Patent Publication Number: US-2023149181-A1

Title: Implantable systems, devices and related methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/894,934, filed on Jun. 8, 2020 (published as U.S. Pat. Pub. No. 2020-0297511), which is a continuation of U.S. patent application Ser. No. 16/115,865, filed on Aug. 29, 2018, now U.S. Pat. No. 10,716,681, which is a continuation of U.S. patent application Ser. No. 14/933,540, filed Jan. 14, 2016, now U.S. Pat. No. 10,092,413, which is a continuation-in-part application of U.S. patent application Ser. No. 14/842,881, filed Sep. 2, 2015, now U.S. Pat. No. 10,034,768, all of which are hereby incorporated by reference in their entireties for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present application is generally directed to implantable systems, devices and related methods pertaining to the spine. 
     BACKGROUND 
     Spinal fusion procedures are performed on patients to treat back pain caused by degenerated discs. During spinal fusion procedures, a surgeon restores a disc space back to its original height before inserting an interbody fusion device. Graft material can be deposited within the interbody fusion device to promote fusion and bone growth. There is thus a need for improved systems and devices for promoting fusion of the spine. 
     SUMMARY OF THE INVENTION 
     The present application is generally directed in some embodiments to a surgical system comprising a frame, wherein the frame comprises a first side, a second side, a third side, and a fourth side that form a continuous perimeter around a frame opening; a spacer received in the frame opening, wherein the spacer comprises a first arm and a second arm that extend around a spacer opening; and one or more fixation members insertable in the frame, wherein the one or more fixation members includes at least a first fixation member that is angled in an upward direction and a second fixation member that is angled in a downward direction. 
     In other embodiments, a surgical system comprises a frame, wherein the frame comprises a leading end, a trailing end, a first sidewall, and a second sidewall that form a continuous perimeter around a frame opening; a spacer received in the frame opening, wherein the spacer comprises a first arm and a second arm that extend around a spacer opening; and one or more fixation members insertable in the trailing end of the frame, wherein the one or more fixation members includes at least a first fixation member that is angled in an upward direction and a second fixation member that is angled in a downward direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a top perspective view of a frame and spacer system in accordance with some embodiments. 
         FIG.  2    shows a side view of the frame and spacer system of  FIG.  1   . 
         FIG.  3    shows a top view of the frame and spacer system of  FIG.  1   . 
         FIG.  4    shows a top perspective view of a frame with fixation members in accordance with some embodiments. 
         FIG.  5    is a side view of the frame of  FIG.  4   . 
         FIG.  6    is a top view of a frame and spacer system without an upper fixation member in accordance with some embodiments. 
         FIG.  7    is a top view of a frame and spacer system without fixation members in accordance with some embodiments. 
         FIG.  8    is a top view of a frame in accordance with some embodiments. 
         FIG.  9    is a side view of the frame of  FIG.  8   . 
         FIG.  10    is a top perspective view of a frame and spacer system having alternative fixation members in accordance with some embodiments. 
         FIG.  11    is a side view of the frame and spacer system of  FIG.  10   . 
         FIG.  12    is a top perspective view of a frame with alternative fixation members in accordance with some embodiments. 
         FIG.  13    is a side view of the frame of  FIG.  12   . 
         FIG.  14    is an anterior view of the frame of  FIG.  12   . 
         FIG.  15    is a top perspective view of a rectangular frame and spacer system in accordance with some embodiments. 
         FIG.  16    is a top perspective view of an alternative rectangular frame and spacer system in accordance with some embodiments. 
         FIG.  17    is a side view of a rectangular frame and spacer system in accordance with some embodiments. 
         FIG.  18    is a side view of a rectangular frame and spacer system without fixation members in accordance with some embodiments. 
         FIG.  19    is a top perspective view of a rectangular frame in accordance with some embodiments. 
         FIG.  20    is a top perspective view of an alternative rectangular frame in accordance with some embodiments. 
         FIG.  21    is an exploded view of a spacer in accordance with some embodiments. 
         FIG.  22    is a top view of a frame and spacer system, wherein the spacer has a convex side and includes a pair of graft chambers in accordance with some embodiments. 
         FIG.  23    is a top view of a frame and spacer system, wherein the spacer has a substantially flat side and includes a pair of graft chambers in accordance with some embodiments. 
         FIG.  24    is a top view of a spacer including a convex side and a pair of graft chambers in accordance with some embodiments. 
         FIG.  25    is an anterior view of the spacer of  FIG.  24   . 
