SYSTEM FOR INSERTING ARTIFICIAL
INTERVERTEBRAL DISCS
CROSS-REFERENCE TO RELATED
APPLICATIONS
[0001] The present application is a continuation of U.S. patent application Ser. No. 10/425,267, filed Apr. 29, 2003, entitled "Wedge Plate Inserter/Impactor and Related. Methods for Use in Implanting an Artificial Intervertebral Disc," now allowed, which is a continuation-in-part application of U.S. patent application Ser. No. 10/282,356, filed Oct. 29, 2002, entitled "Instrumentation and Methods For Use In Implanting an Artificial Intervertebral Disc," which is a continuation-in-part application of U.S. patent application Ser. No. 10/256,160, filed Sep. 26, 2002, entitled "Artificial Intervertebral Disc Having Limited Rotation Using a Captured Ball and Socket Joint With a Solid Ball and Compression Locking Post," which is a continuation-in-part application of U.S. patent application Ser. No. 10/175,417, filed Jun. 19, 2002, entitled "Artificial Intervertebral Disc Utilizing a Ball Joint Coupling," which is a continuation-in-part application of U.S. patent application Ser. No. 10/151,280, filed May 20, 2002, entitled "Tension Bearing Artificial Disc Providing a Centroid of Motion Centrally Located Within an Intervertebral Space," which is a continuation-in-part application of both U.S. patent application Ser. No. 09/970,479, filed Oct. 4, 2001, entitled "Intervertebral Spacer Device Utilizing a Spirally Slotted Belleville Washer Having Radially Extending Grooves," as well as U.S. patent application Ser. No. 10/140,153, filed May 7, 2002, entitled "Artificial Intervertebral Disc Having a Flexible Wire Mesh Vertebral Body Contact Element," the former being a continuationin-part application of U.S. patent application Ser. No. 09/968,046, filed Oct. 1, 2001, entitled "Intervertebral Spacer Device Utilizing a Belleville Washer Having Radially Extending Grooves" and the latter being a continuationin-part application of both U.S. patent application Ser. No. 09/970,479 (detailed above) as well as U.S. patent application Ser. No. 10/128,619, filed Apr. 23, 2002, entitled "Intervertebral Spacer Having a Flexible Wire Mesh Vertebral Body Contact Element," which is a continuation-in-part application of both U.S. patent application Ser. No. 09/906, 119, filed Jul. 16, 2001, and entitled "Trial Intervertebral Distraction Spacers" as well as U.S. patent application Ser. No. 09/982,148, filed Oct. 18, 2001 and entitled "Intervertebral Spacer Device Having Arch Shaped Spring Elements." All of the above mentioned applications are hereby incorporated by reference herein in their respective entireties.
FIELD OF THE INVENTION
[0002] This invention relates generally to systems and methods for use in spine arthroplasty, and more specifically to instruments for inserting and impacting artificial intervertebral discs, and methods of use thereof.
BACKGROUND OF THE INVENTION
[0003] The bones and connective tissue of an adult human spinal column consists of more than twenty discrete bones coupled sequentially to one another by a tri-joint complex that consists of an anterior disc and the two posterior facet joints, the anterior discs of adjacent bones being cushioned by cartilage spacers referred to as intervertebral discs. These
more than twenty bones are anatomically categorized as being members of one of four classifications: cervical, thoracic, lumbar, or sacral. The cervical portion of the spine, which comprises the top of the spine, up to the base of the skull, includes the first seven vertebrae. The intermediate twelve bones are the thoracic vertebrae, and connect to the lower spine comprising the five lumbar vertebrae. The base of the spine is the sacral bones (including the coccyx). The component bones of the cervical spine are generally smaller than those of the thoracic spine, which are in turn smaller than those of the lumbar region. The sacral region connects laterally to the pelvis. While the sacral region is an integral part of the spine, for the purposes of fusion surgeries and for this disclosure, the word spine shall refer only to the cervical, thoracic, and lumbar regions.
[0004] The spinal column is highly complex in that it includes these more than twenty bones coupled to one another, housing and protecting critical elements of the nervous system having innumerable peripheral nerves and circulatory bodies in close proximity. In spite of these complications, the spine is a highly flexible structure, capable of a high degree of curvature and twist in nearly every direction.
