Patent Publication Number: US-2009228046-A1

Title: Transverse vertebral connector

Description:
REFERENCE TO PRIORITY DOCUMENT 
     This application claims priority of co-pending U.S. Provisional Patent Application Ser. No. 60/898,010 filed Mar. 9, 2007. Priority of the aforementioned filing date is hereby claimed and the disclosures of the Provisional Patent Application is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     The use of spinal rods is conventional for correction of spinal trauma or conditions, such as curvature of the spine. Generally, an orthopedic stabilization system may include a pair of elongate members, such as spinal rods or plates, that are coupled to a bone or bones. For the sake of simplicity, the term “rod” is used throughout to refer to any elongate member. The rods are generally contoured and longitudinally disposed adjacent to vertebral bodies of a spine. 
     The strength and stability of the rod assembly can be increased by coupling the two rods with a cross-connector that extends substantially horizontal to the longitudinal axes of the rods across the spine. In some situations, the two rods are geometrically aligned such that the two rods are parallel to each other. However, the two rods are often not three dimensionally geometrically aligned in actual situations. There are several ways to address the variations of geometrical alignment. First, one or both of the rods can be bent to accommodate the transconnector. However, any bending in either of the rods can adversely affect the fixation to the spine and comprise clinical outcome. Furthermore, the bending can also adversely affect the mechanical properties of the rods. The transconnector can also be bent so that the disturbance to the rod positioning is minimized. As is the case with bending of the rods, the mechanical properties of the transconnector could be compromised. 
     Because of the forces acting along the transverse connector and the movement of the spinal rods, the connection between the transverse connector and the rod must be secure to avoid movement of the transverse connector along the spinal rod. Some rod fastening systems of transverse connectors use threaded fasteners to attach the transverse connector to adjacent rods. The threaded fastener can be a set screw or a nut. Not tightening a threaded fastener enough may allow movement of the transverse connector. Overtightening a threaded fastener could result in damage to the system and failure of the transverse connector. 
     SUMMARY 
     In view of the foregoing, there exists a need for an improved transconnector for coupling spinal rods. Disclosed is a transconnector for connecting first and second spinal rods that are positioned longitudinally along a spine. The transconnector comprises a first member having a first clamp member adapted to clamp onto a first spinal rod, the first member having a first connecting region extending away from the clamp member; a second member having a second clamp member adapted to clamp onto a second spinal rod, the second member having a second connecting region extending away from the second clamp member toward the first member, wherein the second member and first member are slidably interconnected along the first and second connecting regions; a first interference pin coupled to the first clamp member and adapted to provide an interfering engagement with the first spinal rod to lock the first spinal rod in the first clamp member; a second interference pin coupled to the second clamp member and adapted to provide an interfering engagement with the second spinal rod to lock the second spinal rod in the second clamp member; and a third interference pin coupled to the first and second connecting regions and adapted to provide an interfering engagement between the first and second connecting regions to lock the first and second members in a fixed position relative to one another. 
     Other features and advantages will 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  shows a schematic of three vertebrae connected by longitudinal members and two transverse connectors. 
         FIG. 2  shows a perspective view of an embodiment of a transverse connector and two longitudinal members. 
         FIG. 3  shows an exploded view of the transverse connector of  FIG. 2 . 
         FIG. 4  shows a cross-sectional view of the transverse connector of  FIG. 2 . 
         FIG. 5  shows a top plan view of the transverse connector of  FIG. 2 . 
         FIG. 6  shows a perspective view of another embodiment of a transverse connector and two longitudinal members. 
         FIG. 7  shows an exploded view of the transverse connector of  FIG. 6 . 
         FIG. 8  shows a cross-sectional view of the transverse connector of  FIG. 6 . 
         FIG. 9  shows a top plan view of the transverse connector of  FIG. 6 . 
         FIG. 10  shows a perspective view of another embodiment of a transverse connector and two longitudinal members. 
         FIG. 11  shows an exploded view of the transverse connector of  FIG. 10 . 
