Abstract:
A spinal implant device immobilizes an attached vertebrae through a minimally invasive surgical approach while providing a compartment within the implant for the placement of bone graft or bone graft substitute. The bone graft material fuses the spinous processes and/or lamina portion of bone of the vertebral bone to which the device is attached.

Description:
REFERENCE TO PRIORITY DOCUMENT 
     This application is a continuation of and claims priority to U.S. patent application Ser. No. 12/727,641, issuing as U.S. Pat. No. 8,303,629 on Nov. 6, 2012, which is hereby incorporated by reference in its entirety, and which claims priority of U.S. Provisional Patent Application Ser. No. 61/210,581 filed Mar. 19, 2009. Priority of the aforementioned filing date is hereby claimed and the disclosure of the Provisional Patent Application is hereby incorporated by reference it its entirety. 
    
    
     BACKGROUND 
     The present disclosure relates to devices and methods that permit fixation and stabilization of the bony elements of the skeleton of a patient. The devices permit adjustment and maintenance of the spatial relationship(s) between neighboring bones. Depending on the specifics of the embodiment design, the motion between adjacent skeletal segments may be limited or completely eliminated. 
     Spinal degeneration is an unavoidable consequence of aging and the disability produced by the aging spine has emerged as a major health problem in the industrialized world. Alterations in the anatomical alignment and physiologic motion that normally exists between adjacent spinal vertebrae can cause significant pain, deformity, weakness, and catastrophic neurological dysfunction. 
     Surgical decompression of the neural tissues and immobilization of the vertebral bones is a common option for the treatment of spinal disease. Currently, vertebral fixation is most frequently accomplished by anchoring bone screws into the pedicle portion of each vertebral body and then connecting the various screw fasteners with an interconnecting rod. Subsequent rigid immobilization of the screw/rod construct produces rigid fixation of the attached bones. 
     A shortcoming of the traditional rod/screw implant is the large surgical dissection required to provide adequate exposure for instrumentation placement. The size of the dissection site produces unintended damage to the muscle layers and otherwise healthy tissues that surround the diseased spine. A less invasive spinal fixation implant would advantageously minimize the damage produced by the surgical exposure of the spine. 
     In U.S. Pat. No. 7,048,736, Robinson et al teach the use of interspinous process plate to fixate adjacent vertebrae. As disclosed, the device is used to supplement orthopedic implant and for bone graft material placed into the intervertebral disc between the attached vertebra. Thus the device functions to immobilize the vertebrae until bone fusion occurs but, in itself, does not provide a compartment for bone graft placement within the posterior aspect of the spine. Since bone graft material must be placed in order to achieve vertebral fusion, the device must be used in conjunction with bone graft material that is placed at a secondary site of the attached vertebra bones, such as within the disc space, between adjacent transverse processes, and the like. This is a significant disadvantage and prevents use of the Robinson device by itself to both immobilize and fuse the vertebral bones. 
     The growing experience with spinal fusion has shed light on the long-term consequences of vertebral immobilization. It is now accepted that fusion of a specific spinal level will increase the load on, and the rate of degeneration of, the spinal segments immediately above and below the fused level. As the number of spinal fusion operations have increased, so have the number of patients who require extension of their fusion to the adjacent, degenerating levels. The rigidity of the spinal fixation method has been shown to correlate with the rate of the degenerative progression of the adjacent segments. In specific, implantation of stiffer instrumentation, such as rod/screw implants, produced a more rapid progression of the degeneration disease at the adjacent segment than use of a less stiff fixation implant. 
     SUMMARY 
     This application discloses several exemplary devices that attach onto the spinous processes of adjacent vertebrae and address the limitation and shortcomings of prior devices and methods. In one embodiment, a device comprises an implant immobilizes the attached vertebrae through a minimally invasive surgical approach while providing a compartment within the implant for the placement of bone graft or bone graft substitute. The bone graft material then fuses the spinous processes and/or lamina portion of bone of the vertebral bone to which the device is attached. In another embodiment, the implant permits movement of the attached bone within a defined range of motion. The device is capable of preventing aberrant anterior and/or posterior spondylolisthesis as well as limiting the extent of flexion, extension, lateral flexion and rotation of the attached vertebral. Spinous process fixation provides good segmental immobilization through a minimally invasive surgical approach. 