         FIG.  26    is a side view of the spacer of  FIG.  24   . 
         FIG.  27    is a top view of a spacer including a substantially flat side and a pair of graft chambers in accordance with some embodiments. 
         FIG.  28    is an anterior view of the spacer of  FIG.  27   . 
         FIG.  29    is a side view of the spacer of  FIG.  27   . 
         FIG.  30    is a top perspective view of an alternative frame and spacer system in accordance with some embodiments. 
         FIG.  31    is a front view of the alternative frame and spacer system of  FIG.  30   . 
         FIG.  32    is a side view of the alternative frame and spacer system of  FIG.  30   . 
         FIG.  33    is a top view of the alternative frame and spacer system of  FIG.  30    without fixation members. 
         FIG.  34    is a top view of the alternative frame and spacer system of  FIG.  30    with fixation members. 
         FIG.  35    is a top perspective view of the alternative frame and spacer system of  FIG.  30    with alternative fixation members. 
         FIG.  36    is a side view of the alternative frame and spacer system of  FIG.  30    with alternative fixation members. 
         FIG.  37    is a top view of a spacer and plug in accordance with some embodiments. 
         FIG.  38    is an exploded view of the spacer and plug of  FIG.  37   . 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     The present application is generally directed to implantable systems, devices and related methods pertaining to the spine. In particular, the present application is generally directed to systems and devices for inserting into a disc space of a spine to promote fusion between vertebrae. The systems and devices can be inserted into the spine via any approach, such as posteriorly, transforaminally, laterally or anteriorly. In some embodiments, the systems and devices described herein can be used at least in part as a vertebral body replacement, such that the systems and devices occupy one or more vertebral bodies in addition or instead of one of more disc members. 
     In some embodiments, a frame and spacer system is provided that can be inserted into a disc space as part of a fusion procedure. Advantageously, the frame is independent from the spacer such that a surgeon can choose the type of spacer (e.g., either PEEK or allograft) to insert within the frame. In addition, if desired, the frame can advantageously be inserted on its own as a standalone device without the spacer in between vertebrae. The frame can be dimensioned to fit between two vertebrae, and can be sturdy enough to support a load from the vertebrae. 
       FIG.  1    shows a top perspective view of a frame and spacer system in accordance with some embodiments. The frame and spacer system  10  comprises a frame  50  having fixation members  32 ,  34 ,  36  and a spacer  80  received therein. The frame and spacer system  10  is configured to be placed in a disc space and receive graft material therein, thereby promoting spinal fusion and bone growth. In some embodiments, the frame and spacer system  10  is sized and configured such that the entire system is of low profile. Advantageously, as the system  10  is of low profile, the frame  50  and the spacer  80  can be completely received within a disc space such that no portion of it protrudes outside of a disc space. In some embodiments, the system  10  can be sized to replace one or more vertebral bodies, or parts thereof, in addition to one or more disc members. 
     As shown in  FIG.  1   , in some embodiments, the frame  50  and the spacer  80  can be of substantially the same height. Advantageously, this allows both the frame  50  and the spacer  80  to share vertebral load. In some embodiments, the upper and lower surfaces of the frame  50  can share the overall contour of the upper and lower surfaces of the spacer  80  and vice versa. For example, in embodiments in which the spacer  80  has a convex upper surface and a convex lower surface, the frame  50  can similarly have a convex upper surface and a convex lower surface. Likewise, in embodiments in which the spacer  80  has a planar upper surface and a planar lower surface, the frame  50  can similarly have a planar upper surface and a planar lower surface. In other embodiments, the spacer  80  can have a height that slightly larger than the frame  50 , while still maintaining an overall low profile system. In other embodiments, the frame  50  can have a height slightly larger than the spacer  80 , while still maintaining an overall low profile system. 
       FIG.  1    shows one type of cage or frame  50  in accordance with some embodiments. The frame  50  comprises a first side  52 , a second side  54 , a third side  56  and a fourth side  58 . The first side  52 , second side  54 , third side  56  and fourth side  58  form a structure having a continuous perimeter. Advantageously, by providing a continuous perimeter that extends around the outside of the spacer  80 , the frame  50  is capable of bearing load. As the frame  50  can bear load, the frame  50  can be used on its own as a fusion device within an intervertebral disc space. As shown in  FIG.  1   , the first side  52 , second side  54 , third side  56  and fourth side  58  surround an opening  59 . A spacer  80  (such as a PEEK or allograft spacer) can optionally be placed in the opening  59  of the frame  50  prior to inserting the frame  50  into a disc space. 
