Patent Document

BACKGROUND 
     Severe back pain and nerve damage may be caused by injured, degraded, or diseased spinal joints and particularly, spinal discs. Current methods of treating these damaged spinal discs may include vertebral fusion, nucleus replacements, or motion preservation disc prostheses. Other treatment methods include spinal stabilization implants whereby a stabilization connector is secured to a pair of vertebral members spaced from one another. Some stabilization connectors are constructed to flex in a certain orientation or plane yet block or restrict movement in another plane. In this regard, determining the proper orientation of the connector relative to spinal joints greatly affects the effectiveness of the connector as a spinal stabilizer. 
     One exemplary connector is a spinal stabilization rod. Conventionally, these rods, which may be straight or pre-bent to have desired curvature, have a circular cross-section. The shape of the spinal stabilization rod has typically been applauded as allowing the surgeon a great degree of freedom in orientating the rod relative to a vertebral member. Notwithstanding this advantage, increasingly there is a desire for the rod to positionable at one of a number of discrete orientations. That is, stabilization rods can be constructed to provide a desired performance when placed in a specific orientation. It is difficult to achieve a specific orientation with conventional rods because the shape of conventional rods results in indefinitely defined possible orientations. 
     Moreover, a set screw is often used to secure the spinal stabilization rod in the rod-receiving channel of a receiver. The set screw typically has a planar surface that interfaces with the outer, and curved, surface of the stabilization rod. As a result, the set screw tangentially seats against the round stabilization rod. This tangential seating can result in focalized or poorly distributed contact forces. 
     Therefore, it would be desirable to have a spinal stabilization connector that presents discrete orientations at which the connector can be oriented. It would also be desirable to have a spinal stabilization connector that presents a relatively planar surface for engagement with the planar surface of a set screw used to secure the connector in a receiver so that contact forces are more effectively distributed. 
     SUMMARY 
     In one aspect of the present disclosure, a spinal stabilizing system is presented having a spinal stabilization connector designed to traverse a space between a pair of vertebral members. The spinal stabilization connector is constructed to have first and second ends shaped to define a plurality of discrete positions relative to the vertebral members. The spinal stabilization connector further has a body connected to the first and second ends, and a curved portion extending between the first and second ends. 
     In another aspect, the present disclosure includes a spinal stabilizing kit. The kit has a pair of receivers, a pair of bone-engaging screws, a spinal stabilization connector, and a pair of locking screws. Each bone-engaging screw is retainable by a receiver and drivingly engageable with a bony structure. The spinal stabilization connector has a curved potion and first and second ends spaced from one another by the curved portion. The first and second ends are shaped to define a discrete number of positions at which the spinal stabilization connector may be retained by the pair of receivers. Each locking screw is designed to lock the spinal stabilization connector in a receiver. 
     According to another aspect of the present disclosure, a surgical method is presented for stabilizing a spinal joint with a spinal stabilizing system that includes a spinal stabilization connector having a curved portion that can be oriented at one of a plurality of discrete orientation positions relative to the spinal joint. The method includes fastening a first receiver to a first vertebral member and determining a desired orientation of the curved portion of the spinal stabilization connector relative to the vertebral member. The method further includes rotating the spinal stabilization connector to the discrete orientation position that corresponds to the desired orientation of the spinal stabilization connector and securing a first end of the spinal stabilization connector to the first receiver. A second receiver is fastened to a second vertebral member spaced from the first vertebral member. A second end of the spinal stabilization connector is then secured to the second receiver. 
     According to a further aspect of the present disclosure, an implant for stabilizing bony structures is presented. The implant has a first boss and a second boss laterally spaced from the first boss. A ribbon member extends between the first boss and the second boss along a plane different from that of the first and the second bosses. Moreover, the ribbon member has a length sufficient to traverse a space between at least two bony structures. 
     These and other aspects, forms, objects, features, and benefits of the present invention will become apparent from the following detailed drawings and descriptions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a pictorial representation of a vertebral column with a vertebral stabilizing system according to one embodiment of the present disclosure. 
         FIG. 2  is a perspective view of the vertebral stabilizing system according to one embodiment of the present disclosure. 
         FIG. 3  is a partial end view of the vertebral stabilizing system according to one embodiment of the present disclosure. 
         FIGS. 4   a - 4   c  are partial perspective views of the vertebral stabilizing system illustrating various orientation positions for a spinal stabilization connector according to one embodiment of the present disclosure. 
         FIGS. 5   a - 5   b  are perspective views of another vertebral stabilizing system illustrating various orientation positions for a spinal stabilization connector according to another embodiment of the present disclosure. 
         FIGS. 6   a - 6   c  are perspective views of yet another vertebral stabilizing system illustrating various orientation positions for a spinal stabilization connector according to yet another embodiment of the present disclosure. 
         FIGS. 7   a - 7   b  are perspective views of another vertebral stabilizing system illustrating various orientation positions for a spinal stabilization connector according to another embodiment of the present disclosure. 
         FIG. 8  is a perspective view of a spinal stabilization connector according to another embodiment of the present disclosure. 
         FIG. 9   a  is a perspective view of the spinal stabilization connector of  FIG. 8  with one end secured within a receiver according to one embodiment of the present disclosure. 
         FIG. 9   b  is a top view of that illustrated in  FIG. 9   a.    
