Abstract:
A modular interspinous system is shown having a first plate, a generally opposing second plate and a modular insert that may be removably or permanently secured to the first plate. The first plate has a coupling means, coupler or connection system in the form of a screw that may be permanently or non-permanently docked or supported in the first plate. The modular insert is adapted, sized and shaped to expose at least a portion of the screw thread of the screw and that portion may cooperate with at least one mating female thread in the second plate, thereby enabling a user to rotate the screw in order to drive the first and second plates towards or away from each other and, for example, into compression with bone.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to provisional U.S. Application Ser. No. 62/120,091, filed Feb. 24, 2015, to which Applicant claims the benefit of the earlier filing date. This provisional application is incorporated herein by reference and made a part hereof. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to fixation systems, and more particularly, to a modular interspinous fixation system including a modular insert that can be mounted to or integral with a first plate and can be slidably received in a generally opposing second plate. 
         [0004]    2. Description of the Related Art 
         [0005]    Many types of devices for surgical stabilization of a spine have been developed. Various screw, rod and plating systems have been utilized for the purpose of stabilizing the spine for the purposes of fixation and spinal fusion. Until recently, such devices have been large constructs requiring extensive surgical exposure and operation time. There is an ongoing shift to provide spinal stabilization for fusing using more compact devices and devices that are simpler in operation. Furthermore, there is an increased need to be able to tailor these devices to the individual anatomy of a specific patient or the treatment needs of an individual diseased process. 
         [0006]    More recently, devices which affix to the spinous processes of adjacent vertebrae have been developed, including U.S. Pat. Nos. 5,645,599; 5,836,948; 5,860,977; 6,048,342; 6,068,630; 6,440,169; 6,451,019; 6,478,796; 6,582,433; 6,641,585; 6,964,883; 6,695,842, 7,048,736; 7,201,751; 7,306,628; 7,585,316; and U.S. Patent Publication Nos. 2008/0177306 and 2008/0183211, all of which are incorporated herein by reference and made a part hereof. The prior art, however does not fully address the needs, so what is needed is a system and method that improves upon the prior art. 
       SUMMARY OF THE INVENTION 
       [0007]    An object of one embodiment is to provide a modular interspinous fixation system and method that utilizes modular components. 
         [0008]    Another object of one embodiment is to provide a modular interspinous fixation system and method that utilizes a modular insert that is removably mounted, permanently secured or integral with a plate member. 
         [0009]    Still another object of one embodiment is to provide a modular insert and plate member that can be sized, shaped and adapted in response to a local anatomy or size of an interspinous space between, for example, a first spinous process and a second spinous process. 
         [0010]    Still another object of one embodiment is to provide a system and method that is adapted to utilize a plurality of modular inserts to provide a user or surgeon with the opportunity to select a modular insert in response to a local anatomy prior to or at the time of surgery or even during surgery. 
         [0011]    Still another object of one embodiment is to provide a plurality of modular inserts having different shapes, sizes, dimensions or configurations. 
         [0012]    Yet another object of one embodiment is to provide a modular insert that allows the user or surgeon to select a desired modular insert at the time of surgery and place or mount the modular insert on a plate, such as a first plate and, thereafter, slidably insert at least a portion of the modular insert in and through a second plate. 
         [0013]    Still another object of one embodiment is to provide a single coupling, connection or means for locking the first and second plates together and that utilizes the same means for moving the plates together into a compressive position. 
         [0014]    Yet another object of one embodiment is to provide a modular insert that can be mounted onto a first plate and wherein the first plate receives and rotatably supports a screw. 
         [0015]    Another object of one embodiment is to provide a plate and modular insert that once a screw is received therein, the modular insert is adapted, configured and sized to expose at least a portion of the screw thread so that it can mate with a mating screw thread, for example, on a second plate when the second plate is slidably received on the modular insert. 
         [0016]    Still another object of one embodiment is to provide a system that substantially simultaneously locks the first and second plates together while also providing means to cause the first and second plates to be moved into compression with bone. 
         [0017]    Another object of one embodiment is to provide a convenient kit having a plurality of modular inserts, second plate members and first plate members and screws. 