     With respect to the frame  50 , the first side  52  opposes the second side  54 . In some embodiments, the first side  52  can comprise a first sidewall and the second side  54  can comprise a second sidewall. The first side  52  comprises a first window  72  and the second side  54  comprises a second window  74 . In some embodiments, the first window  72  is configured to receive a first bump out or protruding portion located on the spacer  80  and the second window  74  is configured to receive a second bump out or protruding portion  84  located on the spacer  80 . By receiving the protruding portions  84  of the spacer  80  in the windows  72 ,  74 , this advantageously provides regions of secure engagement between the frame  50  and the spacer  80 . In some embodiments, to secure the frame  50  to the spacer  80 , the spacer  80  can be downwardly forced into the frame  50  (e.g., via hand or a press assembly) until the protruding portions  84  of the spacer  80  are received in the windows  72 ,  74 . At this point the frame  50  is secured to the spacer  80  such that the two members can be delivered securely to a disc space in preparation for bone fusion. 
     With respect to the frame  50 , the third side  56  opposes the fourth side  58 . In some embodiments, the third side  56  can comprise a posterior or leading edge, while the fourth side  58  can comprise an anterior or trailing edge. In some embodiments, the third side  56  can comprise a third window  76 . In some embodiments, the third window  76  can be configured to receive a bump out or protruding portion on a posterior surface of the spacer  80 . In other embodiments, the third window  76  can simply be used to promote fusion by allowing bone growth through it during a spinal fusion procedure. 
     In some embodiments, the fourth side  58  of the frame  50  can receive fixation members therein to secure the frame  50  to adjacent vertebral bodies. In some embodiments, the frame  50  comprises a first opening  62  for receiving a first fixation member  32 , a second opening  64  for receiving a second fixation member  34 , and a third opening  66  for receiving a third fixation member  36 . The first fixation member  32  is angled in an upward direction to engage an upper vertebra, while the second and third fixation members  34 ,  36  are angled in a downward direction to engage a downward vertebra. In some embodiments, the frame  50  is of such a low profile that no portion of the fixation members  32 ,  34 ,  36  protrudes beyond the disc space. For example, in some embodiments, the fixation members  32 ,  34 ,  36  would not enter into the vertebrae through their anterior faces. In other embodiments, only a rear portion of the fixation members  32 ,  34 ,  36  (e.g., their heads) protrudes beyond the disc space. And in yet other embodiments, only a small portion of their overall bodies (e.g., including the shaft) protrudes beyond the disc space. In these embodiments, it is possible that a minimal portion of the fixation members  32 ,  34 ,  36  can contact the anterior faces of the vertebrae. In some embodiments, the frame  50  is of such a low profile that each of the openings  62 ,  64 ,  66  has a majority of or all of their central longitudinal axes positioned between the height of the spacer  80 , as defined from an upper surface of the spacer  80  to a lower surface of the spacer  80 . 
     To prevent inadvertent backout of the fixation members  32 ,  34 ,  36 , the frame  50  further includes a first blocking member  44  and a second blocking member  46 . The first blocking member  44  includes one or more cut-out regions  45  that allow first and second fixation members  32 ,  34  to be received in the first and second openings  62 ,  64 . Once the first and second fixation members  32 ,  34  are received therein, the first blocking member  44  can be rotated such that a portion of the first blocking member  44  overlies the heads of the each of the first and second fixation members  32 ,  34 , thereby reducing the likelihood of backout of the fixation members. Likewise, the second blocking member  46  includes one or more cut-out regions  47  that allow second and third fixation members  34 ,  36  to be received in the second and third openings  64 ,  66 . Once the second and third fixation members  34 ,  36  are received therein, the second blocking member  46  can be rotated such that a portion of the second blocking member  46  overlies the heads of the each of the first and second fixation members  32 ,  34 , thereby reducing the likelihood of backout of the fixation members. In some embodiments, the first and second blocking members  44 ,  46  do not overlie the heads of the fixation members, but rather about the sides of the heads of the fixation members. Each of the first and second blocking members  44 ,  46  can be considered “multi-blocking” members, as they block two or more fixation members from backing out. In other embodiments, each of the openings  62 ,  64 ,  66  includes its own individual blocking member to reduce the risk of backout of the fixation member. 
