US20060195091A1 - Percutaneous spinal stabilization device and method - Google Patents

Abstract

A system for the percutaneous stabilization of adjacent vertebrae includes a plurality of elongated stabilization devices. Each stabilization device includes a radius of curvature. Each stabilization device further includes a leading end and a trailing end wherein the leading end is pointed for penetration through a vertebral body.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The invention relates to a method and apparatus for percutaneous spinal stabilization. More particularly, the invention relates to a method and apparatus whereby a series of curved stabilization devices are employed in linking adjacent vertebrae.
• 2. Description of the Prior Art
• It is often necessary to stabilize adjacent vertebrae. Various devices and methods for stabilizing the spinal column have been employed over the years. For example, plates and rods have been secured between adjacent vertebral bodies for the stabilization, or fixation, of the adjacent spinal bodies.
• As those skilled in the art will certainly appreciate, the human spine is made up of 24 small bones, called vertebrae. The vertebrae protect and support the spinal cord. They also bear the majority of the weight put upon your spine. Vertebrae, like all bones, have an outer shell called cortical bone that is hard and strong. The inside is made of a soft, spongy type of bone, called cancerous bone.
• The vertebral body is the large, round portion of bone. Each vertebra is attached to a bony ring. When the vertebrae are stacked one on top of the other, the rings create a hollow tube for the spinal cord to pass through. Each vertebra is held to the others by groups of ligaments. There are also tendons that fasten muscles to the vertebrae.
• The bony ring attached to the vertebral body consists of several parts. The laminae extend from the body to cover the spinal canal, which is the hole in the center of the vertebrae. The spinous process is the bony portion opposite the body of the vertebra. There are two transverse processes (little bony bumps), where the back muscles attach to the vertebrae. The pedicle is a bony projection that connects to both sides of the lamina.
• Although a variety of techniques for stabilizing adjacent vertebrae have been developed, many of these techniques involve highly invasive procedures. As recent developments within the surgical area have shown, minimally invasive surgical techniques are particularly desirable. These minimally invasive surgical techniques are well suited for application to procedures affecting the spine.
• The development of percutaneous, minimally invasive spinal procedures has yielded major improvements in reducing recovery time and postoperative pain. These procedures require minimal, if any, muscle dissection and may be performed under local anesthetic. As a result, minimal tissue disruption is encountered.
• With the foregoing in mind, a need continues for improvements in minimally invasive, percutaneous spinal stabilization techniques and apparatuses. The present invention provides such an improvement in percutaneous spinal stabilization.
SUMMARY OF THE INVENTION
• It is, therefore, an object of the present invention to provide a system for the percutaneous stabilization of adjacent vertebrae. The system includes a plurality of elongated stabilization devices. Each stabilization device includes a radius of curvature. Each stabilization device further includes a leading end and a trailing end wherein the leading end is pointed for penetration through a vertebral body.
• It is also an object of the present invention to provide a system including at least four stabilization devices.
• It is another object of the present invention to provide a system wherein each of the stabilization devices is made of a shape memory or super elastic material.
• It is a further object of the present invention to provide a system including an introducer needle shaped and dimensioned for penetration within the pedicles of vertebrae, wherein the introducer needle includes a lumen sized for the passage of the elongated stabilization devices therethrough.
• It is still another object of the present invention to provide a system an introducer rod selectively secured to each of the stabilization devices at a respective trailing end thereof.
• It is yet another object of the present invention to provide a system wherein threading respectively formed along the trailing end of each of the stabilization devices and the introducer rod releasably secures the stabilization devices to the introducer rod.
• It is also an object of the present invention to provide a system wherein each of the stabilization devices includes barbs adjacent the trailing end for fixation with the vertebral body.
• It is also an object of the present invention to provide a method for the percutaneous stabilization of adjacent vertebral bodies. The method is achieved by inserting an elongated stabilization device within the vertebrae such that it extends between adjacent vertebral bodies to securely stabilize the adjacent vertebral bodies.
• Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view showing the introducer needles inserted within the vertebral bodies.
• FIG. 2 is a perspective view showing the stabilization devices inserted within the vertebral bodies.
