Vertebral stabilization assembly and method with rigid and semi-rigid members
A vertebral stabilization assembly for stabilizing vertebrae is provided. The vertebral stabilization assembly includes a first and a second vertebral screw, a first and second connecting screw, and a connecting member. The first and second vertebral screws each have a shaft provided with a threaded portion operable for threading engagement of the first and second vertebral screws with a first and second vertebra, respectively. Each shaft also has an engaging portion. The first and second connecting screws each have a first end adapted to be received by the engaging portions of the first and second pedicle screws, respectively. The connecting member has a first end connected to the first connecting screw and a second end connected to the second connecting screw for stabilization of the first and second vertebra. A method for stabilizing a lower vertebra and an upper vertebra from an anterior side of the vertebrae using a vertebral stabilization assembly is also provided.
This patent application is a continuation-in-part of U.S. continuation patent application Ser. No. 10/823,418, filed Apr. 12, 2004, which is a continuation of U.S. patent application Ser. No. 10/109,172, filed Mar. 28, 2002, which claims priority to U.S. Provisional Patent Application No. 60/327,118, filed Oct. 3, 2001, U.S. Provisional Patent Application No. 60/350,259, filed Nov. 2, 2001, U.S. Provisional Patent Application No. 60/331,857, filed Nov. 20, 2001, and U.S. Provisional Patent Application No. 60/353,691, filed Jan. 31, 2002, each of which is hereby incorporated by reference herein in its entirety.
TECHNICAL FIELD OF THE INVENTIONThe present invention relates generally to a spinal stabilization and more specifically, but not by way of limitation, to a vertebral stabilization assembly and method for stabilizing vertebra.
BACKGROUND OF THE INVENTIONThe human spine frequently requires surgery to repair deformities or injuries. Spinal problems may be caused by a trauma to the spine received during an accident, excessive strain or stress on the spine from physical activities, a sedentary lifestyle and poor posture that may place abnormal pressure on the spine, disease or a variety of other reasons. Spinal fusion is a common surgery intended to alleviate pain caused by these spinal deformities or injuries.
The spinal fusion procedure generally includes removing the disk, packing bone graft between the vertebrae and placing a spinal implant, such as screws attached to a plate, rod or cage, to fuse elements of the spine together. Once the disk is removed and the bone graft is placed between the vertebrae, the bone graft will fuse to the vertebrae over a period of several months following the surgery.
The purpose of the plate is to stabilize the vertebrae until the bone graft has become fused to the vertebrae. The plate is positioned to extend between at least two vertebrae. The plate is attached to screws anchored in each of the adjacent vertebrae, thus immobilizing the desired portion of the spine. The plate is anchored to the screws either on the front, anterior, or back, posterior, sides of the vertebrae.
Another procedure includes utilization of an artificial disc that is arranged and designed to emulate a natural disc. Such “artificial techniques” can be used in lieu of spinal fusion.
While spinal fusion and artificial disc replacement are potential solutions to spine associated problems, these techniques do not come without certain disadvantages, which should be quickly recognized by those skilled in the art.
SUMMARY OF THE INVENTIONFrom the foregoing it may be appreciated that a need has arisen for a vertebral stabilization assembly and method. In accordance with the present invention, a vertebral stabilization assembly and method are provided that substantially eliminate one or more of the disadvantages and problems outlined above.
According to an aspect of the present invention, a vertebral stabilization assembly for stabilizing vertebrae is provided which comprises a first vertebral screw, a first connecting screw, a second vertebral screw, a second connecting screw, and a connecting member. The first vertebral screw has a shaft provided with a threaded portion operable for threading engagement of the first vertebral screw with a vertebral body of a first vertebra. The shaft of the first vertebral screw has an engaging portion. The first connecting screw has a first end and a second end. The first end of the first connecting screw is adapted to be received by the engaging portion of the first vertebral screw. The second vertebral screw has a shaft provided with a threaded portion operable for threading engagement of the second vertebral screw with a vertebral body of a second vertebra. The shaft of the second vertebral screw has an engaging portion. The second connecting screw has a first end and a second end. The first end of the second connecting screw is adapted to be received by the engaging portion of the second vertebral screw. The connecting member has a first end, a second end, a first location and a second location. The connecting member is configured to allow a limited degree of movement between the vertebrae, is operable to couple with the first connecting screw positionable in the first vertebra at the first location of the connecting member, and is operable to couple with the second connecting screw positionable in the second vertebra at the second location of the connecting member for stabilization of the first vertebra and the second vertebra.
According to another aspect of the present invention, a method for stabilizing a lower vertebra and an upper vertebra from an anterior side of the vertebrae using a vertebral stabilization assembly is provided which comprises inserting a first vertebral screw, which includes a shaft provided with a threaded portion operable to threadingly engage the lower vertebra, into the lower vertebra such that a portion of the threaded portion of the shaft engages a vertebral body portion of the lower vertebra, the shaft of the first vertebral screw having an engaging portion; inserting a first end of the first connecting screw into the engaging portion of the first vertebral screw; inserting a second vertebral screw, which includes a shaft provided with a threaded portion operable to threadingly engage the upper vertebra, into the upper vertebra such that a portion of the threaded portion of the shaft engages a vertebral body portion of the upper vertebra, the shaft of the second vertebral screw having an engaging portion; inserting a first end of the second connecting screw into the engaging portion of the second vertebral screw; positioning a connecting member on an anterior side of the upper vertebra and the lower vertebra; coupling a connecting member to a second end of the first connecting screw and to a second end of the second connecting screw; and allowing a limited degree of movement between the upper and lower vertebra via an arrangement of the connecting member.
The various embodiments and implementations of the present invention provide a profusion of potential technical advantages and benefits. A technical advantage of the present invention may include the capability to completely eliminate the need for disc replacement and/or spinal fusion by stabilizing vertebrae.
Another technical advantage of the present invention may include the capability to facilitate the effectiveness of disc replacement and/or spinal fusion by stabilizing vertebrae.
Yet another technical advantage of the present invention may include the capability to alleviate potential damage to spinal discs by stabilizing vertebrae.
Yet another technical advantage of the present invention may include the capability to flexibly stabilize vertebrae from an anterior side of the vertebrae.
Other technical advantages may be readily apparent to one skilled in the art after review of following figures and description, associated herewith.
BRIEF DESCRIPTION OF THE DRAWINGSFor a more complete understanding of the present invention and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts, in which:
It should be understood at the outset that although an exemplary implementation of the present invention is illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present invention should in no way be limited to the exemplary implementations, drawings, and techniques illustrated below, including the exemplary design and implementations illustrated and described herein. Additionally, the drawings contained herein are not necessarily drawn to scale.
The present invention is not intended to be limited to applications in a specific region of the spine, and may, in fact, be utilized equally well with the cervical, thoracic, lumbar and sacrum vertebrae of the spine. However, for purposes of explanation and brevity, discussion will be limited to the lumbar vertebrae region of the spine. Procedurally, anterior, or entry from the stomach region of the patient, lumbar vertebra surgery provides the surgeon with optimum access to the entire intervertebral disk. Posterior, or entry from the back of the patient, surgery is less preferred since access to the disk is restricted.
The vertebral stabilization assembly 10 in
The second pedicle screw 14 is substantially similar to the first pedicle screw 12 in that the second pedicle screw 14 includes a shaft 30 substantially similar to the shaft 16 of the first pedicle screw 12. The shafts 16 and 30 of the first and second pedicle screws 12 and 14, respectively, are substantially cylindrical members. The shaft 30 of the second pedicle screw 14 is similarly provided with a threaded portion 32 similar to the threaded portion 18 provided on the shaft 16 of the first pedicle screw 12. The threaded portion 32 of the shaft 30 is operable for threading engagement of the second pedicle screw 14 with a second vertebra 34. The shaft 30 of the first pedicle screw 14 is provided with an engaging portion 36.
The shafts 16 and 30 of the first and second pedicle screws 12 and 14 are of appropriate length to sufficiently anchor the first and second pedicle screws 12 and 14 in the first and second vertebra 20 and 34, respectively. The threaded portions 18 and 32 of the first and second pedicle screws 12 and 14 may have threads similar to those on ordinary screws which extend a distance from the shafts 16 and 30 sufficient to promote optimum anchoring of the first and second pedicle screws 12 and 14 within the first and second vertebra 20 and 34, respectively. The first and second pedicle screws 12 and 14 are constructed of a rigid material such as, but not limited to, steel, metal, or metal alloys, polymeric material, or a variety of other substantially rigid materials adapted to promote rigid engagement of the first and second pedicle screws 12 and 14 to the first and second vertebra 20 and 34, respectively.
The vertebral stabilization assembly 10 of
The vertebral stabilization assembly 10 of
The vertebral stabilization assembly 10 of
In some configurations, the connecting member 50 may be constructed from a variety of rigid materials such as, but not limited to, titanium, steel, metal, or other metal alloys, rigid polymeric material, or other rigid materials suitable for rigid stabilization between two vertebrae (e.g., the first and second vertebra 20 and 34 by connection to the first and second connecting screws 40 and 42) or three vertebrae (e.g., the first, second, and third vertebra 20, 34, and 834).