     As shown in  FIG.  1   , the fixation members  32 ,  34 ,  36  comprise threaded screws or fasteners. The screws can include a head portion and a threaded shaft. In some embodiments, the threaded shaft can be tapered to assist in insertion into vertebrae. In other embodiments, different fixation members  32 ,  34 ,  36  can be provided. For example, as shown in  FIGS.  10 - 14   , non-threaded blades or shims can be inserted into the vertebrae. Advantageously, these alternative fixation members can be inserted into frame via the same openings  62 ,  64 ,  66 , thereby allowing a user to choose the type of fixation member to use. In some embodiments, the same fixation members (e.g., threaded screws or non-threaded blades) are insertable through the frame  50 . In other embodiments, a combination of different types of fixation members (e.g., one threaded screw and two non-threaded blades) are insertable through the frame  50 . 
     The fourth side of the frame  50  can also include first and second tool engagement holes  68 . As shown in  FIG.  1   , one hole  68  is positioned on a first side of the frame  50 , while a second hole  68  is positioned on a second side of the frame  50 . Each of these holes  68  can be engaged by an insertion tool to facilitate easy delivery of the system  10  into a disc space. 
     The frame  50  of the system  10  also includes an upper surface  51  and a lower surface  53 . The upper surface  51  is configured to engage an upper vertebra, while the lower surface  53  is configured to engage a lower vertebra. In some embodiments, the upper surface  51  and the lower surface  53  can include teeth, protrusions, ribbing or ridges  55  that assist in engagement with an adjacent vertebra. 
     In some embodiments, the frame  50  can be formed of a metal or metal alloy. In some embodiments, the frame  50  can be formed of titanium, titanium alloy, steel, steel alloy or any other biocompatible material. In some embodiments, the frame  50  is of a different material from the spacer  80  that resides within it. For example, the frame  50  can be formed of titanium, while the spacer  80  can be formed of PEEK or allograft. 
       FIG.  1    shows one type of spacer  80  in accordance with some embodiments. The spacer  80  is designed to reside in the opening  59  formed in the frame  50 . Advantageously, a surgeon can choose the type of spacer  80  (e.g., either PEEK or allograft) to insert into the frame  50 , even immediately before a surgical procedure. In some embodiments, a surgeon may desire to promote greater bone growth, thereby choosing an allograft spacer  80 . In other embodiments, a surgeon may desire to promote greater structural strength, thereby choosing a PEEK spacer  80 . 
     As shown in  FIG.  1   , the spacer  80  comprises a C-shaped spacer having an upper surface  81  and an opposing lower surface. The upper and lower surfaces are configured to include teeth, protrusions, ribbing, or ridges  85  that engage adjacent vertebral bodies. The spacer  80  can include an opening  87  formed therethrough in which graft material can be deposited therein. The graft material can be deposited to promote fusion and bone growth. In some embodiments, a plug (e.g., a cancellous plug) can be deposited in the opening  87 . In some embodiments, demineralized bone can be deposited in the opening  87  to further promote fusion and bone growth. 
     In some embodiments, the spacer  80  can comprise a multi-piece spacer that can be formed of a first member  82  joined to a second member  84  (as shown in  FIG.  3   ). Each of the members  82 ,  84  can include a protruding portion  84  that can be received in a corresponding window of the frame  50 . The first member  82  and the second member  84  can be joined together via an adhesive, pins, or other attachment means, thereby forming the C-shaped member. In the C-shaped spacer, the first member  82  forms a first arm of the C-shaped spacer while the second member  84  forms a second arm of the C-shaped spacer. By providing a multi-piece spacer, the spacer  80  is capable of having a large footprint, which is particularly useful for patients having large anatomies and disc spaces. In some embodiments, the spacer  80  can be formed of more than two members, such as three, four, five or more members that are attached to one another to form a unitary spacer  80 . 
       FIG.  2    shows a side view of the frame and spacer system of  FIG.  1   . From this view, one can see the shape of the frame  50  in accordance with some embodiments. The frame  50  includes an upper chamfer  61  and a lower chamfer  63  that forms a tapered leading end. Advantageously, the upper chamfer  61  and the lower chamfer  63  can aid in distraction and/or insertion of the frame  50  into a disc space. In addition, from this view, the upper surface of the frame  50  appears substantially parallel to the lower surface of the frame  50 . However, in some embodiments, one or both of the upper surface and/or lower surface can be curved (e.g., convex). From this view, one can also see the second window  74  and the third window  76  that are formed through different surfaces of the frame  50 . As shown in the figure, the spacer  80  includes a protruding portion  84  that is received in the second window  74 , thereby securing the frame  50  to the spacer  80 . 