         FIG. 12  shows a cross-sectional view of the transverse connector of  FIG. 10 . 
         FIG. 13  shows a top plan view of the transverse connector of  FIG. 10 . 
         FIG. 14  shows a perspective view of another embodiment of a transverse connector and two longitudinal members. 
         FIG. 15  shows an exploded view of the transverse connector of  FIG. 14 . 
         FIG. 16  shows a cross-sectional view of the transverse connector of  FIG. 14 . 
         FIG. 17  shows a top plan view of the transverse connector of  FIG. 14 . 
         FIG. 18  shows a perspective view of another embodiment of a transverse connector. 
         FIG. 19  shows an exploded view of the transverse connector of  FIG. 18 . 
         FIG. 20  shows a cross-sectional view of the transverse connector of  FIG. 18 . 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are methods and devices for interconnecting first and second longitudinal members extending along a spinal column of a patient. 
       FIGS. 2-17  illustrate various embodiments of exemplary transverse connectors  100 ,  200 ,  300  and  400 , and in each of the illustrated embodiments the transverse connector  100 ,  200 ,  300 ,  400  generally includes a first connecting member  105 ,  205 ,  305 ,  405  and a second connecting member  110 ,  210 ,  310 ,  410 . Each pair of connecting member  105 ,  205 ,  305 ,  405 ,  110 ,  210 ,  310 ,  410  connect to each other transversely (i.e., across the midline of the vertebral column) in a variety of configurations. Each pair of connecting members  105 ,  205 ,  305 ,  405 ,  110 ,  210 ,  310 ,  410  are fixed to each other by a variety mechanisms generally involving a set screw  114 ,  118 ,  214 ,  314 ,  414 . Further, each embodiment of the transverse connector  100 ,  200 ,  300  and  400  includes a clamping mechanism that is adapted to selectively lock a longitudinal member extending along a spinal column of a patient, such as a spinal fixation element, and in particular a spinal fixation rod. The fixation of the connecting member pairs and the clamping mechanisms allow for transverse as well as rotational adjustability of the transverse connectors  100 ,  200 ,  300  and  400 . 
     A person skilled in the art will appreciate that while each transverse connector  100 ,  200 ,  300 ,  400  is described herein as being adapted to engage a spinal fixation element, and in particular a spinal fixation rod, that a transverse connector disclosed herein can be configured to engage a variety of spinal fixation devices, such as anchors, cables, fixation plates, etc. Moreover, the transverse connectors can include only one connector member for engaging a spinal fixation device, and the opposed terminal end of the transverse connectors can be adapted for other uses. For example, the opposed terminal end of the transverse connectors can be configured to be fixedly attached to a vertebra. The transverse connectors disclosed herein can also include any combination of features described and/or illustrated herein, and the transverse connectors are not limited to the illustrated embodiments. 
     As indicated above, the transverse connector in certain exemplary embodiments includes a first connecting member and a second connecting member that extend toward each other between each longitudinal member or spinal rod. The first and second connecting members can connect by a variety of mechanisms or configurations. The first and second connecting members can be generally elongate and positioned a distance apart from one another and adjusted transversely. The first and second connecting members can also be rotationally adjustable to allow the connecting members to be positioned as desired. The transverse and rotational adjustability of the transverse connectors allows them to mate to parallel, non-parallel, diverging, and converging spinal rods that are implanted within a patient&#39;s spinal system. 
       FIG. 1  shows an exemplary transverse connector  100  for interconnecting a pair of longitudinal members or rods  120  connected to vertebrae V of a spinal column. Although the transverse connector  100  is shown interconnecting rods  120 , it is contemplated that the transverse connector  100  may interconnect any suitable longitudinal member, such as plates or rods of other shapes, such as hexagonal rods. The rods  120  can be located anywhere along the spinal column. The location of the rods illustrated in  FIG. 1  is for example purposes. 