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates generally to the field of orthopedic surgery, and more particularly to systems and methods for stabilizing a spinal joint. For the purposes of promoting an understanding of the principles of the invention, reference will now be made to embodiments or examples illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alteration and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. 
     Referring to  FIGS. 1-2 , the numeral  10  refers to a spinal column having a series of vertebral joints  12 , each including an intervertebral disc  14 . One of the vertebral joints  12  will be described further with reference to adjacent vertebrae  16 ,  18 . The vertebra  16  includes transverse processes  20 ,  22 , a spinous process  24 , superior articular processes  26 ,  28 , and inferior articular processes  30 ,  32 . Similarly, the vertebra  18  includes transverse processes  34 ,  36 , a spinous process  38 , superior articular processes  40 ,  42 , and inferior articular processes (not labeled). Although the illustration of  FIG. 1  generally depicts the vertebral joint  12  as a lumbar vertebral joint, it is understood that the devices, systems, and methods of this disclosure may also be applied to all regions of the vertebral column, including the cervical and thoracic regions. Furthermore, the devices, systems, and methods of this disclosure may be used in non-spinal orthopedic applications. 
     A facet joint  44  is formed, in part, by the adjacent articular processes  32 ,  40 . Likewise, another facet joint  46  is formed, in part, by the adjacent articular processes  30 ,  42 . Facet joints also may be referred to as zygapophyseal joints. A healthy facet joint includes a facet capsule extending between the adjacent articular processes. The facet capsule comprises cartilage and synovial fluid to permit the articulating surfaces of the articular processes to remain lubricated and glide over one another. The type of motion permitted by the facet joints is dependent on the region of the vertebral column. For example, in a healthy lumbar region, the facet joints limit rotational motion but permit greater freedom for flexion, extension, and lateral bending motions. By contrast, in a healthy cervical region of the vertebral column, the facet joints permit rotational motion as well as flexion, extension, and lateral bending motions. As the facet joint deteriorates, the facet capsule may become compressed and worn, losing its ability to provide a smooth, lubricated interface between the articular surfaces of the articular processes. This may cause pain and limit motion at the affected joint. Facet joint deterioration may also cause inflammation and enlargement of the facet joint which may, in turn, contribute to spinal stenosis. Removal of an afflicted articular process may result in abnormal motions and loading on the remaining components of the joint. The embodiments described below may be used to stabilize a deteriorated facet joint while still allowing some level of natural motion. 
     Injury, disease, and deterioration of the intervertebral disc  14  may also cause pain and limit motion. In a healthy intervertebral joint, the intervertebral disc permits rotation, lateral bending, flexion, and extension motions. As the intervertebral joint deteriorates, the intervertebral disc may become compressed, displaced, or herniated, resulting in excess pressure in other areas of the spine, particularly the posterior bony elements of the afflicted vertebrae. This deterioration may lead to spinal stenosis. In one application, the embodiments described below may restore more natural spacing to the posterior bony elements of the vertebrae, decompress an intervertebral disc, and/or may relieve spinal stenosis. Referring still to  FIGS. 1-2 , in one embodiment, a vertebral stabilizing system  48  may be used to provide support to the vertebrae  16 ,  18 , at least partially decompress the disc  14  and the facet joint  46 , and/or relieve stenosis. 
     Connected at each end to vertebral fasteners  50 ,  52 , a spinal stabilization connector  54  may provide compressive support and load distribution, providing relief to the intervertebral disc  14 . In addition, the spinal stabilization connector  54  may dampen the forces on the intervertebral disc  14  and facet joint  46  during motion such as flexion. Because the spinal stabilization connector  54  is securely connected to the vertebral fasteners  50 ,  52 , the spinal stabilization connector  54  also provides relief in tension/extension. Accordingly, during bending or in extension, the spinal stabilization connector  54  may assist in providing a flexible dampening force to limit the chance of overcompression or overextension when muscles are weak. In addition, the spinal stabilization connector  54  allows at least some torsional movement of the vertebra  16  relative to the vertebra  18 . In one exemplary embodiment, the fasteners  50 ,  52  include a pedicle screw  56 ,  58  that together with receivers  60 ,  62  secure the spinal stabilization connector  54  in place. Such an exemplary fastener is described in U.S. Pat. No. 6,280,442, the disclosure of which is incorporated herein by reference. 
     Referring now to  FIG. 2 , the spinal stabilizing system  48  is shown as having a spinal stabilization connector  54  with a hexagonal cross-section. In this regard, the spinal stabilization connector  54  is defined by six sidewalls  64 ( a ),  64 ( b ),  64 ( c ),  64 ( d ),  64 ( e ), and  64 ( f ) that, in the illustrated example, run along the entire length of the spinal stabilization connector. Only sidewalls  64 ( a ),  64 ( b ), and  64 ( c ) are viewable in  FIG. 2 . Each end of the spinal stabilization connector, as described with respect to  FIG. 1 , is retained in a vertebral fastener  50 ,  52 . 