In other configurations, the connecting member 50 can be configured for flexible stabilization, allowing a limited degree of movement between vertebrae (e.g., between the first and second vertebra 20 and 34 or between the first, second, and third vertebra 20, 34, and 834)—viewed alternatively as being configured to limit the degree of movement between the vertebrae. As an example of flexible stabilization, intended for illustrative purposes only, any of the connecting members 50 described herein as well as other connecting members that will become apparent to one of ordinary skill in the art can made of flexible material—such flexible materials including, but not limited to a variety of flexible plastics, metals, and the like. The flexible material of the connecting member allows a limited amount of movement between the vertebrae—e.g., to emulate natural movement, but to limit movement that may damage portions of a natural disc, artificial disc, or fused disc configuration. As another example of flexible stabilization, (e.g., in configurations in which the connecting member 50 spans two or more vertebrae), the connecting member 50 may include a cable 905 stretched between two or more vertebrae (e.g., the first, second, and third vertebra 20, 34, and 834). Such a cable 905 may, for example, allow a maximum amount of tension (the tension in the cable 905 precipitated by movement of the vertebrae in relation to one another). As still another example of flexible stabilization, (e.g., in configurations in which the connecting member 50 spans two or more vertebrae), the connecting member 50 may include one or more hinged or pivoting elements (not shown) disposed between one or more pairs of the one or more vertebrae (e.g., between the first, second, and third vertebra 20, 34, and 834). Each hinged or pivoting element (not shown) may be adjustable to allow movement between vertebrae ranging from no movement (e.g., to prevent further damage possibly due to failed disc replacement procedure) to a some higher level of movement (e.g., to emulate natural movement, but to limit movement that may damage portions of a natural disc, artificial disc, or fused disc configuration). Adjustment of each hinged or pivoting element (not shown) may be performed percutaneously or through the skin requiring only a small incision, and avoiding the disadvantages associated with large, invasive posterior procedures which require significant interference and dissection of adjacent muscles. Other configurations should become apparent to one of ordinary skill in the art, including not only configurations that are now known, but also those that will be later developed.
In flexible stabilization configurations, several benefits will become apparent to one of ordinary skill in the art. One such benefit includes a reduction of weight on a disc (either natural or artificially constructed), which in turn can reduce the likelihood of disc degeneration. In some flexible stabilization configurations, the flexible connecting member 50 can be utilized in lieu of disc replacement and/or vertebral fusion procedures. In yet other configurations, the flexible connecting member 50 can be utilized in conjunction with disc replacement and/or vertebral fusion procedures. In setting forth the above examples, it should be understood that the examples described above are intended as only exemplifying some of many configurations that can be utilized. Other configurations along with the associated benefits therewith will become apparent one of ordinary skill in the art after review of the specification. For example, multiple connecting members 50 can be placed between vertebra. As an example, a connecting member can be placed on both anterior sides of the vertebra; or, one or more connecting members 50 can be placed on the anterior side vertebra and one or more connecting members can be placed on the posterior side of the vertebra.
Additionally shown in
In other configurations (not shown) the heads 60 and 62 of the first and second pedicle screws 12 and 14 may be configured unlike the head of the standard screw and instead be unitarily formed, for example, rectangularly from the shaft 16 and 30 for mating engagement with a unique tool adapted to receive the rectangularly-formed shaft.
It will be appreciated that a variety of constructions and configurations of the heads 60 and 62 of the first and second pedicle screws 12 and 14 will readily suggest themselves to one of ordinary skill in the art and may be provided in numerous configurations such that a tool may be attached temporarily to the heads 60 and 62 for imparting a rotation upon the first and second pedicle screws 12 and 14.
In the present illustration, the engaging portion 22 of the shaft 16 can be more easily seen as adapted to receive the first end 44 of the first connecting screw 40. The engaging portion 22 of the shaft 16 is a threaded opening formed in the shaft 16 of the first pedicle screw 12 and adapted to receive a threaded first end 44 of the first connecting screw 40. In this manner the first connecting screw 40 threadingly engages the engaging portion 22 to achieve a rigid locking connection between the first pedicle screw 12 and the first connecting screw 40.
In other configurations (not shown) the engaging portion 22 may be a tension connection opening in the shaft 16 for receiving and engaging in a tensioning fashion the first end 44 of the first connecting screw 40. In yet other configurations (not shown) the engaging portion 22 may be a locking assembly adapted to receive the first end 44 of the first connecting screw 40 and lock into place upon insertion. The locking engagement of the engaging portion 22 may be accomplished in a variety of manners including a keyed design of the engaging portion 22 such that when the first end 44 of the first connecting screw 40 is inserted into the engaging portion 22 it is locked into place upon rotation of the first connecting screw 40.
Yet in other configurations (not shown), the engaging portion 22 may be a modification to the outer surface of the shaft 16 of the first pedicle screw 12 such that the first end 44 of the first connecting screw 40 may be adapted to receive the engaging portion 22 of the shaft 16 within an opening in the first end 44 of the first connecting screw 40. In this manner the locking or tensioning mechanism may be retained by the first end 44 of the first connecting screw 40 for engaging the first connecting screw 40 with the first pedicle screw 12.
A number of other connections including spring, ball, or other tensioning connections, as well as, threading, locking, and other mating connections for engaging the first end 44 of the first connecting screw 40 with the engaging portion 22 of the shaft 16 of the first pedicle screw 12 will readily suggest themselves to one of ordinary skill in the art and are within the spirit and scope of the present invention. It will be appreciated that the engaging portion 36 of the shaft 30 of the second pedicle screw 14 may be constructed substantially identical to the engaging portion 22 of the shaft 16 of the first pedicle screw 12. For purposes of brevity no further discussion of the engaging portion 36 is deemed necessary to enable one of ordinary skill in the art on the variety of means for engaging the first and second connecting screw 40 and 42 with the first and second pedicle screw 12 and 14 in light of the discussion regarding the engaging portion 22 of the first pedicle screw 12.
The first connecting screw 40 is constructed substantially similar to the second connecting screw 42 and for this reason, only the first connecting screw 40 will be discussed and described for purposes of brevity. The first connecting screw 40 is connected to the connecting member 50 near a second end 64 of the first connecting screw 40. The connection of the first connecting screw 40 to the connecting member 50 may be accomplished in a variety of manners such as, as shown in the present illustration, by providing a threaded portion on the second end 64 of the first connecting screw 40.
In this manner, a coupling 70 may be coupled to the second end 64 of the first connecting screw 40 and attached using a standard nut threadingly engaged with the threaded portion 66 of the second end 64 of the first connecting screw 40. The coupling portion 70 may be provided with an offset member 74 adapted to receive a rod 76. The offset member 74 thereby tensions the portion of the rod 76 extending through the offset member 74 for rigid engagement of the rod 76 to the coupling 70.
The tensioning engagement of the rod 76 by the offset member 74 may be accomplished by providing a screw (not shown), or other tension-imparting structure, threaded through the offset member 74 and into contact with the portion of the rod 76 extending through the offset member 74. The use of the coupling 70 and the rod 76 is a simple and useful design, according to one aspect, of the connecting member 50 for stabilization of the first and second vertebrae 20 and 34 via the first and second connecting screws 40 and 42.
It should be appreciated, however, that the connecting member 50 may be accomplished utilizing a variety of other structural connections to the first and second connecting screws 40 and 42. For example, in one configuration (not shown), an opening may extend through the second end 64 of the first connecting screw 40. The opening of sufficient diameter to receive the rod 76 there through the opening in the second end 64 of the connecting screw 40. A tensioning connection, such as a screw or a nut may be utilized to tensionally engage the rod to the second end 64 of the first connecting screw 40. Other configurations of the coupling 70 may be utilized for these purposes and are within the spirit and scope of the present invention and will readily suggest themselves to one of ordinary skill in the art.
The bracket 90 is a substantially flat plate provided with the first and second openings extending therethrough for receiving the first and second connecting screws 40 and 42. In this manner, the second end 64 of the first connecting screw 40 may be caused to extend through the first opening 92 of the bracket 90. The nut or other similar device 72 can then be threadingly engaged about the threaded portion 66 and caused to engage the bracket 90 to the second end 64 of the first connecting screw 40. Similarly, the second opening 94 may be adapted to receive the second connecting screw 42 for attachment thereto.
The symmetrical nature of the vertebral stabilization assembly 10 lends itself to stabilization of a plurality of vertebrae. For example, the first and second pedicle screws 12 and 14 are substantially similar, as are the first and second connecting screws 40 and 42. Thus, it is contemplated that two or more vertebrae can be stabilized. For example, in other configurations (e.g., similar to
One advantage of the vertebral stabilization assembly 10 of the present invention is that the connecting member 50, whether utilizing the bracket 90 or the coupling 70 with the rod 76 (see
Another advantage of the present invention is that the first pedicle screw 12 engaging the first connecting screw 40 provides for maximum stabilization in the vertebra 20. As such, secure attachment to the vertebra 20 is optimized and greater stabilization can be accomplished by the innovations provided according to the present invention. Furthermore, the first pedicle screw 12 so connected to the first connecting screw 40 has the effect of inhibiting the first pedicle screw 12 from backing out of the vertebra 20, as well as preventing the first connecting screw 40 from backing out of the vertebra 20 as well.
The bracket 90 is useful where the first connecting screw 40 and the second connecting screw 42 are not substantially aligned vertically. Thus, the notches 99 are provided so that the first and second connecting screws 40 and 42 may be connected to the bracket 90 at various notches 99 on the first and second ends 97 and 98, respectively, of the bracket 90 while maintaining the bracket 90 disposed in a substantially vertical manner while the first and second connecting screws 40 and 42 may not be substantially vertical with respect to one another.