     Each of the rods  120  ( FIG. 1 ) is elongate and has a sufficient length to span at least two vertebrae V. A plurality of connectors  101  connect the rods  120  with the vertebrae V. The connectors  101  can be of any known or desired configuration. In an embodiment, the connectors  101  are pedicle screw assemblies that include a receiver member that removably mates with a screw member in a poly-axial or mono-axial configuration. 
     At least one transverse connector  100  ( FIG. 1 ) interconnects the rods  120  across the vertebral midline. The transverse connector  100  blocks relative movement of the rods  120  so that the vertebrae V connected to the rods  120  are maintained in their desired relative positions and do not pivot relative to an anterior/posterior axis or a longitudinal central axis of the spinal column, shown as the vertebral midline M. The transverse connector  100  increases the torsional strength of the rod construct to provide stability when the spinal column twists, such as when the shoulders are turned or angled relative to the legs in a standing position. The transverse connector  100  can be located anywhere along the rods  120  and any number of transverse connectors  100  can be used. 
       FIGS. 2-5  show a first exemplary embodiment of a transverse connector  100 . Transverse connector  100  includes a first connecting member  105 , a second connecting member  110  and a clamp member  115 . The first connecting member  105  includes an integrated clamp portion  125  having a threaded bore  146 . The first connecting member  105  also includes an elongate arm  150  extending away from the region of the bore  146 . The arm  150  has an elongate opening  144  extending through its middle region and a threaded bore  142  near its terminus opposite bore  146 . The second connecting member  110  includes a threaded bore  132  and an elongate arm  160  extending away from the region of bore  132 . The arm  160  has an elongate opening  134  extending through its middle region and a threaded bore  136  near its terminus opposite bore  132 . The bores do not necessarily have to be threaded. Threads can optionally be used to provide fixation between components of the transverse connector  100 . 
     The second connecting member  110  is removably connectable with clamp member  115  in contrast to the first connecting member  105 , which has an integrated clamp portion  125 . Clamp member  115  is independent of the second connecting member  110 . The second connecting member  110  is connectable with clamp member  115  by way of a threadable clamp screw  112 . Threaded bore  132  of the second connecting member  110  can align with a threaded bore  152  of the clamp member  115 . Clamp screw  112  threads through aligned bores  132  and  152  thereby fixing the clamp member  115  to the second connecting member  110 . Prior to fixing, the clamp  115  can rotate about the axis of the clamp screw  112  relative to the connecting member  110 . 
     Clamp portion  125  and clamp member  115  each has a recess  107  and  109  (shown in  FIG. 3 ). Recess  107  is sized to removably receive a portion of spine rod  120   a . Spine rod  120   a  is fixed within recess  107  by clamp screw  116 , which tightens onto the spine rod  120   a . Clamp screw  116  engages the first connecting member  105  through bore  146 . Recess  109  is sized to receive a portion of spine rod  120   b . Spine rod  120   b  is fixed within recess  109  by clamp screw  112 , which tightens onto the spine rod  120   b . Clamp screw  112  engages the second connecting member  110  through threaded bore  132  and clamp member  115  through threaded bore  152 , which is aligned with threaded bore  132 . Spine rod  120   b  is fixed within recess  109  by threading clamp screw  112  through aligned bores  132  and  152  of the second connecting member  110  and the clamp member  115 , respectively. The spine rods can be fixed within the recesses of clamp members by the clamp screws pressing downward on the top of the rods. The spine rods can also be fixed within the recesses of the clamp members by the clamp screws threading against the side of the spine rods thereby trapping or pressing them within the recesses from the side or top of the spine rods. 
     As mentioned above, the first connecting member  105  has an elongate arm  150  that extends toward the second connecting member  110  and away from the region of bore  146 . The second connecting member  110  similarly has an elongate arm  160  that extends toward the first connecting member  105  and away from the region of bore  132 . The elongate opening  144  of arm  150  and elongate opening  134  of arm  160  extend generally transverse to the rods  120   a ,  120   b  when the rods  120   a ,  120   b  are fixed within the recesses  109 ,  107  by the clamp screws  116 ,  112 , as described above. 