     Vertebral fastener  50  includes a receiver  60 , pedicle screw  56 , and a locking screw or cap  66 . More particularly, receiver  60  defines an upper opening portion  60 ( a ) and a lower opening portion  60 ( b ), which collectively form a single opening (not numbered) that extends through the receiver  60  from an upper aperture (shown occupied by locking screw  66 ) in top end  72  and a lower aperture (shown occupied by pedicle screw  56 ) in bottom end  74 . Although not shown, the bottom end  74  includes an annular groove that is sized to receive a retaining ring (not shown) against which the head (not shown) of the pedicle screw  56  seats. 
     Receiver  60  includes a pair of upright branches  76 ,  78  that collectively define a U-shaped channel  80  transverse to the single opening defined longitudinally through the receiver. Moreover, the U-shaped channel  80  communicates with upper opening portion  60 ( a ) and lower opening portion  60 ( b ). The U-shaped channel  80  is sized to receive the distal end  82  of spinal stabilization connector  54 . 
     Locking cap  66  has a threaded body  84  that includes a series of threads that are compatible with internal threads (not shown) formed along the interior walls  86 ,  88  of branches  76 ,  78 , respectively. In one embodiment, the internal threads of branches  76 ,  78  are reverse angle threads, such as disclosed in U.S. Pat. No. 6,296,242, the disclosure of which is incorporated herein by reference. It is understood, however, that the present disclosure is applicable with vertebral fasteners having other thread orientations. The branches  76 ,  78  also have indentations or holes  90 ,  92  that allow a surgeon to grip the receiver  60  with an appropriate gripping tool (not shown). 
     Vertebral fastener  50  also has a crown member  94  shaped to accommodate the head of pedicle screw  56 . One exemplary crown member is more fully described in U.S. Pat. No. 6,280,442, the disclosure of which is incorporated herein by reference. Crown member  94  is constructed to fit within the lower opening portion  60 ( b ) and compresses against the head of the pedicle screw when the spinal stabilization connector  54  is secured within U-shaped channel  80 . 
     More particularly, crown member  94  and pedicle screw  56  are retained within the receiver  60  by inserting the crown member  94  and the head of the pedicle screw  56  through the lower aperture in bottom end  74 . The retaining ring is then positioned within the annual groove defined in the bottom end  74  of the receiver to prevent the crown member  94  and pedicle screw  56  from translating through the lower aperture. A hole (not shown) formed in the crown member  94  allows a surgeon to engage a driving tool with a corresponding printed surface (not shown) of the pedicle screw head. In this regard, once a hole is appropriately prepared in a vertebral member, the pedicle screw can be threaded into the vertebral member. It is understood that the present disclosure is applicable with vertebral fasteners having configurations different from the vertebral fasteners described herein. 
     Following insertion of the pedicle screw  56  into the vertebral member, the spinal stabilization connector  54  is placed in the U-shaped channel  80  and in contact with the top surface of crown member  94 . Locking screw  66  or other compression member is then threaded into corresponding threads of the receiver  60  and into contact with the spinal stabilization connector  54 . As the locking screw  66  is driven into contact with the spinal stabilization connector  54 , the spinal stabilization connector  54  is forced downward against the crown member  94  which then compresses against the head of the pedicle screw  56 . It is understood that the present disclosure is applicable with other known or to be developed locking configurations. 
     Once the spinal stabilization connector  54  is secured by fastener  50 , the proximal end  96  of the spinal stabilization connector  54  is secured to fastener  52 . Fastener  52  is similar in design to fastener  50  described above. Specifically, vertebral fastener  52  includes receiver  62 , pedicle screw  56 , and a locking screw or cap  98 . Receiver  62  defines an upper opening portion  62 ( a ) and a lower opening portion  62 ( b ), which collectively form a single opening (not numbered) that extends through the receiver  62  from an upper aperture (shown occupied by locking screw  98 ) in top end  100  and a lower aperture (shown occupied by pedicle screw  58 ) in bottom end  102 . Although not shown, the bottom end  102  includes an annular groove that is sized to receive a retaining ring (not shown) against which the head (not shown) of the pedicle screw  58  seats. 
     Receiver  62  includes a pair of upright branches  104 ,  106  that collectively define a U-shaped channel  108  transverse to the single opening defined longitudinally through the receiver. Moreover, the U-shaped channel  108  communicates with upper opening portion  62 ( a ) and lower opening portion  62 ( b ). The U-shaped channel  108  is sized to receive the proximal end  96  of spinal stabilization connector  54 . 
     Locking cap  98  has a threaded body  110  that includes a series of threads that are compatible with internal threads (not shown) formed along the interior walls  112 ,  114  of branches  104 ,  106 , respectively. In one embodiment, the internal threads of branches  104 ,  106  are reverse angle threads, such as disclosed in U.S. Pat. No. 6,296,242, the disclosure of which is incorporated herein by reference. It is understood, however, that the present disclosure is applicable with vertebral fasteners having other thread orientations. The branches  104 ,  106  also have indentations or holes  116 ,  118  that allow a surgeon to grip the receiver  62  with an appropriate gripping tool (not shown). 
     Vertebral fastener  52  also has a crown member  120  shaped to accommodate the head of pedicle screw  58 . One exemplary crown member is more fully described in U.S. Pat. No. 6,280,442, the disclosure of which is incorporated herein by reference. Crown member  120  is constructed to fit within the lower opening portion  62 ( b ) and compresses against the head of the pedicle screw  58  when the spinal stabilization connector  54  is secured within U-shaped channel  108 . 