The coupling portion 100 is adapted to connect a guide member (which will be discussed in greater detail with reference to
As previously mentioned, the engaging portion 22 of shaft 16 is operable to receive the first connecting screw 40. The engaging portion 22 in one configuration may be provided as an opening on the shaft 16 extending completely through the shaft 16. The purpose of the engaging portion 22, as previously discussed, is to provide stabilizing engagement of the first connecting screw 40 with the first pedicle screw 12. As previously discussed, this engagement may be provided in a variety of manners, such as, but not limited to, a locking engagement, a threading engagement, a tensioning or other coupling connection of the first connecting screw 40 with the first pedicle screw 12 about the engaging portion 22.
Referring also to
Posterior placement through the pedicle 120 of the vertebra 118 provides optimum stability and anchoring of the first pedicle screw 12 by threading engagement through the most rigid portions of the vertebra 118. Significant problems arise when the first pedicle screw 12 is not well anchored within the vertebra 118 and alternate placement is then required. Furthermore, stabile anchoring is critical to reduce the likelihood that the first pedicle screw 12 will back out, or come backwards out of its placement, of the vertebra 118. The illustrated placement of first pedicle screw 12 advantageously overcomes the disadvantages associated with unstable attachment common with anterior vertebral stabilization systems.
As previously mentioned, the connecting member 50 is positionable on the anterior side 124 of the vertebra 118. Thus, the vertebral stabilization assembly 10 of the present invention achieves the advantages of anterior vertebral stabilization, since the connecting member is positioned on the anterior side 124 of the vertebra 118, while simultaneously achieving the stability associated with posterior procedures.
The first pedicle screw 12 may be placed in the vertebra 118, substantially as shown, percutaneously or through the skin requiring only a small incision, and avoiding the disadvantages associated with large, invasive posterior procedures which require significant interference and dissection of adjacent muscles.
In yet another aspect of the present invention the pedicle screw 12 may be provided with a cannulated shaft 16 such that a passageway 110 extends through the shaft 16 from the head 60 to the distal end 102 thereof the shaft 16. By utilizing the passageway 110 extending through the shaft 16 of the first pedicle screw 12, a tool (not shown) such as a tap or drill bit may be placed through this cannulated portion of the shaft 16 such that the tool or drill bit enters near the head 60 of the first pedicle screw 12. The tool is then extended through the passageway 110 towards the distal end 102.
The tool may then be utilized to drill through to the anterior side 124 of the vertebra 118 for location of the distal end 102 of the pedicle screw 12 from the anterior side 124 of the vertebra 118. Since only a small distance must be drilled, there is minimal risk to soft tissue or blood vessels. Furthermore, once the tool penetrates the anterior side 124 of the vertebra 118, the surgeon should be able to sense the reduced resistance and friction on the tool. Furthermore, the tool may be provided with stops or a drill bit may be cannulated to prevent extension of the drill beyond the anterior side 124 of the vertebra 118.
In the present configuration right side 126 placement of the first pedicle screw 12 is preferable to avoid soft tissue injuries to the patient's anterior caused by penetration of the drill bit through the anterior side 124 of the vertebra 118 via the passageway 110 of the first pedicle screw 12. Anatomically, fragile soft tissue and blood vessels are positioned adjacent the right side 126 on the anterior side 124 of the vertebra 118. By using any number of surgical retraction techniques, these blood vessels may be held toward the right side 126 of the anterior side 124 of the vertebra 118. As such, the right side 126 placement of the first pedicle screw 12 represents the most efficient, as well as safest, placement for utilizing the first pedicle screw 12 in accordance with the present invention. In some instances, however, left side 128 placement of the first pedicle screw 12 in the vertebra 118 will be necessary. Left side 128 placement of the first pedicle screw 12 will be discussed in greater detail with reference to
The guide member 150 may be constructed from a variety of materials such as, but not limited to, titanium, steel, metal or other metal alloys, a substantially rigid polymeric material, aluminum or other substantially rigid materials sufficient for these purposes. The coupling portion 152 is provided with a first end 160 and a second end 162. The first end 160 of the coupling portion 152 may be threaded for threading engagement to the coupling portion 100 of the first pedicle screw 12.
It should be appreciated, however, that a number of connecting methods may be utilized to accomplish the connection of the first end 160 of the coupling portion 152 to the coupling portion 100 of the first pedicle screw 12. For example, the first end 160 may be shaped so as to be substantially rectangular or other geometric shape about a portion of the first end 160 such that a similarly geometrically configured opening in the coupling portion 100 in the distal end 102 of the first pedicle screw 12 is adapted to receive the first end 160 of the coupling portion 152. Other locking or tensioning engagements of the first end 160 of the coupling portion 152 to the coupling portion 100 of the first pedicle screw 12, as well as a variety of other methods for achieving this attachment, will readily suggest themselves to one of ordinary skill in the art and are within the spirit and scope of the present invention.
The second end 162 of the coupling portion 152 is attached to the offset member 154. The attachment of the coupling portion 152 to the offset member 154 may be of a connecting, such as threading or tensioning or locking connection, or may be accomplished by a welded or bonded connection of the second end 162 of the coupling portion 152 to the offset member 154. Although welding or bonding engagements of various components of the vertebral stabilization assembly 10 of the present invention are preferable, it should be appreciated that bonding or other gluing or tacking materials may be used for this connection and satisfactory for these purposes.
The offset member 154 is shown as a substantially arcuate member extending from the second end 162 of the coupling portion 152 to the alignment member 156. However, in other configurations, one of which is described hereinafter, the alignment member 156 may be comprised of a number of foldable or extendable or hinging segments to promote use within the confinements of the patient's anterior. While the offset member 154 is shown as a substantially rigid arcuate member, a number of other configurations of the offset member 154, such as a substantially straight member, or a stair-stepped member, as well as the offset member 154 being comprised of several connectable or extendable members are contemplated according to other aspects (not shown) of the present invention.
A number of configurations of the offset member 154, such as formation of a portion of the offset member 154 unitarily with the coupling portion 152 and formation of a remaining portion of the offset member 154 unitarily formed with the alignment member 156 may also be utilized for these purposes. Although the offset member 154 is shown in the preferred aspect, a variety of configurations of the offset member 154 will readily suggest themselves to one of ordinary skill in the art for positioning the alignment member 156 relative to a portion of the first pedicle screw 12 when the coupling portion 152 of the guide member 150 is connected to the coupling portion 100 of the first pedicle screw 12 and are within the spirit and scope of the present invention and will not be discussed in further detail for the purposes of brevity.
The alignment member 156 is rigidly connected to the offset member 154 by welding or bonding or other similar means. However, attachment of the alignment member 156 to the offset member 154 may be accomplished by a threading, locking or tensioning engagement and is satisfactory for these purposes. The alignment member 156 is a substantially tubular member having a first end 164 and a second end 166 and an opening 168 extending through from the first end 164 to the second end 166.
The alignment member 156 is provided such that the opening 168 is of a sufficient diameter to receive a drilling device 170, shown in phantom, through the opening 168 for alignment with the engaging portion 22 on the shaft 16 of the first pedicle screw 12. The drilling device 170 may be a bit of a drill or other devices operative to drill an opening into vertebral bone. Thus, the alignment member 156 receives the drilling device 170 that drills an opening properly aligned for attachment of the first connecting screw 40 to the first pedicle screw 12. Thus, the guide member 150 is advantageously provided for creating an opening aligned with the engaging portion 22 of the first pedicle screw 12.
It should be appreciated that while the alignment member 156 of the present aspect is illustrated as a substantially tubular member having an opening 168, other configurations of the alignment member 156 may not be a completely tubular, and instead, be provided as a guide or positioning member for alignment of the first connecting screw 40 with the engaging portion 22 of the first pedicle screw 12.
Numerous configurations for aligning the first connecting screw 40 with the engaging portion 22 of the first pedicle screw 12 may be utilized for these purposes and will readily suggest themselves to one of ordinary skill in the art and are within the spirit and scope of the present invention and will not be discussed further for purposes of brevity.
At this point, the guide member 150 may be positioned such that the coupling portion 152 extends through the drilled opening on the anterior side 124 of the vertebra 118. The coupling portion 152 of the guide member 150 is then connected to the coupling portion 100 of the first pedicle screw 12. An innovative aspect of the pedicle screw 12 is that the coupling portion 100 on the distal end 102 of the first pedicle screw 12 is associated with the engaging portion 22 on the shaft 16 of the first pedicle screw 12. The association of the coupling portion 100 and engaging portion 22 of the first pedicle screw 12 is a significant advantage of the first pedicle screw 12 according to the present invention. That is, this association allows for the guide member 150 to be configured relative to this association. Thus, the coupling portion 152 of the guide member 150, when coupled to the first pedicle screw 12, aligns the alignment member 156 with the engaging portion 22 on the shaft 16 of the first pedicle screw 12. Utilizing the guide member 150, several methods exist for aligning and securing the first connecting screw 40 to the first pedicle screw 12. It may be preferable to utilize the drilling device 170 to create an opening in the anterior side 124 of the vertebra 118. Thereafter, the guide member 150 may be removed and the first connecting screw 40 disposed through the opening drilled in the vertebra 118 and connected to the first pedicle screw 12.
In some instances, it may be beneficial for the alignment member 156 to be adapted to receive the first connecting screw 40 positioned to extend through the opening 168 of the alignment member 156. The first connecting screw 40 may then be drilled or threaded directly into the left side 128 of the anterior side 124 of the vertebra 118. Whether an opening is first drilled or the first connecting screw 40 is directly drilled into the vertebra 118, the unique configuration of the guide member 150 relative to the first pedicle screw 12 insures that the first connecting screw 40 will be properly aligned so as to locate the engaging portion 22 of the first pedicle screw 12 for engaging attachment thereto.