       FIG.  3    shows a top view of the frame and spacer system of  FIG.  1   . The spacer  80  is nested in the opening  59  of the frame  50 . The spacer  80  is formed of a first member  82  and a second member  84  attached to one another at an interface  86  to form a C-shaped implant. The two members  82 ,  84  surround a spacer opening  87  through which a plug or graft material can be deposited therein. In some embodiments, a plug such as a cancellous plug (as shown in  FIGS.  22  and  23   ) can be deposited in the spacer opening  87 . As shown in  FIG.  3   , the spacer  80  can comprise of a convex leading end and a concave trailing end. The spacer  80  can comprise an upper chamfer and a lower chamfer. In some embodiments, the upper chamfer and lower chamfer of the spacer  80  substantially match the upper and lower chamfer of the frame  50 . 
     From this view, one can also see the overall shape of the frame  50 . The first side  52  and second side  54  of the frame  50  can be curved. The third side  56 , or leading side, of the frame  50  can also be curved. The fourth side  58 , or trailing side, of the frame  50  can be flat or curved in accordance with some embodiments. As shown in  FIG.  3   , the fourth side  58 , which houses the fixation members and blocking members, has a greater thickness than the third side  56 . 
       FIG.  4    shows a top perspective view of a frame with fixation members in accordance with some embodiments, while  FIG.  5    is a side view of the same frame. The frame  50  can advantageously be used as a standalone device that is operable on its own without a spacer  80 . From this view, one can see how the frame  50  includes a first window  72 , a second window  74  and a third window  76 . One or more of the windows can permit graft material to extend therethrough, thereby promoting fusion in a disc space. 
       FIG.  6    is a top view of a frame and spacer system without an upper fixation member in accordance with some embodiments. With the upper or first fixation member  32  removed, one can see how the first opening  62  extends through the fourth side  58  of the frame  50 . As shown in  FIG.  6   , the first opening  62  begins and extends through an anterior surface of the fourth side  58  of the frame  50 , and exits through an edge of a posterior surface of the fourth side  58  of the frame  50 . 
       FIG.  7    is a top view of a frame and spacer system without fixation members in accordance with some embodiments. With the upper or first fixation member  32  removed, one can see how the first opening  62  extends through the fourth side  58  of the frame  50 . As shown in  FIG.  7   , the first opening  62  begins and extends through an anterior surface of the fourth side  58  of the frame  50 , and exits through an edge of a posterior surface of the fourth side  58  of the frame  50 . 
       FIG.  8    is a top view of a frame, while  FIG.  9    is a side view of the frame, in accordance with some embodiments. The frame  50  is shown without a spacer  80  or any of the fixation elements. The frame  50  includes a convex anterior or leading end, as well as a slightly convex posterior or trailing end. The anterior end has an upper chamfer  61  and a lower chamfer  63  (shown in  FIG.  2   ). The frame  50  includes a number of surface protrusions, teeth, ribbing or ridges  55  that provide engagement surfaces with adjacent vertebrae. As shown in  FIG.  8   , portions of the upper and/or lower chamfered surfaces of the spacer  80  do not include ridges  55 . 
       FIG.  10    is a top perspective view of a frame and spacer system having alternative fixation members in accordance with some embodiments. The frame and spacer system  110  shares many similar features as in prior embodiments, including a frame  50  for receiving fixation members and a spacer  80  received therein. A first fixation member  132 , a second fixation member  134 , and a third fixation member  136  are received through the frame  50 . However, in the present embodiment, each of the fixation members  132 ,  134 ,  136  are blades or shims. Advantageously, the fixation members  132 ,  134 ,  136  can be non-threaded such that they are easily inserted into bone, thereby saving time. 
       FIG.  11    is a side view of the frame and spacer system of  FIG.  10   . From this view, one can see the first fixation member  132  and the third fixation member  136 , which are non-threaded. In addition, one can see how the spacer  80  is retained in the frame  50  via one or more bump outs or protruding portions  84 . 
       FIG.  12    is a top perspective view of a frame with alternative fixation members in accordance with some embodiments, while  FIG.  13    is a side view. The frame  50  can be a standalone frame that can be used on its own without a spacer. In some embodiments, the frame  50  has a height that enables it to support a load, and is configured to receive one or more fixation members  132 ,  134 ,  136  to secure the frame  50  to vertebral bodies. 