     The first connecting member  105  and the second connecting member  110  interconnect, as follows. An upper surface of arm  150  contacts a lower surface of arm  160  such that the second connecting member  110  rests atop the first connecting member  105  along transverse axis, shown in  FIG. 5 . Thus, the first connecting member  105  lies below the horizontal plane of the second connecting member  110 . Threaded bore  142  of arm  150  aligns with at least a portion of elongate opening  134  and threaded bore  136  aligns with at least a portion of elongate opening  144 . The overlap of the first and second connecting members  105 ,  110  is fixed by a pair of set screws  114 ,  118 . Set screw  114  can be threaded from a lower surface of arm  150  through elongate opening  134  into threaded bore  142  of arm  150 . Set screw  118  can be threaded from a lower surface of arm  150  through elongate opening  144  into threaded bore  136  of arm  160 . 
     Connecting members  105 ,  110  are slideably adjustable along transverse axis A with respect to one another such as in a telescoping manner. The telescoping connecting members  105 ,  110  can be fixed at a plurality of lengths and into a plurality of positions by set screws  114 ,  118  as described above. As described above, clamp portion  125  is integral with the first connecting member  105 . Second connecting member  110  does not have an integrated clamp mechanism. Instead, clamp member  115  is independent of the second connecting member  110 . As best shown in  FIG. 5 , this configuration allows for rotational adjustment of the second connecting member  110  with respect to the longitudinal member or rod  120   b  around the axis of clamp screw  112  as shown by arrow α. Transverse and rotational adjustment of connecting members  105 ,  110  are particularly useful in regions of the spine where the spinal fixation elements implanted therein are not parallel to one another. 
       FIGS. 6-9  show another embodiment of a transverse connector  200 , in which the first and second connecting members  205 ,  210  slideably connect by way of a dovetail-like interface. Transverse connector  200  includes a first connecting member  205 , a second connecting member  210  and two clamp members  215 ,  225 . The first connecting member  205  includes a threaded bore  246  and an elongate arm  250  that extends away from bore  246 . The arm  250  has a threaded bore  242  near its terminus opposite the region of the bore  246 . The second connecting member  210  includes a threaded bore  232  and an elongate arm  260  extending away from the bore  232 . The arm  260  has an elongate groove  234  that extends through its middle region. The groove  234  has a receiving window  236  at its terminus or the region nearest the vertebral midline when connected to the spinal column. The receiving window  236  is sized and shaped to receive the arm  250  for insertion into the groove  234 . 
     The connecting members  205 ,  210  are removably connectable with clamp members  225 ,  215 . The first connecting member  205  is connectable with clamp member  225  by way of a threadable clamp screw  216 . Threaded bore  246  of the first connecting member  205  can be aligned with a threaded bore  248  of the clamp member  225 . Clamp screw  216  threads through the aligned bores  246 ,  248  thereby fixing the clamp member  225  to the first connecting member  205 . The second connecting member  210  is connectable with clamp member  215  by way of a threadable clamp screw  212 . Threaded bore  232  of the second connecting member  210  can be aligned with a threaded bore  252  of the clamp member  215 . Clamp screw  212  threads through the aligned bores  232 ,  252  thereby fixing the clamp member  215  to the second connecting member  210 . 