     Thus, once an appropriate hole is formed a vertebral member, pedicle screw  58 , having been placed and secured within receiver  62 , is inserted into the vertebral member. Once secured, the spinal stabilization connector  54  is placed within rod-receiving channel  108 . Locking cap  98  is then threadingly connected to the receiver  62 , in a manner similar to that described above. The locking cap  98  contacts against the proximal end  96  of the spinal stabilization connector  54 , which causes the spinal stabilization connector  54  to push against crown member  120 . Crown member  120  then compresses against the head of the pedicle screw  58  thereby locking fastener  52  and the spinal stabilization connector  54  into place. It is recognized that the spinal stabilization connector  54  may have a length greater than the distance between the fasteners  50 ,  52 . As such, an appropriate cutting tool (not shown) may be used to cut-off lengths of the spinal stabilization connector  54  that extends distally past fastener  50  and proximally past fastener  52 . 
     Referring now to  FIG. 3 , an end view of vertebral fastener  52  illustrates one aspect of the present disclosure. As illustrated, the threaded body  110  of locking screw  98  has a proximal end  122  designed to engage an appropriate tool (not shown) for threading the locking screw  98  into the receiver  62 . The distal end  124  of the locking screw  98  has a relatively planar surface that contacts a corresponding planar or flat surface  64 ( a ) of the spinal stabilization connector  54 . That is, as described above, in contrast to conventional round stabilizing rods, spinal stabilization connector  54  has a plurality of discretely defined and planar sidewalls that run along its length. Since the sidewalls have a planar exterior surface, a relatively planar or flat interface is provided for the distal end  124  of the locking screw. This provides a more force distributing interface than that provided by the tangential interface formed with the curved exterior surface of a conventional stabilizing rod. 
     Alternatively, the spinal stabilization connector can be constructed to have a groove defined along its length, or portion thereof, that is contoured to receive the distal end of the locking screw. In this arrangement, the groove in the connector provides a contoured seat for the locking screw. In another alternate embodiment, the crown member of each vertebral fastener can be constructed to have a groove or other geometry matched to the shape of the spinal stabilization connector. In this regard, the crown member is contoured to match the shape of the spinal stabilization connector and to thereby provide a seat for the spinal stabilization connector. For example, if the spinal stabilization connector is constructed to have a triangular cross-section, the crown member could be constructed to have a V-shaped groove appropriately contoured to receive the spinal stabilization connector. 
     In addition to providing a planar contact interface between the spinal stabilization connector  54  and the locking screw  98 , the symmetry of the spinal stabilization connector  54  results in a planar interface with crown member  120 . As shown in  FIG. 3 , the sidewall  64 ( f ) opposite of sidewall  64 ( a ) abuts the top surface  126  of crown member  120 . As such, a force distributing interface is also formed between the spinal stabilization connector and the crown member. In one embodiment, the spinal stabilization connector has an equal number of planar sidewalls such that planar interfaces are formed between the spinal stabilization connector and the locking screw and between the spinal stabilization connector and the crown member, as described above. However, it is contemplated that the spinal stabilization connector could be constructed to have an odd number of planar sidewalls. With such a construction, it is preferred that a planar interface be formed between the spinal stabilization connector and the locking screw whereas a point interface is formed between the spinal stabilization connector and the crown member. 
     In addition to providing planar interfaces, the planar sidewalls of the spinal stabilization connector  54  define discrete positions of orientation for the spinal stabilization connector  54 . As shown in  FIG. 2 , the spinal stabilization connector includes a curved portion  128  defined between the distal end  84  and the proximal end  96  that is offset from the line-of-sight axis defined between the vertebral fasteners. Moreover, in the illustrated example, the curved portion  128  extends along a plane that is 60 degrees offset from parallel vertical axes extending through the receivers. 
     Increasingly, spinal stabilization connectors are being manufactured to perform differently based on the orientation of the spinal stabilization connector relative to a spinal joint. In this regard, by constructing the spinal stabilization connector to have a plurality of discrete positions at which the spinal stabilization connector can be placed, optimal or preferred performance characteristics of the spinal stabilization connector can be readily achieved with appropriate placement of the spinal stabilization connector in the vertebral fasteners. In the case of the illustrated example, the spinal stabilization connector  54  can be placed at six discrete orientations based on the planar sidewall that is used to interface with the locking screw  98 . Moreover, since the curvature is pre-defined along the length of the spinal stabilization connector  54 , discrete angular positions of the curved portion  128  relative to the vertical axes can be similarly realized. That is, if it is desired for the curved portion  128  to be offset from the vertical axes by 240 degrees, than the spinal stabilization is rotated in such a manner to place planar sidewall  64 ( d ) perpendicular to the vertical axes and thereby forming a planar interface between the planar sidewall  64 ( d ) and the planar distal surface  124  of the locking screw  98 . It is understood that the number of discrete positions can be more or less than the six positions defined by the spinal stabilization connector  54  illustrated in  FIGS. 1-3 . Moreover, the curved portion of the spinal stabilization connector can be constructed to have other geometries than those described above, as will be described with respect to  FIGS. 7   a - 9   b.    
