|Publication number||US20080114361 A1|
|Application number||US 12/008,550|
|Publication date||May 15, 2008|
|Filing date||Jan 11, 2008|
|Priority date||Dec 22, 2003|
|Also published as||EP1711113A2, EP1711113A4, EP1711113B1, EP1711114A2, EP1711114A4, EP2246002A1, US7318825, US8182518, US20050137597, US20050149026, WO2005062900A2, WO2005062900A3, WO2005062902A2, WO2005062902A3|
|Publication number||008550, 12008550, US 2008/0114361 A1, US 2008/114361 A1, US 20080114361 A1, US 20080114361A1, US 2008114361 A1, US 2008114361A1, US-A1-20080114361, US-A1-2008114361, US2008/0114361A1, US2008/114361A1, US20080114361 A1, US20080114361A1, US2008114361 A1, US2008114361A1|
|Inventors||Michael Butler, Michael Milella|
|Original Assignee||Life Spine Llc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (5), Classifications (13), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This U.S. non-provisional patent application claims the benefit of and/or priority to U.S. provisional patent application Ser. No. 60/531,657 filed Dec. 22, 2003 entitled “Static and Dynamic Cervical Plate Construct”, the entire contents of which is specifically incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to devices for the internal fixation of the spine particularly within the fields of orthopedics and/or neurosurgery such as spinal implants for holding vertebral bones fixed relative to one another and, more particularly, to static and/or a dynamic bone fixation implants for use in spinal surgical procedures for stabilizing the relative motion of, temporarily or permanently immobilizing, bones of the spine.
2. Background Information
Cervical plates have been used for more than 20 years to increase neck stability following single and multi-level cervical surgery. Cervical plates, implanted during surgery for reasons such as disease, trauma, defect, accident or the like, are used to stabilize one or more cervical vertebrae. Stabilization leads to a proper healing or a desired outcome. The cervical plate is mounted to one or more vertebrae during the surgery. Typically, screws are used to mount the cervical plate to the one or more vertebrae. It is important during the mounting process that the plate be properly aligned on the vertebrae for receipt of the mounting screws.
In some instances, it is desirous to cause the fusion of two adjacent vertebrae. If this is the case, the surgeon makes a small incision in the front of the neck to reach the cervical spine. Tissues and muscles are retracted (spread apart) to reveal the proper level in the cervical spine. The cartilaginous material or disc between the two vertebrae is removed and the bone surface abraded to encourage a bleeding surface. Blood from the bleeding surfaces is desired in order for the bones to fuse. The space between the adjacent vertebrae is filled with bone graft. A cervical plate is then screwed into the superior (top) and inferior (bottom) vertebrae. This stabilizes the cervical spine to facilitate fusion and healing. With current cervical plates however, once the plate is secured over the graft area, the only manner of accessing the graft area is to remove the plate. Moreover, with current cervical plates, it is necessary to provide the bone graft material before mounting the plate.
Heretofore, cervical plates were almost exclusively static, in that they have fixed dimensions. It has been realized that it is desirable in certain situations to allow shifting or slight movement between the plate-mounted vertebrae. The prior art is relatively devoid of dynamic cervical plates.
It is thus evident from the above that what is needed is a cervical plate that allows access to a bone graft area of a cervical surgical site.
It is thus further evident from the above that what is needed are various dynamic cervical plates and dynamic cervical plate constructs.
This need and others are accomplished through application of the principles of the subject invention and/or as embodied in one or more various forms and/or structures such as are shown and/or described herein.
N-level internally dynamizing cervical plates and cervical plate constructs in accordance with the present principles, provide unconstrained sliding interconnection between the various plate components after installation on a cervical spine. The N-level dynamic cervical plate has a tongue-and-groove configuration between the various plate component or segments thereof that provides a constant thickness over the dynamizing portions. A graft window is defined extending between each pair of bone screw bores, with a pair of bone screw bores disposed on each plate component. Detents provided relative the tongue-and-groove portions allows the various plate components to be permanently joined, but movable relative to one another. Various bone screw anti-backing, anti-rotation or locking devices for cervical bone plates are also provided that allow releasable locking of bone screws relative to the cervical plate.
In one form of the invention, a three-component, two level dynamic cervical bone plate is configured such that a middle component accepts an identical end component at both ends of the middle component via a mutual tongue and groove configuration. The end component may be a 180° interchangeable part. The middle component may be a 180° interchangeable part. The middle component and the end component have cooperating configurations and complementarily configured tongue and groove structures that allow sliding movement between the middle component and the end components. The 2-L dynamic plate in accordance with the principles of the subject invention provides for pure vertebral body translation without creating guesswork with respect to screw positioning.
As well, in another form of the invention, there is provided a kit for assembling an N-level dynamic cervical plate. The kit includes a middle component and two, identical end components. The end components is slidingly assembled to each longitudinal end of N number of extension components to provide a dynamic N level (N-L) cervical plate that includes a graft window between each level, pair of bone screws on each component, or as formed between the components as graft window portions or segments thereof. Moreover, the end components are configured such that they present the same interconnectivity to the middle component when rotated 180° relative to a plane defined by the body thereof.