     Clamp members  215 ,  225  each has a recess  209  and  207  (shown in  FIG. 7 ). Recess  207  receives a portion of spine rod  120   a . Spine rod  120   a  is fixed within the recess  207  by clamp screw  216 . Clamp screw  216  engages the first connecting member  205  through threaded bore  246  and the clamp member  225  through threaded bore  248 , which is aligned with threaded bore  246 . Spine rod  120   a  is fixed within recess  207  by threading clamp screw  216  through aligned bores  246  and  248  of the first connecting member  205  and the clamp member  225 , respectively. Recess  209  receives a portion of spine rod  120   b . Spine rod  120   b  is fixed within the recess  209  by clamp screw  212 . Clamp screw  212  engages the second connecting member  210  through threaded bore  232  and the clamp member  215  through threaded bore  252 , which is aligned with threaded bore  232 . Spine rod  120   b  is fixed within recess  209  by threading clamp screw  212  through aligned bores  232  and  252  of the second connecting member  210  and the clamp member  215 , respectively. The spine rods can be fixed within the recesses of clamp members by the clamp screws pressing downward on the top of the rods. The spine rods can also be fixed within the recesses of the clamp members by the clamp screws threading against the top or side of the spine rods thereby trapping or pressing them within the recesses from the side. 
     As mentioned above, the first connecting member  205  includes an elongate arm  250 . Arm  250  extends toward the second connecting member  210  and away from the region of bore  246 . The second connecting member  210  similarly includes an elongate arm  260  that extends toward the first connecting member  205  and away from the region of bore  232 . Arm  260  has a groove  234  running through it. The arms  250  and  260  extend toward each other in a generally transverse direction to the rods  120   a ,  120   b  when the rods  120   a ,  120   b  are fixed within the recesses  207 ,  209  by the clamp screws  216 ,  212 , as described above. 
     The first connecting member  205  and the second connecting member  210  interconnect by slideably inserting elongate arm  250  inside of elongate arm  260  and engagement by a set screw  214 , described as follows. The elongate groove  234  of the second connecting member  210  has openings at the upper and lower surface of the arm  260  as well as a receiving window  236  at the end nearest the vertebral midline. The receiving window  236  is configured to receive arm  250 . In this regard, the receiving window  236  can optionally have a shape that corresponds to the shape of the arm  250 . For example, if the cross-sectional shape of the arm  250  is rectangular, the shape of the receiving window  236  is likewise rectangular. In an embodiment, the shape of the elongate groove  234  generally mirrors the cross-sectional shape of the arm  250  such that the arm  250  can be Inserted through the elongate groove  234  with little resistance. A mirrored or complimentary shape between the groove  234  and the arm  250  provides a smooth interfit that promotes a clean sliding movement between the groove  234  and the arm  250 . However, it is not necessary that the shapes be mirrored or complimentary. 
     The connection between the arm  250  of the first connecting member  205  inside the arm  260  of the second connecting member  210  is fixed by way of a set screw  214 . Upon insertion of the arm  250  into the receiving window  236 , threaded bore  242  is aligned with at least a portion of the elongate groove  234 . The set screw  214  can be threaded from above through an upper opening of the elongate groove  234  into the threaded bore  242 . This fixates the first connecting member  205  inside the second connecting member  210  such that the first and second connecting members interlock transversely along the same horizontal plane. 
     The arm  250  includes a step  253  that abuts a shoulder  255  on the arm  260  as the arm  250  is inserted into the arm  260 . The interface between the step  253  and the shoulder  255  provides a stop that limits movement of the arm  250  into the arm  260 . The relative positions of the step  253  and shoulder  255  can be selected to provide a predetermined amount of relative sliding movement between the arms  250  and  260 . The interface between the screw  214  and an inner wall  257  of the slot  234  can also limit movement between the arms  250  and  260 . 
     Thus, connecting members  205 ,  210  are slideably adjustable along transverse axis A with respect to one another such as in a telescoping manner as shown in  FIG. 9 . The telescoping connecting members  205 ,  210  can be fixed at a plurality of lengths and into a plurality of positions by the set screw  214  as described above. In addition, the clamp portions  215  and  225  can be rotationally adjusted relative to the axes of the screws  212  and  216  as shown by arrow α. 