     In other exemplary embodiments, the implant is anchored to the pedicle portion of at least one vertebral bone to provide superior bone fixation. In another embodiment, a bone anchor is placed through the pedicle of the inferior vertebra, across the disc space above the inferior vertebra, and into the lower boney surface of the upper vertebral bone. The implant employs a fastener that can be placed as free-standing device, or it can then be anchored to or interconnected with a fixation device that is anchored onto at least one spinous process. Further, a fastener may be used in this way through each of the two pedicles that are located on each side of the vertebral midline. 
     In another embodiment, an implant or orthopedic device is adapted to fixate the spinous processes of vertebral bones. The implant includes at least one bone engagement or abutment member located on each side of a spinous process of a first vertebra and a second vertebra, wherein the abutment members are adapted to forcibly abut the side of each spinous process. The implant has a locking mechanism that is adapted to rigidly immobilize at least a first abutment member on one side of the spinous process with at least a second abutment member on the other side of the spinous process (i.e., across the vertebral midline in the mid-sagittal plane from the first abutment member) using an interconnecting member (such as, for example, a rod, plate, etc) that crosses the vertebral midline. The locking mechanism is capable of reversibly transitioning between a first state, wherein the orientation between at least one abutment member and the interconnecting member is changeable in at least one plane and a second state, wherein the orientation between at least one abutment member and the interconnecting member is rigidly affixed. The implant further includes a compartment within at least one abutment member that is adapted to contain bone graft material, which can be bone graft, bone graft substitute, or a combination thereof. 
     In an aspect, there is disclosed an orthopedic implant for the fusion of adjacent bony segment. The implant comprises a first member and a second member opposed to the first member, wherein the first and second member define a space therebetween sized to receive a bone. The first and second members have opposed surfaces each surface having at least one spiked protrusion for capturing a bone therebetween. At least one of the members defines an internal compartment adapted to contain a bone graft material, the compartment communicating with at least one bore hole in the at least one member for communicating the bone graft material with the captured bone. The bone graft material in the compartment extends from a first side of the first captured bone to a first side of a second captured bone, wherein the first side of the first and second captured bones are also the sides penetrated by the spike protrusions. 
     In another aspect, an orthopedic device configured to attach onto a spinous process of a first vertebral bone is disclosed. In one embodiment, the device comprises a first body comprising (i) a bone abutment surface configured to abut an ipsilateral side of the spinous process, and a second surface configured to oppose the bone abutment surface, (ii) a second body comprising a bone abutment surface configured to substantially face the bone abutment surface of the first body, and to abut a contralateral side of the spinous process, and a second surface configured to oppose the bone abutment surface, (iii) an interconnecting member configured to movably couple the first body and the second body, and (iv) a locking feature comprising an unlocked state and a locked state, the locked state configured to limit movement between the interconnecting member and at least one of the first body and the second body. At least one aperture is configured to extend from an opening of the bone abutment surface of the first body to an opening of the second surface of the first body, the aperture being sized to permit bony fusion between the ipsilateral side of the spinous process and a bone forming material positioned within a cavity configured to abut the second surface of the first body. The cavity is configured to permit placement of at least a portion of the bone forming material after attachment of the orthopedic device onto the spinous process of the first vertebral bone. 
     In yet another aspect, a method for stabilization of a first vertebral bone and a second vertebral bone is disclosed. In one embodiment, the method comprises: (i) positioning a first fixation member relative an ipsilateral side of a spinous process of the first vertebral bone and an ipsilateral side of a spinous process of the second vertebral bone, (ii) positioning a second fixation member relative a contralateral side of the spinous process of the first vertebral bone and a contralateral side of the spinous process of the second vertebral bone, (iii) advancing at least one of the first and second fixation members towards the other, (iv) capturing the spinous process of the first vertebral bone and the spinous process of the second vertebral bone between the first and second fixation members, (v) preventing separation of the first and second fixation members after the advancement, and (vi) advancing a bone screw through a pedicle portion of one the first and second vertebral bones, the bone screw traversing a disc space between the first and second vertebral bones, and comprising a distal segment positioned within the body of an other one of the first and second vertebral bones. 
