said lower plate;
- a ball interposed a lower face of said upper plate and an upper face of said lower plate;
- a plurality of posts, each said post projecting from one of said faces toward the other of said faces; and
- a plurality of detents for engaging said posts, each said detent corresponding to one of said posts and being provided on the one of said faces opposite the face from which said corresponding post projects.
2. The artificial disc as recited in claim 1, wherein:
- at least one said post projects from said lower face of said upper plate; and
- at least one said detent, corresponding to said post projecting from said lower face of said upper plate, is provided on said upper face of said lower plate and positioned opposite said post projecting from said lower face of said upper plate.
3. The artificial disc as recited in claim 2, wherein:
- each said post projects from said lower face of said upper plate; and
- each said detent, corresponding to one of said posts, is provided on said upper face of said lower plate and positioned opposite said corresponding post.
4. The artificial disc as recited in claim 1, wherein:
- at least one said post projects from said upper face of said lower plate; and
- at least one said detent, corresponding to said post projecting from said upper face of said lower plate, is provided on said lower face of said upper plate and positioned opposite said post projecting from said upper face of said lower plate.
5. The artificial disc as recited in claim 4, wherein:
- each said post projects from said upper face of said lower plate; and
- each said detent, corresponding to one of said posts, is provided on said lower face of said upper plate and positioned opposite said corresponding post.
6. The artificial disc as recited in claim 1, wherein each said post comprises a generally reniform cross section.
7. The artificial disc as recited in claim 6, wherein each said detent comprises a generally reniform perimeter.
8. The artificial disc as recited in claim 1, wherein each said detent comprises a generally reniform perimeter.
9. The artificial disc as recited in claim 1, wherein said anterior section and said posterior section of each said plate is interconnected one to the other with a section connection assembly, each said section connection assembly comprising a connecting rod inserted into and between said anterior section and said posterior section and oriented to lie substantially within both a sagittal plane and an axial plane.
10. The artificial disc as recited in claim 9, wherein each said anterior section of said plates comprises a first bore for receiving therein an anterior section of one of said connecting rods and each said posterior section of said plates comprises a second bore for receiving therein a posterior section of one of said connecting rods.
6733533 | May 11, 2004 | Lozier |
7214243 | May 8, 2007 | Taylor |
7323011 | January 29, 2008 | Shepard et al. |
7601173 | October 13, 2009 | Messerli et al. |
20020029084 | March 7, 2002 | Paul et al. |
20020099444 | July 25, 2002 | Boyd et al. |
20030204261 | October 30, 2003 | Eisermann et al. |
20040024460 | February 5, 2004 | Ferree |
20040093082 | May 13, 2004 | Ferree |
20040186577 | September 23, 2004 | Ferree |
20040254644 | December 16, 2004 | Taylor |
20050033439 | February 10, 2005 | Gordon et al. |
20050154461 | July 14, 2005 | Humphreys et al. |
20050154466 | July 14, 2005 | Humphreys et al. |
20050165487 | July 28, 2005 | Muhanna et al. |
20050171610 | August 4, 2005 | Humphreys et al. |
20050187633 | August 25, 2005 | Ferree |
20050192674 | September 1, 2005 | Ferree |
20050277930 | December 15, 2005 | Parsons |
20060004454 | January 5, 2006 | Ferree et al. |
20060052785 | March 9, 2006 | Augostino et al. |
20060052870 | March 9, 2006 | Ferree |
20060190084 | August 24, 2006 | Doubler et al. |
20060247778 | November 2, 2006 | Feree et al. |
Type: Grant
Filed: Sep 26, 2006
Date of Patent: Aug 2, 2011
Inventor: James W. Simmons, Jr. (San Antonio, TX)
Primary Examiner: Dan Pihulic
Attorney: Wayne J. Colton, Inc.
Application Number: 11/528,023