       FIGS. 10-13  show another embodiment of a transverse connector  300  in which the first and second connecting members  305 ,  310  feature a cross pin connection. Transverse connector  300  includes a first connecting member  305 , a second connecting member  310  and two clamp members  315 ,  325 . The first connecting member  305  includes a threaded bore  346  and a forked region  350  that extends toward the second connecting member  310  and away from the bore  346 . The forked region  350  includes a pair of parallel arms  356   a ,  356   b , at which the terminus of each is a hole  358   a ,  358   b . The second connecting member  310  includes a threaded bore  332  and an elongate arm  360  that extends away from the bore  332  and toward the first connecting member  305 . The arm  360  has an elongate slot  334  that extends through its middle region and a threaded bore  336  at the end region located opposite to the region of the threaded bore  332 . 
     The connecting members  305 ,  310  are removably connectable with clamp members  325 ,  315 . The first connecting member  305  is connectable with clamp member  325  by way of a threadable clamp screw  316 . Threaded bore  346  of the first connecting member  305  can be aligned with a threaded bore  348  of the clamp member  325 . Clamp screw  316  threads through the aligned bores  346 ,  348  thereby fixing the clamp member  325  to the first connecting member  305 . The second connecting member  310  is connectable with clamp member  315  by way of a threadable clamp screw  312 . Threaded bore  332  of the second connecting member  310  can be aligned with a threaded bore  352  of the clamp member  315 . Clamp screw  312  threads through the aligned bores  332 ,  352  thereby fixing the clamp member  315  to the second connecting member  310 . 
     Clamp members  315 ,  325  each has a recess  309  and  307  (shown in  FIG. 11 ). Recess  307  receives a portion of spine rod  120   a . Spine rod  120   a  is fixed within the recess  307  by clamp screw  316 . Clamp screw  316  engages the first connecting member  305  through threaded bore  346  and the clamp member  325  through threaded bore  348 , which is aligned with threaded bore  346 . Spine rod  120   a  is fixed within recess  307  by threading clamp screw  316  through aligned bores  346  and  348  of the first connecting member  305  and the clamp member  325 , respectively. Recess  309  receives a portion of spine rod  120   b . Spine rod  120   b  is fixed within the recess  309  by clamp screw  312 . Clamp screw  312  engages the second connecting member  310  through threaded bore  332  and the clamp member  315  through threaded bore  352 , which is aligned with threaded bore  332 . Spine rod  120   b  is fixed within recess  309  by threading clamp screw  312  through aligned bores  332  and  352  of the second connecting member  310  and the clamp member  315 , respectively. The spine rods can be fixed within the recesses of clamp members by the clamp screws pressing downward on the top of the rods. The spine rods can also be fixed within the recesses of the clamp members by the clamp screws threading against the side or top of the spine rods thereby trapping or pressing them within the recesses from the side. 
     As mentioned above, the first connecting member  305  includes a forked region  350  that has parallel arms  356   a ,  356   b  extending away from the region of bore  346  toward the second connecting member  310 . The second connecting member  310  includes an elongate arm  360  that extends away from the region of bore  332  toward the first connecting member  305 . The arms  356   a ,  356   b  and arm  360  extend toward each other in a generally transverse direction to the rods  120   a ,  120   b  when the rods  120   a ,  120   b  are fixed within the recesses  307 ,  309  by the clamp screws  316 ,  312 , as described above. 
     The first connecting member  305  and the second connecting member  310  interconnect by positioning elongate arm  360  between parallel arms  356   a ,  356   b  of the forked region  350 . Arm  360  is positioned between the parallel arms  356   a ,  356   b  such that the holes  358   a ,  358   b  align with the elongated slot  334 . In an embodiment, the shape of arm  360  generally mirrors or complements the shape of the recess of the forked region  350  formed by arms  356   a ,  356   b.    