The present invention provides advantages over the teachings of the prior art with respect to cervical plating technology. The principles accompanying the present invention allows the fixation plate to be used with greater accuracy. This may ultimately increase the efficacy of an established procedure. For instance the present invention provides a window within the center area of the plate. This allows viewing of graft material during and after placement. Such is accomplished by utilizing a constant plate surface area thickness tongue and groove interface that is angled in one plane and curved in a perpendicular plane for both the static and dynamic plates, and for all levels (1-L, 2-l, N-L) of fixation plates.
The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the inventions will be better understood by reference to the following description of embodiments of the inventions taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent various embodiments of the invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the invention. Also, the exemplifications set out herein illustrate various embodiments of the invention, but such exemplifications are not to be construed as limiting the scope of the invention in any manner.
The body 102 has an opening, window, void or the like 104 (collectively hereinafter, window) in a middle, center or central portion of the body 102 bounded by surface 107. While the window 104 may be formed in various configurations, it is preferable that the window extend essentially from proximate to adjacent bone screw bores 106 that are situated on ends 121, 123 of the 1-L plate 100. In the exemplary plate 100, the window 104 is configured in a somewhat oblong shape defining a first peak 111 and a second peak 113. As developed more fully below, the elongation of the window allows for better alignment of the plate 100 on the vertebra by the surgeon. The window 104 itself provides visualization of the bone graft abutment to the posterior section of the plate while in situ. The opening 104 defines a first leg 103 a and a second leg 103 b to the body 102 that extend between ends 121 and 123 of the body 102. The length (l) is longer then the width (w) of the opening 104. The length (l) is elongated or extended to span essentially between the edges of each screw bore 106.
The window/leg configuration creates a “dual pillar” like support foundation for plate strength as between the first and second ends 121, 123, such as against twisting or flexing. The size and configuration of the window 104 (forming two legs or a dual pillar configuration) provides an easy bone screw placement and/or allows for bone graft viewing. Each leg 103 a/103 b preferably, but not necessarily, has the same cross-sectional profile. Moreover, the cross-sectional profile of each leg is preferably, but not necessarily, consistent throughout its length between ends 121, 123. Furthermore, the legs 103 a/103 b have the same height profile as the overall plate body 102.
The ends 121 and 123 each have two bone screw bores 106 each one of which is disposed on corners of the respective ends. The four bone screw bores 106 are preferably, but not necessarily, aligned to correspond to vertices of a rectangle, the rectangle preferably, but not necessarily, being a scaled version of the rectangular body 102. The scaled rectangle forming a pattern for placement of screw bores on a patient's vertebra. The ends 121 and 123 each have an outer contour that defines a notch 109. Each bone screw bore 106 is sized, configured and/or situated such that a portion thereof is adjacent a proximate portion of the opening 104.
Each bone screw bore 106 has a ledge 105 formed in the interior thereof. The ledge 105 is configured to capture an undersurface of a head of a bone screw. As such, each ledge 105 is somewhat dish-shaped to accommodate the complementary shape of the undersurface of the bone screw head. Each ledge 105 is also angled to allow the inserted bone screw to achieve a proper orientation during implantation. The bone screw bores 106 are configured to utilize various types of bone screws such as fixed angle screws, emergency screws, and variable angle screws, examples of which are incorporated herewith through the parent provisional application. Moreover, the bore/ledge allows variable bone screw angulation while fixing or mounting the plate to the vertebrae. Such angulation is up to 30° cephalad—caudal, and 20° lateral—medial.
The body 102 further includes two bores 108 each one of which is situated proximate (here shown as between) bone screw bore pairs 106 of each end 121 and 123. Each bore 108 is configured to receive a boss or fastening device/portion of a bone screw retainer device, cover plate, retention clip, or the like such as described herein for preventing rotation and/or backout of a bone screw that has been implanted.
The cover 110 moreover surrounds the window 104 and most of each bone screw bore 106 (which would be most of a bone screw head when so installed). This helps to keep, retain or releasably lock the bone screws from backing out and/or turning. The cover also will provide protection against potential graft migrating out of the inter-vertebral space post operatively. The cover further will allow for post-operative visualization via radiograph. The cover 110 includes two cover bosses 112 that are configured to provide a snap fit into plate bores 108 when installed, such that the cover 110 is retained on the plate 100. While normal use will not cause the cover 110 to separate from body 102, a simple tool may allow removal of the cover 110.
The cover 110 is exemplary of the type of covers that may be used as bone screw locking mechanisms with the 1-L static cervical plate 100. As such, covers 110 may be manufactured in various sizes to accommodate various sizes of cervical plates 110. The cover 110 is also fabricated from a biocompatible material like the material for the plate 100. The plate 100 may also accommodate other styles of covers.