         [0018]    In one aspect, one embodiment comprises an implant system comprising a first plate member, a second plate member, at least one modular insert having an opening adapted to receive a coupling member, thereby permitting the coupling member to be rotated or moved when the coupling member is received in the second plate member, and a coupling for coupling the first plate member to the second plate member and adapted to cause the first plate member and the second plate member to move towards each other and cooperate to compress bone in response to a predetermined actuation of the coupling. 
         [0019]    In another aspect, another embodiment comprises a modular interspinous fixation system comprising a first member, a second member, one of the first member or the second member having at least one female thread associated therewith, the other of the first member or the second member supporting a generally elongated rotatable screw that mates with the at least one female thread, a modular insert extending between the end plates and generally enclosing the generally elongated rotatable screw, and at least a portion of the modular insert being slidable into and through one of the first member or the second member in response to rotation of the generally elongated rotatable screw. 
         [0020]    In another aspect, another embodiment comprises an interspinous fixation system comprising a set of elongated end plates in parallel spaced opposing relation, the plates having opposing bone engaging projections, one of the end plates having spaced opposing threads disposed between spaced guide ways, the other end plate supporting an elongated rotatable screw extending between the opposing threads in the opposing end plate, a bone spacer module extending between the end plates and enclosing the screw, and the spacer module extending into the guide ways and slidable in the guide ways to maintain alignment of the end plates in response to rotation of the screw. 
         [0021]    This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the following list of features: 
         [0022]    The implant system wherein the coupling comprises a threaded member having at least a portion rotatably mounted in the first plate member. 
         [0023]    The implant system wherein the a least a portion of the threaded member is comprises a head comprising a channel adapted to receive a lock to rotatably retain the at least a portion of the threaded member in the first plate member, thereby enabling the head to be rotatably docked in the first plate member. 
         [0024]    The implant system wherein the lock is a set screw adapted to permit the threaded member to be rotatably retained in the first plate member when in a first or unlocked position and to engage the head to lock it against rotation when the set screw is set or tightened. 
         [0025]    The implant system wherein at least one of the first plate member or the second plate member comprises at least one wall that defines a receiving channel having a first predetermined configuration, the at least one modular insert having at least one of a shape, size or configuration that generally complements a first predetermined shape to permit the at least one modular insert to be received in and translate or move in the receiving channel. 
         [0026]    The implant system wherein the at least one coupling comprises at least one connecting member associated with at least one of the first plate member or the second plate member, at least one mating coupling associated with the other of the second plate member or the first plate member, respectively, adapted to receive the at least one connecting member to fix the first plate member to the second plate member. 
         [0027]    The implant system wherein the at least one connecting member comprises at least one male threaded member and the at least one mating coupling comprises at least one female thread adapted to threadably receive the at least one male threaded member, the first plate member and the second plate member becoming closer together upon a rotation of the at least one male threaded member. 
         [0028]    The implant system wherein the at least one male threaded member is rotatably mounted in the first plate member, the second plate member comprising a plate wall having the at least one female thread integrally or monolithically formed therein. 
         [0029]    The implant system wherein the at least one female thread is interrupted. 
         [0030]    The implant system wherein the at least one modular insert comprises at least one wall or projection, the second plate member comprising at least one guide slot adapted to receive the at least one wall or projection and permitting at least a portion of the at least one modular insert to pass through the at second plate member. 
         [0031]    The implant system wherein the at least one female thread is interrupted and defines at least one female threaded aperture, the at least one guide slot being in communication with the at least one female threaded aperture. 
         [0032]    The implant system wherein the at least one female threaded aperture and the at least one guide slot cooperate to define a modular insert receiving aperture configured and dimensioned to generally complement a configuration of the at least one modular insert so that the at least one modular insert can be received in the modular insert receiving aperture to permit at least a portion of the at least one modular insert to pass therethrough and through the second plate member. 
         [0033]    The implant system wherein the at least one coupling comprises at least one male threaded member associated with the first plate member and at least one female threaded member associated with the second plate member, the at least one modular insert having at least one wall that defines a thread-exposing window in the at least one modular insert so that when the at least one connecting member is received in the at least one modular insert, at least a portion of at least one male threaded member is exposed for threadable engagement with the at least one female threaded member. 