     The connection between the first and second connecting members  305 ,  310  is fixed by way of a set screw  314  and a cross pin  354 . Threaded bore  336  extends through the region of the arm  360  located opposite of bore  332 . Upon positioning of arm  360  between arms  356   a ,  356   b , holes  358   a ,  358   b  are aligned with at least a portion of the elongated slot  334 . The cross pin  354  can be inserted through holes  358   a ,  358   b  thereby preventing the first connecting member  305  from sliding out of the second connecting member  310 . In this manner, the cross pin  354  acts as a detent that limits the amount of telescoping movement (represented by A in  FIG. 13  between the first and second connecting members. Set screw  314  threadably engages the second connecting member  310  through threaded bore  336 . The set screw  314  can be tightened to fixate the first and second members relative to one another. In addition, the clamp portions  315  and  325  can be rotationally adjusted relative to the axes of the screws  312  and  316  as shown by arrow α in  FIG. 13 . 
       FIGS. 14-17  show another embodiment of a transverse connector  400  in which the first and second connecting members  405 ,  410  interlock in a free sliding belt-buckle configuration. Transverse connector  400  includes a first connecting member  405 , a second connecting member  410  and two clamp members  415 ,  425 . The first connecting member  405  includes a threaded bore  446  and an elongate arm  450 . The arm  450  extends away from the bore  446  and toward the second connecting member  410 . The arm  450  has a threaded bore  442  at its terminus. The second connecting member  410  includes a threaded bore  432  and an elongate arm  460 . The arm  460  extends away from the bore  432  and toward the first connecting member  405 . The arm  460  has an elongate slot  434  extending through its middle region and a receiving window  436  located at the end opposite of bore  432 . Further, the receiving window  436  lies below the horizontal plane of the arm  460 . 
     The connecting member  405 ,  410  are connectable with clamp members  325 ,  315 . The first connecting member  405  is connectable with clamp member  425  by way of a threadable clamp screw  416 . Threaded bore  446  of the first connecting member  405  can be aligned with a threaded bore  448  of the clamp member  425 . Clamp screw  416  threads through the aligned bores  446 ,  448  thereby fixing the clamp member  425  to the first connecting member  405 . The second connecting member  410  is connectable with clamp member  415  by way of a threadable clamp screw  412 . Threaded bore  432  of the second connecting member  410  can be aligned with a threaded bore  452  of the clamp member  415 . Clamp screw  412  threads through the aligned bore  432 ,  452  thereby fixing the clamp member  415  to the second connecting member  410 . 
     Clamp members  415 ,  425  each has a recess  409  and  407  (shown in  FIG. 15 ). Recess  407  receives a portion of spine rod  120   a . Spine rod  120   a  is fixed within the recess  407  by clamp screw  416 . Clamp screw  416  engages the first connecting member  405  through threaded bore  446  and the clamp member  425  through threaded bore  448 , which is aligned with threaded bore  446 . Spine rod  120   a  is fixed within recess  407  by threading clamp screw  416  through aligned bores  446  and  448  of the first connecting member  405  and the clamp member  425 , respectively. Recess  409  receives a portion of spine rod  120   b . Spine rod  120   b  is fixed within the recess  409  by clamp screw  412 . Clamp screw  412  engages the second connecting member  410  through threaded bore  432  and the clamp member  415  through threaded bore  452 , which is aligned with threaded bore  432 . Spine rod  120   b  is fixed within recess  409  by threading clamp screw  412  through aligned bores  432  and  452  of the second connecting member  410  and the clamp member  415 , respectively. The spine rods can be fixed within the recesses of clamp members by the clamp screws pressing downward on the top of the rods. The spine rods can also be fixed within the recesses of the clamp members by the clamp screws threading against the side or top of the spine rods thereby trapping or pressing them within the recesses from the side. 
     As mentioned above, the first connecting member  405  includes an elongate arm  450  that extends away from the region of bore  446  toward the second connecting member  410 . The second connecting member includes an elongate slot  434  extending through its middle region and a receiving window  436  located below the horizontal plane of the arm  460 . Arms  450  and  460  extend toward each other in a generally transverse direction to the rods  120   a ,  120   b  when the rods  120   a ,  120   b  are fixed within the recesses  407 ,  409  by the clamp screws  416 ,  412 , as described above. 