       FIG.  14    is an anterior view of the frame of  FIG.  12   . As shown in the figure, the frame  50  includes an upper surface  102  and a lower surface  104 . In some embodiments, the upper surface  102  is convex. In some embodiments, the lower surface  104  is convex. From this view, one can also see how the first blocking member  44  and the second blocking member  46  cover the upper heads of the fixation members  132 ,  134 ,  136  to reduce the likelihood of backout of the fixation members. Each of the blocking members  44 ,  46  resides in a recess that is formed adjacent a pair of openings. Each of the blocking members  44 ,  46  thus serves as a multi-block device, capable of reducing the risk of backout of two fixation members. 
       FIG.  15    is a top perspective view of a rectangular frame and spacer system in accordance with some embodiments. The system  210  includes a rectangular cage or frame  250  that receives a spacer  280  therein. 
     The frame  250  comprises a first side  252 , a second side  254 , a third side  256 , and a fourth side  258 . The sides  252 ,  254 ,  256 ,  258  form a continuous perimeter for receiving a spacer  280  therein. First side  252  opposes the second side  254 , while third side  256  opposes the fourth side  258 . In some embodiments, the third side  256  can be considered a posterior or leading end, while the fourth side  258  can be considered an anterior or trailing end. As shown in  FIG.  15   , the fourth side  258  includes a first opening  62  for receiving a first fixation member  32 , a second opening  64  for receiving a second fixation member  34  and a third opening  66  for receiving a third fixation member  36 . In the present embodiment, the fixation members  32 ,  34 ,  36  are all threaded screws, while in other embodiments, one or more of the fixation members can be non-threaded blades or shims. 
     As in prior embodiments, frame includes one or more windows  74  which can serve one or more functions. In some embodiments, the windows  72 ,  74  (shown in  FIG.  20   ) can be used to receive graft material therethrough. In addition, the windows  72 ,  74  can be used to retain one or more bump out or protruding portions of the spacer  280 , thereby helping to secure the spacer  280  with the frame  250 . 
     Additionally, in some embodiments, the frame  250  includes one or more protrusions or nubs  294  (shown in  FIG.  20   ) that can also be used to secure the frame  250  to the spacer  280 . As shown in  FIG.  15   , the spacer  280  can include one or more grooves or notches  284  formed along a sidewall that can receive the one or more nubs  294  therein. Advantageously, in some embodiments, the combination of the one or more nubs  294  and the one or more notches  284  forms a tight friction or interference fit, thereby securing the frame  250  to the spacer  280 . In the present embodiment, the frame  250  includes a single nub  294  formed along an inner wall of its third side  256 . However, in other embodiment, the frame  250  can include one, two, three or more nubs  294  formed on different inner walls. 
     The spacer  280  is configured to be received within an opening  259  in the frame  250 . As in prior embodiments, the spacer  280  can be formed of PEEK or allograft, as desired by the surgeon. The spacer  280  is configured to include an opening  287  therein. In some embodiments, graft material is received in the opening  287 . In other embodiments, a plug can be received in the opening  287 . The spacer  280  can be formed of one, two, three, four or more members that are assembled0 together via an adhesive or mechanical connection assembly. In the present embodiment, the spacer  280  has an overall rectangular profile that is configured to substantially match the contour of the frame  250 . 
     As shown in  FIG.  15   , the spacer  280  includes one or more grooves or notches  284  for receiving one or more nubs  294  of the frame  250 . The one or more notches  284  advantageously help to secure the frame  250  to the spacer  280 . The notches  284  can be formed vertically along an outer wall of the spacer  280 . For example, in the embodiment in  FIG.  15   , the notch  284  is formed on an outer wall of the spacer  280  that is adjacent the leading or third side of the frame  250 . In other embodiments, the frame  250  can include one or more notches, while the spacer  280  includes one or more nubs, thereby creating a friction fit between the two members. 
       FIG.  16    is a top perspective view of an alternative rectangular frame and spacer system in accordance with some embodiments. The frame and spacer system  210  has many similar features to that shown in  FIG.  15   , including a top surface  251  and a bottom surface  253 , and four walls that provide a continuous perimeter around a spacer. However, in the present embodiment, the frame  250  includes at least one side including multiple windows  74  in the form of a lattice  274 . By providing the windows in the form of a lattice  274 , this advantageously provides multiple sites of possible bone growth along the side of the frame  250 . 
       FIG.  17    is a side view of a rectangular frame and spacer system in accordance with some embodiments, while  FIG.  18    is a side view of a rectangular frame and spacer system without fixation members in accordance with some embodiments. From these views, one can see how the spacer  280  is received in the frame  250 . As shown in the figures, the spacer  280  can have a height that is the same as or less than the height of the frame  250 . Also, from these views, one can see how the frame  250  includes ridges  55  that protrude upwardly from its surface to assist in engagement with bone. The frame  250  includes an upper chamfer  261  and a lower chamfer  263 . 