       FIGS. 4   a - 9   b  illustrate spinal stabilization connectors according to alternate embodiments of the present disclosure. In some of the figures, the spinal stabilization connectors are shown connected to a single fastener. However, it is understood that in practice, the spinal stabilization connectors would be connected to at least two vertebral fasteners to provide spinal stabilization. Also, in describing the spinal stabilization connectors of  FIGS. 4   a - 9   b , various features of the vertebral stabilizer will be referenced. These features, as well as additional features not described with respect to  FIGS. 4   a - 9   b  are described and illustrated in  FIGS. 1-3 . Therefore, unless otherwise noted, the vertebral fasteners described in  FIGS. 4   a - 9   b  are similar in construction to the vertebral fasteners described in  FIGS. 1-3 . Additionally, reference will be made to the spinal stabilization connectors being fastened to vertebral fastener  52  in the description of  FIGS. 4   a - 9   b , but it is understood that the spinal stabilization connectors would fasten in a similar manner to vertebral fastener  54  described in  FIGS. 1-3 . Also, where appropriate, parts illustrated in  FIGS. 4   a - 9   b  will be referenced with like numbers as corresponding parts illustrated in and described with respect to  FIGS. 1-3 . 
       FIGS. 4   a - 4   c  illustrate a spinal stabilization connector  54 ( a ) constructed to have four equally sized sidewalls  64 ( g ),  64 ( h ),  64 ( i ),  64 ( j ), i.e., a square cross-section. The spinal stabilization connector  54 ( a ) is shown connected at one end to vertebral fastener  52 . Specifically,  FIG. 4   a  shows the spinal stabilization connector  54 ( a ) connected to the vertebral fastener  52  such that the curved portion  128 ( a ) is oriented to not be offset from the vertical axes extending through the vertebral fastener  52 . However, because of the defined curvature, the spinal stabilization connector  54 ( a ) has a relatively concave shape between ends  84 ( a ) and  96 ( a ). If the spinal stabilization connector  54 ( a ) was rotated 180 degrees from the position shown in  FIG. 4   a , the spinal stabilization connector  54 ( a ) would have a relative convex shape defined between ends  84 ( a ) and  96 ( a ).  FIG. 4   b  illustrates the orientation of the spinal stabilization connector  54 ( a ) relative to vertebral member  52  if the spinal stabilization connector  54 ( a ) is rotated 90 degrees to the right from the orientation shown in  FIG. 4   a . It is noted that in both orientations, a planar interface is formed between the distal planar surface  124  of the locking screw  98  and a planar sidewall of the spinal stabilization connector  54 ( a ). Specifically, in  FIG. 4   a , the distal planar surface  124  of the locking screw  98  abuts against planar sidewall  64 ( g ) whereas in  FIG. 4   b , the distal planar surface  124  abuts against planar sidewall  64 ( j ).  FIG. 4   c  is a an end view of that shown in  FIG. 4   b , which illustrates the curvature of the spinal stabilization connector  54 ( a ) as being offset from the line-of-sight axis that extends through the vertebral fastener  52  along the rod-receiving channel. It is noted that the present disclosure includes spinal stabilization connectors having more or less than four sidewalls. 
       FIGS. 5   a  and  5   b  illustrate a spinal stabilization connector  54 ( b ) according to another embodiment of the present disclosure. Spinal stabilization connector  54 ( b ) has a curved portion  128 ( b ) with a circular cross-section with ends  84 ( b ) and  96 ( b ) each having a multi-sided boss  130 ,  132 , respectively. In the illustrated embodiment, boss  130  has four planar sidewalls, of which sidewalls  134 ,  136 , and  138  are shown. Similarly, boss  132  has four planar sidewalls, of which sidewalls  140  and  142  are shown. In one embodiment, bosses  130 ,  132  are integrally formed with curved portion  128 ( b ). Alternately, the bosses may be separately formed and connected using adhesive or other mechanical connections, such as twist-lock or threaded engagements. Similar to the spinal stabilization connectors described above, the sidewalls of bosses  130 ,  132  define discrete positions at which the spinal stabilization connector  54 ( b ) can be oriented relative to a spinal joint. In  FIG. 5   a , the spinal stabilization connector  54 ( b ) is placed in the vertebral fastener  52  such that sidewall  140  of boss  132  and sidewall  134  of boss  130  are perpendicular to the vertical axis that extends through the vertebral fastener.  FIG. 5   b  shows the position of the spinal stabilization connector  54 ( b ) having been rotated 90 degrees to the left. As such, sidewalls  134 ,  140  are parallel to the vertical axes that extends through the vertebral fastener  52 . 
     Also,  FIGS. 5   a  and  5   b  illustrate the vertebral fastener  52  with the locking screw  98  removed. As such, the internal threads  144  of branch  106  are shown. Branch  104  similarly has internal threads (not shown). As described above, these internal threads engage the threaded body of the locking screw when the locking screw is fastened to the receiver  62 . Additionally, while the spinal stabilization connector is shown as having two bosses, one at each end; it is noted that the spinal stabilization connector may be constructed to have more than two bosses formed along its length. Also, a spinal stabilization connector may have bosses of different sizes. For example, the spinal stabilization connector may have one boss to accommodate a single screw and have another, but longer, boss sized to accommodate multiple screws. 