         [0034]    The implant system wherein the at least one coupling comprises at least one male threaded member associated with the first plate member and at least one female threaded member associated with the second plate member, the at least one modular insert having plurality of walls adapted to define a plurality of thread-exposing windows in the at least one modular insert so that when the at least one connecting member is received in the at least one modular insert, a plurality of portions of the at least one male threaded member are exposed for threadable engagement with the at least one female member. 
         [0035]    The implant system wherein the at least one female threaded member comprises a first female thread portion and a second female thread portion integrally formed in the second plate member, the plurality of portions of the at least one female threaded member comprises a first exposed male threaded area and a second exposed male threaded area, the first and second exposed male threaded areas threadably engaging the first and second female thread portions, respectively, when the at least one modular insert is at least partially inserted into the second plate member. 
         [0036]    The implant system wherein the at least one modular insert is adapted to be removebly secured, affixed or locked to at least one of the first plate member or the second plate member. 
         [0037]    The implant system wherein the at least one modular insert is permanently secured to at least one of the first or second plate members. 
         [0038]    The implant system wherein the implant system comprises at least one of a lock or locking members for removeably securing, affixing or locking the at least one modular insert to the at least one of the first plate member or the second plate member. 
         [0039]    The implant system wherein the at least one of a lock or locking means comprises a male projection located on either the first plate member or the at least one modular insert and a female mating aperture located on the other of the first plate member or the at least one modular insert, the male projection and the female mating aperture being sized and dimension to permit a snap-fit or press fit, thereby securing, affixing or locking the at least one modular insert to the first plate member. 
         [0040]    The implant system wherein the at least one of a lock or locking means comprises a plurality of male projection located on the first plate member and a female mating aperture located on the other of the first plate member or the at least one modular insert, the male projection and the female mating aperture being sized and dimension to permit a snap-fit or press fit, thereby securing, affixing or locking the at least one modular insert to the first plate member. 
         [0041]    The implant system wherein the second plate member comprises a modular insert aperture for receiving the at least one modular insert and permitting the at least one modular insert to pass through the second plate member. 
         [0042]    The implant system wherein the at least one modular insert and the receiving aperture are adapted to align the first plate member to the second plate member and provide a spacer therebetween. 
         [0043]    The implant system wherein the coupling comprises a male threaded member associated with the first plate member, the at least one modular insert receiving the male threaded member, the at least one modular insert being configured to permit at least a portion of the male threaded member to threadably engage a mating female thread associated with the second plate member. 
         [0044]    The implant system wherein the implant system comprises a plurality of modular inserts, at least some of the plurality of modular inserts being different shapes sizes or configurations. 
         [0045]    The implant system wherein the implant system comprises a plurality of second plate members each having a modular receiving aperture adapted and configured to generally compliment a shape of at least one of the plurality of modular inserts, respectively. 
         [0046]    The implant system wherein coupling comprises a male threaded member having a head, the first plate member having a set screw for engaging the threaded member and retaining it in the first plate member. 
         [0047]    The implant system wherein head has a circumferential aperture for receiving the set screw in order to permit the male threaded member to rotate while being retained in the first plate member. 
         [0048]    The implant system wherein at least a portion of the at least one modular insert comprises a predetermined shape that is generally I-shaped or generally H-shaped in cross section. 
         [0049]    The implant system wherein the second plate member has an aperture that generally complements the predetermined shape so that the at least one modular insert can pass into and through the second plate member. 
         [0050]    The implant system wherein each of the first plate member and the second plate member comprises at least one anti-movement feature. 
         [0051]    The implant system wherein the first plate member comprises a first plate member surface and the second plate member comprises a second plate member surface, at least one anti-movement feature comprises a first plurality of pointed projections that extend from the first plate member surface and a second plurality of pointed projections that extend from the second plate member surface. 
         [0052]    The modular interspinous fixation system wherein the first member rotatably supports the generally elongated rotatable screw, the second member comprising the at least one female thread having a first thread and a second thread that is spaced from and generally opposed to the first thread. 