• FIG. 3 is a perspective view of the introducer needle and steering tube assembly.
• FIG. 4 is a perspective view of a stabilization device in accordance with the present invention.
• FIG. 5 is a side view of a stabilization device in accordance with the present invention.
• FIG. 6 is an exploded view of the steering tube assembly.
• FIG. 7 is a perspective view of the steering tube assembly.
• FIG. 8 is a perspective view of the loading tube.
• FIG. 9 is a perspective view of the steering tube assembly with the loading tube mounted over the stabilization device.
• FIG. 10 is an alternate embodiment showing the utilization of a half circle configuration stabilization device.
• FIG. 11 is a perspective view of a stabilization device in accordance with an alternate embodiment.
• FIG. 12 is an exploded view of the components making up the stabilization device shown inFIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENT
• The detailed embodiment of the present invention is disclosed herein. It should be understood, however, that the disclosed embodiment is merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limited, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention.
• With reference to the various figures, astabilization device10 and method for percutaneous spinal stabilization is disclosed. Generally, thestabilization device10 is used in the stabilization of adjacentvertebral bodies12,14 and is inserted along the patient's posterior. The pedicles of thevertebral bodies12,14 to be stabilized are accessed with anintroducer needle16 positioned just beyond the posterior cortex of thevertebral bodies12,14 as shown inFIG. 1. As those skilled in the art will appreciate, it is contemplated pedicular access can also be achieved with a drill (hand or power) if needed.
• Briefly, and as discussed below in greater detail, theintroducer needle16, in conjunction with itsinner stylet18, are first inserted into the pedicles of thevertebral bodies12,14 to be stabilized. They are advanced just beyond the posterior cortex of thevertebral bodies12,14. Once properly positioned, theinner stylet18 of theintroducer needle16 is removed and a curved shape memory or super-elastic coring cannula (not shown) may be used to pre-drill a pilot channel for thestabilization devices10,10′. The coring cannula is removed, and thestabilization device10,10′ is positioned proximal to theintroducer rod22.
• Thestabilization device10 is then advanced through theintroducer needle16 and into thevertebral bodies12,14 by passing it between adjacentvertebral bodies12,14 through thedisc space20 separating the adjacentvertebral bodies12,14. Once thefirst stabilization device10 is positioned within and between thevertebral bodies12,14, asecond stabilization device10′ is advanced from the uppervertebral body12 to the lowervertebral body14 forming a crisscross or curved “X” (seeFIG. 2). In accordance with a preferred embodiment, the procedure is repeated on the contralateral side, producing a total of fourstabilization devices10,10′ used at each level to be stabilized.
• Once the position of thestabilization devices10,10′ is satisfactory,introducer rods22 utilized in positioning thestabilization devices10,10′ are removed and PMMA (polymethylmethacrylate) or other bone filer or bioadhesive (example cyanoacrylate)24 is inserted to aide in the fixation of the leading ends26 and trailing ends28 of thestabilization devices10,10′.
• More particularly, and with reference toFIG. 3, the spinal stabilization system in accordance with the present invention employs a plurality ofelongated stabilization devices10,10′, anintroducer needle16 shaped and dimensioned for penetration within the pedicles of avertebral body12,14 and asteering tube assembly29, including anintroducer rod22, selectively secured to thevarious stabilization devices10,10′.
• With regard to thestabilization devices10,10′, only afirst stabilization device10 is described herein as those skilled in the art will appreciate that the other stabilization devices used in accordance with the present method are substantially identical. Thestabilization devices10,10′ are preferably made of solid, tubular or porous Nitinol, or other similar shape memory or superelastic materials. As a result, and as will be discussed below in greater detail, thestabilization devices10,10′ are substantially straight as it extends within theintroducer needle16 and only takes its desired curved configuration upon exiting theintroducer needle16 and entering the predeterminedvertebral bodies12,14.
• Referring toFIGS. 4 and 5, theelongated stabilization device10 includes aleading end26 and a trailingend28. The leadingend26 is preferably configured with asharp tip30 such as a pencil, trocar or bevel point to facilitate passage through thevertebral bodies12,14 andbarbs32 to enhance secure positioning within thevertebral bodies12,14. Several ridges, orbarbs34, are also placed along the trailingend28 to enhance secure positioning of thestabilization device10 within thevertebral bodies12,14. Thebarbs32,34 at the respective leadingend26 and trailingend28 of thestabilization device10 are formed to face in opposite directions, ensuring secure placement of thestabilization devices10,10′ within thevertebral bodies12,14. Alternatively, and as shown inFIGS. 4 and 5, holes35 could be placed on the leading and trailing ends26,28 of thestabilization devices10,10′ to aid bony ingrowth or fixation with polymethylmethacrylate (PMMA), a bone filler or bioadhesive (example cyanoacrylate).