       FIGS. 6   a - 6   c  illustrated spinal stabilization connectors according to additional aspects of the present disclosure. The spinal stabilization connectors illustrated in  FIGS. 6   a - 6   c  have oval-shaped cross-sections. For example, spinal stabilization connector  54 ( c ) has a curved portion  128 ( c ) defined between ends  84 ( c ) and  96 ( c ). The curved portion  128 ( c ) is defined by a pair of facing arcuate sidewalls  64 ( k ),  64 ( l ). The arcuate sidewalls are joined together by a pair of facing planar sidewalls, of which sidewall  64 ( m ) is shown. The pair of planar sidewalls define two discrete positions of orientation for spinal stabilization connector  54 ( c ). The two discrete positions are rotated 180 degrees from one another such that spinal stabilization connector  54 ( c ) can be placed in the vertebral fastener so that the curved extends to the left in the figure or to the right in the figure. 
     Contrastingly, the spinal stabilization connector  54 ( d ) illustrated in  FIGS. 6   b  and  6   c , which also is shaped to have an oval cross-section, defines a pair of discrete positions that result in curved portion  128 ( d ) pointing upward in the figure or pointing downward in the figure. That is, in  FIGS. 6   b  and  6   c , the spinal stabilization connector  54 ( d ) is placed in the vertebral fastener  52  so that the curved portion is concave between ends  84 ( d ) and  96 ( d ). Rotating the spinal stabilization connector  54 ( d ) by 180 degrees, for example, would result in the curved portion having a convex orientation between ends  84 ( d ) and  96 ( d ). It is recognized that the direction of curvature of the spinal stabilization connectors illustrated in  FIGS. 6   a - 6   c  can be changed by changing the relative position of the planar sidewalls relative to the arcuate sidewalls. That is, the spinal stabilization connector may be constructed such that the angular displacement between the pair of discrete positions is less than (or more than) 180 degrees. 
       FIGS. 7   a - 9   b  illustrate spinal stabilization connectors according to another aspect of the invention. As will be described, the spinal stabilization connectors illustrated in  FIGS. 7   a - 9   b  have a curved portion shaped as a ribbon feature disposed between bosses at respective ends of a spinal stabilization connector. For example, spinal stabilization connector  54 ( e ), as shown in  FIGS. 7   a  and  7   b , has a pair of bosses  130 ( a ), 132 ( b ) at ends  84 ( e ),  96 ( e ), respectively. A curved portion  128 ( e ) extends between the pair of bosses  130 ( a ),  132 ( a ) and is shaped as a ribbon feature. In the illustrated example, the spinal stabilization connector  54 ( e ) is a four-sided connector with a pair of planar sidewalls that run along the entire length of the spinal stabilization connector  54 ( e ), of which sidewall  64 ( q ) is shown. Opposite the planar sidewalls are non-planar sidewalls, of which sidewalls  64 ( r ),  64 ( s ), are shown. Sidewalls  64 ( r ),  64 ( s ) are not entirely planar along their length as a result of the ribbon feature. However, as the ribbon feature does not extend to ends  84 ( e ),  96 ( e ), the bosses  130 ( a ),  132 ( a ) are defined by four planar surfaces. Thus, in a manner similar to that described with respect to  FIGS. 5   a  and  5   b , the spinal stabilization connector  54 ( e ) can be oriented at one of four discrete positions of orientation. One such position is shown in  FIG. 7   a . Another position, rotated ninety degrees from that shown in  FIG. 7   a , is illustrated in  FIG. 7   b . In both positions, as well as the other two possible orientations not shown, a planar interface is formed between the spinal stabilization connector  54 ( e ) and the locking screw  98 . 
       FIGS. 8 through 9   b  illustrate a spinal stabilization connector  54 ( f ) incorporating translational stops. While the translational stops are illustrated with respect to a spinal stabilization connector similar to that illustrated in  FIGS. 7   a  through  7   b , it is understood that the other spinal stabilization connectors described herein, or equivalents thereof, may also be constructed to have translational stops. 
     Spinal stabilization connector  54 ( f ) is similar to the spinal stabilization connector illustrated in  FIGS. 7   a  and  7   b  with the addition of flanges  146 ,  148  that extend from bosses  130 ( b ),  132 ( b ), respectively. Flanges  146 ,  148  operate as translational stops thereby limiting the translational movement of the spinal stabilization connector  54 ( f ) relative to the vertebral fasteners. More particularly, the spinal stabilization connector  54 ( f ) may be constructed to have an optimal or preferred distance between vertebral fasteners. The flanges  146 ,  148  define that distance. As such, when a surgeon is implanting the vertebral fasteners, the distance between the vertebral fasteners should be such that the flanges  146 ,  148  rest against or abut the face of respective receivers, as illustrated in  FIG. 9   a , for example. As shown in  FIG. 9   a , when the spinal stabilization connector  54 ( f ) is properly placed in the receiver  62 , flange  146  abuts against the face  150  of branch  104 . As shown in  FIG. 9   b , in one embodiment, spinal stabilization connector  54 ( f ) has a total of four flanges  146 ,  148 ,  152 ,  154 , two positioned at each of the bosses  130 ( b ),  132 ( b ). As such, flanges  146 ,  152  will abut against receiver  62 . Specifically, flange  146  abuts face  150  of branch  104  and flange  152  abuts face  156  of branch  106 . Flanges  148 ,  154  will similarly abut against faces of receiver  60  when the spinal stabilization connector  54 ( f ) is placed therein. It is contemplated that the spinal stabilization connector could be constructed to have less than or more than four flanges. 