In this embodiment, the cover 114 includes a depression or concavity 120 that is configured like the opening 104 in order to extend into the opening 104 when the cover 114 is installed. Moreover, the cover 114 includes four screw bore depressions or concavities 118 each of which is configured to extend into one of the bone screw bores 106 of the body 102 of the plate 100. The covers or cover plates may be fashioned from an alloy of metals, titanium, a titanium alloy, PEEK, or suitable biocompatible material.
While none of
Referring now to
The plate 150 is defined by a body 152 that may be considered as having a middle portion or section 167, a first end portion or section 166 on one side of the middle portion 167, and a second end portion or section 168 on another side of the middle portion 167. The middle portion 167 defines a fastening, mounting or attachment portion that is adapted to be attached to a central vertebra of a three vertebrae fusion. The end portions 166 and 168 also define a fastening, mounting or attachment portion that is adapted to be attached to separate outer vertebra of the three vertebrae fusion. As such, and keeping with the principles set forth herein with respect to the 1-L static plate 100, the static 2-L plate 150 includes dual (two) openings, windows, voids or the like 153 and 155, one opening for each level or between each end portion 166, 168 and the middle portion 167. Each window 153 and 155 is centrally, located defines leg pairs (pillars) 164 a/164 b and 165 a/165 b.
The opening 153 is disposed in the middle, center or central portion of the area between the end portion 166 and the middle portion 167, being bounded by surface 154. The window 153 is configured in an exemplary fashion as an elongated oval that extends from just adjacent to a portion of each screw bore 157 of the end portion 166 (proximate the reception bore 160 of the end portion 166) to just adjacent to a portion of each screw bore 161 of the middle portion 167 (proximate the reception bore 160 of the middle portion 167).
The opening 155 is disposed in the middle, center or central portion of the area between the end portion 168 and the middle portion 167, being bounded by surface 156. The opening 155 is configured as an elongated oval that extends from just adjacent to a portion of each screw bore 157 of the end portion 168 (proximate the reception bore 160 of the end portion 168) to just adjacent to a portion of each screw bore 161 of the middle portion 167 (proximate the reception bore 160 of the middle portion 167).
The elongation of the openings 153, 155 allow for alignment of the plate 150 during surgery and mounting thereof by the surgeon. The size and configuration of the openings 153, 155 (forming two legs or a dual pillar configuration) provides easy bone screw placement and/or allows for bone graft viewing.
Each leg pair 164 a/164 b and 165 a/165 b preferably, but not necessarily, has the same cross-sectional profile. As well, each leg 164 a/b and 165 a/b preferably, but not necessarily has the same cross-sectional profile. Moreover, the cross-sectional profile of each leg is preferably, but not necessarily, consistent throughout its length between the middle portion 167 and end portions 166 and 168. Furthermore, the legs 164 a/b and 165 a/b have the same height profile as the overall plate body 152.
The ends 166 and 168 each have two bone screw bores 157 each one of which is disposed on corners of the respective ends and at least partially defining the fastening portions. The ends 166 and 168 each have an outer contour that defines a notch. Each bone screw bore 106 is sized, configured and/or situated such that a portion thereof is adjacent a proximate portion of its respective opening 153, 155. Each bone screw bore 157 has a ledge 158 formed in the interior thereof. Each ledge 158 is configured to capture an undersurface of a head of a bone screw. As such, each ledge 158 is somewhat dish-shaped to accommodate the complementary shape of the undersurface of the bone screw head. Each ledge 158 is also angled to allow the inserted bone screw to achieve a proper orientation during implantation. The bone screw bores 157 are configured to utilize various types of bone screws as described above. Additionally, the bone screw bores 157 are configured to utilize various types of bone screws such as fixed angle screws, emergency screws, and variable angle screws, examples of which are incorporated herewith through the parent provisional application. Moreover, the bore/ledge allows variable bone screw angulation while fixing or mounting the plate to the vertebrae. Again, such angulation may be up to 30° cephalad—caudal, and 20° lateral—medial.
The middle portion 167 also has two bone screw bores 161 disposed as pairs of screw bores in like manner to the other screw bores at least partially defining the fastening portion. Each bone screw bore 161 is sized, configured and/or situated such that a portion thereof is adjacent a proximate portion of an opening 153, 155. Each bone screw bore 161 has a ledge 162 formed around the interior thereof. Each ledge 162 is configured to capture an undersurface of a head of a bone screw. As such, each ledge 158 is somewhat dish-shaped to accommodate the complementary shape of the undersurface of the bone screw head. Each ledge 158 is also designed to receive the inserted bone screw in a fairly straight manner to achieve a proper orientation during implantation. The bone screw bores 161 are configured to utilize various types of bone screws like those above.
The body 152 further includes two bores 160 each one of which is situated between bone screw bore pairs 157 of each end portion 166 and 168. An additional like bore 160 is positioned in the middle portion 167. Each bore 160 is configured to receive a boss or fastener of a bone screw retainer device, cover plate, retention clip, or the like.
Additionally referring to
Each prong 176, 178 is adapted to be received in a bone screw head socket. It should be appreciated, that the use of clips 170 is not limited to static 2-L plates as shown, but may be used with static 1-L plates, static multi-level plates, and dynamic plates of all levels. The clip 170 is provided in various sizes in order to be used with plates of various sizes, since the span between bone screw heads may be different for different size plates. The clip 170 also has a low profile (thickness) so as to remain relatively flat against the plate 150.