Thus, another advantage of the guide member 150 of the present invention is that the coupling portion 152 of the guide member 150 is operable to couple with the coupling portion 100 of the first pedicle screw 12 such that the offset member 154 extends in a predetermined direction relative to the coupling of the coupling portion 152 of the guide member 150 to the coupling portion 100 of the first pedicle screw 12. The offset member 154 of the guide member 150 is positionable relative to the coupling of the coupling portion 152 of the guide member 150 with the coupling portion 100 of the first pedicle screw 12.
It will be appreciated that the connection of the coupling portion 152 of the guide member 150 to the coupling portion 100 of the first pedicle screw 12 must be a locking or fitted type connection such that the offset member 154 properly extends in the proper direction to position the alignment member 156 for alignment with the engaging portion 22 of the first pedicle screw 12. Achieving the accuracy necessary to locate the engaging portion 22 of the first pedicle screw 12, which will not be visible since the first pedicle screw 12 will be embedded within the vertebra 118, is preferably accomplished through the accurate coupling connection of the coupling portion 152 of the guide member 150 to the coupling portion 100 of the first pedicle screw 12.
It should be understood, however, that a number of other methods of locating the engaging portion 22 of the first pedicle screw 12 for alignment with the first connecting screw 40 may be utilized. For example, providing indicia or markings on the head 60 of the first pedicle screw 12 indicating the relative position of the engaging portion 22 of the first pedicle screw 12. The coupling portion 152 may further include an extension (not shown) extendable through the passageway 110 of the shaft 16 of the first pedicle screw 12. The extension of the coupling portion 152 of the guide member 150 similarly provided with indicia, markings, or an alignment with the indicia provided on the head 60 of the first pedicle screw 12. In this manner, when the indicia are aligned, so is the alignment member 156 aligned with the engaging portion 22 on the first pedicle screw 12.
A variety of other methods for obtaining this positioning and alignment for connecting the first connecting screw 40 to the first pedicle screw 12 will readily suggest themselves to one of ordinary skill in the art and are within the spirit and scope of the present invention and will not be discussed for purposes of brevity.
The significant difference between the first pedicle screw 12 utilized for right side 126 placement, as opposed to left side 128 placement, is an angle 176 of the engaging portion 22 of the first pedicle screw 12 relative to an axis extending centrally through the shaft 16, such as the passageway 110 of the first pedicle screw 12. It can be seen that the angle 176 of the engaging portion 22 of the first pedicle screw 12 necessary for placement of the first connecting screw 40 about the left side 128 of the anterior side 124 of the vertebra 118 varies considerably depending upon whether the first pedicle screw 12 is connected from the left side 128 or the right side 126 of the vertebra 118. For this reason, a unique first pedicle screw 12 and guide member 150 will be constructed for the left side 128 versus right side 126 placement, such that the guide member 150, when connected to the first pedicle screw 12, properly aligns the first connecting screw 40 based upon which vertebral placement, and corresponding first pedicle screw 12 is utilized.
In this aspect the guide member 150 is shown having a substantially non-arcuate offset member 154 such that the alignment member 156 extends angularly from the offset member 154. The coupling portion 152 is shown as a substantially tubular member having a channel 180 extending through the coupling portion 152. The coupling portion 152 is provided with a recess 182 extending into the channel 180 near the first end 160 of the coupling portion 152. Furthermore, in this aspect, the first end 160 of the coupling portion 152 is adapted to matingly receive the first pedicle screw 12 near the distal end 102 thereof. As previously discussed, the first pedicle screw 12 is provided with a coupling portion 100 provided, in this aspect, as an opening in the distal end 102 of the first pedicle screw 12.
A locking screw 184 may be extended through the channel 180 from the second end 162 toward the first end 160 of the coupling portion 152. The locking screw 184 is provided with a head 186 having a larger diameter than that of a shaft 188 portion of the locking screw 184. The first end 160 of the coupling portion 152 is matingly connectable to the distal end 102 of the first pedicle screw 12. The locking screw 184 is positioned through the channel 180 until the shaft 188 portion of the locking screw 184 couples with the coupling portion 100 of the first pedicle screw 12.
A tool (not shown) having any standard screw driver or hex, octagonal-type or other connection, for example, may be extended down the channel 180 and used to connect the locking screw 184 to the coupling portion 100 of the first pedicle screw 12. The locking screw 184 may be threadingly screwed into engagement with the first pedicle screw 12 or connected in other manners which are well known and will readily suggest themselves to one of ordinary skill in the art.
In this manner, the head 186 of the locking screw 184 engages the recess 182 within the channel 180 of the coupling portion 152 thereby engaging the coupling portion 152 to the first pedicle screw 12. It will be appreciated that the locking screw 184, the coupling portion 152 and the guide member 150 may be provided with indicia or markings to indicate locking engagement and alignment with both the first pedicle screw 12 and the vertebra 118 since it is critical that the locking screw 184 couple the coupling portion 152 to the first pedicle screw 12 at a particular position relative to the vertebra 118. The indicia or markings may include cross-hair lines, a single line or mark, an arrow, or other markings indicating a rotational position desired for achieving this connection and location.
Such accurate positioning may be accomplished based on the threads of the shaft 188 of the locking screw 184 corresponding to threaded openings within the coupling portion 100 of the first pedicle screw 12. A variety of different structural attachments for obtaining this locking connection for alignment of the guide member 150 with the first pedicle screw 12 such that the alignment member 156 is substantially aligned with the engaging portion 22 on the shaft 16 of the first pedicle screw 12 may be utilized and are within the spirit and scope of the present invention and will readily suggest themselves to one of ordinary skill in the art.
In some aspects, the guide member 150 may be provided with a rotational coupling 190 such as a recess or opening in the offset member 154 of the guide member 150. The rotational coupling 190 may be adapted as an opening to receive a tool or device for obtaining leverage on the guide member 150 for rotation of the guide member 150. It will be appreciated that while the first pedicle screw 12 may be provided with indicia or other markings on the head 60 of the first pedicle screw 12 for determining the location and disposition of the engaging portion 22 of the first pedicle screw 12, a surgeon may have difficulty determining from the posterior side 122 of the vertebra 118 the optimum location for placement of the connecting screw, such as the first connecting screw 40.
Once the patient has been rotated and the guide member 150 connected to the first pedicle screw 12 on the anterior side 124 of the vertebra 118, only then will the surgeon be able to determine the preferable placement of the first connecting screw 40 relative to the body of the vertebra 118. In the event the first pedicle screw 12 is not aligned preferably for the first connecting screw 40, by use of the rotational coupling 190, such as with a tool connected thereto, the surgeon may rotate the guide member 150 and the first pedicle screw 12 rigidly connected thereto, via the locking screw 184, to obtain the optimum placement of the first connecting screw 40 into a desired point in the body of the vertebra 118. In other configurations, the guide member 150 may not include the rotational coupling 190 and, as such, this rotational alignment may be achieved by grasping and rotating the offset member 154 or other portions of the guide member 150.
Once this optimum positioning has been obtained by rotation using the rotational coupling 190 the tool coupled to the rotational coupling 190 may be removed and a drill or other tool may be utilized and aligned via the alignment member 156 for drilling an opening into the body of the vertebra 118 at the desired location. Thereafter, the locking screw 184 and a guide member 150 may be removed for connection of the first connecting screw 40 to the engaging portion 22 of the first pedicle screw 12.
It will be appreciated that the locking screw 184 may be connected in a variety of manners to the coupling portion 152 of the guide member 150 to obtain a corresponding rotation of the guide member 150 with the first pedicle screw 12 for these rotational purposes which will readily suggest themselves to one of ordinary skill in the art and are within the spirit and scope of the present invention.
The coupling portion 152 of the guide member 150, in the present aspect, is provided with a substantially rectangular opening 196 in the first end 160 of the coupling portion 152. The substantially rectangular opening 196 is sized to matingly receive the rectangular coupling portion 100 to achieve a fitted coupling there between. In this aspect, the coupling portion 100 may be provided with a threaded opening 198 on the distal end 102 of the first pedicle screw 12. In this manner, the channel 180 extending through the coupling portion 152 may be provided to guide a connecting member, such as the locking screw 184 or other engaging structure, to be threadingly received by the threaded opening 198 in the distal end 102 of the first pedicle screw 12.
In this manner, the combination of the locking mechanism, such as the locking screw 184, as well as the rectangular configuration of the coupling portion 100 of the first pedicle screw 12 with the substantially rectangular opening 196 in the first end 160 of the coupling portion 152 promotes an accurately engaged connection of the guide member 150 with the first pedicle screw 12. It should be appreciated that in other aspects the threaded opening 198 and the channel 180 may be eliminated and only the mating connection of the rectangular coupling portion 100 of the first pedicle screw 12 with the substantially rectangular opening 196 of the coupling portion 152 will be sufficient for this connection.
It will be appreciated that the configuration illustrated in the current aspect promotes a sufficient engagement of the guide member 150 to the first pedicle screw 12 to achieve engaging rotation of the first pedicle screw 12 by the guide member 150 when such adjustment for alignment purposes of the first pedicle screw 12 is desirous. It should be appreciated that while the coupling portion 100 of the current aspect is shown as substantially rectangular in configuration as is the substantially rectangular opening 196 of the coupling portion 152 of the guide member 150, a variety of other configurations such as, but not limited to, triangular configurations, will readily suggest themselves to one of ordinary skill in the art and are within the spirit and scope of the present invention, as are a variety of other coupling connections between the coupling portion 152 and the first pedicle screw 12 which may be utilized to achieve these purposes.