     In a further embodiment, the method comprises: (i) positioning a first fixation member such that the first fixation member extends from an ipsilateral side of a spinous process of each of the first and second vertebral bones, (ii) positioning a second fixation member such that the second fixation member extends from a contralateral side of the spinous processes of each of the first and second vertebral bones, (iii) advancing at least one of the first and second fixation members towards the other thereby capturing the spinous processes of the first and second vertebral bones there between, (iv) preventing separation of the first and second fixation members after the advancement, (v) advancing a fastener through a pedicle portion of one of the first and second vertebral bones, (vi) seating at least a segment of the interconnecting member within a receptacle of the fastener, and (vii) coupling the receptacle of the fastener to the interconnecting member. 
     Multiple additional embodiments are described herein. Other features and advantages should be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the disclosed devices and methods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates perspective and orthogonal views of a pair of vertebral bones. 
         FIG. 2  shows a perspective view of a bone implant system in a completely assembled state 
         FIG. 3  shows the system with an interconnecting rod detached. 
         FIG. 4  shows the system in an exploded state 
         FIG. 5  shows various orthogonal views of an exemplary body member of the system. 
         FIGS. 6A and 6B  show plan views of the body member. 
         FIG. 7  shows perspective views of a locking member of the system. 
         FIG. 8  show orthogonal views of the locking member. 
         FIGS. 9A and 9B  shows an embodiment of the system including a rod with spherical ends. 
         FIG. 10  shows a method of implanting and using the system  105 . 
         FIG. 11  shows the system in an implanted state. 
         FIG. 12A  shows an embodiment of an assembled bone screw assembly. 
         FIG. 12B  shows the bone screw assembly in an exploded state. 
         FIGS. 13A ,  13 B,  14 , and  15  show a method and device for using the bone implant system with one or more bone screw assemblies. 
         FIG. 16  shows use of the system wherein one vertebral bone does not have a spinous process that will permit device fixation. 
         FIGS. 17A and 17B  show an additional embodiment of the system  105  that may be used with a bone screw. 
         FIG. 18  illustrates an embodiment wherein a fastener is positioned through the pedicle of the inferior vertebra V 1 , across the disc space between the two vertebrae and into the inferior aspect of the upper vertebra. 
         FIGS. 19A-19C  show an exemplary embodiment of the fastener of  FIG. 18 . 
         FIG. 20  shows the fastener in an implanted state. 
         FIG. 21  shows the fastener and the system in an implanted state. 
     
    
    
     DETAILED DESCRIPTION 
     In order to promote an understanding of the principals of the disclosure, reference is made to the drawings and the embodiments illustrated therein. Nevertheless, it will be understood that the drawings are illustrative and no limitation of the scope of the invention is thereby intended, Any such alterations and further modifications in the illustrated embodiments, and any such further applications of the principles of the invention as illustrated herein are contemplated as would normally occur to one of ordinary skill in the art. 
       FIG. 1  illustrates perspective and orthogonal views of a pair of vertebral bones. The vertebrae are represented schematically and those skilled in the art will appreciate that actual vertebral bones may contain features that are not depicted in  FIG. 1 . 
       FIG. 2  shows a perspective view of a bone implant system  105  in an assembled state. The system  105  includes several components, including at least two body members  110  and an elongated interconnecting member, such as a rod  112  or plate, that interconnects the body members  110  in a spaced relationship with the space between the body members  110  sized and shaped to receive a portion of a vertebral body, such as a spinous process. (The system  105  is described herein in the exemplary context of being used with a rod  112  but it should be appreciated that a plate or other interconnecting member may be used in place of the rod  112 .) 