[0005] Genetic or developmental irregularities, trauma, chronic stress, tumors, and degenerative wear are a few of the causes that can result in spinal pathologies for which surgical intervention may be necessary. With respect to the failure of the intervertebral disc, and the insertion of implants and/or height restorative devices, several methods and devices have been disclosed in the prior art that achieve immobilization and/or fusion of adjacent bones by implanting artificial assemblies in or on the spinal column. More recently, the development of non-fusion implant devices, which purport to permit continued natural movement in the tri-joint complex, have provided great promise as a preferably alternative to fusion devices. The region of the back that needs to be corrected, as well as the individual variations in anatomy, determine the appropriate surgical protocol and implantation assembly. Generally, the preparation of the intervertebral space for the receipt of fusion or non-fusion devices involves removing the damaged disc material and thereafter distracting the adjacent vertebral bones to their appropriate distance apart. Once the proper height of the intervertebral space is restored, the fusion or non-fusion device can be implanted.
[0006] It is an object of the invention to provide instrumentation and methods that enable surgeons to more accurately, easily, and efficiently implant fusion or non-fusion devices. Other objects of the invention not explicitly stated will be set forth and will be more clearly understood in conjunction with the descriptions of the preferred embodiments disclosed hereafter.
SUMMARY OF THE INVENTION
[0007] The preceding objects are achieved by the invention, which includes, among other aspects, an inserter/ impactor (sometimes referred to herein as an "inserter/ impactor") useful for holding and manipulating artificial intervertebral discs.
[0008] More particularly, the systems and methods disclosed herein are intended for use in spine arthroplasty procedures, and specifically for use with the systems and
methods described herein in conjunction with the systems and methods in conjunction with the systems and methods described in U.S. patent application Ser. No. 10/282,356 (filed Oct. 29, 2002) entitled "Instrumentation and Methods For Use In Implanting an Artificial Intervertebral Disc" (hereinafter referred to as "the '356 application") as well as U.S. patent application Ser. No. 10/256,160 (filed Sep. 26, 2002) entitled "Artificial Intervertebral Disc Having Limited Rotation Using a Captured Ball and Socket Joint With a Solid Ball and Compression Locking Post" (hereinafter referred to as "the '160 application") as well as U.S. patent application Ser. No. 09/906,127 (filed Jul. 16, 2001) entitled "Insertion Tool For Use With Intervertebral Spacers" (hereinafter referred to as 'the '127 application"), both applications of which are mentioned above. However, it should be understood that the systems and methods described herein are also suitable for use with other systems and methods without departing from the scope of the invention.
[0009] While the instrumentation described herein (e.g., the inserter/impactor) will be discussed for use with the artificial intervertebral disc of FIGS, la-h of the present application (hereinafter, such figures will merely be referred to as "FIGS, la-h"), such discussions are merely by way of example and not intended to be limiting of their uses. Thus, it should be understood that the instrumentation and methods can be used with any of the artificial intervertebral discs disclosed in the '356 or '160 applications, or any other artificial intervertebral disc having (or being modifiable or modified to have) suitable features therefor. Moreover, it is anticipated that the features of the artificial intervertebral discs (e.g., plate surfaces and engagement holes) that are used by the inserter/impactor discussed herein to hold and/or manipulate the artificial intervertebral disc can be applied, individually, or collectively or in various combinations, to other trials, spacers, artificial intervertebral discs, or other orthopedic devices as stand-alone innovative features for enabling such trials, spacers, artificial intervertebral discs, or other orthopedic devices to be more efficiently and more effectively held and/or manipulated by the inserter/impactor described herein or by tools having suitable features. In addition, it should be understood that the invention encompasses instrumentation and methods for implanting artificial intervertebral discs, spacers, trials (static or dynamic), and/ or other orthopedic devices, that have one or more of the features disclosed herein, in any combination, and that the invention is therefore not limited to artificial intervertebral discs, spacers, trials, and/or other orthopedic devices having all of the features simultaneously.
[0010] Preferably, with regards to each artificial intervertebral disc to be implanted, a plurality of sizes of the artificial intervertebral disc would be available (e.g., the artificial intervertebral disc 160 of FIGS. la-h). That is, preferably, a plurality of the same type of artificial intervertebral disc would be available, each of the plurality having a respective width and depth dimension combination that allows it to fit within a correspondingly dimensioned intervertebral space. For example, the plurality of artificial intervertebral discs could include artificial intervertebral discs having widths being either 35 mm or 40 mm, and depths ranging from 14 mm to 18 mm in 1 mm increments, for a total of 10 discs. It should be understood that the artificial intervertebral discs can be offered in a variety of dimensions without departing from the scope of the invention, and that the dimensions specifically identified and
quantified herein are merely exemplary. Each of the plurality of artificial intervertebral disc preferably further includes features that can be used by the inserter/impactor (described below) and/or the inserter/impactor described in the '356 application.