The method further includes, at a block 204, inserting a second pedicle screw 14 into the upper vertebra 118A through the pedicle 120 and vertebral body of the upper vertebra 118A from the posterior side 122 of the upper vertebra 118A. The second pedicle screw 14 including the shaft 30 provided with the threaded portion 32 operable to threadingly engage the upper vertebra 118A. The shaft 30 of the second pedicle screw 14 provided with an engaging portion 36 operable to receive the second connecting screw 42. The shaft 30 of the second pedicle screw 14 having a coupling portion 100, substantially similar to the coupling portion 100 of the first pedicle screw 12, to couple with the guide member 150.
The first and second pedicle screws 12 and 14 are preferably placed on the posterior side 122 on the right side 126 of the upper and lower vertebra 118A and 118B, respectively. It will be appreciated that in one aspect the present invention may be utilized preferably with respect to the lumbar vertebra, while in other configurations the present invention may be preferably utilized with regard to the thoracic vertebra.
At a block 206, the method includes locating the coupling portion 100 of the shaft 16 of the first pedicle screw 12 from the anterior side 124 of the lower vertebra 118B. As previously discussed, in one aspect the pedicle screw 12 of the present invention may be provided with the cannulated shaft 16 having the passageway 110 extending through the shaft 16 of the first pedicle screw 12. In this aspect a tool, such as a drill operable to drill through a portion of the lower vertebra 118B, may be extended through the passageway 110 of the shaft 16 of the first pedicle screw 12. The tool may be used to drill through a portion of the lower vertebra 118B such that the tool extends partially through the anterior side 124 at the lower vertebra 118B. Similarly, the second pedicle screw 14 may be similarly provided with the passageway 110 for passing the tool there through to drill through a portion of the upper vertebra 118A such that the drill extends at least partially through the anterior side 124 of the upper vertebra 118A.
At a block 208 the method includes coupling the guide member 150 to the coupling portion 100 of the shaft 16 of the first pedicle screw 12 from the anterior side 124 of the lower vertebra 118B. In one aspect the coupling of the guide member may be more readily accomplished after an opening has been drilled through to the anterior side 124 of the lower vertebra 118B. The method further includes, at a block 210, inserting the lower connecting screw, such as the first connecting screw 40, through the anterior side 124 of the lower vertebra 118B using the guide member 150. As previously discussed, the guide member is a useful tool for aligning the alignment member 156 of the guide member 150 and correspondingly the first connecting screw 40 with the engaging portion 22 of the first pedicle screw 12.
The method further provides, at a block 212, locating the coupling portion 100 of the shaft 30 of the second pedicle screw 14 from the anterior side 124 of the upper vertebra 118A. The method further provides, at a block 214, for coupling the guide member 150 to the coupling portion 100 of the shaft 30 of the second pedicle screw 16 from the anterior side 124 of the upper vertebra 118A.
At a block 216, the method includes inserting an upper connecting screw, such as the second connecting screw 42 through the anterior side 124 of the upper vertebra 118A utilizing the guide member 150 for proper alignment. The method also provides, at a block 218, for connecting the upper and lower connecting screws, such as the first and second connecting screws 40 and 42, to the connecting member 50 for stabilization of the upper and lower vertebra 118A and 118B.
As the first pedicle screw 12 is threadingly engaged into the pedicle portion of the vertebra, such as the first vertebra 20, the first threaded portion 236 will threadingly engage and retain the first pedicle screw 12 within the first vertebra 20. In the present configuration the reinforced portion 230 is not provided with threads, however, in other configurations the reinforced portion may be provided with threads similar to the plurality of threads 238 or threads extending less far from the reinforced portion 230 than the plurality of threads 238 extend from the first threaded portion 236 of the shaft 16. In one aspect, the diameter 232 of the reinforced portion 230 is about 6.5 millimeters. However, in other configurations the diameter 232 of the reinforced portion 230 may be greater or less than 6.5 millimeters as may be necessary to properly engage the shaft 16 of the first pedicle screw 12 in the first vertebra 20.
The shaft 16 of the first pedicle screw 12 is further provided with a second threaded portion 242 having a plurality of threads 244 for engaging the first vertebra 20. In the present aspect, the diameter 232 of the reinforced portion 230 is less than the diameter 246 measured from an outermost edge of the plurality of threads 244 provided on the second threaded portion 242. As the first pedicle screw 12, of the present aspect, is engaged into the first vertebra 20, the first threaded portion 236 will threadingly engage the pedicle portion and thereafter an interior vertebral body portion of the first vertebra 20. As the reinforced portion 230 of the first pedicle screw 12 follows behind the first threaded portion 236, the reinforced portion 230 may have the affect of smoothing the threading engagement within the vertebral body. For this reason, it may be advantageous to provide the plurality of threads 244 having a greater diameter 246 for providing additional threading engagement of the first pedicle screw. In other aspects (not shown) frictional engaging surface structure, such as small or low profile threads, may be provided on the reinforced portion 230 for frictionally engaging the inner vertebral body at the first vertebra 20.
In the present aspect, the diameter 246 of the plurality of threads 244 may be about 7.0 millimeters to achieve additional threading engagement of the second threaded portion 242 of the shaft 16 for stable engagement of the first pedicle screw 12 within the first vertebra 20. It will be appreciated, however, that in other aspects (not shown) the diameter 246 of the plurality of threads 244 may be of larger or smaller diameter or may be of a similar or smaller diameter than the diameter 232 of the reinforced portion 230 and be adequate for these purposes. Furthermore, in other aspects (not shown) the diameter 234 of the first threaded portion 236 of the shaft 16 may be the same or larger diameter than that of the diameter 232 of the reinforced portion 230. The reinforced portion 230 of the shaft 16 provides significant additional structural stability for connection of the first connecting screw 40 to the first pedicle screw 12 via the engaging portion 22. While the length of the reinforced portion 230 relative to the length of the entire shaft 16 of the first pedicle screw 12 is shown in relative proportion according to the present aspect, the reinforced portion 230, according to other aspects (not shown), may be of significantly greater length and diameter or having a smaller length and diameter relative to the shaft 16 of the first pedicle screw 12 and are within the spirit and scope of the present invention as disclosed and described herein.
In this view, it can be seen that a number of grooves 250 such as two or four grooves 250 may promote improved engagement by a tool of the first pedicle screw 12 near the distal end 102, however, any number of grooves 250 may be utilized and are within the spirit and scope of the present invention.
It will be appreciated that the configuration of the first pedicle screw 12 illustrated having one or more grooves 250 extending a distance along the length of the shaft 16 may also be utilized with respect to the configuration of the first and second connecting screws 40 and 42. In this manner, a tool may be utilized to connect to the second end 64 of the first connecting screw 40 for inserting the first connecting screw 40 into the engaging portion 22 of the first pedicle screw 12, as well as for removal of the first connecting screw 40 from the engaging portion 22 of the first pedicle screw 12.
From time to time it may be necessary to remove portions of the vertebral stabilization assembly 10 of the present invention from the patient and it will become necessary for the first connecting screw 40 and the first pedicle screw 12 to be configured so as to be easily removable. It will be appreciated that metal tightly connected frequently galls or becomes frozen. In this manner, configuration of the first pedicle screw 12 and the first connecting screw 40 having, for example, grooves 250 and other similar configurations, as previously discussed, and utilization of a tool adapted to engage the grooves 250 along the shaft 16 of the first pedicle screw 12, for example, will be beneficial for obtaining the necessary leverage for installation and removal purposes.
A flat surface 264 on the distal end 102 of the first pedicle screw 12 further promotes connection and engagement of a tool to the first pedicle screw 12 for purposes which will be discussed hereinafter. In this aspect, the cap 260 will be necessary to reduce or minimize any damage or aggravation caused by placement of the pedicle screw to any nerves or tissue in or about the area of the first vertebra 20, such as nerves positioned near the pedicle portion of the first vertebra 20.
The cap 260 is shown as a substantially conical member having an inner surface 266 that is provided with one or more notches 268 provided on the inner surface 266 of the cap 260. The notches 268 are configured to be tensioningly received by a recess 270 which may be provided on the shaft 16 of the first pedicle screw 12 as shown in
A connector 290 is provided on the second end 288 of the tool 280 and configured so as to receive, for example, the shaft 16 of the first pedicle screw 12 provided with one or more grooves 250 on the shaft 16. In this manner, the connector 290 is provided with mating notches 292 adapted to be received by the grooves 250 on the shaft 16 of the first pedicle screw 12.
Once positioned near the distal end 102 of the first pedicle screw 12, the mating notches 292 will receive and engage the first pedicle screw 12 so that the tool 280, when rotated by the individual, will have the affect of rotating the first pedicle screw 12, or, as previously discussed, for stabilizing and retaining the first pedicle screw 12 while removing or installing the connecting screws, such as the first connecting screw 40. As previously discussed, it may be necessary to utilize the tool 280 to stabilize the first pedicle screw 12, particularly when attempting to remove the rigid connection of the first connecting screw 40.
During the removal of the vertebral stabilization assembly 10, the first connecting screw 40 will likely be rigidly engaged in the engaging portion 22 of the first pedicle screw 12. When utilizing a first tool, such as the tool 280, to connect to for removal of the first connecting screw 40, it may be necessary to utilize a second tool, such as the tool 280, to engage the distal end 102 of the first pedicle screw 12 to retain the first pedicle screw 12 while removing the first connecting screw 40. Utilization of one or more of the tools 280 may be beneficial while installing, as well as removing the vertebral stabilization assembly 10.
