US20060036261A1 - Insertion guide for a spinal implant - Google Patents

Abstract

A spinal implant insertion guide is disclosed. The insertion guide includes at least one channel suitable for receiving and facilitating movement of a spinal implant into an intervertebral space between two vertebrae and a portion suitable for insertion into the intervertebral space. In embodiments for use with spinal implant having multiple pieces, the pieces of the spinal implant remain in cooperation throughout movement. The guide may further include a plunger for facilitating the movement of the spinal implant.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• his application claims the benefit of the filing date of U.S. Provisional Patent Application No. 60/601,461 filed Aug. 13, 2004, the disclosure of which is hereby incorporated herein by reference
BACKGROUND OF THE INVENTION
• The present invention relates generally to apparatus and methods for use in spinal disc arthroplasty, and more particularly, to apparatus and methods for use in the insertion of disc replacement implants into the intervertebral space between two adjacent vertebrae.
• Whether due to injury, wear, or genetic defect, intervertebral disc degeneration is a problem suffered by many people. Typically, this spinal problem has been addressed by removing the disc material and replacing it with a spinal implant which fuses two adjacent vertebrae. Recently, however, there has been a significant amount of activity directed toward filling the intervertebral space with spinal implants that permit relatively natural movement of the two adjacent vertebrae with respect to each other. In other words, it is now becoming relatively common to utilize disc replacement implants which act like normal functioning spinal discs.
• During a standard spinal disc arthroplasty, the damaged spinal disc material is removed and the two adjacent vertebrae are distracted to a distance sufficient to receive the spinal implant. Regardless of the type or size of implant utilized during spinal disc arthroplasty, one of the most difficult steps involves implanting the spinal implant in the intervertebral space. Often, a surgeon will struggle with properly inserting the spinal implant between two vertebrae. This is because inserting the implant requires moving the implant into the intervertebral space, while simultaneously distracting or spreading the two vertebrae. Heretofore, instruments utilized in this process have been rather cumbersome and difficult to manipulate, especially when implanting the aforementioned disc replacement implants.
• For the foregoing reasons, there exists a need for an insertion guide for and a method of inserting a disc replacement implant into an intervertebral space.
SUMMARY OF THE INVENTION
• In one preferred embodiment of the present invention, a spinal implant insertion guide includes at least one channel adapted for receiving and facilitating movement of at least two cooperating pieces of a spinal implant and a portion suitable for insertion into the intervertebral space between two vertebrae. The portion suitable for insertion into the intervertebral space is a projecting portion having a sloped height and a rounded end. This shape allows the portion to be easily inserted between the two vertebrae. After the projecting portion has been inserted between two vertebrae, the channel desirably extends into the intervertebral space, thereby allowing the implant to be implanted therein. The two pieces of the spinal implant may remain in cooperation with each other throughout movement in the at least one channel, however, slight movement of the pieces may be possible. There may be several embodiments relating to this aspect of the invention. For example, the channel may further include slots for positioning the pieces of the spinal implant in cooperation with one another. The insertion guide according to this embodiment of the present invention may also include a plunger for facilitating the movement of the spinal implant pieces. The portion suitable for insertion into the intervertebral space between two vertebrae may cause distraction of the two vertebrae upon insertion. In certain embodiments, the insertion guide may be packaged with the spinal implant preloaded therein. In other preferred embodiments, the spinal implant may be loaded into the insertion guide immediately before a surgical procedure. The insertion guide may be constructed of a broad range of biocompatible materials such as stainless steel. In certain preferred embodiments, the insertion guide is made of a polymeric material, thereby making it relatively inexpensive to construct and disposable.
• Another preferred embodiment of the present invention includes a spinal implant insertion guide having at least one channel suitable for receiving and facilitating movement of a spinal implant, the at least one channel extending into an intervertebral space between two vertebrae. The insertion guide desirably includes a portion suitable for insertion into the intervertebral space, and a plunger for facilitating the movement of the spinal implant into the intervertebral space. This embodiment of the present invention may be configured to allow for the insertion of a spinal implant of unitary construction.