The diameter of the post 173 is slightly less than the diameter of the receiving bore in the plate (e.g. bore 160 of plate 150) so that the receiving bore may receive the post. The rim 174, however, defines a diameter that is oversized for the receiving bore in the plate. The notches or slots 175 allow the ends of the post 173 to slightly compress, reducing the effective diameter of the rim 174, causing the rim 174 to pass through the receiving bore. Once the rim 174 is through the receiving bore, the post 173 returns to its uncompressed state such that the end 177 of the rim 174 contacts the underside of the plate, preventing the clip 170 from pulling out of the receiving bore without a special tool or the like. The resilient boss 174 is thus configured to be releasably, but snugly snap or press fit received into an appropriate plate bore.
The interaction of the clip 170 with the plate 150 and the bone screw pairs is best seen in
The boss 172 of the clip 170 is situated in the bore 157 (snap-fit received). One prong 176 extends into the socket 182 of the head 181 of the upper bone screw 180 while the other prong 178 extends into the socket 182 of the head 181 of the lower bone screw 180. The prongs interact with the polygon socket of the head to limit rotation of a screw. The first and second configured flanges 176, 178 are configured to be press or snap fit received in the bone screw head socket.
The first section 202 has a body 203 supporting two bone screw bores 206 which, while not shown, may include configured ledges such as the configured ledges 158 of bone screw bores 157 of plate 150 (see, e.g.
The second section 204 has a body 205 supporting two bone screw bores 218, which, while not shown, may include configured ledges such as the configured ledges 158 of bone screw bores 157 of plate 150 (see, e.g.
As such, the dynamic plate 230 has extended windows or openings formed by the dual pillar structure and, more particularly, has two windows formed by two dual pillar structures. The dynamic plate 230 is a two level (2-L) plate that is composed of three components which are shown in exploded view relative to one another in
End component 232 a is defined by a body 233 a having bone screw bores 235 a and configured ledges 234 a such as described above. A retention bore 236 a for a locking clip 170 or cover plate boss is provided between the two bone screw bores. The body 233 a defines a first leg 238 a having a configured channel or cutout 237 a therein. The shape of the channel 237 a provides lateral and up/down stability to a joining or mating piece of the middle component 250. Thus, the configuration of the channel may be changed as appropriate under the present principles. In this particular form, the channel 237 a is configured akin to a dovetail. A second leg 244 a of the body 233 a is configured akin to the channel 237 a dovetail. It should be observed that the end components 232 a and 232 b may be joined or assembled into a dynamic 1L plate without the use of the middle component 250 since the leg 244 b (identical to leg 244 a) will be received in leg channel 237 a while the leg 244 a will be received in leg channel 237 b (identical to leg channel 237 a).
The end component 234 b is defined by a body 233 b having bone screw bores 235 b and configured ledges 234 b such as described above. A retention bore 236 b for a retention clip or cover boss is provided between the two bone screw bores. The body 233 b defines a first leg 238 b having a configured channel or cutout 237 b therein. The shape of the channel 237 b provides lateral and up/down stability to a joining or mating piece of the middle component 250. Thus, the configuration of the channel may be changed as appropriate under the present principles. In this particular form, the channel 237 b is configured akin to a dovetail. A second leg 244 b of the body 233 b is configured akin to the channel 237 b dovetail.
The middle or expansion component 250 is defined by a body 252 having two bone screw bores 254 having head seats 255, and a boss bore 256. The body 252 also includes a first leg 258 having a configured channel 260 therein. The channel 260 receives the configured leg 244 a of the section 232 a (or flange 272 of another expansion component) and is thus configured appropriately. A second leg 262 of the body 252 includes a configured flange 264 that is configured to be received in the channel 237 a of the section 230 (or a channel 268 of another expansion component) and is thus configured appropriately. A third leg 270 includes the configured flange 272 receivable in the channel 237 b of the section 232 b (or in the channel 260 of another expansion component). A fourth leg 266 of the body 252 includes the channel 268 that receives the configured flange 244 of the section 230 or the flange 264 of another expansion device. This structure and/or interrelationship of the middle component 250 to itself and to the end components 232, provides the ability to assemble N-level, dynamic plates. The 2-L dynamic plate 230, when assembled, defines first and second windows, voids or openings 275, 277 between the middle component 250 and each end component 232. The legs and flanges when assembled each have the same cross-section. The truncated triangle cross-section provides loading stability. This is an example of one embodiment. Other embodiments may be fashioned and utilized.
End components 304 a/b is defined by a body 333 a/b having bone screw bores 335 a/b and configured ledges 334 a/b such as described above. A retention bore 336 a/b for a retention clip or cover boss is provided between the two bone screw bores. The body 333 a/b defines a first leg 338 a/b having a configured mating structure thereon. The body 333 a/b also defines a thickened second let 340 a/b that has a channel for receiving a like configured leg portion of the middle component 302, the shape of which provides lateral and up/down stability to a joining or mating piece of the middle component 302. Thus, the configuration of the channel may be changed as appropriate under the present principles. It should be observed that the end components 304 a and 304 b may be joined or assembled into a dynamic 1L plate without the use of the middle component 302.