         [0053]    The modular interspinous fixation system wherein the second member comprises at least one guideway, the at least a portion of the modular insert being adapted and configured to be slidably received in the at least one guideway and facilitating maintaining alignment of the first and second members in response to or during rotation of the generally elongated rotatable screw. 
         [0054]    The modular interspinous fixation system wherein the second member comprises a plurality of guide ways, the modular insert having a plurality of projections adapted and configured to be slidably received in the plurality of guide ways, respectively, to facilitate maintaining alignment of the first and second members in response to or during rotation of the generally elongated rotatable screw. 
         [0055]    The modular interspinous fixation system wherein the first member rotatably supports the generally elongated rotatable screw, the second member comprising the at least one female thread having a first thread and a second thread that is spaced from and generally opposed to the first thread, the first thread and the second thread being disposed between at least two of the plurality of guide ways. 
         [0056]    The modular interspinous fixation system wherein the first thread and the second thread defining a receiving area for receiving the generally elongated rotatable screw, the receiving area being in communication with at least one of the plurality of guide ways. 
         [0057]    The modular interspinous fixation system wherein the receiving area is in communication with each of the plurality of guide ways. 
         [0058]    The modular interspinous fixation system wherein the first member comprises a first member bone-engaging surface and the second member comprises a second member bone engaging surface, the modular interspinous fixation system having a plurality of bone-engaging projections located on at least one of the first member bone-engaging surface or the second member bone engaging surface. 
         [0059]    The modular interspinous fixation system wherein generally elongated rotatable screw comprises a head that is received within a head-receiving aperture defined by a wall in the first member, the first member also comprising at least one anti-rotation lock for locking the head in an anti-rotation position. 
         [0060]    The modular interspinous fixation system wherein the at least one anti-rotation lock is associated with the wall and comprises at least one of a flexible or resilient arm or a set screw associated with the head-receiving aperture. 
         [0061]    The modular interspinous fixation system wherein the anti-rotation lock comprises the set screw, the head comprising a circumferential channel and set screw is adapted to be received in the circumferential channel and permit a threaded member to be rotatably retained in the first member when in a first or unlocked position and to engage the head to lock it against rotation when the set screw is set or tightened. 
         [0062]    The modular interspinous fixation system wherein the modular insert comprises at least one wall that defines a thread-exposing window in the modular insert so that when the modular insert is received on the generally elongated rotatable screw, at least a portion of a thread is exposed for threadable engagement with the at least one female thread. 
         [0063]    The modular interspinous fixation system wherein the modular insert comprises at least one wall that defines a thread-exposing window in the modular insert so that when the modular insert is received on the generally elongated rotatable screw, at least a portion of a thread is exposed for threadable engagement with the at least one female thread, the modular insert having plurality of walls adapted to define a plurality of thread-exposing windows in the modular insert so that when generally elongated rotatable screw is received in the modular insert, a plurality of portions of the a thread on the generally elongated rotatable screw are exposed for threadable engagement with the first thread and the second thread. 
         [0064]    The modular interspinous fixation system wherein the second member comprises a first female thread portion and a second female thread portion integrally formed in the second member, the plurality of portions of the at least one female threaded member comprises a first exposed male threaded area and a second exposed male threaded area, the first and second exposed male threaded areas threadably engaging the first and second female thread portions, respectively, when the modular insert is at least partially inserted into the second member. 
         [0065]    The modular interspinous fixation system wherein the modular insert is adapted to be removably secured, affixed or locked to at least one of the first member or the second member. 
         [0066]    The modular interspinous fixation system wherein the modular insert is permanently secured to at least one of the first or second members. 
         [0067]    The modular interspinous fixation system wherein the modular interspinous fixation system comprises at least one of a lock or locking members for removeably securing, affixing or locking the modular insert to the at least one of the first member or the second member. 
         [0068]    The modular interspinous fixation system wherein the at least one of a lock or locking means comprises a male projection located on either the first member or the modular insert and a female mating aperture located on the other of the first member or the modular insert, the male projection and the female mating aperture being sized and dimension to permit a snap-fit or press fit, thereby securing, affixing or locking the modular insert to the first member. 