• Yet another preferred embodiment of the present invention is a disposable spinal implant insertion guide including at least one channel suitable for receiving and facilitating movement of a spinal implant, the at least one channel extending into an intervertebral space between two vertebra, and a portion suitable for insertion into the intervertebral space. The disposable insertion guide according to this embodiment may be constructed from a broad range of materials including stainless steel or other metals. In one preferred embodiment, the insertion guide is made of a polymeric material.
• Another preferred embodiment of the present invention provides a spinal insertion guide kit. The kit desirably includes at least two insertion guides, the at least two insertion guides being of different dimensions. Each guide includes at least one channel suitable for receiving and facilitating movement of at least two cooperating pieces of a spinal implant, the at least one channel extending into an intervertebral space between two vertebrae. Each guide also includes a portion suitable for insertion into the intervertebral space. The pieces of the spinal implant remain in cooperation throughout movement in the at least one channel. In certain embodiments according to this aspect of the present invention, the at least two insertion guides have different sized projecting portions suitable for insertion into the intervertebral space. In other embodiments according to this aspect of the present invention, the at least two insertion guides have different sized channels.
• In another preferred embodiment of the present invention, a method of inserting an at least two piece spinal implant includes providing an insertion guide having at least one channel, inserting at least a portion of the insertion guide into an intervertebral space between two vertebrae, placing the at least two piece spinal implant into the at least one channel such that the spinal implant pieces cooperate with one another, and moving the spinal implant pieces together into the intervertebral space. The implant pieces preferably remain in cooperation throughout their insertion. The method according to this aspect of the present invention may also include distracting the vertebrae and/or preparing the vertebrae for receiving the spinal implant. The method may also include stabilizing the guide with respect to the vertebrae, with or without an external support. Finally, this method may also include providing and utilizing a plunger for facilitating the movement of the implant.
• Yet another preferred embodiment of the present invention includes a method of implanting a spinal implant of unitary construction. The method according to this embodiment includes providing an insertion guide having at least one channel, inserting at least a portion of the insertion guide into an intervertebral space between two vertebrae, placing the spinal implant into the at least one channel, and moving the spinal implant into the intervertebral space by manipulating a plunger in the at least one channel.
• Yet another embodiment of the present invention includes a method of implanting a multi-piece spinal implant. The method according to this embodiment includes providing an insertion guide having at least one channel, inserting at least a portion of the guide into an intervertebral space between two vertebrae, and moving the pieces through the at least one channel into the intervertebral space. During this movement of the pieces into the intervertebral space, the pieces are capable of slight movement with respect to each other.
• A preferred method in accordance with the present invention may be a method of inserting a multi-piece spinal implant. This method may include the steps of providing an insertion guide defined by a channel having at least two slots therein, inserting at least a portion of the insertion guide into an intervertebral space between two vertebrae, placing each piece of the multi-piece spinal implant into the channel such that each implant piece engages at least one slot and the spinal implant pieces cooperate with on another, and moving the spinal implant pieces into the intervertebral space while maintaining the spinal implant pieces in cooperation with one another and allowing slight movement of the spinal implant pieces with respect to each other.
• A preferred multi-piece spinal implant insertion guide in accordance with the present invention may include a channel including at least two slots, each of the at least two slots capable of engaging a different portion of a multi-piece spinal implant, and at least one extension suitable for insertion into an intervertebral space. Preferably, the guide should be configured so that the pieces of the multi-piece spinal implant remain in cooperation throughout movement in the channel and are capable of slight movement with respect to each other.