The middle or expansion component 302 is defined by a body 352 having two bone screw bores 354 having head seats 355, and a boss bore 356. The body 352 also includes a first thickened leg 358 having a channel therein that is configured to receive the configured leg 338 a of the end component 304 a (or flange 366 of another middle component 350) and is thus configured appropriately. A second leg 364 of the body 352 includes a flange that is configured to be received in the channel structure 340 a of the end component 304 a (or a channel 366 of another middle component) and is thus configured appropriately. A third leg 372 includes configured flange receivable in the channel structure 340 b of the end section 232 b (or in the channel of another middle component). A fourth leg 366 of the body 352 includes a channel structure that receives the configured flange 338 b of the end component 304 b or the flange of another middle component. This structure and/or interrelationship of the middle component 302 to itself and to the end components 304, provides the ability to assemble N-level, dynamic plates. The 2-L dynamic plate 300, when assembled, defines first and second windows, voids or openings 308, 310 between the middle component 302 and each end component 304. The legs and flanges when assembled each have the same cross-section.
The legs and flanges when assembled each have the same cross-section.
The various dynamic plates of the present invention are assembled from a number of end and middle components depending on the desired plate level. The various components are slidingly interconnected to one another. It should be appreciated that once assembled, the plate components, while slidable with respect to each other, have a disassembly stop or constraining mechanism or device such that the plate components will not disassemble once assembled. The disassembly constraining mechanism constrains or limits the length of travel of the leg assemblies (slidingly connected legs of the plate components) of the two plate components relative to one another in a disassembled direction of travel.
To this end and referring to
The channeled arm 380 has a detent 384 within the groove (the underside per
During assembly, the detent 386 is to the left of detent 384. While the heights of the detents are such that the apex of each detent extends beyond the apex of the other detent, as the two detents 384, 386 meet their angled or ramped surfaces meet. Continued travel allows the ramps to slide relative to another. The small overlap in detent height thus allows the detent 384 to reside in area 385 once full assembly has taken place. In one direction of travel, the detent 384 will contact ledge 388, while in the other direction the difference in detent height creates a stop. Of course, other types of stop mechanisms may be employed that allow assembly but prevents disassembly or makes disassembly extremely difficult.
The middle component 452 is configured to present the same face when rotated about the plane of the paper (i.e. rotatable 180° and still present the same configuration) and/or symmetric about a top to bottom plane through the bone screw bores 458. In this manner a single configuration of end plate component 454 is used at both ends of the middle component 450. The middle plate component 450 allows one-plane movement (‘dynamization’) relative to both end plate components 454 a, 454 b when mounted, or between each end plate component 454 a, 454 b and the middle plate component 452.
Referring additionally to
The middle plate component 452 has two legs or flanges, 462 and 464 extending from one end of the body 456. The two legs 462, 464 are spaced apart and parallel, but preferably, but not necessarily, slightly curved downwardly (as per
The middle plate component 452 also has two more legs or flanges, 468 and 470 extending from another end of the body 456, opposite the legs 462, 464. The two legs 468, 470 are spaced apart and parallel, but preferably, but not necessarily, slightly curved downwardly (as per
With respect to the end plate component, attention is drawn to
The middle plate component 454 has two legs or flanges, 490 and 492 extending from one end of the body 486. The two legs 490, 492 are spaced apart and parallel, but preferably, but not necessarily, slightly curved upwardly (as per
This is particularly illustrated in
It should be appreciated from the above that while the legs or projections of the 2-L dynamic plate 450 are in sliding interconnectivity when assembled in like manner to the previously discussed 2-L dynamic plates of the present invention, the manner of such sliding interconnectivity is different. The present dynamic plate 450 utilizes an extended or modified tongue and groove configuration on rim portions of the various projections.
Referring now to
While identical (thus 180° rotatable in the plane of the paper) end plate components 520 a and 520 b of the dynamic plate 502 have the same configuration, features and functions as the end plate components 354 a and 354 b, the end plate components 520 a and 520 b are assembled from two pieces rather than formed as one piece. Each end plate component 520 a and 520 b has an upper end plate component portion 522 a and 522 b and a lower end plate component portion 524 a and 524 b that join to form the respective end plate components 520 a and 520 b. The upper and lower end plate components 522 and 524 are essentially a split or half of the like end plate component 354 of the dynamic plate 350.
As such, and referring to the end plate component 520 b, the upper end plate component portion 522 b includes bone screw bores 525 b and two extending legs 528 b and 530 b. The legs 528 b and 530 b are spaced in a U-shape to define the window 565 when assembled. While not discernable in
The construct 500 is shown with a bone screw capture or releasable bone screw locking (anti-rotation/backout) device 506. It should be appreciated that the construct 500 preferably includes a screw capture device 506 for each bone screw 504/bone screw bore of the dynamic plate 502. The screw capture device 506 is characterized by a body 507 that may be formed of a suitable biocompatible polymer or metal. The body 507 is dome shaped having an annular rim 508. The domed body 506 includes a plurality of slits or slots from a central opening 511.