         [0069]    The modular interspinous fixation system wherein the at least one of a lock or locking means comprises a plurality of male projection located on the first member and a female mating aperture located on the other of the first member or the modular insert, the male projection and the female mating aperture being sized and dimension to permit a snap-fit or press fit, thereby securing, affixing or locking the modular insert to the first member. 
         [0070]    The modular interspinous fixation system wherein the second member comprises a modular insert aperture for receiving the modular insert and permitting the modular insert to pass through the second member. 
         [0071]    The modular interspinous fixation system wherein the modular insert and the receiving aperture are adapted to align the first member to the second member and provide a spacer therebetween. 
         [0072]    The modular interspinous fixation system wherein the modular interspinous fixation system comprises a plurality of modular inserts, at least some of the plurality of modular inserts being different shapes sizes or configurations. 
         [0073]    The modular interspinous fixation system wherein the modular interspinous fixation system comprises a plurality of second members each having a modular insert receiving aperture adapted and configured to generally compliment a shape of at least one of the plurality of modular inserts, respectively. 
         [0074]    The modular interspinous fixation system wherein the second member has a modular insert aperture that generally complements a predetermined shape so that the modular insert can pass into and through the second member. 
         [0075]    The modular interspinous fixation system wherein at least a portion of the modular insert comprises a predetermined shape that is generally I-shaped or generally H-shaped in cross section. 
         [0076]    The modular interspinous fixation system wherein the second member comprises a plurality of guide ways that cooperate with a screw-receiving aperture to define the modular insert aperture. 
         [0077]    These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
         [0078]      FIG. 1  is a perspective view of a first plate, having a modular insert attached thereto and generally enclosing an elongated rotatable screw; 
           [0079]      FIG. 2  is an exploded view of a modular interspinous fixation system and threaded component; 
           [0080]      FIG. 3A  is another exploded view showing other details of the embodiment shown in  FIG. 2 ; 
           [0081]      FIG. 3B  is another perspective exploded view showing further details of the embodiment shown in  FIG. 2 ; 
           [0082]      FIG. 4  is a view illustrating the modular insert passing through a second plate and after the elongated rotatable screw has been screwed; 
           [0083]      FIG. 4A  is a sectional view taken along the line  4 A- 4 A in  FIG. 4 ; 
           [0084]      FIG. 5A  is a view similar to  FIG. 4  but showing the plates in a different position relative to each other and in response to rotation of the screw; 
           [0085]      FIG. 5B  is a bottom perspective view of the embodiment shown in  FIG. 4 ; 
           [0086]      FIG. 6A  is a perspective view of the modular insert shown in  FIG. 1 ; 
           [0087]      FIG. 6B  is another view of the modular insert shown in  FIG. 6A  showing features of a nose of the modular insert; 
           [0088]      FIG. 6C  is a sectional view taken along the line  6 C- 6 C in  FIG. 6A ; 
           [0089]      FIG. 6D  is a sectional view taken along the line  6 D- 6 D in  FIG. 6B ; 
           [0090]      FIG. 7  is various views of different modular inserts and second plates showing different shapes, sizes and/or configurations that may be used in the system; and 
           [0091]      FIG. 8  is an exploded view of the modular interspinous fixation system and threaded component. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0092]    Referring now to  FIG. 1 , a modular interspinous fixation system or implant system  10  is shown. The modular interspinous fixation system or implant system  10  comprises a first member or first plate member  12  and a second member or second plate member  14 . 
         [0093]    The modular interspinous fixation system or implant system  10  comprises at least one or a plurality of modular inserts  16  having a first end  17   a  and a second end  17   b . As will be described later herein, the first end  16   a  is detachably secured to a wall  12   a  of the first plate member  12 . As best illustrated in  FIG. 2 , the modular interspinous fixation system or implant system  10  comprises a coupling or connector  18  for detachably coupling the first plate member  12  to the second plate member  14 . In the illustration being described, the coupling or connector  18  is adapted to cause the first plate member  12  and the second plate member  14  to move towards or away from each other, and into compression with bone in response to a predetermined actuation of the coupling or connector  18 . In the illustration being described, the coupling or connector  18  comprises a threaded member or screw  20  that is rotatable and elongated and that has a head  22  that is rotatably received in an aperture  33  ( FIG. 1 ) defined by a stepped wall  52  in order to retain the head  22  in the first plate member  12  using a set screw  24  as illustrated. 