     Each body member  110  has a corresponding locking member  122  that couples to the respective body member  110  as described below. In addition, each locking member  122  has a corresponding locking nut  123  that can be threaded onto the locking member  122  and used to apply a downward locking force onto the respective member  110  and the rod  112  to immobilize the member  110 , rod  112 , and locking member  122  relative to one another, as described more fully below.  FIG. 3  shows the system  105  with the interconnecting rod  112  detached.  FIG. 4  shows the system  105  in an exploded state. It should be appreciated that the use of terms herein such as “upward”, “downward”, “front” and “back” are with reference to the orientation shown in drawings and are not intended to be limiting. 
     An exemplary embodiment of the body member  110  is now described with reference to  FIG. 5  and  FIGS. 6A and 6B .  FIG. 5  shows various orthogonal views of the body member  110  while  FIGS. 6A and 6B  show plan views of the body member  110 .  FIG. 6A  shows the body member  110  with internal lines and  FIG. 6B  shows the body member  110  without internal lines. The illustrated embodiment of the system  105  includes a pair of body members  110 , each of which is a mirror image of the other. 
     With reference to  FIGS. 5 ,  6 A, and  6 B, each body member  110  is an elongated body having outer walls that define a cavity that is at least partially enclosed by the outer walls. The body members are sized and shaped to be positioned next to and abut a spinous process of a vertebral body. In particular, each body member  110  includes a first side wall  1102 , a second side wall  1104  opposed to the first side wall, a front wall  1106  and a back wall  1108  opposed to the front wall  1106 . The walls  1102 ,  1104 ,  1106 , and  1108  define an inner cavity  1109 . The upper and lower boundaries of the inner cavity  1109  may be at least partially open, as depicted, or completely closed by additional walls. The cavity  1109  is adapted to open onto the space outside of member  110  through at least one aperture of the walls  1102 ,  1104 ,  1106 , and/or  1108  and/or through the upper and lower boundaries of the cavity  109 . That is, in an embodiment, the cavity  1109  is not a completely closed cavity. Thus, the walls  1102 ,  1104 ,  1106 , and/or  1108  may include one or more holes, apertures, or openings that provide communication between the cavity  109  and a location outside of the body member  110 . 
     The cavity  1109  is adapted to receive and contain a bone graft material (which can be bone graft, bone graft substitute, or a combination thereof) so that, when the system is implanted in the spine, the contained bone graft material can contact at least one vertebral bony surface through the aforementioned aperture of the walls or through the upper lower boundaries of the cavity  109  that surround cavity  1109 . The bone graft material may then form a fusion mass with that bony surface. 
     With reference to  FIG. 5  and  FIG. 6B , the side wall  1102  of each body member  110  includes a channel  11022  that is sized and shaped to accept a corresponding locking member  122 . The other side wall  1102  also includes a complementary channel  11042 . The locking member  122  is sized and shaped so that it can be inserted onto a respective body member  110  over the channels  11022  and  11042  as shown in  FIG. 2 . 
     With reference still to  FIGS. 5 ,  6 A, and  6 B, the wall  1102  includes one or more cut outs or seats  11024  sized and shaped to accept an instrument that can compress each of the two body members  110  toward and into the side bony aspect of a vertebral spinous process once the system  105  is coupled to a vertebral body. The seat  11024  does not necessarily extend through the full thickness of wall  1102 . 
     The wall  1104  of each body member  110  includes one or more protrusions  11044  that are adapted to forcibly penetrate and fixate onto a bony surface of a vertebral bone onto which member  110  is forcibly applied. The protrusions have a shape, such as a pointed shape, that is configured to facilitate penetration into and fixation with the bony surface. One or more full thickness bore holes  11046  may extend through the wall  1104  of each body member  110  so that bone graft material contained in cavity  1109  can pass through the hole(s)  11046  and contact at least a portion of the vertebral bony surface that is in contact with the wall  1104  and thereby form a fusion mass with the vertebral bone. 