• As briefly discussed above, thestabilization devices10,10′ has a predetermined curved shape determined so as to provide the greatest contact between the adjacentvertebral bodies12,14. Theelongated stabilization devices10,10′ can come in variable lengths from 1 cm to 10 cm, predetermined by patient anatomy. The radius of curvature of the deployedstabilization devices10,10′ can vary from 0.5 cm to 10 cm, more preferably, 3 cm to 6 cm, and the arc of the radius can encompass 10° to 240°, more preferably, 60° to 110°. While these parameters are disclosed in accordance with a preferred embodiment of the present invention, those skilled in the art will appreciate that variations are certainly possible without departing from the spirit of the present invention. For example, and with reference toFIG. 10, thestabilization device10,10′ may be formed in a C-shape or a complete semicircle.
• It is contemplated the stabilization device might have a flexible point or articulation in a central region thereof to allow slight flexion within thedisc space20. Thestabilization device10 may also be formed in various lengths as will be determined by those skilled in the art.
• As discussed above, the percutaneous spinal stabilization system further includes anintroducer rod22. Referring toFIGS. 3, 6,7 and9, theintroducer rod22 includes afirst end36 having ahandle38 and asecond end40. Thehandle38 is formed withmarkings41 providing users with orientation information when thestabilization device10 is hidden from view during the installation procedure discussed below.
• Theintroducer rod22 includes adriver rod46 that selectively extends through alumen48 in theintroducer rod22. Thedriver rod46 includes a threadedend42 shaped and dimensioned for engagement with a threadedcavity44 formed within the trailingend28 of thestabilization device10. Although the introducer rod is disclosed as having a threaded cavity in accordance with a preferred embodiment of the present invention, the male and female components may be switched without departing from the spirit of the present invention.
• Alignment of thestabilization devices10,10′ with theintroducer rod22 is further enhanced by the provision of keyingelements43a,43bat thesecond end40 of theintroducer rod22 and the trailingend28 of thestabilization devices10,10′. This ensures that theintroducer rod22 is timed correctly with the direction of the arc described by thestabilization devices10,10′ and allows for steering of thestabilization devices10,10′ during placement. While a threaded connection with keying elements is disclosed in accordance with a preferred embodiment of the present invention, it is contemplated other attachment structures may be employed without departing from the spirit of the present invention.
• Theshaft23 of theintroducer rod22 is preferably formed from stainless steel and thehandle38 is formed of hard steel such that it may be struck with a hammer to aid in insertion of thestabilization devices10,10′. However, those skilled in the art will appreciate that other materials may be used without departing from the spirit of the present invention.
• The trailingend28 of thestabilization devices10,10′ is keyed43band threaded44 for engagement within the threadedend42 formed at the end of thedriver rod46. As such, and as will be discussed below in greater detail, once thestabilization devices10,10′ is properly positioned between thevertebral bodies12,14, the integral threaded drivingrod46 within thelumen48 of theintroducer rod22 may be simply rotated, for example, in a counterclockwise manner, to release thestabilization device10. As such, theintroducer rod22 is provided with adirectional arrow41 on thehandle38 at itsfirst end36 to indicate the direction of curvature of thestabilization device10 and the desired rotation for deployment of thestabilization device10.
• The introducer rod22 (including the driver rod46) functions in conjunction with aloading tube50 to create the steeringtube assembly29 used during placement of thestabilization devices10,10′ in accordance a preferred embodiment of the present invention. As mentioned above, thedriver rod46 is shaped and dimensioned for placement within thelumen48 extending from thefirst end36 of theintroducer rod22 to thesecond end38 of theintroducer rod22. Thedriver rod46 is placed within thelumen48 of theintroducer rod22 during the installation procedure and is threadingly coupled to thestabilization devices10,10′. Thedriver rod46 also acts as a stabilizing structure while the steeringtube assembly29 is struck during installation. With this in mind, thedriver rod46 is formed with ahead member54 shaped and dimensioned such that it may be rotated during coupling and uncoupling, or struck by a hammer or other surgical instrument during installation in accordance with the present invention.
• Since thestabilization devices10,10′ are formed to assume an arced shaped once installed within the vertebral body, theloading tube50 is provided to assist in the loading of thestabilization devices10,10′ andintroducer rod22 within theintroducer needle16. Referring toFIGS. 3, 8 and9, theloading tube50 includes afirst end56 with a notchedhead58 shaped and dimensioned for keyed placement within arecess60 formed in theintroducer needle16. Theloading tube50 further includes alumen62 extending its entire length for passage of thestabilization devices10,10′ andintroducer rod22 therethrough during the installation process.