[0011] With regard to features that can be used by the inserter/impactor described in the '356 application, each artificial intervertebral disc includes an anteriorly facing flat surface, flanked by two anteriolaterally facing flat surfaces (one on each side of the anteriorly facing flat surface), and, to provide for holding of the disc for an anterior insertion approach, a hole spaced from the anteriorly facing flat surface, the hole having a longitudinal axis parallel to the anteriorly facing flat surface. The holding pin of the inserter/ impactor fits within the hole, and the angled flat surfaces of the disc fit against the correspondingly angled flat surfaces of the inserter/impactor, and operation of the inserter/impactor pulls the holding pin toward the flat surface of the inserter/impactor opposite the pin, to rigidly hold the disc by the lower baseplate. The holding pin protrudes from the wedge-shaped extended surface of the distal end of the inserter/impactor and is restricted from upward movement with respect to the distal head by the presence of the wedge-shaped extended surface of the distal end of the inserter/impactor. More particularly, with any attempted upward movement of the holding pin, the pin encounters the upper surface of the channel in which the pin travels, preventing any such upward movement. When the intervertebral disc is held in this manner, rotation of the disc about a longitudinal axis relative to the inserter/impactor is prevented by interference of the corners of the disc's flat surfaces and the corners of the inserter/impactor's flat surfaces, similar to the manner in which a wrench holding a nut prevents rotation of the nut relative to the wrench. Further, when the disc is held in this manner, rotation of the disc about a lateral axis of the disc relative to the inserter/ impactor is prevented by interference of the inwardly facing surface of the first baseplate (e.g., upper baseplate) of the disc and the corresponding surface (e.g., upper surface) of the wedge on the distal end, and by interference of the inwardly facing surface of the second baseplate (e.g., lower baseplate) of the disc and the corresponding surface (e.g., lower surface) of the wedge on the distal end. It is preferable that the wedge on the inserter/impactor will interfere between the first and second baseplates (e.g., upper and lower) so that the surfaces of the first and second baseplates align at a preferred 15 degrees angle of lordosis when the disc is held by the inserter/impactor.
[0012] Preferably, in order to provide for a holding of the disc for two additional (here, anteriolateral) insertion approaches, each disc also include two additional holes, one spaced apart from one of the anteriolaterally facing flat surfaces, and the other spaced apart from the other of the anteriolaterally facing flat surfaces. Accordingly, operation of the inserter/impactor can fit the holding pin into either of these two additional holes, and hold the anteriolaterally facing flat surface (the one associated with the hole into which the pin is fit) of the disc against the flat surface of the inserter/impactor opposite the pin. It should be understood that preferably, in order to facilitate these two additional approaches, the angle separating the anteriorly facing flat surface of the disc and one of the anteriolaterally facing flat
surfaces of the disc is equal to the angle separating the anteriorly facing flat surface and the other of the anteriolaterally facing flat surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGS, la-h of the present application show front (FIG. la), side cutaway (FIG. lb), top (FIG. lc), perspective cutaway (FIG. Id), bottom cutaway (FIG. le), top cutaway (FIG. If), bottom perspective (FIG. lg), and top perspective (FIG. IK) views of an exemplary artificial intervertebral disc for use with the present invention.
[0014] FIGS. 2a-c show side (FIG. 2a), perspective (FIG. 2b), and close-up perspective (FIG. 2c) views of a wedge plate inserter/impactor of the present invention.
[0015] FIGS. 3a-d show bottom (FIG. 3a), side (FIG. 3b), top (FIG. 3c), and side cutaway (FIG. 3d) views of a distal end of a wedge plate inserter/impactor of the present invention.
[0016] FIGS. 4a-b show top (FIG. 4a) and side (FIG. 4b) views of a wedge plate inserter/impactor of the present invention holding an exemplary artificial intervertebral disc.
[0017] FIGS. 4c-e show top (FIG. 4c), side (FIG. 4d), and side cutaway (FIG. 4e) views of a distal end of a wedge plate inserter/impactor of the present invention holding an exemplary artificial intervertebral disc.