         [0094]    As best illustrated in  FIGS. 2 and 4A , note that the head  22  comprises a generally U-shaped wall  22   a  that defines a circumferential channel  26  as shown. As best illustrated in  FIG. 4A , the channel  26  of the head  22  receives the set screw  24 . In the illustration being described, when the set screw  24  is slightly untightened, the screw  20  can be rotated or screwed using a tool (not shown) that is inserted into the hex opening  28 . As described later herein, after the screw  20  is rotated, the set screw  24  can be tightened to lock the screw  20 . Although not shown, other types of screw head locks may be utilized, such as the locking system shown in U.S. Pat. Nos. 7,182,782; 7,655,028; 7,641,701; 8,821,553; 8,372,152; 8,062,367; 8,282,682; 8,734,493; 8,795,370 and U.S. Patent Publications No. 2014/0324173; all of which are incorporated herein by reference and made a part hereof. 
         [0095]    Referring now to  FIGS. 2 and 4A , note that the first plate member  12  has a wall  53  having a seat or shoulder  55  that becomes generally opposed to a surface  22   a   1  of the screw head  22  to support the screw head  22  in the head receiving area  52  after the screw head  22  has been received in the head receiving area  52  of the first plate member  12 , the set screw  24  may be screwed into the thread  25  ( FIG. 2 ) in order to lock the screw  20  in the first plate member  12 . 
         [0096]    Note that the modular insert  16  is detachably locked or mounted onto the wall  12   a  of the first plate member  12 . In this regard, the modular insert  16  comprises two semi-circular and stepped walls  16   a  and  16   b  that define two laterally extending channels  16   a   1  and  16   b   1 . The laterally extending channels  16   a   1  and  16   b   1  are adapted to receive a first male locking projection  30  and a second male locking projection  32 , respectively. In the illustration being described, the first male locking projection  30  and the second male locking projection  32  are somewhat elastic and flexible and are also stepped and complement the shape of the laterally extending channels  16   a   1  and  16   b   1 , respectively, so that the modular insert  16  can be detachably snap-fit onto the first male locking projection  30  and the second male locking projection  32  in order to detachably secure the modular insert  16  to the first plate member  12 . It should be understood that in the illustration being described, the modular interspinous fixation system or implant system  10  is adapted and provided with a plurality of modular inserts of different sizes, shapes or configurations, such as the modular inserts  16 - 16 ′″ in  FIG. 7 . In the illustration being described, the surgeon selects the modular insert  16  based upon the anatomical environment of the patient. In this regard, the modular insert  16  may act as a support or spacer that is situated between two bones, such as a first spinous process SP 1  ( FIG. 8 ) and a second spinous process SP 2  ( FIG. 8 ). 
         [0097]    Once a surgeon has selected the modular insert  16 , it may be provided on the first plate member  12  or detachably secured to the first plate member  12  by snap-fitting the first male locking projection  30  ( FIG. 3B ) and the second male locking projection  32  into the laterally extending channels  16   a   1  and  16   b   1 , respectively, thereby locking the modular insert  16  onto the first plate member  12 . The modular insert  16  is adapted to receive and generally or partially encloses the threaded portion  20   a  of the screw  20  after the screw  20  is rotatably mounted into the first plate member  12 . In this regard, note that the modular insert  16  comprises a generally circular wall  16   c  ( FIGS. 2, 3A, 3B, 6A and 6B ) that defines a screw-receiving aperture or opening  16   d . Note that when the modular insert  16  is mounted on the first plate member  12 , the screw  20  and threaded portion  20   a  are received in the aperture  16   d  as shown. 