• With regard to theintroducer needle16, it is shaped and dimensioned for penetration within the pedicles of thevertebral bodies12,14. As with other known introducer needles, theintroducer needle16 will include acentral stylet18 that may be removed once proper positioning of theintroducer needle16 is achieved. Theintroducer needle16 includes a lumen sized for the passage of theelongated stabilization devices10,10′ and theintroducer rod22 therethrough. For example, it is contemplated that a 10 or 11gauge needle16 will be sufficient for the purposes of the present invention, although those skilled in the art will appreciate that other sizes could be used without departing from the spirit of the present invention.
• Alternatively, an introducer needle could be used to reach the cortex of the pedicle. The inner stylet would then be removed and a guide wire (k-wire) placed inside the needle lumen. The needle would then be removed, leaving the guide wire. A drill (hand or power) could then be anvanced over the wire guide. Pedicular access would then be obtained by drilling into the pedicle just beyond the posterior cortex of the vertebral body. The drill would then be removed over the wire guide and then a cannula would then be advanced over the wire guide. The cannula is for passage of the stabilization device as described.
• The steeringtube assembly29 andintroducer needle16 are assembled in the following manner for use in accordance with the present invention. Thestabilization device10 is first positioned within theloading tube50 and theintroducer rod22 is then passed within thelumen62 of theloading tube50 and engaged with thestabilization device10 by threading the drivingrod46 and thestabilization device10 together. Because of the keyingelements43a,43bon the trailingend28 of thestabilization device10 and thesecond end40 of theintroducer rod22, as well as the marking41 on thehandle38 of theintroducer rod22, orientation of thestabilization device10 is always known despite the fact it is hidden within theloading tube50.
• Thereafter, thehead58 of theloading tube50 is installed within therecess60 of theintroducer needle16. The assembly is now ready for use in the placement of astabilization device10 within thevertebral body12,14 of a patient.
• It is contemplated that the loading of the present assembly may be varied through the removal of the loading tube prior to completion of the assembly. It is believed this technique would slightly reduce the length of the assembly. More particularly, the stabilization device is positioned within the loading tube as discussed above. However, the stabilization device/loading tube is then mounted upon the introducer needle and the stabilization device is moved within the needle. Thereafter, the loading tube is removed, the introducer rod is secured to the stabilization device (while it sits within the introducer needle) and the driver rod is placed within the lumen of the introducer rod.
• As briefly discussed above, percutaneous spinal stabilization in accordance with the present invention is achieved by first inserting the introducer needles16 within the pedicles of thevertebral bodies12,14 to a position just beyond the posterior cortex of thevertebral bodies12,14 into which thestabilization devices10,10′ are to be positioned. Positioning as discussed below is monitored through the use of real time imaging technology. It is preferred that all fourintroducer needles16 are inserted initially, followed by placement of thestabilization devices10,10′. However, the specific approach adopted by individual practitioners may vary depending upon specific preferences.
• As discussed above, the following procedure is preferably repeated four times, creating a criss-cross pattern between adjacentverterbral bodies12,14. However, the procedure will only be discussed herein once, as those skilled in the art will understand how to create the appropriate criss-crossing arrangement by insertingstabilization devices10,10′ into both the upper and lowervertebral bodies12,14.
• Once theintroducer needle16 is properly positioned, theinner stylet18 of theintroducer needle16 is removed and a curved shape memory or super elastic coring cannula (not shown) may be used to pre-drill a pilot channel for thestabilization device10. The coring cannula is then removed, and thestabilization device10 is positioned distal to theintroducer rod22. Alternatively, thestabilization device10 may be used independently without the curved coring needle described herein.
• Thestabilization device10, with theintroducer rod22 secured and keyed to its trailingend28, is forced through theintroducer needle16 under the control of theintroducer rod22, into the uppervertebral body12, through the uppervertebral body12 and into the lowervertebral body14 such that approximately half of thestabilization device10 is positioned within the uppervertebral body12 and half is positioned within the lowervertebral body14. As discussed above, this procedure is repeated for each of thestabilization devices10,10′ to be deployed with twostabilization devices10,10′ entering the lowervertebral body14 and extending toward the uppervertebral body12 and twostabilization devices10 entering the uppervertebral body12 and extending toward the lowervertebral body14. More particularly, and with reference toFIG. 2, thestabilization devices10,10′ are positioned within thevertebral bodies12,14 such that they criss-cross when view in both a lateral view and a frontal view.