       FIG.  19    is a top perspective view of a rectangular frame in accordance with some embodiments, while  FIG.  20    is a top perspective view of an alternative rectangular frame in accordance with some embodiments. As in prior embodiments, the frame  250  can be a standalone frame wherein it can be inserted into a disc space without including a spacer if desired. 
       FIG.  21    is an exploded view of a spacer in accordance with some embodiments. As shown in  FIG.  21   , the spacer  380  can be a multi-piece spacer formed of different members that are connected together via one or more connection mechanisms (e.g., pins). The spacer  380  can be formed of any suitable biocompatible material, including metal, PEEK or bone. In particular, spacers  380  that are formed of bone (e.g., allograft) may benefit from being formed of multiple members, as this allows spacers are greater sizes to be formed. The spacer  380  includes an upper surface and a lower surface including surface texturing, protrusions, teeth or ridges  355  formed thereon. 
     In  FIG.  21   , the spacer  380  includes a first member  382 , a second member  384  and a third member  386 . When the members  382 ,  384 ,  386  are joined together, they form a C-shaped spacer  380 , similar to that shown in  FIG.  1   . In some embodiments, each of the members  382 ,  384 ,  386  includes a chamfered upper surface and a chamfered lower surface, such that when the members are joined, the spacer  380  includes an upper chamfer and a lower chamfer. For example, as shown in  FIG.  21   , the spacer  380  will include an upper chamfer  387 . 
     As shown in  FIG.  21   , the different members  382 ,  384 ,  386  of the spacer  380  can be secured together via one or more pin members  391 . In some embodiments, the one or more pin members  391  can be formed of a similar material as one or more members  382 ,  384 ,  386  of the spacer  380 . In some embodiments, one or more members  382 ,  384 ,  386  of the spacer  380  can be formed of allograft bone, and one or more pin members  391  can also be formed of allograft bone. In some embodiments, the one or more pin members  391  are formed at an angle other than parallel or 90 degrees relative to an interface formed between two members. In addition, in some embodiments, the one or more pin members  391  are received in blind pin holes, whereby at least one side of the pin holes is not exposed or open. In other embodiments, the one or more pin members  391  are received in non-blind pin holes. While in  FIG.  21   , the different members  382 ,  384 ,  386  are positioned horizontally to one another, in other embodiments, the different members can be stacked and connected vertically to one another. 
       FIG.  22    is a top view of a frame and spacer system, wherein the spacer has a convex side and includes a pair of graft chambers in accordance with some embodiments. In the present embodiment, the system comprises a frame  50  and a spacer  480  that is received within the frame  50 . Advantageously, the spacer  480  is in the form of an E-shape, such that it has a first chamber  497  and a second chamber  499 . The chambers  497 ,  499  are separated by a strut  420  formed on the frame  50 . Advantageously, both the first chamber  497  and the second chamber  499  are capable of receiving a plug  444  therein, as shown in  FIG.  22   . In some embodiments, one or more of the plugs  444  is formed of bone (e.g., cortical or cancellous) and assists in fusion. In some embodiments, one or more of the plugs  444  includes bone fibers. In some embodiments, one or more of the plugs  444  is demineralized. By providing a pair of chambers  497 ,  499  for receiving bone-growth material therein, this advantageously increases the area for promoting bone-growth material. In addition, it allows for multiple smaller pieces of bone growth material (e.g., two plugs) to be used, as opposed to fewer larger pieces of bone growth material, which can be difficult to source. 
       FIG.  23    is a top view of a frame and spacer system, wherein the spacer has a substantially flat side and includes a pair of graft chambers in accordance with some embodiments. The spacer  580  is similar to the spacer  480  in that it includes a first chamber  497  independent from a second chamber  499 . The overall shape of the spacer  580 , however, is more like a rectangle, such that it is designed to fit within a substantially rectangular region of a frame. 
       FIG.  24    is a top view of a spacer including a convex side and a pair of graft chambers in accordance with some embodiments. The spacer  480  is an E-shaped spacer having a first chamber  497  and a second chamber  499 . The spacer  480  includes a convex outer wall  495 . In the present embodiment, the spacer  480  is formed of four members: a first member  482 , a second member  484 , a third member  486  and a fourth member  488 . 