     As mentioned, the upper and lower boundaries of the cavity  1109  may be at least partially open (as shown in  FIG. 5 ). The open upper and lower boundaries provide access to the cavity  109  to facilitate the placement of the bone graft material into cavity  1109 . The open upper and lower boundaries may also serve as means through which bone graft material contained in cavity  1109  may come into contact with the adjacent vertebral bone. Further, in an embodiment, either the upper and/or lower boundaries of the cavity  1109  may contain a closed portion that encloses the upper or lower boundary. For example, the body member  110  may include a lower wall  11092  ( FIG. 6B ) that entirely or at least partially encloses the lower boundary of the cavity  1109  so as to limit contact between the graft material contained in cavity  1109  and structures that are preferably protected from bone graft contact. Such structures may include the dural surface of the spinal nerve column or spinal nerve. The lower wall  11092  may serve other functions, as discussed more fully bellow. 
     An exemplary embodiment of a locking member  122  is now described with reference to  FIGS. 7 and 8 . Each locking member has a pair of opposed, upwardly extending side walls  1222  that form a space therebetween. The space between the side walls is sized and shaped to complement the shape of the channels  11022  and  11042  on the body member  110 . In this manner, the locking member  122  can be slid or otherwise coupled onto a corresponding body member  110  in the region of the channels  11022  and  11042 . The region of the locking member  122  below the side walls  1222  includes a protrusion  1226  that is contoured or shaped to form a seat that is sized and shaped to receive the rod  112 , as described more fully below. The seat has a rounded surface that may complement the shape of the rod  112  so that the rod  112  can be firmly seated onto the seat. In addition, the lower region of the side walls  1222  form ledges that overhang the seat. 
     The ledges and protrusion  1226  collectively form a space/seat in which the interconnecting rod can be captured and/or immobilized relative to the locking member  1222 . The protrusion  1226  may include one more features adapted to accept a spherical portion of the interconnecting rod. For example, an indentation  12262  may be positioned on the protrusion for receiving a spherical portion of the interconnecting rod. The indentation may be sized and shaped to receive any of a variety of shaped portions of the rod not limited to a spherical portion. 
     With reference to  FIG. 7 , the interior surface of the side walls  1222  may have threads  1224  that threadingly mate with a corresponding locking nut  123 . This permits the locking nut  123  to be threaded downward into the space between the side walls  1222 . 
     The assembled system  105  is now further described with reference to  FIG. 2 . The two body members  122  are positioned in a spaced apart relationship and coupled to one another via the rod  112 . That is, the rod  112  is seated onto the seats formed by the protrusions  1226  on the lower portion of the locking members  122 . Each of the locking members  122  is positioned on a respective body member  110  such as over the channels  11042  and  11022  ( FIG. 5 ). Thus, the locking members  122  are attached to the body members while the rod  112  is seated on the locking members  122  such that a space is defined between the body members  110  to collectively form the system  105 . 
     The body members  110 , locking members  122 , and rod  112  can all be locked and immobilized relative to one another using the locking nuts  123 . In particular, each locking nut is advanced downward into a locking member  122  such that the locking nut provides a downward force onto the body member  110 , at least a portion of which is positioned between the locking nut  123  and rod  112 . With downward advancement of nut  123 , a lower or an inferior surface of the locking nut  123  is moved toward, and forced against, the upper edge(s) of the respective body member  110 . The upper edge(s) may include each of the first side wall  1102  and/or the second side wall  1104 . 
     The locking member  122  is thus forced upward relative to member  110  and the interconnecting rod  112  is forcibly constrained between ledge  1226  of the locking member  122  and the surface of the lower wall  11092  ( FIG. 6A ,  6 B) of the cavity  1109 . In this way, each of the body members  110  is immobilized relative to the interconnecting rod. 
     While rod  112  is depicted as having a spherical portion  1122  in  FIGS. 2-3 , a rod having a spherical end (as shown in  FIGS. 9A-9B ) may be alternatively used. Further, a straight or curvilinear rod without a spherical protrusion, a plate, or an interconnecting member of any applicable geometric configuration may be alternatively used to interconnect the body members  110 . As can be seen in FIGS.  2  and  9 A- 9 B, the spherical portion of rod  112  interacts with the indentation  12262  in the seat of locking member  122  and also with the lower surface of the wall  11092  of the member  110 . This interaction allows the interconnecting rod  112  to be oriented and fixed in any one of a variety of positions (including non-orthogonal positions) relative to the body member  110  to which it is attached. 