Furthermore, it will be appreciated that in other aspects the connector 290 may be provided on an electric or pneumatic device such as a drill or other apparatus.
A number of configurations of the opening 296 on the second end 64 may be utilized such as one or more grooves 250, and may be provided with associated tools, such as the tool 280 to establish a rigid engagement of the tool 280 to the connecting screw, such as the first connecting screw 40, and the first pedicle screw 12. It is within the scope of the present invention that the various configurations of the first pedicle screw 12 and the first connecting screw 40 may be interchanged along with the configurations of the tool 280 to promote maximum utility for installation and removal of the vertebral stabilization assembly. For example, the grooves 250 may be provided on the shaft 16 of the first pedicle screw 12, substantially as shown with respect to
In this manner, one or more configurations of tools may be utilized on one or more of the elements of the vertebral stabilization assembly 10 and are within the spirit and scope of the present invention as disclosed and described herein. Furthermore, it will be appreciated that the opening 296 provided on the first connecting screw 40 or on the distal end 102 of the first pedicle screw 12 may be tapped and threaded opening in a standard or reverse threaded manner for engagement of, for example, the connector 290 having a threaded connector 290 (not shown) for engagement of the tool 280 to the first connecting screw 40 or the first pedicle screw 12.
Also, for example, where the distal end 102 of the first pedicle screw 12 is substantially rectangularly shaped, such as in the aspect illustrated in
Furthermore, it is within the spirit and scope of the present invention that the first connecting screw 40 may be provided with a double-bolted configuration on the threaded portion 66 of the first connecting screw 40 and the connector 290 may be a socket-type connection to receive the bolt or bolts for removal of the first connecting screw 40 utilizing the tool 280.
The bore screw 300 is shown disposed in the pedicle 120 at a desirable angle extending through the vertebra 118. In this manner the bore screw 300 may be utilized to create a bore opening (not shown) that may be useful for placing the pedicle screw, such as the first pedicle screw 12, for placement of the pedicle screw from the anterior side 124 of the vertebra 118. In such a procedure the bore screw 300 may be percutaneously placed in the posterior 122 of the vertebra 118. Thereafter the patient may be rotated such that the anterior 124 of the vertebra 118 is exposed. The bore screw 300 may be provided with a coupling portion 308 adapted for attachment by a tool (not shown) for removal of the bore screw 300 through the anterior 124 side of the vertebra 118.
In other aspects, the bore screw 300 may be utilized from the anterior 124 for tapping the vertebra 118. In other aspects, the coupling portion 308 is adapted to engage the guide member 150 for determining alignment. For example, the guide member 150 may be attached to the coupling portion 308 of the bore screw 300 to determine the approximate location of the connecting screw, such as the first connecting screw 40, and where the second end 64 of the first connecting screw 40 will be exposed on the anterior 124 side of vertebra 118.
Attachment of the guide member 150 to the bore screw 300 provides another advantage of the present aspect in that it may be easily determined whether the bore screw 300 is placed at the appropriate location in the vertebra 118 or whether another placement will be necessary. This eliminates the need to place the pedicle screw, such as the first pedicle screw 12, and then determine whether the placement is acceptable.
The shaft 314 may be a substantially rigid shaft of sufficient length to extend down the length of the bore opening 310 and be operable to retain the light 316 and communicate sufficient electrical power to maintain the light 316 with power for driving the light 316. In other aspects, the shaft 314 may be a substantially flexible material such as wire or other flexible cording or material.
The indicator 312 is a useful device for indicating the location of the bore opening 310 from the anterior side 124 of the vertebra 118. As previously discussed, a number of soft tissues exist on the right side 126 on the anterior side 124 of the vertebra 118. For this reason, whether a bore screw 300 or a drill is utilized to create the bore opening 310 from the posterior side 122, it will be necessary in many cases to prevent penetration of the bore screw 300 or drill completely through the vertebra 118 on the anterior side 124 to prevent damage to the soft tissues on the anterior side 124. The indicator 312 provides an opportunity once the patient has been rotated to retract the soft tissues and identify the location of the bore opening 310 from the anterior side 124.
For example, the light 316 shown in the bore opening 310 will be perceptible by the surgeon from the anterior side 124 of the vertebra 118. The surgeon may then drill from the anterior side 124 to complete the bore opening 310. Where the bore screw 300 is utilized, the bore screw may be provided with a light, such as the light 316, provided on the distal end of the bore screw 300 and will be sufficient for these purposes. Once the light 316, whether provided on the indicator 312 or the bore screw 300, has been identified and the bore opening has been drilled to communicate with the anterior side 124 of the vertebra 118, the indicator 312 or bore screw 300 may then be removed from the anterior side. The indicator 314, such as when the light 316 is a high intensity LED or laser light, may be disposed near the posterior side 122 or only slightly within the bore opening 310 such that the light produced by the light 316 projects down through the bore opening 310 and is sufficient to identify the bore opening 310 from the anterior side 124 of the vertebra 118.
Furthermore, the indicator 312 may, in other aspects, be provided with a pneumatic or hydraulically operated capability for punching or extending through the anterior side 124 of the vertebra 118 when the indicator 312 is extended through the bore opening 310, such as by utilizing a drill. In this manner, the indicator 312 may be left in place in the bore opening 310 and after the patient has been rotated such that the anterior side 124 of the vertebra 118 has been exposed, the pneumatic or hydraulically-operated indicator 312 may be activated so as to extend through the anterior side 124 for communication into the bore opening 310.
The indicator 312 may be pulled through the anterior side 124 of the vertebra 118, and in instances where the shaft 314 is a flexible material, it may be severed from, for example, behind the patient, for easy removal through the anterior side. 124. Where the bore screw 300 is utilized and still in place, a tool (not shown) may be connected to the coupling portion 308 of the bore screw 300 so that the bore screw 300 may be removed through the anterior side 124 of the vertebra 118. This is advantageous since it eliminates the rotation of the patient for removal of the bore screw 300 or the indicator 312. The elimination of a rotational procedure further reduces the time of the overall procedure and is another advantage of the present aspect of the vertebral stabilization assembly 10 invention disclosed herein.
It will be appreciated that the exact angle of placement of the first pedicle screw 12 and resulting angle 320 with respect to the engaging portion 22 and first connecting screw 40 will be unknown until such time that the first pedicle screw 12 is actually in place in the vertebra 118. By previously providing the bore opening 310, the proper pedicle screw may be selected based upon the desired resulting angle 320 sought for the resulting placement of the first connecting screw 40. That is, it may be advantageous in certain instances to provide the second end 64 of the first connecting screw 40 at a specific location on the left side 128 on the anterior side 124 of the vertebra 118. Unless the first pedicle screw 12 is exactly placed, the resulting location of the second end 64 of the first connecting screw 40 may be significantly different than that desired. For this reason, a number of pedicle screws may be advantageously provided to the surgeon each having a different length and a different engaging portion 22 with respect to the angle of connection of the first connecting screw 40 to the engaging portion 22. By having a number of choices available to the surgeon, and based upon the angle of the bore opening 310, the first pedicle screw 12 may be selected as having an engaging portion 22 that will provide the angle 320 that will result in the second end 64 of the first connecting screw 40 being positioned at the desired location on the anterior side 124 of the vertebra 118.
Anterior side 124 placement of the first pedicle screw 12 within the vertebra 118 provides numerous additional advantages including the dimensions of the first pedicle screw 12 and resulting stability that may be achieved from such placement. For example, the first pedicle screw 12, such as that illustrated in
Since the reinforced portion 230 will not obtain the threading engagement, it is necessary for the plurality of threads 244 of the first pedicle screw 12 to be slightly larger to achieve a satisfactory anchoring and threading engagement of the first pedicle screw 12. Otherwise, the reinforced portion 230 might have the affect of smoothing the opening such that the plurality of threads 244 do not successfully engage within the vertebra 118.
Conversely, anterior side 124 placement of the pedicle screw allows for the plurality of threads 238 near the distal end 102 of the first pedicle screw 12 to be of a maximum diameter 240 for optimum anchoring and stabilization of the pedicle screw within the vertebra 118 and particularly within the pedicle portion 120. At the same time, the diameter 232 of the reinforced portion 230 may be of a maximum diameter for reinforcement to optimize the connection and engagement of the first connecting screw 40 and such structure will not reduce or minimize the engagement of the first pedicle screw 12 with the vertebra 118. The reason for this is that the plurality of threads 238 will be in front of the reinforced portion 230 when anteriorly placed versus behind the reinforced portion 230, as is the case with the plurality of threads 244 when the pedicle screw 12 is posteriorly placed. In one aspect, diameter 232 of the reinforced portion 230 is similarly sized relative to the diameter 246 of the plurality of threads 244 or any other threads provided on the shaft 16. However, numerous configurations of shaft 16 sized and thread sizes will readily suggest themselves to one of ordinary skill in the art and are within the spirit and scope of the present invention.
It should be appreciated that a variety of configurations of pedicle screws have been disclosed and shown herein and any of the various configurations may be utilized both for posterior placement of the first pedicle screw 12 as well as for anterior placement of the first pedicle screw 12. Furthermore, it will be appreciated that a number of tools, such as the tool 280 illustrated in
Thereafter utilizing technology typically employed for such purposes, such as an image intensifier, x-ray and templates, and/or other stealth technology, a K-wire or other drill or penetrating implement may be utilized to penetrate in a direction toward the posterior side 122 along a line 326. The K-wire may be obliquely placed through the vertebral body into the pedicle 120 on the right side 126. A cannulated drill may be utilized to drill over the K-wire to ream out a hole or opening for placement of the first pedicle screw 12 therein. The drill and K-wire may be removed and the first pedicle screw 12 may be anteriorly placed in the drilled opening substantially along the line 326 for proper placement of the first pedicle screw 12 in the vertebra 118. This aspect, as previously discussed, advantageously provides for selecting, in advance, the proper pedicle screw, such as the first pedicle screw 12, having the engaging portion 22 to achieve the desired angle of connection of the connecting screw, such as the first connecting screw 40.