The screw capture device 506 is situated and captured between the end plate component portions 522 and 524 and any number of middle components 510 and 512. Particularly, the rim 508 is constrained by the ledge of the bone screw bores. The inner surface of the body 506 compresses against the head of the bone screw to provide anti-backing or anti-rotation of the bone screw 504 once installed.
As indicated above, the integral anti-backout feature of the bone screw 700 is used in conjunction with an integral anti-backout feature of a bone screw bore. As such, attention is drawn to
Referring now to
The middle component 902 is configured to present the same configuration when rotated in a plane defined by its body (i.e. rotatable 180° and still present the same configuration) and/or symmetric about a top to bottom plane through its bone screw bores 910. The end components 904 and 906 are configured to be received for sliding engagement with configured ends of the middle component 902 and, more particularly, for sliding engagement for assembly of the end component (904 or 906) to the middle component 902 and thereafter for sliding engagement or interconnectivity within a limited length of longitudinal travel between a fully closed (closed) position relative to the middle plate 902 and a fully open (open) position defined by ends of the components and configured stops that allow for sliding assembly of the components, but hinders disassembly. Since the middle component 902 presents the same configuration when rotated around end to end (in a plane defined by the body 908), at least the connection portions of the first and second end components 904, 906 are identical or nearly so. Preferably, however, and as shown in the figures, the first and second end components 904 and 906 are entirely identical. This allows the manufacture of only one configuration of end component (not including different sizes for different sizes of middle components).
In accordance with the principles of the subject invention, the plate 900 includes two graft windows 907, 909, one for each level. Each graft window 907 and 909 preferably, but not necessarily, has the same shape. Particularly, the graft window 907 extends essentially from the pair of bone screw bores 998 of the first end component 904 to the pair of bone screw bores 910 of the middle component 902. Likewise, the graft window 909 extends essentially from the pair of bone screw bores 998 of the second end component 906 to the pair of bone screw bores 910 of the middle component 902. Moreover, as discussed further below, the width of each window 907, 909 increases from an end of the window relative to the middle component 902 to and end of the window relative to the respective end component 904, 906. Of course, the windows 907, 909 may take other shapes.
Referring additionally to
The middle component 902 defines four lateral sides or side portions 914, 916, 918 and 920, with side portions 914 and 916 extending from one longitudinal end of the body 908 and side portions 918 and 920 extending from another longitudinal end of the body 908. The side portions 914 and 918 are diametrically opposed, while side portions 916 and 920 are diametrically opposed. Each side portion 914, 916, 918 and 920 is formed with a configured connection and/or reception interface portion or section 924, 932, 940 and 948, respectively, formed as a configured groove or channel within a respective side of the body 908. The side portions 914 and 916 define a connection and/or reception interface for the end component 904, while side portions 918 and 920 define a connection and/or reception interface for the end component 906. Except for the window portion 958, forming part of the window 907, the reception interface of the side portions 914 and 916 for the end component 904 extends from one lateral side of the body 908 to the other lateral side of the body 908. Likewise, except for the window portion 964, forming a part of the window 909, the reception interface of the side portions 918 and 920 for the end component 906 extends from one lateral side of the body 908 to the other lateral side of the body 908.
Side portion 914 includes a flange or projection 922 such that the groove 924 extends from an end 925 of the side portion 914 through the flange 922. Likewise, the side portion 916 includes a flange or projection 930 such that the groove 932 extends from an end 933 of the side portion 916 through the flange 930. Further, likewise, the side portion 918 includes a flange or projection 938 such that the groove 940 extends from an end 941 of the side portion 918 through the flange 938. Even further, likewise, the side portion 920 includes a flange or projection 946 such that the groove 948 extends from an end 949 of the side portion 920 through the flange 946.
Moreover, and still referring specifically to
Likewise, with respect to the side portion 920, the groove or channel 948 is preferably disposed in the center or middle of the depth (top to bottom per
With respect to the end component, attention is drawn to
The middle component 906 has a first elongated flange or tongue 1016 extending from a first projection or prong 1014 of the body 996. The middle component 906 further has a second elongated flange or tongue 1026 extending from a second projection or prong 1024 of the body 996. The first tongue 1016 is configured to be slidingly received (assembled) and interconnected with one side portion (either side portion 918 or side portion 916) of the middle component 902, while the second tongue 1026 is configured to be slidingly received (assembled) and interconnected with one side portion (either side portion 920 or side portion 914) of the middle component 902. In this manner, the first and second tongues 1016 and 1026 are slidingly received or interconnected with the grooves of the flanges of a longitudinal end of the middle plate 902. Maximum extension occurs when the ends of the tongues reach the end of the grooves.