       FIG. 10  shows a method of implanting and using the system  105 . In use, the system is positioned posterior to the spinous processes, SP 1  and SP 2 , of the vertebral bones to be immobilized. (Note that in  FIG. 10 , the system  105  is positioned above the posterior aspect of the vertebral bones. Thus, the system  105  is actually shown in a position that is anatomically posterior to the vertebral spinous processes, SP 1  and SP 2 .) At this point in the implantation of the system  105 , each of the locking nuts  123  is sufficiently loose so that each body member  110  can move relative to the interconnecting member  112 . The system  105  is then moved so that each body member  110  rests adjacent to a side of each of the spinous processes SP 1  and SP 2  of the two vertebral bones to be immobilized. That is, the body members will be positioned on either side of at least one spinous process such that a spinous process is positioned between a pair of body members  110 . Each body member  110  is then forced towards (that is, medial) the spinous processes positioned between the body members so that the protrusions  11044  of each second side wall  1104  of each body member  110  is forced into the side of the spinous process that is adjacent to it. In other words, the body members  110  are forced toward one another and also toward the spinous processes positioned between the body members  110  such that the protrusions penetrate the sides of the spinous processes. 
     The body members  110  are forced towards one another by the action of at least one driver instrument (in an embodiment, the driver instrument may be shaped like pliers) that is preferably adapted to interact with and compress each body member  110  toward one another. The driver instrument may interact with at, at least, one of indentations/cut outs  11024  of side wall  1102  of each body member  110 . While at least one driver instrument maintains compression across the opposing body members  110  (and maintain a force that pushes the body members  110  toward one another), each of the locking nuts  123  is advanced downward toward the body members, as described above. The locking nuts  123  are advanced until all members (body member  110 , locking member  122 , and rod  112 ) of the system  105  are immobilized relative to one another. The driver instrument(s) is removed and each cavity  1109  (of the body members  110 ) is packed with bone graft material. Note that the bone graft material is then be placed in contact with the lateral wall of the spinous process, or forced out the lower surface of cavity  1109  and placed into contact with the posterior aspect of the vertebral lamina (VL), or both. (In the implanted state, the vertebral lamina are situated anatomically anterior to the implant.) The implanted system is shown in  FIG. 11 . 
     There is now described an additional embodiment wherein a bone screw assembly may be anchored into the pedicle portion of the vertebral bone and used as an additional point of device fixation.  FIG. 12A  shows an embodiment of an assembled bone screw assembly.  FIG. 12B  shows the bone screw assembly in an exploded state. The illustrated screw assembly is for example and those of ordinary skill in the art will appreciate that a large number of bone screws that are presently known, and/or yet to be known, may be alternative used in this application. 
     With reference to  FIGS. 12A and 12B , the exemplary embodiment of the bone screw assembly includes a bone screw having a head and a shank. The head of the bone screw can be seated in a receiver assembly of the bone screw assembly. The receiver assembly includes an outer housing and an inner housing that collectively form a seat for the head of the bone screw. The bone screw assembly further includes a locking nut assembly that includes an upper member that is positioned above the head of the bone screw, a washer member and a locking nut. The upper member has a pair of outwardly extending arms that fit between upwardly extending prongs of the inner and outer housings of the housing assembly. 
     In use, with reference to  FIG. 13A  and  FIG. 13B , at lease one bone screw assembly is placed into a pedicle portion of the vertebral bone. A screw assembly may be placed into the pedicle portion of each of the two pedicles of the lower (i.e., inferior) vertebral bone of the pair of vertebrae to be immobilized. In use, each bone screw may be positioned into the pedicle portion of the vertebral bones using any trajectory that permits proper screw placement. In a preferred embodiment, at least one bone screw is placed into the pedicle portion of the lower vertebral bone through a bone entry point that rests immediately inferior to the inferior articulating process of the upper (i.e., superior) vertebral bone of the pair of vertebrae to be immobilized. In this way, the inferior articulating process of the upper vertebral bone abuts the superior surface of the bone screw and prevents further extension of the upper vertebra relative to the lower vertebra. (Note that a facet joint is anatomically comprised of the articulation between the inferior articulating process (IAP) of an upper (superior) vertebral bone and the superior articulating process (SAP) of a lower (inferior) bone. These definitions of anatomical structures are known to those of ordinary skill in the art. They are described in more detail in  Atlas of Human Anatomy , by Frank Netter, third edition, Icon Learning Systems, Teterboro, N.J. The text is hereby incorporated by reference in its entirety.) 