         [0098]    Note in  FIGS. 5A-5B and 6C , that the modular insert  16  comprises a first wall  16   e  and a generally opposed second wall  16   f . The first wall  16   e  comprises a first wall portion  16   e   1 , a second wall portion  16   e   2  and a third wall portion  16   e   3 . Likewise, the second wall  16   f , comprises a first wall portion  16   f   1 , a second wall portion  16   f   2  and a third wall portion  16   f   3 . In the illustration being described, the first wall portion  16   e   1  generally opposes and cooperates with the first wall portion  16   f   1  to define a first opening or window  33  ( FIG. 4A ). Likewise, the wall portions  16   e   3  and  16   f   3  are generally opposed and cooperate to define a second opening or window  35  as shown. The wall portion  16   e   2  generally opposes the wall portion  16   f   2  and they are arcuate or curved as shown and generally complement a shape of the screw  20  and cooperate to rotatably support the screw  20 . It is important to note as best illustrated in  FIGS. 1, 4, 4A and 5A-5B  that the wall portions  16   e   2  and  16   f   2  are dimensioned such that the dimension D 1  ( FIGS. 4A and 6C ) is slightly smaller than a diameter of the threaded portion  20   a  of the screw  20 , which are adapted to permit a first portion  20   a   1  and a second portion  20   a   2  of the threaded portion  20   a  to be exposed. In this regard, note that the second plate member  14  comprises a first female thread  40  and a generally opposing second female thread  42  as illustrated in  FIGS. 2 and 4A . Advantageously, having the first portion  20   a   1  and the second portion  20   a   2  of the threaded portion  20   a  exposed permits them to threadably engage with the first female thread  40  and the second female thread  42  when the modular insert  16  is inserted into a modular insert opening or receiving area  44  ( FIG. 2 ) in the second plate member  14 . In this regard, note that a nose  16   i  of the modular insert  16  generally opposes a rear wall  16   j  at end  16   a . As mentioned earlier herein, the rear wall  16   j  comprises the circular wall  16   c  that defines the generally circular opening  16   d . Note that a dimension D 2  ( FIG. 4A ) of the nose  16   i  is also smaller than the diameter of the threaded portion  20   a . The nose  16   i  has beveled surfaces adapted to facilitate guiding and inserting the modular insert  16  into the modular insert aperture  44 . 
         [0099]    Referring back to  FIGS. 1, 2 and 4A-5B , note that the modular insert  16  extends between the first plate member  12  and the second plate member  14  and through the second plate member  14  as illustrated in  FIG. 4 . Notice how the modular insert  16  captures and generally encloses the screw  20  and threaded portion  20   a  as illustrated in  FIG. 1 . At least a portion of the modular insert  16  is slidable into and through the second plate member  14  particularly in response to a rotation of the generally elongated screw  20 . Notice that the second plate member  14  comprises at least one female screw thread  40 . In the illustration being described, the second plate member  14  comprises the first female screw thread  40  and the second female screw thread  42  that generally opposes the first female screw thread  40  as shown. In the illustration being described, the second plate member  14  also comprises at least one or a plurality of guide ways. In this regard, notice that the second plate member  14  comprises a first guide way wall  46  and a second guide way wall  48  that define a first guide way  46   a  and a second guide way  48   a , respectively. In one illustrative embodiment, the first and second threads  40  and  42  cooperate to define the receiving area  44  for receiving the threaded portion  20   a  of the screw  20 . Note that the receiving area  44  is in communication with at least one of the guide ways  46   a  and  48   a  as shown. In one illustrative embodiment, the receiving area  44  is in communication with both guide ways  46   a  and  48   a.    
         [0100]    As illustrated in  FIG. 6C , the modular insert  16  has a generally I or H shape in cross section. In the illustration being described, the shape, size, dimension and configuration of the modular insert  16  is such that it generally complements a shape of the guide ways  46   a  and  48   a  and the receiving area  44 . In the illustration being described, the complementary shape of the modular insert  16  and the guide ways  46   a  and  48   a  and the receiving area  44  are configured such that the modular insert  16  can be slidably guided and received in the second plate member  14 . This feature facilitates maintaining alignment of the first and second plate member  12  and  14  in response to or during rotation of the generally elongated screw  20 . When the screw  20  is inserted into the first plate member  12  and into the modular insert  16 , the portions  20   a   1  and  20   a   2  may threadably engage with the first female thread  40  and second female thread  42 , respectively, as shown. The screw  20  may then be rotated which causes the second plate member  14  to move toward the first plate member  12  as illustrated in  FIGS. 4, 5A and 6 . The screw  20  may be rotated using the tool (not shown) to apply a compressive force in order to secure the first and second plate members  12  and  14  and the modular insert  16  into compressive engagement with the bone of a patient. It should be appreciated that one significant advantage of this design is that the coupling or connector  18  of the screw  20  cooperates with the first and second female threads  40  and  42  and not only function to couple the first and second plate members  12  and  14  together, but also causes the first and second plate members  12  and  14  to apply a compressive force against the bone(s) of the patient as illustrated in  FIG. 4 . 