• Yet another preferred multi-piece spinal implant insertion guide in accordance with the present invention may include a channel including at least two slots, each of the at least two slots capable of engaging a different portion of a multi-piece spinal implant, at least one extension suitable for insertion into an intervertebral space, and a plunger for facilitating movement of the spinal implant pieces. Preferably, the guide should be configured so that the pieces of the multi-piece spinal implant remain in cooperation throughout movement in the channel and are capable of slight movement with respect to each other.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present invention will be better understood on reading the following detailed description of non-limiting embodiments thereof, and on examining the accompanying drawings, in which:
• FIG. 1 is a top perspective view of a spinal implant insertion guide according to an embodiment of the present invention.
• FIG. 2 is a side cross sectional view of the spinal implant insertion guide shown inFIG. 1.
• FIG. 3 is a top plan view of the spinal implant insertion guide shown inFIG. 1.
• FIG. 4 is a top perspective view of a spinal implant insertion guide according to another embodiment of the present invention.
• FIG. 5 is a side cross sectional view of the spinal implant insertion guide shown inFIG. 4.
• FIG. 6 is a front plan view of a spinal implant insertion guide according to another embodiment of the present invention.
DETAILED DESCRIPTION
• In describing the preferred embodiments of the subject matter illustrated and to be described with respect to the drawings, specific terminology will be used for the sake of clarity. However, the invention is not intended to be limited to the specific terminology and includes all technical equivalence which operates in a similar manner to accomplish a similar purpose.
• Referring to the drawings, wherein like reference numerals represent like elements, there is shown inFIGS. 1-3, in accordance with an embodiment of the present invention, an insertion guide for a spinal implant designated generally byreference numeral10. In the preferred embodiment shown in the figures,insertion guide10 is designed to be used in aiding in the insertion of aspinal implant7. As best shown inFIG. 1,insertion guide10 is of unitary construction having atop side12, abottom side14, aproximal end16, and adistal end18.Guide10 also includes achannel20 adapted to receive aspinal implant7, andintervertebral extensions22 and24 that project from thedistal end18 ofinsertion guide10.Guide10 is adapted for being inserted between twoadjacent vertebrae3 and5 during a spinal surgical procedure. Theintervertebral extensions22 and24 are preferably inserted into theintervertebral space2 for distracting theadjacent vertebrae3 and5, as shown inFIG. 2. However, it is noted thatextensions22 and24 can be sized so that their insertion does not distractvertebrae3 and5.
• Channel20 is an opening withinguide10 configured and dimensioned to receive and allow sliding movement ofspinal implant7 from theproximal end16 toward thedistal end18. As best shown inFIG. 2, the sliding movement allows insertion ofimplant7 intointervertebral space2 betweenvertebrae3 and5.Channel20 is defined by firstlateral wall26, secondlateral wall28, anddistal end wall30.Distal end wall30 preferably connectsfirst wall26 tosecond wall28. In the particular preferred embodiment shown inFIG. 1, theguide10 includes achannel20 capable of receiving a multi-piecespinal implant7 having two pieces8aand8b.In order to facilitate this reception,channel20 further includes four slots,32aand32bwhich are cut intofirst wall26 and32cand32dwhich are cut intosecond wall28. The slots are preferably cut into the inner faces of the first and secondlateral walls26 and28. These slots engage and allow for two portions of each piece8aand8bto ride throughchannel20, while remaining in cooperation with one another. In certain embodiments, a second distal end wall may be located directly belowposterior wall30 to provide even more stability between the first and second lateral walls. Preferably,implant7 is sized so that its height is less than the distance betweenposterior wall30 and any second posterior end wall located directly below wall30 (not shown). Thus, a clearance between the implant and these walls exists, andimplant7 can be moved throughchannel20.
• Intervertebral extensions22 and24 are preferably narrower in height than the height of the firstlateral wall26 and secondlateral wall28, respectively.Extensions22 and24 extend beyond the portion of the first and second walls at whichdistal end wall30 intersects them. As best shown inFIGS. 1 and 2,extensions22 and24 preferably increase in height in a direction from thedistal end18 toward theproximal end16. In the embodiment shown, the distal ends ofextensions22,24 are rounded in order to facilitate easy insertion into the space between the two vertebrae, and are spread to cause distraction ofvertebrae3 and5 upon insertion. However, the distal ends ofextensions22 and24 may be of any shape. As mentioned above, in certain preferred embodiments,extensions22,24 may sized to distract or properly fit between the twovertebrae3 and5. A result of the latter construction is that the two vertebrae are not distracted upon insertion of theextensions22,24 therebetween. This may be useful in a surgery in which a separate distraction tool is utilized.