     An elongated interconnecting rod is used to interconnect the screw assemblies. A system  105  is placed with body members  110  on each side of the spinous process (as described above) and coupled onto the rod as described above. (Alternatively, the interconnecting rod can be implanted with system  105  assembled and then lowered onto the screw assemblies.) After the placement of all instrumentation, the locking nuts  123  and the locking nut assembly  52  (shown in  FIG. 12 ) of the bone screws assemblies are then locked and all members of the system  105  and bone screw assembly are immobilized.  FIGS. 13 and 14  shown an assembled construct. This provides a significant increase in the immobilization power of the system  105 . 
     In another embodiment, multi-level fixation can be performed with serial implantation of multiple systems  105 . The stepped configuration of each system  105  permits the placement of more than one system  105  on a single spinous process.  FIG. 15  shows the fixation of three adjacent vertebral bones using two systems  105 . While the systems  105  are shown attached to bone screws as in the embodiment of  FIGS. 13 and 14 , the systems  105  may be alternatively used without a bone screw anchor, as in the embodiment of  FIG. 11 . 
       FIG. 16  shows use of the system  105  wherein one vertebral bone does not have a spinous process that will permit device fixation. This situation can occur when, for example, the system  105  is used to immobilize the L 5  and S 1  vertebral bones. In that application, the S 1  spinous process is often too small to accommodate the fixation of a portion of body member  110 . In an additional embodiment, the situation can also arise when one of the vertebral bones had undergone a prior laminectomy. In either situation, the system  105  placed such that the body members  110  are affixed to the spinous process of a first vertebra and the pedicle portion of a second vertebra, wherein the attachment to the pedicles is preferably performed through the use of pedicle bone screws. That is, the system  105  is attached to pedicle screws via the rod  112 . 
     By way of illustration,  FIG. 16  shows that the lamina and spinous process of the inferior vertebra bone V 1  have been removed. The lamina  207  and spinous process  209  of the upper vertebra V 2  remains intact. While the protrusions  11044  of each body member  110  over the inferior vertebra bone V 1  are shown as not contacting one another, in actual application the protrusions  11044  from each body member  110  over the removed lamina may abut at least a portion of the wall  1104  of the other member  110 . 
       FIGS. 17A and 17B  show an additional embodiment of the system  105  that may be used with a bone screw. In this embodiment, the bone screw  214  transverse the pedicle portion of a first vertebral bone, crosses the disc space between the first and second vertebral bones and enters the inferior surface of the second vertebral bone. While the bone screw is shown being detached from the system  105 , it may be alternatively comprised of a bone screw assembly that can fixate onto the interconnecting rod (similar to the embodiments of  FIGS. 13 and 14 ). 
     As shown in  FIGS. 17A and 17B , a bone screw is used to cross the disc space and fixate the two vertebral bones. This fixation compliments the posterior fixation provided by the system  105  and thus provides fixation of the two vertebral bones that is both anterior and posterior to the spinal canal. 
     In an alternative embodiment, a fastener or bone screw may be similarly positioned into the pedicle of the inferior vertebra. The fastener then transverses the pedicle, crosses the disc space between the two vertebrae and enters the inferior aspect of the upper vertebra. The fastener may be further adapted to move the top vertebral bone relative to the lower vertebral bone. After re-positioning of the two vertebral bones, a system  105  may be then applied to the posterior aspect of the two vertebrae. These devices and methods of use are particularly useful to re-align, at least partially, vertebral bones that may be mal-aligned. 