The first tongue 1016 is defined by tongue portions 1018 and 1020 whose outer shape is configured to that of the grooves of the flanges of the body 908 of the middle component 902. A stop or detent mechanism 1022 is disposed at a junction or transition between the tongue portions 1018 and 1020. A second tongue 1026 is defined by tongue portions 1028 and 1030 whose outer shape is configured to that of the grooves of the flanges of the body 908 of the middle component 902. A stop or detent mechanism 1032 is disposed at a junction or transition between the tongue portions 1028 and 1030. Moreover, a window portion 1036 as part of a graft window 907 or 909 is defined between the first and second tongues 1016 and 1026.
Particularly a first surface 1038 defines one side of the window portion 1036 while a second surface 1039 defines another, opposing side of the window portion 1036. These side surfaces 1038 and 1039 are not parallel, but are situated so as to form an angle c relative to an imaginary convergence point of the sides 1038 and 1039 (i.e. the boss bore 912 of the middle component 902). Thus, the window portion 1036 increases in width as it extends longitudinally outward from the tongues 1016, 1026 to the bone screw bores 998.
It should be appreciate that the principles of the 2-L dynamic plates of
With respect to a 1-L plate, this may be accomplished in one manner by modifying one end component to have the same configuration as the configuration of the middle component. With respect to an N-level plate, this may be accomplished by modifying the middle component to have one end configuration the same as an end component, and modifying the middle component accordingly. In summation, the various ends of the end components and the middle components may be mixed to provide mating interconnectivity.
The cervical plates described above are intended for anterior screw fixation to the cervical spine (C2 through T1) for various conditions such as at least the conditions of spondylolisthesis, fracture, spinal stenosis, and tumor.
Each plate is preferably, but not necessarily, formed from titanium (e.g. titanium 6A1-4V ELI per AASTM F-136). Other suitable metals, ceramics may be used if appropriate. Moreover, it should be appreciated that the configuration(s) and/or principles of the 1-L dynamic plate(s) described herein are applicable to and/or may be used in the various 2-L dynamic plates also described herein and n-level dynamic plates. As well, 2-L dynamic plate configurations described herein may be used in the 1-L plates described herein and any n-level dynamic plates. This is particularly true with respect to the various leg or projection configurations and the sliding connectivity thereof.
In general, the preferred embodiment of the present cervical plates will embody curvature in two planes (sagittal and coronal) to more closely resemble the anatomical aspects of the spine. The cervical plates may be provided without curvature or with curvature in one plane as necessary. The plates are made in various sizes (e.g. 14 mm through 110 mm) to accommodate various spines. The plates have a nominal thickness of about 1.8 mm to 3.0 mm and a width of about 18 mm. The plates are configured to accept bone screws having a diameter of about 4.0 through 4.5 mm. Moreover, the bone screw holes of the plates are configured to accommodate both static and variable angle bone screws. This is accomplished by use of a unique pocket design of the bone screw holes. The bone screws are affixed using a typical screw driver (e.g. hexalobullar driver, x10).
Once the plate has been installed with the appropriate bone screws, the bone screws may be locked via several methods. In one method, a single locking plate locks a pair of screws. The locking plate includes a center post that locks into a cover plate bore in the plate, and which has two configured flanges that are received in the head of the screw. In another form, the cover includes integral locking flanges for the bone screws. The cover and/or locking flanges are preferably made of PEEK, plastic, alloy or titanium.
A plate may be utilized as follows. A plate is placed onto the anterior aspect of a vertebral body of the cervical spine by inserting a 4.0 mm cancellous bone screw or a 4.3 mm expansion screw through the cephalad holes and into the vertebral body. The screw or expansion screws are then inserted into the caudal holes in the plate and inserted into the vertebral bodies of the cervical spine. The locking mechanisms are then inserted in a single step over the entire plate (e.g. a cover), or two locking mechanism are inserted over each set of screws (cephalad and caudel). The locking mechanisms will snap into place.
The present invention also provides for dynamically fusing the cervical spine of a patient via various methods, particularly, but not necessarily, utilizing a cervical plate as described herein. One such method includes the opening of an access aperture in the patient to permit access to an appropriate area of the cervical spine of the patient. A vertebral disc is removed between each vertebra (level) as appropriate (e.g. one disc for a 1-L, two discs for a 2-L, etc.). Bone graft is then sized for placement into the space where the spinal disc has been removed. A dynamic 2-L cervical plate, such as any described herein, is selected for implanting onto the spine (vertebrae). The selected dynamic cervical plate is sized to allow for the best anatomical settling (motion), e.g. between 0 and 4 mm per level, of the vertebral bodies. The selected and sized dynamic plate is placed over the inserted bone graft(s) onto the vertebrae. The graft(s) is then visualized through the window(s) within the dynamic plate for proper fitment. Each section is accomplished in the same manner for proper fitment. The plate is secured onto the spine by bone screws placed through the bone screw bores within the plate components or segments. After each bone screw is attached, a locking mechanism is installed onto/over the bone screws/plate. The aperture is then closed. This method may be utilized with an N-level dynamic plate as described herein.