         [0101]    Each of the first and second plate members  12  and  14  may comprise at least one or a plurality of anti-movement features or means. The at least one or plurality of anti-movement features comprises a plurality of anti-movement projections  50  as shown. When the first and second plate members  12  and  14  are mounted on the patient, the plurality of anti-movement projections  50  engage bone and facilitate preventing the first and second plate members  12  and  14  from moving after they are mounted in place. 
         [0102]    During a surgical procedure and after the surgeon has selected the appropriate sized modular insert  16 - 16 ′″ ( FIG. 7 ), the set screw  24  may be loosened to permit the screw  20  to be received in the first plate member  12  and even after having been received in the first plate member  12 . The modular insert  16  may be mounted onto the first plate member  12  either prior to mounting the screw  20  in the first plate member  12  or after the screw  20  has been received in the first plate member  12 . After the first plate member  12 , the modular insert  16  and the screw  20  are assembled as illustrated in  FIG. 1 , then the second plate member  14  can be selected and then slidably mounted or positioned on the modular insert  16  as mentioned and shown. Note again, that this may be performed either prior to or during the surgical procedure. After the first plate member  12  and second plate member  14  are compressed against bone, the surgeon may set the set screw  24  in order to lock the screw  20  in the first plate member  12 . Although not shown, other means may be provided on, integral or monolithically formed with the first plate member  12  in order to lock the screw  20  in place. For example, some of the features of the aforementioned U.S. patents may be provided with the first plate member  12  in order to lock the screw  20  in the first plate member  12 . 
         [0103]    As illustrated in  FIG. 7 , it should be emphasized that the modular interspinous fixation system or implant system  10  is a modular system and is intended to be used with modular inserts  16  of different shapes, sizes or configurations, all of which may be provided in a single kit to enable a surgeon to select the appropriate modular insert  16  for use during a particular procedure.  FIG. 7  illustrates four illustrative examples of the modular inserts  16 ,  16 ′,  16 ″ and  16 ′″ of different shapes, sizes and/or configurations. Advantageously, this allows for a selection of modular inserts  16 - 16 ′″ to conform to the patient&#39;s interspinous space. 
       ADDITIONAL CONSIDERATIONS 
       [0104]    Advantageously, the locking means or lock in the form of the first and second male projections  30  and  32  that cooperate with the walls  16   a  and  16   b  enable the modular insert  16  to be locked onto the first plate member  12  in a manner that prevents release or rotation of the modular insert  16 . The guide ways  46   a  and  48   a  of the second plate member  14  also facilitate preventing rotation of the modular insert  16  and also maintain alignment of the first and second plate members  12  and  14  as they move together in response to rotation of the screw  20 . 
         [0105]    Although not shown, the coupling or connector  18  between the first and second plate members  12  and  14  has been shown and described as the screw  20  cooperating with the first and second female threads  40  and  42 , it should be understood that other types of non-threaded connection or connectors could be used. 
         [0106]    In the illustration being described, the second plate member  14  has been shown and described with a plurality of opposing female threads  40  and  42 . These could be viewed as a single, but interrupted, female thread. 
         [0107]    Note that the various surfaces of the modular insert  16 , such as the nose  16   i  and walls  16   e   1 ,  16   e   3 ,  16   f   1  and  16   f   3 , may have surfaces that are beveled or even rounded to facilitate guiding and inserting the modular insert  16  or at least a portion thereof into and through the second plate member  14 . 
         [0108]    This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the Summary of the Invention and the claims. 
         [0109]    While the system, apparatus and method herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise system, apparatus and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.