     The spinal stabilization connectors shown in  FIGS. 7   a - 9   b  have a curved portion shaped as a ribbon feature. It is noted that the ribbon feature illustrates one exemplary geometry contemplated for the curved portion of the spinal stabilization connector. In this regard, it is contemplated that the curved portion may have other geometries or shapes different from those shown in the figures. Moreover, is contemplated that the curved portions may be vertically offset from the ends or bosses of the respective spinal stabilization connectors described herein. That is, in the example of  FIGS. 7   a - 9   b , the connectors may be constructed to include a riser (not shown) connected or otherwise extending from each of the bosses. The riser vertically offsets the curved portion from the bosses by the height of the risers. It is noted that the risers could be integrally formed with the bosses, e.g. L-shaped bosses, or may mechanically affixed to the bosses using a known or to be developed affixation technique. 
     The spinal stabilization connectors described herein may be placed directly adjacent the vertebrae, or alternatively, may be spaced from the vertebrae. In some embodiments, placement of the spinal stabilization connector directly adjacent the vertebrae may impart specific characteristics to the spinal stabilization connector. In some examples, the spinal stabilization connector may be spaced from the vertebrae. Accordingly even when the vertebral column is in flexion, causing the spine to bend forward, the vertebral fasteners maintain a line of sight position, so that the spinal stabilization connector extends only along a single axis, without bending. In other examples, after placement, the spinal stabilization connector may contact portions of the vertebrae during the flexion process. For example, during flexion, the vertebrae may move so that the first and second vertebral fasteners do not have a line of sight position. Accordingly, the spinal stabilization connector may be forced to bend around a protruding portion of the vertebrae. This may impart additional characteristics to the spinal stabilization connector. For example, because the spinal stabilization connector would effectively contact the spinal column at three locations (its two ends and somewhere between the two ends), its resistance to extension might be increased. 
     In the exemplary embodiments described, the spinal stabilization connector is the only component extending from one vertebral fastener to the other. This may be referred to as a single spinal stabilization connector. This single spinal stabilization connector may be contrasted with conventional systems that employ more than one connector extending between attachment points, such as systems with one component connected at the attachment points and another component extending between attachment points. Because it employs a single spinal stabilization connector, the vertebral stabilizing system disclosed herein may be easier and quicker to install, may be less complex, and may be more reliable than prior devices. 
     It should be noted however, that a spinal column may employ the spinal stabilization connector to extend across a first vertebral space, with a second spinal stabilization connector extending across a second vertebral space. Accordingly, more than one vertebral stabilizing system may be used in a spinal column. In some instances where more than one stabilizing system is use, the first and second vertebral spaces may be adjacent. In alternative embodiments, a vertebral stabilizing system may have a single spinal stabilization connector with a length allowing it to extend across more than one intervertebral space, with or without connecting to an intermediate vertebra. 
     Additionally, it is noted that a spinal stabilization connector can have a length that spans multiple spinal joints and, if necessary, more than two vertebral fasteners may be used to secure the spinal stabilization connector to vertebral members. Moreover, while the figures have been described with respect to placement of vertebral fasteners at the ends of a spinal stabilization connector, it is noted that vertebral fasteners could be placed at any position along the length of the spinal stabilization connector as deemed appropriate. It also noted that in the figures above, the geometry of the curved portion of a spinal stabilization connector is shown as being uniform in shape and size; however, it is contemplated that the spinal stabilization connector can have a variability in size and geometry along its length. For example, the spinal stabilization connector could be tapered from one end to the other or have multiple geometries defined along its length. In another example, spinal stabilization across multiple spinal joints is provided by using multiple spinal stabilization systems connected to one another. In this regard, it is contemplated that multiple spinal stabilization connectors can extend along the spinal column. Moreover, it is contemplated that the geometry (or size) of the spinal stabilization connectors used to provide spinal stabilization may vary along the length of the spinal column. 
     Also, a spinal stabilization connector has been described and shown as having planar sidewalls extending along its length. It is contemplated that the spinal stabilization connector could be constructed to have “soft” or slightly curved joints formed between the generally planar sidewalls rather than the “hard” joints shown in the figures. Further, the spinal stabilization connectors have been described and shown as having ends that are similarly shaped. However, it is contemplated that a spinal stabilization connector may have one end (or fastening position) with a first geometry and may have another end (or other fastening position) with a second geometry, different from the first geometry. Additionally, the present disclosure has been described with respect to various threaded engagements; however, it is understood that other types of engagements could be used, such as twist-locks, quarter-turn or half-turn locks, straps, clamps, and the like. 
     In certain anatomies, the vertebral stabilizing system may be used alone to provide decompression or compression to a single targeted facet joint or to relieve pressure on a particular side of the intervertebral disc, such as a herniation area. However, in some instances, a second vertebral stabilizing system may be installed on the opposite lateral side of the vertebrae across from the vertebral stabilizing system. Use of first and second vertebral stabilizing systems may provide more balanced support and equalized stabilization. The second vertebral stabilizing system may be substantially similar to system and therefore will not be described in detail. 