       FIG. 18  illustrates an embodiment wherein a bone screw or fastener  310  is positioned through the pedicle of the inferior vertebra V 1 , across the disc space between the two vertebrae and into the inferior aspect of the upper vertebra.  FIG. 19A  shows an exemplary embodiment of the fastener  310 . The fastener includes a first threaded elongated segment  3102  and a second threaded elongated segment  3104  that are attached to one another in an assembled state.  FIG. 19B  shows an assembled fastener wherein the two device segments  3102  and  3104  are attached with at least one link member  3106 . The link members  3106  are elongated members that attach at opposite ends to the device segments  3102  and  3104  in a pivoting manner. The fastener  310  is implanted while in the configuration depicted in  FIG. 19B . In this configuration, the link members  3106  are pivoted outward such that the segments  3102  and  3104  are moved further away from one another. After placement, the fastener is transitioned into the configuration shown in  FIG. 19C  wherein the link members  3106  are pivoted inward such that the segments  3102  and  3104  are moved toward away one another. The instrumentation needed to place the fastener into bone is not shown, but may be a simple driver that engages head  3101 . While not shown, the mechanism and/or instrumentation needed to transition the fastener from the configuration of  FIG. 19B  into the configuration of  FIG. 19C  may include any of the mechanism/instruments known in the art movement of a member  3104  relative to a member  3102 . For example, it is contemplated that a small internal threaded screw is positioned within proximal member  3102 . The engagable head of the small internal screw rests within head  3101  and the internal screw has a trajectory within the interior of the screw  310  that is eccentrically positioned along the long axis of member  3102 . The trajectory of the small internal screw is schematically shown by A in  FIG. 19C . To transition the screw  310  from the embodiment of  FIG. 19B  to the embodiment of  FIG. 19C , the small screw is engaged and threadedly advanced so as to forcibly abut the member  3106  within the interior of screw  310  at or about point X ( FIG. 19C ). With advancement of the small internal screw, member  3106  is forcibly rotated about a fixation pin  31066 . 
       FIG. 20  illustrates how, with transition to the configuration of  FIG. 19C , the fastener  310  can produce the posterior movement of the upper vertebra V 2 , as well as an increase in the distance between the vertebra across the disc space. The fastener can also produce an increase in segmental lordosis, wherein the lordotic curvature of the lumbar spine is reformed, with a change to the configuration of  FIG. 19C . While the link members  3106  are shown as being substantially equal in length, they may alternatively be non-equal so at produce desired movement of the bones (such as additional lordosis) with configuration change of the fastener. After reducing the bones as shown in  FIG. 20 , the system  105  may be attached to the spinous processes of the vertebral bones in order to immobilize the vertebrae in this position. This is shown in  FIG. 21 . While bone screw  310  is illustrated as a singular bone screw with the movable feature discussed above, it may alternatively contain a proximal housing assembly that is adapted to accept an interconnecting rod. A example of a screw assembly is shown in  FIG. 12 . The illustrated screw assembly is for example and those of ordinary skill in the art will appreciate that a large number of bone screws that are presently known, and/or yet to be known, may be alternative used in this application. 
     The disclosed devices or any of their components can be made of any biologically adaptable or compatible materials. Materials considered acceptable for biological implantation are well known and include, but are not limited to, stainless steel, titanium, tantalum, shape memory alloys, combination metallic alloys, various plastics, resins, ceramics, biologically absorbable materials and the like. Any components may be also coated/made with osteo-conductive (such as deminerized bone matrix, hydroxyapatite, and the like) and/or osteo-inductive (such as Transforming Growth Factor “TGF-B,” Platelet-Derived Growth Factor “PDGF,” Bone-Morphogenic Protein “BMP,” and the like) bio-active materials that promote bone formation. Further, any surface may be made with a porous ingrowth surface (such as titanium wire mesh, plasma-sprayed titanium, tantalum, porous CoCr, and the like), provided with a bioactive coating, made using tantalum, and/or helical rosette carbon nanotubes (or other carbon nanotube-based coating) in order to promote bone in-growth or establish a mineralized connection between the bone and the implant, and reduce the likelihood of implant loosening. Lastly, the system or any of its components can also be entirely or partially made of a shape memory material or other deformable material. 
     While this specification contains many specifics, these should not be construed as limitations on the scope of an invention that is claimed or of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. 
     Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.