     The first connecting member  405  and the second connecting member  410  interconnect by slidably inserting elongate arm  450  through the receiving window  436  of arm  460  and engagement by a set screw  414 , described as follows. The receiving window  436  is configured to receive arm  450  of the first connecting member  405 . In this regard, the window  436  has a size that is larger than the cross-sectional size of the arm  450  such that the arm  450  is insertable into the window  436 . The window  436  can optionally have a shape that complements or mirrors the cross-sectional shape of the arm  450 . For example, if the cross-sectional shape of the arm  450  is rectangular, the shape of the window  436  is likewise rectangular. The shape of the window  436  can generally mirror the cross-sectional shape of arm  450  such that the arm  450  can be inserted through the window  436  with little resistance. 
     The connection between the arm  450  of the first connecting member  405  inside the arm  460  of the second connecting member  410  is fixed by way of a set screw  414 . Upon insertion of the arm  450  through the receiving window  436  of arm  460 , threaded bore  442  is aligned with at least a portion of the elongate slot  434 . Because the window  436  is positioned below the horizontal plane of arm  460 , the upper surface of the arm  450  contacts the bottom surface of arm  460 . The set screw  414  can be threaded from above through an upper opening of the elongate slot  434  into the threaded bore  442 . This fixates the first connecting member  405  through the receiving window  436  and under the second connecting member  410  such that the first and second connecting members interlock transversely. 
     When connected, the first and second members  410  and  405  can move relative to one another in a telescoping manner as limited by the set screw  414  abutting the edges of the slot  434 . In addition, the clamp portions  415  and  425  can be rotationally adjusted relative to the axes of the screws  412  and  416  as shown by arrow a in  FIG. 17 . 
       FIGS. 18-20  shows another embodiment of a transverse connector  500  in which the first and second connecting members  505 ,  510 , respectively, are slidably connected to one another. An end of the connecting member  505  has a clamp member  515  that is integrally or monolithically formed with the connecting member  505 . The clamp member  515  has a recess that is sized and shaped to receive an elongate rod therein. In this regard, a clamp screw  516  couples to a bore in the connecting member  505  such as in a threaded relationship. The clamp screw  516  can be threaded downward toward a rod positioned within the cavity to tighten against the rod and lock it in the cavity. 
     An end of the connecting member  510  also has a clamp member  525 , which is removably attached to the connecting member  510 . The clamp member  525  has a recess that is sized and shaped to receive an elongate rod therein. A clamp screw  512  couples to a bore in the connecting member  510  such as in a threaded relationship. The clamp screw  512  can be threaded downward toward a rod positioned within the cavity to tighten against the rod and lock it in the cavity. The clamp screw  512  is also used to removably secure the clamp member  525  to the connecting member  510 . 
     With reference to  FIGS. 18-20 , the connecting member  510  is formed of a pair of forked arms  540   a  and  540   b  (collectively arms  540 ) that define a space therebetween. A stop member  541  interconnects the arms  540  at a predetermined location to serve as detent or stop that limits slidable movement between the connecting members  510  and  505 , as described more fully below. The connecting member  505  also has a pair of forked arms  545   a  and  545   b  (collectively arms  545 ) that form a space therebetween, wherein the space is aligned along a plane that is normal to a plane defined by the space between the arms  540 . A pair of aligned boreholes extend through the arms  545  for receipt of a lock screw  547 . The lock screw  547  can be threaded or otherwise engaged into the boreholes to provide a locking force that locks the arms  545  in a fixed position relative to the arms  540 . 
     As shown in  FIG. 18 , the arms  540  can mate with the arms  545  such that the connecting member  510  is slidably engaged with the connecting member  505 . The arms  540  and  545  serve as a sliding interconnection that permits sliding, relative movement between the first and second connecting members. The space between the arms  540  is aligned with the space between the arms  545  such that the arms are adjacent to one another. The locking screw  547  can be tightened downward to provide a compressive force between the arms  545  such that the arms  545  compress the arms  540  and lock the connecting members in a fixed position relative to one another. 
     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.