Another method of dynamically fusing the cervical spine includes providing a dynamic 2-L cervical plate wherein the end components of the provided 2-L dynamic cervical plate move relative to one another utilizing a tongue and groove structure that provides sliding movement relative to one another and that defines a graft window between each level, pair of bone screw bores and/or plate components.
Another method of dynamically fusing the cervical spine includes opening of an access aperture in the patient to permit access to three adjacent vertebra of the cervical spine of the patient to be fused and removing two vertebral discs between the three vertebrae. Bone graft is then sized for placement into the spaces where the vertebral discs have been removed. A two level dynamic cervical plate having a tongue and groove sliding interconnection configuration between end components and a middle component that defines a graft window between each level is provided for implanting onto the three vertebra. The provided dynamic 2-L plate is sized to allow for the best anatomical settling of the vertebral bodies and placed over the inserted bone grafts onto the three vertebra. The grafts are visualized through the graft windows of the dynamic 2-L plate for proper fitment. Thereafter, each component of the two level dynamic plate is attached in sequence for proper fitment. The 2-L plate is assembled prior to placement on the spine. Final fitment on the spine is accomplished by securing each component onto each of the three vertebra by bone screws placed through the bone screw bores of the components. After, a locking mechanism is installed onto each pair of bone screws after each bone screw is attached.
Moreover, any of the methods, such as those above, may include the providing of a 1-level to an N-level (such as a two (2) level) dynamic cervical plate, plate construct, or plate kit, wherein the end segments may be 180° interchangeable relative to a middle segment or an end (with respect to a 1-L plate). The end segments move from 0 to 8 mm or greater depending on size.
The subject invention provides several key attributes that other plates and/or plate systems do not including:
1. The curvatures placed on the window portion of the plate allow the surgeon to align the plate more accurately to the vertebral body.
2. The curvatures placed on the window portion of the plate allow the surgeon to place bone screws more accurately because the bottom of the screw holes mate with a top of the plate window. This provides a positive visual indication that the plate is situated properly.
3. The screw holes have a unique geometry allowing a simple change of screws to utilize the plate as a variable angle screw/plate construct or as a fixed angle screw plate construct.
4. The plate construct may utilize an optional bone screw locking mechanism. The optional screw locking mechanism is a single-piece, snap on cover that is preferably, but not necessarily, made of PEEK or Titanium.
5. In one form, the optional screw locking mechanism attaches into the cervical plate by one of the midline holes. The locking mechanism will cover two screws at one time and lock into the plate using a pronged shaft. Radial projections (propeller like structures) have teeth on the extended ends that mate with the corresponding screws. The teeth lock into the lobes within the screw preventing them from both turning and backing out. This mechanism, like the other, snaps into place but remains removable with the proper instrument.
6. The dynamic plate form of the present invention will allow the fused vertebral bodies to settle onto the graft centered between them. This new dynamic plate and technique will allow fused segments to move, settle or subside which will provide for more constant bone-graft-bone contact. The present dynamic plate design allows the settling to occur in an anatomical fashion, due to plate curvatures. The bodies will translate in stabilized directions on two separate planes (pure translation).
7. The present invention provides the ability to control subsidence of the plate. This is important in order to prevent the plate from migrating into the healthy adjacent disc space. Moreover the present invention aids in preventing the destruction of the host endplate or the graft from unmitigated settling that may lead to pseudarthrosis.
It should be appreciated that the above description is only exemplary of the principles of the subject invention. Therefore, other embodiments are contemplated and within the present scope.
It should be appreciated that the above description is only exemplary of the principles of the subject invention. Therefore, other embodiments are contemplated and within the present scope.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, of adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and that fall within the limits of the appended claims.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7951151||Feb 21, 2007||May 31, 2011||Life Spine, Inc.||Structure for joining and retaining multi-part orthopedic implants|
|US8206390||Nov 2, 2006||Jun 26, 2012||Warsaw Orthopedic, Inc.||Uni-directional ratcheting bone plate assembly|
|US8348949||Aug 28, 2009||Jan 8, 2013||Life Spine, Inc.||Single-sided dynamic spine plates|
|US8784458||Oct 13, 2009||Jul 22, 2014||Greatbatch Medical S.A.||Polyaxial insert for surgical screws|
|US9095387||Apr 13, 2011||Aug 4, 2015||Globus Medical, Inc.||Spine stabilization|
|International Classification||A61B17/58, A61B17/56, A61B17/70, A61B17/80|
|Cooperative Classification||A61B17/7059, A61B17/8023, A61B17/8042, A61B17/8047|
|European Classification||A61B17/70K, A61B17/80D4, A61B17/80D6, A61B17/80B|
|Feb 24, 2011||AS||Assignment|
Free format text: SECURITY AGREEMENT;ASSIGNOR:LIFE SPINE, INC.;REEL/FRAME:025846/0010
Effective date: 20110208
Owner name: SILICON VALLEY BANK, COLORADO
|Sep 21, 2011||AS||Assignment|
Owner name: LIFE SPINE, INC., ILLINOIS
Effective date: 20110920
Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:SILICON VALLEY BANK;REEL/FRAME:026944/0931