• Once thestabilization device10 is properly positioned, theintroducer rod22 is removed by simply twisting the integral threadeddriver rod46 positioned within thelumen48 of theintroducer rod22 in a counterclockwise direction to thereby unscrew and uncouple thesecond end40 of theintroducer rod22 from the trailingend28 of thestabilization device10. Thereafter, adhesive or bone filler is forced within the aperture created by, or through the center of thestabilization device10. For example, polymethylmethacrylate (PMMA) is injected into thevertebral bodies12,14 through theintroducer needle16 to aid in fixation. Small holes can be placed in the leading and trailing ends of the stabilization device to further facilitate bony ingrowth. Alternatively, the stabilization device may be made of a porous material and coated with an osteoconductive substance (for example bone morphogenetic protein), or a combination thereof Also, instead of injecting PMMA to facilitate device fixation, a synthetic cortical bone void filler, such as beta tricalciumphosphate or bioadhesive (example cyanoacrylate) may also be employed.
• In accordance with an alternate embodiment of the present invention, it may be desirable to have the stabilization device pre-loaded into a cartridge. The pedicles of the vertebral bodies to be stabilized are accessed with a 9 or 10 gauge introducer needle. A curved Nitinol introducer needle is advanced through the first needle from the vertebral body below across the disc space to be stabilized to the vertebral body above. Likewise, a second curved needle is advanced from the vertebral body above to the vertebral body below, forming a cross. The stabilization device (preloaded into an introducer cartridge) is inserted into the curved needle. A push rod is used to advance the stabilization device to the end of the curved needle. The device is now positioned across the disc space to be stabilized. Holding the push rod stationary, the curved needle is retracted uncovering the stabilization device. The device is now positioned across the disc space. Likewise, a second device is deployed in a similar fashion through the other curved needle forming a cross. The procedure is repeated on the contralateral hemivertebrae. A total of four devices can be used. PMMA, bone filler or bioadhesive (example cyanoacrylate) can then be inserted to aid in device fixation. It is possible that adequate stabilization can be achieved by inserting only two devices, one from each hemi-vertebrae.
• Another method of spinal stabilization with the present stabilization device involves insertion of a 9 or 10 gauge needle into the pedicles (four) of the vertebral bodies to be stabilized. A curved needle is then advanced to the disc space to be stabilized. A second curved needle is advanced to the disc space from the vertebral body above. The two curved needle tips are advanced until they meet in the disc space. The stabilization device (preloaded into an introducer cartridge) is inserted into one of the curved needles. A push rod is used to advance the stabilization device through the first needle and into the second needle across the disc space. The device will resemble a half circle or C-shape across the disc space. Holding the push rod stationary, one curved needle is retracted uncovering one half of the stabilization device. The push rod is then inserted into the other curved needle. Holding the push rod stationary, the second curved needle is retracted uncovering the second half of the device. The device is now positioned across the disc space. The procedure is repeated on the contralateral side. Likewise, PMMA, bone filler bioadhesive can be inserted to aid in fixation.
• In accordance with yet a further embodiment of the present invention, and with reference toFIGS. 11 and 12, acoaxial stabilization device110 design is disclosed. Thecoaxial stabilization device110 includes anouter stabilization member112. Theouter stabilization member112 is sized and dimensioned for insertion in the manner described above with reference to the prior embodiment.
• Thecoaxial stabilization device110 includes a secondary, or inner,stabilization member114 timed and inserted coaxially inside theouter stabilization member112. Thesecondary stabilization member114 is pushed within theouter stabilization member112 after it is positioned within the vertebral bodies and is installed in a manner substantially as described above with reference to the first embodiment.
• Once in place, reverse-facingbarbs116,118 formed on thesecondary stabilization member114 lock into theclearance holes120,122 in the proximal and distal ends of theouter stabilization member112, thereby preventing movement in both directions, as could happen if the vertebra were moved in compression or tension.
• The coaxial arrangement would double the wall thickness of the stabilization device, allowing for easier introduction of the device due to the two thinner walls, and subsequently reduce bending force. If flexibility is desired in the implant, this could be varied by using different wall thicknesses to fine tune the bending force.
• While the preferred embodiments have been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention.