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS
[0018] While the invention will be described more fully hereinafter with reference to the accompanying drawings, it is to be understood at the outset that persons skilled in the art may modify the invention herein described while achieving the functions and results of the invention. Accordingly, the descriptions that follow are to be understood as illustrative and exemplary of specific structures, aspects and features within the broad scope of the invention and not as limiting of such broad scope. Like numbers refer to similar features of like elements throughout.
[0019] A preferred embodiment of an artificial intervertebral disc (e.g., artificial intervertebral disc 160) for use with the instrumentation of the present invention is referenced and described in the '356 application, and the same description is hereby incorporated by reference herein. The artificial intervertebral disc illustrated in FIGS, la-h of the present application is discussed herein with reference to such figures, as an example of an artificial intervertebral disc suitable for use with the present invention.
[0020] Referring now to FIGS, la-h, an artificial intervertebral disc of the present invention is shown in front (FIG. la), side cutaway (FIG. lb), top (FIG. lc), side cutaway (FIG. Id), bottom cutaway (FIG. le), top cutaway (FIG. If), bottom perspective (FIG. lg), and top perspective (FIG. lh) views.
[0021] It should be understood that the illustration and reference herein to the artificial intervertebral disc shown in FIGS, la-lh is merely to show an example of one type of artificial intervertebral disc that is contemplated by, encompassed by, and suitable for use with, the present invention, and that such illustration and reference herein is not meant to limit the scope of the present invention or limit the uses
of the present invention. Rather, any other artificial intervertebral disc (or any other orthopedic device) having suitable features for being manipulated by the instrumentation and methods described herein are contemplated by the present invention. Indeed, the features suitable for manipulation (e.g., angled flat surfaces with adjacent holes) are encompassed by the present invention, regardless of to what orthopedic device they may be applied. Other exemplary suitable artificial intervertebral discs include, but are not limited to, the artificial intervertebral discs described in the '160 application. The artificial intervertebral disc shown in FIGS, la-lh has features similar to those of these other suitable artificial intervertebral discs of the '160 application, and it should be understood that such similar features are structurally and functionally as described in the '160 application. Such similar features include an inwardly facing surface of the upper baseplate 164a, and a convex structure 162 on the lower baseplate 168b, the convex structure 162 having an inwardly facing surface 164b.
[0022] And, while the instrumentation described herein will be discussed for use with the artificial intervertebral disc of FIGS, la-lh, such discussions are merely by way of example and are not intended to be limiting of their uses. Thus, it should be understood that the tools can be used with any of the artificial intervertebral discs disclosed in the '160 application, or any other artificial intervertebral disc having (or being modifiable or modified to have) suitable features therefor. Moreover, it is anticipated that the features of the artificial intervertebral disc (e.g., the flat surfaces and accompanying holes) and/or the static trials (e.g., the cylindrical trunks and flat surfaces and accompanying holes) that are used by the tools discussed herein to hold and/or manipulate these devices can be applied, individually or collectively or in various combinations, to other trials, spacers, artificial intervertebral discs or other orthopedic devices as stand-alone innovative features for enabling such trials, spacers, artificial intervertebral discs, or other orthopedic devices to be more efficiently and more effectively held and/or manipulated by the tools described herein or by other tools having similar features. In addition, it should be understood that the invention encompasses artificial intervertebral discs, spacers, trials (static or dynamic), and/or other orthopedic devices, that have one or more of the features disclosed herein, in any combination, and that the invention is therefore not limited to artificial intervertebral discs, spacers, trials, and/or other orthopedic devices having all of the features simultaneously.
[0023] A plurality of static trials are provided primarily for use in determining the appropriate size of an artificial intervertebral disc to be implanted (or whether a particular size of the artificial intervertebral disc can be implanted) into the distracted intervertebral space (e.g., the artificial intervertebral disc 160 of FIGS, la-lh). Preferably, for each artificial intervertebral disc to be implanted, a plurality of sizes of the artificial intervertebral disc would be available. That is, preferably, a plurality of the same type of artificial intervertebral disc would be available, each of the plurality having a respective width and depth dimension combination that allows it to fit within a correspondingly dimensioned intervertebral space. For example, the plurality of artificial intervertebral discs could include artificial intervertebral discs having widths being either 35 mm or 40 mm, and depths ranging from 14 mm to 18 mm in 1 mm increments, for a total of 10 discs. Accordingly, preferably, each of the
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