     The vertebral stabilizing system, as installed, may flexibly restrict over-compression of the vertebrae, thereby relieving pressure on the intervertebral disc and the facet joint. In addition, the vertebral stabilizing system may flexibly restrict axial over-extension of the intervertebral disc and the facet joint. By controlling both compression and extension, the vertebral stabilizing system may reduce wear and further degeneration. The spinal stabilization connector may also dampen the forces on the intervertebral disc and facet joint during motion such as flexion and extension. Because the spinal stabilization connector may be positioned relatively close to the natural axis of flexion, the vertebral stabilizing system may be less likely to induce kyphosis as compared to systems that rely upon inter-spinous process devices to provide compressive and tensile support. Additionally, the system may be installed minimally invasively with less dissection than the inter-spinous process devices of the prior art. Furthermore, an inter-pedicular system can be used on each lateral side of the vertebrae, and may provide greater and more balanced stabilization than single inter-spinous process devices. 
     It should be noted that in some embodiments, the spinal stabilization connector may be configured so that orientation in one direction provides one set of stabilizing properties to the vertebrae, while orienting the spinal stabilization connector in the other direction would provide a second set of stabilizing properties. Also, while the figures have been described with respect to a spinal stabilization rod, it is understood that the present disclosure is applicable with other types of connectors or tension members such as spinal stabilization plates. 
     It should be noted that the spinal stabilization connector can be made of elastic or semi-elastic materials in parts or in its entirety. On the other hand, the spinal stabilization connector can be made of a composite of elastic/semi-elastic and inelastic or rigid materials, such as that described in U.S. Ser. No. 11/7413,448, the disclosure of which is incorporated herein by reference. Exemplary elastic materials include polyurethane, silicone, silicone-polyurethane, polyolefin rubbers, hydrogels, and the like. The elastic materials can be resorbable, semi-resorbable, or non-resorbable. Exemplary inelastic materials include polymers, such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polylactic acid materials (PLA and PLDLA), metals, such as titanium, NITINOL, and stainless steel, and/or ceramics, such as calcium phosphate and alumina. Further, the various connector components can be solid, hollow, semi-hollow, braided, woven, mesh, porous, or combinations thereof. The connector can also be reinforced or semi-reinforced. Additionally, the connector can be made to have a variable rigidity, such as that described in U.S. Ser. No. 11/563,594, the disclosure of which is incorporated herein by reference. It is also contemplated that the connector can be fabricated using a number of fabrication techniques, such as injection molding as described in U.S. Ser. No. 11/469,354, the disclosure of which is incorporated herein by reference. Also, in one embodiment, the width between the planar sidewalls is equal to the diameter of conventional round spinal stabilization connectors; however, it is contemplated the distance between the planar sidewalls could be more or less than the diameter of conventional round spinal stabilization rounds. Therefore, it is also contemplated that the vertebral fasteners could be constructed to have a wider or narrow rod-receiving channel to accommodate the width of the spinal stabilization connectors described herein. Also, the spinal stabilization connectors may have different cross-sectional shapes than those shown and described. For example, the spinal stabilization connector could be constructed to have a D-shaped cross-section. 
     Although disclosed as being used at the posterior areas of the spine, the spinal stabilization connector may also be used in the anterior region of the spine to support the anterior column. In such a use, the spinal stabilization connector may be oriented adjacent to and connect to the anterior column, and may span a vertebral disc space. 
     The foregoing embodiments of the stabilization system may be provided individually or in a kit providing a variety of sizes of components as well as a variety of strengths for the connector. It is also contemplated that the connector&#39;s characteristics may be color coded or otherwise indicated on the connector itself to expedite identification of a desired connector. 
     The invention is also embodied in a surgical method for spinal or other bone stabilization. In accordance with this method, a surgeon performs a conventional interbody fusion/nucleus replacement/disc replacement followed by placement of pedicles/bone screws or other inserters into appropriate vertebral or other bony structures. The surgeon may then anchor one end of a connector into a first vertebral or other bony structure. If necessary or otherwise desired, tension is applied to the connector spanning the space between bony structures. The un-anchored end of the connector is then anchored to a second vertebral or other bony structure spaced from the first vertebral or other bony structure. 
     It is noted that various embodiments of the spinal stabilization connector described herein may include disjointed sections that can be threadingly engaged or otherwise connected to each other on a per patient basis. Thus, the above surgical method contemplates a surgeon connecting segments to each other until a desired length, elasticity, and the like is achieved. Moreover, a surgeon can construct such a connector on-the-fly quickly and with relative ease by connecting segments or components to one another. 
     Although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this disclosure. Accordingly, all such modifications and alternative are intended to be included within the scope of the invention as defined in the following claims. Those skilled in the art should also realize that such modifications and equivalent constructions or methods do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. It is understood that all spatial references, such as “horizontal,” “vertical,” “top,” “upper,” “lower,” “bottom,” “left,” “right,” “cephalad,” “caudal,” “upper,” and “lower,” are for illustrative purposes only and can be varied within the scope of the disclosure. Further, the embodiments of the present disclosure may be adapted to work singly or in combination over multiple spinal levels and vertebral motion segments. Also, though the embodiments have been described with respect to the spine and, more particularly, to vertebral motion segments, the present disclosure has similar application to other motion segments and parts of the body. In the claims, means-plus-function clauses are intended to cover the elements described herein as performing the recited function and not only structural equivalents, but also equivalent elements.

Technology Category: 1