Claims (21)

1. A system for the percutaneous stabilization of adjacent vertebrae, comprising:

a plurality of elongated stabilization devices;

each stabilization device includes a radius of curvature, each stabilization device further including a leading end and a trailing end wherein the leading end is pointed for penetration through a vertebral body.

2. The system according toclaim 1, wherein the system includes at least four stabilization devices.

3. The system according toclaim 1, wherein each of the stabilization devices is made of a shape memory or super elastic material.

4. The system according toclaim 1, further including an introducer needle shaped and dimensioned for penetration within the pedicles of vertebrae, wherein the introducer needle includes a lumen sized for the passage of the elongated stabilization devices therethrough.

5. The system according toclaim 4, further including an introducer rod selectively secured to each of the stabilization devices at a respective trailing end thereof, the introducer rod is used to force the stabilization devices through the vertebral bodies during insertion of the stabilization devices within the vertebral bodies.

6. The system according toclaim 5, wherein threading respectively formed along the trailing end of each of the stabilization devices and the introducer rod releasably secures the stabilization devices to the introducer rod.

7. The system according toclaim 1, wherein each of the stabilization devices includes barbs adjacent the trailing end for fixation with the vertebral body.

8. The system according toclaim 1, further including an introducer rod selectively secured to each of the stabilization devices at a respective trailing end thereof, the introducer rod is used to force the stabilization devices through the vertebral bodies during insertion of the stabilization devices within the vertebral bodies.

9. The system according toclaim 8, wherein threading respectively formed along the trailing end of each of the stabilization devices and the introducer rod releasably secures the stabilization devices to the introducer rod.

10. A method for the percutaneous stabilization of adjacent vertebral bodies, comprising:

inserting an elongated stabilization device within the vertebrae such that it extends between adjacent vertebral bodies to securely stabilize the adjacent vertebral bodies.

11. The method according toclaim 10, wherein the stabilization device is substantially cylindrical in cross section with a radius of curvature, and the stabilization device includes a leading end and a trailing end wherein the leading end is pointed for penetration through a vertebral body.

12. The method according toclaim 10, further including the step of inserting a plurality of elongated stabilization devices within the vertebrae such that they extend between adjacent vertebral bodies to securely stabilize the adjacent vertebral bodies.

13. The method according toclaim 12, wherein at least four stabilization devices are inserted.

14. The method according toclaim 10, wherein the stabilization device is made of a shape memory material.

15. The method according toclaim 10, further including the step of inserting an introducer needle within one of the adjacent vertebral bodies prior to insertion of the stabilization device, wherein the stabilization device is inserted through the introducer needle.

16. The method according toclaim 15, wherein the step of inserting includes releasably securing the stabilization device to an introducer rod and using the introducer rod to force the stabilization device through the adjacent vertebral bodies during insertion.

17. The method according toclaim 16, wherein threading respectively formed along the trailing end of the stabilization device and the introducer rod releasably secures the stabilization device to the introducer rod.

18. The method according toclaim 10, wherein the stabilization device includes barbs adjacent the trailing end for fixation with the vertebral body.

19. The method according toclaim 10, wherein the step of inserting includes securing the stabilization device to an introducer rod and using the introducer rod to force the stabilization device through the adjacent vertebral bodies during insertion.

20. The method according toclaim 19, wherein the introducer rod is releasably secured to the trailing end of the stabilization device.

21. The method according toclaim 20, wherein threading respectively formed along the trailing end of the stabilization device and the introducer rod releasably secures the stabilization device to the introducer rod.

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