• Preferably, as shown inFIG. 3,extensions22,24 each have a width which creates a space between the two extensions large enough to allow passage ofimplant7 therethrough. In other words, in the preferred embodiment, implant pieces8aand8bare preferably allowed to ride alongslots32a,32b,32cand32dandpast extensions22,24 during insertion betweenvertebrae3 and5. Preferably, once implant pieces8aand8bpass through the slots, the forced cooperation of the pieces is retained by way ofvertebrae3 and5. Thus,extensions22,24 are not required to contact any portion ofimplant7. However, it is contemplated to provide slots, likeslots32a,32b,32cand32d,which continue along the length ofextensions22,24. Therefore, these slots would guide and retain implant pieces8aand8bin cooperation with one another throughout the entire passage throughguide10.
• As best shown inFIGS. 2 and 3, guide10 may be fitted with a plunger ordriver40.Plunger40 includes a channelsized end42, anelongate shaft44, and ahandle46. Channelsized end42, as shown inFIGS. 2 and 3, is sized to fit snuggly withinchannel20, while also being capable of contactingimplant7.Handle46 is an easily operable handle, which allows a surgeon to facilitate movement ofplunger40.Handle46 preferably has a wide variety of designs, including ergonomic designs and thumb operable designs.Elongate shaft44 creates a connection betweenend42 and handle46. In certain preferred embodiments theelongate shaft44 is dimensioned in length to allow for the full implantation ofimplant7 withinintervertebral space2, without the introduction ofhandle46 intochannel20.
• Another aspect of the present invention is a method for inserting a spinal implant into an intervertebral space. The method according to this aspect of the invention includes the step of providing an insertion guide as discussed above. It is noted that the guide can be in accordance with any of the various embodiments disclosed herein, as the particular design may not cause the standard method step to significantly deviate. For the sake of ease in explaining the method,insertion guide10 will be utilized below.
• Initially,intervertebral extensions22 and24 ofguide10 are inserted betweenvertebrae3 and5. Depending upon the dimensions ofextensions22 and24, the insertion of such may cause distraction ofvertebrae3 and5 from one another. A surgeon may simply utilize his own bare hands to pushextensions22 and24 intointervertebral space2, or other tools such as hammers and mallets may be utilized, as for example in situations wherevertebrae3 and5 are distracted during insertion of the guide. This distraction is accomplished by utilizing the rounded ends and/or sloped nature of the extensions to slowly insertguide10 betweenvertebrae3 and5 to simultaneously distract the same. However, as mentioned above,extensions22 and24 need not be sized for such distraction and can be dimensioned to allow for a snug fit betweenvertebrae3 and5 without causing significant distraction.
• In certain embodiments,vertebrae3 and5 may be prepared to receive an implant prior to the insertion ofextensions22 and24. Depending upon the type of implant, this may include the removal of the deteriorated or damaged disc material, and/or the shaping of the bone to better receive the implant. For example, when utilizing implants that include keels, spikes or other protrusions, it may be necessary to cut channels or otherwise remove bone fromvertebrae3 and5 to allow for proper implantation of the implant. It is also contemplated that onceguide10 is inserted betweenvertebrae3 and5, it may be supported by means other than the snug connection between the vertebrae. For example, an external support may be utilized to supportguide10 outside of the vertebrae. However, it is noted that often times, the fit ofextensions22,24 betweenvertebrae3 and5 and the pressure exerted thereby isenough hold guide10 in place.
• Subsequent to guide10 being inserted intointervertebral space2,spinal implant7 is preferably then placed intochannel20. It is also possible to pre-seatspinal implant7 withinchannel20, prior to guide10 being inserted between the vertebrae. The latter design may be important in providing prepackaged, easily autoclaved or otherwise sterilized individual units. Regardless of whenimplant7 is placed intochannel20, the inserted position ofguide10 allows for the implant to be moved intointervertebral space2. For embodiments in which a spinal implant having two or more pieces is being implanted, it should be noted that the multiple pieces are placed into the insertion guide so that they cooperate with one another (e.g.—their articulating surfaces mate), and remain in this cooperation throughout their movement into the intervertebral space. It should also be noted that while pieces8aand8bofimplant7 are in cooperation with each other, these pieces may be capable of slightly moving with respect to each other. This slight motion may aid in the insertion ofimplant7. For example, the slight motion may allow a surgeon to better manipulate pieces8aand8bto overcome hindrances caused by the adjacent vertebrae.