Another advantage of anterior placement of the first pedicle screw 12 is that it provides the opportunity for stabilization from the posterior side 122 when such may be desirable. In this aspect, the first pedicle screw 12, such as that illustrated and previously disclosed herein in a number of different configurations, may be utilized by placement initially from the anterior side 124 such that the distal end 102 is anchored substantially in the pedicle 120 portion of the vertebra 118. Thereafter, the first pedicle screw 12 may be utilized for connection of connecting members, such as the connecting member 50, for standard posterior anchoring and stabilization when such is necessary because of a failure to achieve adequate stabilization from the anterior side 124 as preferably provided herein.
Under the preferred anterior stabilization and when the first pedicle screw 12 is placed from the anterior side 124 of the vertebra 118, the first pedicle screw 12 is provided with a coupling portion 100 near the head 60 of the first pedicle screw 12, substantially as shown in
Utilization of the vertebral stabilization assembly 10 according to the aspect illustrated in
Once the first pedicle screw 12 has been placed on the anterior side 124 of the vertebra 118 substantially as shown and discussed above with respect to
It should be appreciated that it is within the scope of the present invention to anteriorly place the first pedicle screw 12 on the left anterior side 124, similar to that shown in
In this manner, the engaging portion 22 may be retained in the manner such that the engaging portion 22 may be rotated to receive the first connecting screw 40 at various angles 332. Although two angles 332 are shown, a variety of angles may be achieved utilizing the present aspect of the engaging portion 22. The engaging portion 22 may be retained on bearings or other floating structural devices within the engaging opening 330, such that when the first connecting screw 40 is coupled with the engaging portion 22, the engaging portion 22 becomes fixed with respect to the initial angle 332 of engagement.
Such variable positioning of the engaging portion 22 can further be obtained by a hinge or a latch connected to the engaging portion 22 for hinging or latching rotation at the engaging portion 22 within the engaging opening 330. Also, the engaging portion 22 may be provided on a rotational or ratcheted body (not shown) within the engaging opening 330. It will be appreciated that a wide variety of structures may be utilized for obtaining and achieving an engaging portion, such as the engaging portion 22 to obtain various angulations, such as the angles 332 of connection of the first pedicle screw 12 relative to the first connecting screw 40 and are well known to those of ordinary skill in the art and are within the spirit and scope of the present invention and for brevity will not be further discussed herein.
The advantage of the engaging portion 22 adapted for angular adjustment is that it eliminates the need for a number of pedicle screws having different engaging portions with different angles for connection to the first connecting screw 40. However, it should be appreciated that in other aspects the engaging portion 22 is a fixed and rigid structure for engagement of the first connecting screw 40 and, as such, a plurality of pedicle screws may be necessary each having a different angle of engagement of the first connecting screw 40 at the engaging portion 22 based upon the angle of placement of the first pedicle screw 12 in the vertebra 118.
Furthermore, according to other aspects of the present invention, it is anticipated that a variety of pedicle screws, such as the first pedicle screw 12, having significantly different lengths will be utilized for various adaptations and placements. Also, a variety of pedicle screws, such as the first pedicle screw 12, where the fixed engaging portion 22 is available in variety of angles of connection of the connecting screw relative to the shaft 16 of the first pedicle screw 12.
A gap 342 is disposed between the first portion 338 and the second portion 340 of the non-continuous threads 336. The gap is a portion of the shaft 16 that is not provided with threads and may be of various circumferential dimensions and be suitable for these purposes. It will be appreciated that frequently the first pedicle screw 12 and particularly the threads on the shaft 16 may cause aggravation and irritation to nerves adjacent the vertebra 18. Once it has been determined that a nerve is aggravated by the placement of the first pedicle screw 12, adjustment or replacement of the first pedicle screw 12 is necessitated. Frequently, this requires completely removing and relocating the first pedicle screw 12 according to another oblique angle in the vertebra 118. By providing the first pedicle screw 12 having one or more of the non-continuous threads 336, according to the present aspect, aggravation of the nerve may be potentially alleviated by only a minor rotation of the first pedicle screw 12 since it is likely that the thread on the shaft 16 may be causing the irritation or aggravation of the nerve. Thus, upon a minor or slight rotation of the first pedicle screw 12 the gap 342 will replace, for example, the non-continuous threads 336 and alleviate the aggravation of the nerve and, thus, eliminate the necessity for completely removing and repositioning the first pedicle screw 12. It will be appreciated that the position and distribution of the non-continuous threads 336 with respect to their symmetrical placement may be altered or modified and are within the spirit and scope of the present invention as described and disclosed herein and will readily suggest themselves to one of ordinary skill in the art.
In some aspects the engaging portion 402b of the pedicle screw 400b may be an opening sufficient to receive the connecting screw 404 through the opening, as well as for engaging the shaft of 408 of the connecting screw 404. It is readily apparent that this configuration of the dual pedicle screws 400a and 400b provides significant vertebral support and stability. Furthermore, although only the vertebra 118 is shown it should be understood that the present configuration, including the dual pedicle screws 400a and 400b and a connecting screw 404, may be utilized for placement in a plurality of vertebra to provide increased stabilization for a plurality of vertebra for the purposes previously discussed and disclosed herein.
In another aspect, the present invention provides a fixation tool 430 for properly aligning the dual pedicle screws 400a and 400b for placement in the vertebra 118. Accurate alignment and placement of the dual pedicle screws 400a and 400b, according to one aspect, may be advantageously provided by utilizing the fixation tool 430. The fixation tool 430 is provided with alignment members 432a and 432b to achieve the proper alignment of the dual pedicle screws 400a and 400b in the vertebra 118. The alignment members 432a and 432b may be similar to the alignment member 156 of the guide member 150 previously disclosed and described above.
It may be advantageous, according to other aspects, to provide indicia on the dual pedicle screws 400a and 400b to provide for the proper alignment of the pedicle screws 400a and 400b. In other aspects the fixation tool 430 may be unnecessary when employing x-ray, stealth, or other imaging technologies to ensure the accurate alignment and placement of the dual pedicle screws 400a and 400b. In other aspects, however, the fixation tool 430 may be used such that the dual pedicle screws 400a and 400b may be simultaneously placed to ensure the engaging portions 402a and 402b of the dual pedicle screws 400a and 400b, respectively, are in proper alignment for connection by the connecting screw 404.
The pedicle screws 400a and 400b may also utilize guiding and locating techniques, previously discussed above, such that the pedicle screws 400a and 400b may be placed posteriorly, percutaneously or otherwise, and the connecting screw 404 may be placed anteriorly. Once the pedicle screws 400a and 400b have been inserted, the patient may then be rotated. A guide member, such as the guide member 150 may be utilized for connection and alignment of the connecting screw 404, as previously discussed above.
Thus, the guide member 150 is coupled, for example, to the pedicle screw 400a such that the alignment member 156 is operable to properly align the connecting screw 404 for coupling to the dual pedicle screws 400a and 400b. This may include, as previously discussed, drilling a tap hole or other guiding hole for accurate placement and alignment of the connecting screw 404. In any event, the connecting screw 404 may then be connected to the dual pedicle screws 400a and 400b in a configuration substantially as illustrated in the present aspect.
In one aspect, the fixation tool 430 may be implemented by determining the point 440 on the vertebra 118 to desirably place the connecting screw 404. A pin, tack or other means may be employed to position and orient the alignment portion 442 which will provide the proper alignment for the connecting screw 404. Once the desired placement for the connecting screw 404 has been located, the dual pedicle screws 400a and 400b may then be aligned and placed in the vertebra 118 utilizing the alignment members 432a and 432b of the alignment tool 430. In some aspects the alignment members 432a and 432b may be provided with an inner and an outer barrel (not shown) wherein the inner barrel may be utilized to drill a guide hole in the vertebra 118 and the outer barrel may then be used to guide the pedicle screws 400a and 400b into place.
With the general description of
It is further intended that any of the configurations, described herein with reference to the remaining FIGURES, can generally avail themselves of the aspect of the invention, described with reference to
The vertebral stabilization assembly 10 in this configuration includes a first pedicle screw 12 and a second pedicle screw 14. The first pedicle screw 12 includes a shaft 16 provided with a threaded portion 18. The threaded portion 18 of the shaft 16 is operable for threading engagement of the first pedicle screw 12 with the vertebra 118. The shaft 16 of the pedicle screw 12 further includes an engaging portion 22.
The second pedicle screw 14 can be substantially similar to the first pedicle screw 12 in that the second pedicle screw 14 can include a shaft 30 substantially similar to the shaft 16 of the first pedicle screw 12. Additionally, the shafts 16 and 30 of the first and second pedicle screws 12 and 14, respectively, can be substantially cylindrical members. Similarly, the shaft 30 of the second pedicle screw 14 can be provided with a threaded portion 32 similar to the threaded portion 18 provided on the shaft 16 of the first pedicle screw 12. The threaded portion 32 of the shaft 30 is operable for threading engagement of the second pedicle screw 14 with a second vertebra 34. The shaft 30 of the second pedicle screw 14 is provided with an engaging portion 36.
The shafts 16 and 30 of the first and second pedicle screws 12 and 14 can generally be a length that is sufficient to anchor the first pedicle screw 12 into the vertebra 118 and the second pedicle screw 14 into the vertebra 34. The lengths of the first pedicle screw 12 and the second pedicle screw 14 as shown in
The first pedicle screw 12 (shown in ghosted view) extends through an anterior portion 124 of the vertebra 118 and traverses at least a portion of the vertebral body of the vertebra 118; however, the first pedicle screw 12 does not extend into the pedicle 120 (better seen in
The vertebral stabilization assembly 10 is further provided with a first connecting screw 40 and a second connecting screw 42. The first and second connecting screws 40 and 42 can be substantially cylindrical members and may be constructed from materials similar to that of the first and second pedicle screws 12 and 14, such as, but not limited to, titanium, steel, metal or other metal alloys, substantially rigid polymeric material or a variety of other rigid metallic materials adapted and suitable for these purposes. The first connecting screw 40 has a first end 44 and a second end 64. The second connecting screw 42 has a first end 46 and a second end 65. The first end 44 of the first connecting screw 40 is adapted to be received by the engaging portion 22 on the shaft 16 of the first pedicle screw 12. The first end 46 of the second connecting screw 42 is adapted to be received by the engaging portion 36 of the shaft 30 of the second pedicle screw 14.
The vertebral stabilization assembly 10 further includes a connecting member 50 that has a first end 52 and a second end 54. The first end 52 of the connecting member 50 is connected to or coupled near or adjacent the second end 64 of the connecting screw 40 that is positionable in the vertebra 118. The second end 54 of the connecting member 50 is connected to or coupled near or adjacent the second end 65 of the second connecting screw 42 positionable in the second vertebra 34. The connecting member 50 may be constructed from a variety of materials similar to that of the first and second pedicle screws 12 and 14 such as, but not limited to, titanium, steel, metal, or other metal alloys, rigid polymeric material, or other rigid materials suitable for stabilization of the vertebra 118 and the second vertebra 34 by connection to the first and second connecting screws 40 and 42.
The vertebra 118 and the second vertebra 34 of
With reference to
It should be understood that the vertebra 118 and the second vertebra 34 may be any vertebra or structure of the spine, such as, for example, lumbar, thoracic and cervical vertebrae.
Thus, it is apparent that there has been provided, in accordance with the present invention, a vertebral stabilization assembly and method that satisfies one or more of the advantages set forth above. Although the preferred embodiment has been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of the present invention, even if all of the advantages and benefits identified above are not present. For example, the various elements or components may be combined or integrated in another system or certain features may not be implemented. Also, the techniques, systems, sub-systems, and methods described and illustrated in the preferred embodiment as discrete or separate may be combined or integrated with other systems, techniques, or methods without departing from the scope of the present invention. For example, any of the vertebral screws described herein can be utilized; and, the vertebral screws can be inserted from either an anterior or a posterior side of the vertebra. Other examples of changes, substitutions, and alterations are readily ascertainable by one skilled in the art and could be made without departing from the spirit and scope of the present invention.
Claims
1. A vertebral stabilization assembly for stabilizing vertebrae, the assembly comprising:
- a first vertebral screw having a shaft provided with a threaded portion operable for threading engagement of the first vertebral screw with a vertebral body of a first vertebra, the shaft having an engaging portion;
- a first connecting screw having a first end and a second end, the first end adapted to be received by the engaging portion of the first vertebral screw;
- a second vertebral screw having a shaft provided with a threaded portion operable for threading engagement of the second vertebral screw with a vertebral body of a second vertebra, the shaft having an engaging portion;
- a second connecting screw having a first end and a second end, the first end adapted to be received by the engaging portion of the second vertebral screw; and
- a connecting member having a first end, a second end, a first location and a second location, wherein: the connecting member is configured to allow a limited degree of movement between the vertebrae; the connecting member is operable to couple with the first connecting screw positionable in the first vertebra at the first location of the connecting member; and the connecting member is operable to couple with the second connecting screw positionable in the second vertebra at the second location of the connecting member for stabilization of the first vertebra and the second vertebra.
2. The vertebral stabilization assembly of claim 1, further comprising:
- an artificial disc disposed between the first vertebra and the second vertebra.
3. The vertebral stabilization assembly of claim 1, further comprising:
- a third vertebral screw having a shaft provided with a threaded portion operable for threading engagement of the third vertebral screw with a vertebral body of a third vertebra, the shaft having an engaging portion; and
- a third connecting screw having a first end and a second end, the first end adapted to be received by the engaging portion of the third vertebral screw, wherein: the connecting member has a third location; and the connecting member is operable to couple with the third connecting screw positionable in the third vertebra at the third location of the connecting member for stabilization of the third vertebra with the first and second vertebra.
4. The vertebral stabilization assembly of claim 3, wherein the connecting member is a cable.
5. The vertebral stabilization assembly of claim 1, wherein the connecting member is a plurality of connecting members.
6. The vertebral stabilization assembly of claim 1, wherein the connecting member is made of flexible material.
7. The vertebral stabilization assembly of claim 6, wherein the connecting member is defined as a flexible rod.
8. The vertebral stabilization assembly of claim 1, wherein the first vertebral screw is operable to be positioned in the first vertebra from an anterior side of the first vertebra into the vertebral body of the first vertebra, and the second vertebral screw is operable to be positioned in the second vertebra from an anterior side of the second vertebra into the vertebral body of the second vertebra.
9. The vertebral stabilization assembly of claim 1, wherein the connecting member connected to the first and second connecting screw is sized to retain the first vertebra a distance from the second vertebra.
10. The vertebral stabilization assembly of claim 1, wherein the connecting member is defined as a bracket.
11. The vertebral stabilization assembly of claim 1, wherein the connecting member is defined as a plate.
12. The vertebral stabilization assembly of claim 8, wherein the first vertebral screw is operable to be positioned through the vertebral body of the first vertebra and into a pedicle portion of the first vertebra, and the second vertebral screw is operable to be positioned through the vertebral body of the second vertebra and into a pedicle portion of the second vertebra.
13. The vertebral stabilization assembly of claim 8, wherein the first vertebral screw is operable to be positioned through the vertebral body of the first vertebra but not into a pedicle portion of the first vertebra, and the second vertebral screw is operable to be positioned through the vertebral body of the second vertebra but not into a pedicle portion of the second vertebra.
14. The vertebral stabilization assembly of claim 1, wherein the first vertebral screw is a first anterior vertebral screw, and the second vertebral screw is a second anterior vertebral screw.
15. The vertebral stabilization assembly of claim 1, wherein the first vertebral screw is a first pedicle screw, and the second vertebral screw is a second pedicle screw.
16. The vertebral stabilization assembly of claim 1, wherein the connecting member is coupled to the first connecting screw adjacent the second end of the first connecting screw, wherein the connecting member is coupled to the second connecting screw adjacent the second end of the second connecting screw.
17. The vertebral stabilization assembly of claim 16, wherein the first location of the connecting member is at the first end of the connecting member, wherein the second location of the connecting member is at the second end of the connecting member.
18. The vertebral stabilization assembly of claim 1, wherein the connecting member is coupled to the first connecting screw at the second end of the first connecting screw, wherein the connecting member is coupled to the second connecting screw at the second end of the second connecting screw.
19. A method for stabilizing a lower vertebra and an upper vertebra from an anterior side of the vertebrae using a vertebral stabilization assembly, the method comprising:
- inserting a first vertebral screw, which includes a shaft provided with a threaded portion operable to threadingly engage the lower vertebra, into the lower vertebra such that a portion of the threaded portion of the shaft engages a vertebral body portion of the lower vertebra, the shaft of the first vertebral screw having an engaging portion;
- inserting a first end of the first connecting screw into the engaging portion of the first vertebral screw;
- inserting a second vertebral screw, which includes a shaft provided with a threaded portion operable to threadingly engage the upper vertebra, into the upper vertebra such that a portion of the threaded portion of the shaft engages a vertebral body portion of the upper vertebra, the shaft of the second vertebral screw having an engaging portion;
- inserting a first end of the second connecting screw into the engaging portion of the second vertebral screw;
- positioning a connecting member on an anterior side of the upper vertebra and the lower vertebra;
- coupling a connecting member to a second end of the first connecting screw and to a second end of the second connecting screw; and
- allowing a limited degree of movement between the upper and lower vertebra via an arrangement of the connecting member.
20. The method of claim 19, further comprising:
- inserting an artificial disc between the lower vertebra and the upper vertebra.
21. The method of claim 19, wherein:
- the first vertebral screw is inserted from an anterior side of the lower vertebra and is operable to be positioned through the vertebral body of the lower vertebra and into a pedicle portion of the lower vertebra, and
- the second vertebral screw is inserted from an anterior side of the upper vertebra and is operable to be positioned through the vertebral body of the upper vertebra and into a pedicle portion of the upper vertebra.
22. The method of claim 20, wherein:
- the first vertebral screw is inserted from an anterior side of the lower vertebra and is operable to be positioned through the vertebral body of the lower vertebra but not into a pedicle portion of the lower vertebra, and
- the second vertebral screw is inserted from an anterior side of the upper vertebra and is operable to be positioned through the vertebral body of the upper vertebra but not into a pedicle portion of the upper vertebra.
Type: Application
Filed: Jul 21, 2005
Publication Date: Dec 1, 2005
Inventor: Paul Vaughan (Dallas, TX)
Application Number: 11/185,793