• In a preferred embodiment, guide10 is configured and dimensioned so as to allow for the above noted slight movement of pieces8aand8bofimplant7 with respect to each other. More particularly,channel20 andslots32a,32b,32cand32dmay be configured and dimensioned to allow for enough clearance so that slight canting of implant pieces8aand8b,or slight translation of the two implant pieces may be accomplished. In certain embodiments, the slots may simply be larger than the portions of pieces8aand8bbeing inserted therein. This would create a clearance that may allow for the two implant pieces to be moved with respect to one another. It is noted that any movement of pieces8aand8bwith respect to each other should be such that the articulation surfaces of the two pieces remain in cooperation with each other. For example, the movement may be slight movement that is merely a portion of that which is allowed by the aforementioned articulation surfaces of pieces8aand8b.As mentioned above, allowing such slight movement may aid a surgeon during the implantation ofimplant7. However, in certain cases, such movement may not be necessary.
• The movement ofspinal implant7 intointervertebral space2 is accomplished by applying a force to push the implant throughchannel20 of theguide10 and into the space. This force may be provided by utilizing aplunger40, as described above. In these embodiments,plunger40 is inserted intochannel20 subsequent to the placing ofimplant7 therein. Once again, in the prepackaged units mentioned above,plunger40 may be packaged in an inserted position. Operation ofhandle46 allows a surgeon to more easily pushimplant7 intointervertebral space2. In certain preferred embodiments, the sizing ofplunger40 should be such that the channelsized end42 can fully situateimplant7 intointervertebral space2, withouthandle46 enteringchannel20. Onceimplant7 is moved intointervertebral space2, guide10 may be removed from its position betweenvertebrae3 and5. Thereafter,implant7 may be seated inintervertebral space2 in accordance with standard practices relating to the particular implant. For example, the individual pieces8aand8bofspinal implant7 may both be cemented to adjacent vertebrae. However, it is also contemplated that various implants may have many different manners of being seated within an intervertebral space. For example, certain spinal implants may include flanges for facilitating connection with a bone screw or keels/spikes for implantation into the vertebral endplates. It is noted that in certain embodiments, end42 ofplunger40 may be operatively connected toimplant7, or in other embodiments, may merely be capable of abutting the implant.
• In certain embodiments,extensions22 and24 are sized so that insertion betweenvertebrae3 and5 causes distraction. However, this is not necessary. In embodiments in which the extensions are sized to facilitate distraction, the sloped configuration ofextensions22 and24 allows for the increase of distraction of the vertebrae with respect to the further insertion of the extensions between the vertebrae. Upon implantation ofimplant7, guide10 may be removed. Similarly, guide10 may be removed prior to the fixation ofimplant7 tovertebrae3 and5, respectively. In embodiments in whichextensions22 and24 are sized and configured to cause distraction ofvertebrae3 and5, removal ofguide10 may cause the vertebrae to return to their non-distracted position, thereby clamping and/orseating implant7 in place. For implants that utilize keels or spikes, this vertebrae movement may cause the projections to become seated in their respective vertebrae.
• FIGS. 4 and 5 depict aninsertion guide110 used for insertingsingle piece implant107 in accordance with other preferred embodiments of the present invention. As shown in these figures, guide110 is similar in design to guide10, the only deviation in design residing in the inclusion of only two slots132aand132b,as opposed to the four slots ofguide10. As in the design ofguide10, slots132aand132bare cut into firstlateral wall126 and secondlateral wall128. Also as inguide10, guide110 may be utilized in conjunction with a properly sized and dimensionedplunger40, in a manner like that disclosed above.
• It is also contemplated that while the designs of both guide10 and guide110 include at least two slots for receiving and holding the spinal implant, designs are envisioned that do not require slots. For example, as shown inFIG. 6, a guide210 includes anenclosed channel220 for receiving a spinal implant.Walls226,228,230, and232 definechannel220, and rid guide210 of the need for any slots. Rather than the substantially square cross section ofguide220, other guides may include cross sections that better suit the cross section of particular spinal implants. For example, guides having a rectangular cross section may be employed. Similarly, the exterior surface of certain embodiments of the present invention may be shaped to allow for the easier insertion of the guide through an incision. For example, the exterior surface of a guide may be rounded. Once again, guide210, likeguides10 and100, can be used in conjunction with a properly sized and dimensionedplunger40, in a manner like that disclosed above. Finally, it is noted that any of the above guides and/or each of their respective elements and components may be constructed of any type of material suitable for insertion into the human body. For example, it is contemplated to construct any of the guides and/or plungers of metals such as stainless steel. In addition, these devices may be constructed of polymers.
• Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (20)

1. A method of inserting a multi-piece spinal implant comprising:

providing an insertion guide defined by a channel having at least two slots therein;

inserting at least a portion of the insertion guide into an intervertebral space between two vertebrae;

placing each piece of the multi-piece spinal implant into the channel such that each implant piece engages at least one slot and the spinal implant pieces cooperate with one another; and

moving the spinal implant pieces into the intervertebral space while maintaining the spinal implant pieces in cooperation with one another and allowing slight canting of the spinal implant pieces with respect to each other.

2. The method according toclaim 1, wherein said insertion guide further includes at least one extension for insertion into the intervertebral space.

3. The method according toclaim 2, wherein said inserting step includes distracting the vertebrae.

4. The method according toclaim 1, further including the step of preparing each vertebrae for receiving the spinal implant.

5. The method according toclaim 1, further including the step of stabilizing the insertion guide with respect to the vertebrae.

6. The method according toclaim 5, wherein the stabilization is achieved by supporting the insertion guide outside of the vertebrae.

7. The method according toclaim 1, wherein the stabilization is achieved by supporting the insertion guide within the vertebrae.

8. The method according toclaim 1, wherein the insertion guide further includes a plunger.

9. The method according toclaim 8, wherein said moving step includes manipulating the plunger to move the spinal implant pieces.

10. The method according toclaim 9, wherein the plunger is inserted into the channel subsequent to the spinal implant pieces.

11. The method according toclaim 1, wherein said placing step is performed prior to said inserting step.

12. A multi-piece spinal implant insertion guide comprising:

a channel including at least two slots lying in a transverse plane, each of the at least two slots capable of engaging a different portion of a multi-piece spinal implant; and

at least one extension suitable for insertion into an intervertebral space,

wherein said guide is configured so that the pieces of the multi-piece spinal implant remain in cooperation throughout movement in said channel and are capable of slight movement with respect to each other.

13. The multi-piece spinal implant insertion guide ofclaim 12, further comprising a plunger for facilitating movement of the spinal implant pieces.

14. The multi-piece spinal implant insertion guide ofclaim 12, wherein said at least one extension is capable of causing distraction of adjacent vertebrae.

15. The multi-piece spinal implant insertion guide ofclaim 12, wherein the cooperation of the pieces of the multi-piece spinal implant includes the mating of at least two articulating surfaces.

16. The multi-piece spinal implant insertion guide ofclaim 12, further comprising a multi-piece implant disposed within said channel.

17. The spinal implant insertion guide ofclaim 12, wherein said insertion guide is packaged with a spinal implant.

18. The spinal implant insertion guide ofclaim 17, wherein said insertion guide and the spinal implant are sterilized.

19. The spinal implant insertion guide ofclaim 12, wherein said insertion guide is constructed of a polymeric material.

20. A multi-piece spinal implant insertion guide comprising:

a channel including at least two slots lying in a transverse plane, each of the at least two slots capable of engaging a different portion of a multi-piece spinal implant;

at least one extension suitable for insertion into an intervertebral space; and,

a plunger for facilitating movement of the spinal implant pieces,

wherein said guide is configured so that the pieces of the multi-piece spinal implant remain in cooperation throughout movement in said channel and are capable of slight movement with respect to each other.

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