       FIG.  25    is an anterior view of the spacer of  FIG.  24   . From this view, one can see how the spacer  480  includes a convex upper surface  481  and a convex lower surface  483 . Accordingly, the spacer  480  can advantageously have convexity in multiple planes, thereby accommodating different anatomical features. In some embodiments, the spacer  480  has convexity in at least two planes: an X-Y plane (as shown in  FIG.  24   ) and an X-Z plane (as shown in  FIG.  25   ). The spacer  480  can be considered biconvex in two planes. 
       FIG.  26    is a side view of the spacer of  FIG.  24   . From this view, one can see how the spacer  480  includes an upper surface  481 , an opposing lower surface  483 , an upper chamfer  489  and a lower chamfer  491 . In some embodiments, the spacer can be in the form of a wedge member that is able to self-distract between two vertebrae in preparation for performing a fusion procedure. 
       FIG.  27    is a top view of a spacer including a substantially flat side and a pair of graft chambers in accordance with some embodiments. The spacer  580  is an E-shaped spacer having a first chamber  597  and a second chamber  599 . The spacer  580  includes a slightly curved outer wall  595 . In the present embodiment, the spacer  580  is formed of three members: a first member  582 , a second member  584 , and a third member  586 . 
       FIG.  28    is an anterior view of the spacer of  FIG.  27   . From this view, one can see how the spacer  580  includes a convex upper surface  581  and a convex lower surface  583 . Accordingly, the spacer  580  can advantageously have convexity in multiple planes, thereby accommodating different anatomical features. In some embodiments, the spacer  580  has curvature in at least two planes: an X-Y plane (as shown in  FIG.  27   ) and an X-Z plane (as shown in  FIG.  28   ). 
       FIG.  29    is a side view of the spacer of  FIG.  27   . From this view, one can see how the spacer  580  includes an upper surface  581 , an opposing lower surface  583 , an upper chamfer  589  and a lower chamfer  591 . In some embodiments, the spacer can be in the form of a wedge member that is able to self-distract between two vertebrae in preparation for performing a fusion procedure. 
     Methods of using the systems and devices are now provided. In some embodiments, a disc space is formed between a first vertebra and a second vertebra. A frame and spacer system  10 , such as shown in  FIG.  1   , can be prepared to be delivered to the disc space. A surgeon can choose the type of spacer  80  to attach to the frame  50 , and can then attach the elements together via a press mechanism. The spacer  80  can be retained in the frame  50  via bump out or protruding portions  84 . The frame and spacer system  10  (without fixation members) can be attached to an insertion tool via its first and second tool engagement holes  68 . The frame and spacer system  10  can then be delivered via the tool into the disc space, such as via an anterior approach. The frame and spacer system  10  is of a low profile such that it is positioned completely within the disc space. Optional graft material could be packed within the frame and spacer system  10  prior to delivery. Once the frame and spacer system  10  is positioned within the disc space, one or more fixation members  32 ,  34 ,  36  can be delivered to secure the frame  50  and spacer  80  to the first and second vertebrae. The frame and spacer system  10  can be left in the surgical site, whereby it will be used to promote fusion and bone growth. 
     In alternative embodiments, a standalone frame  50 , as shown in  FIG.  4   , can be prepared to be delivered to the disc space. The standalone frame  50  can be delivered to the disc space without a spacer  80 . The frame  50  (without fixation members) can be attached to an insertion tool via its first and second tool engagement holes  68 . The frame  50  can then be delivered via the tool into the disc space, such as via an anterior approach. The frame  50  is of a low profile such that it is positioned completely within the disc space. Optional graft material could be packed within the frame  50  prior to delivery. Once the frame  50  is positioned within the disc space, one or more fixation members  32 ,  34 ,  36  can be delivered to secure the frame  50  to the first and second vertebrae. The standalone frame  50  can be left in the surgical site, whereby it will be used to promote fusion and bone growth. 
       FIG.  30    is a top perspective view of an alternative frame and spacer system in accordance with some embodiments. The frame and spacer system  610  includes similar features as in prior embodiments, including a frame  650 , a spacer  680 , a first fixation member  632 , a second fixation member  634  and a third fixation member  636 . The frame  650  comprises an upper surface  651  and a lower surface  653 , each of which is designed to engage a vertebral member. The frame  650  includes an opening  659  for receiving the spacer  680  therein. Moreover, the frame  650  includes openings for receiving fixation members  632 ,  634 ,  636  therein. To prevent back out of the fixation members  632 ,  634 ,  636 , a first blocking member  644  and a second blocking member  646  can be provided. In addition to these features, the frame and spacer system  610  has distinct geometrical features that advantageously allow it to be of low profile and to better accommodate a patient&#39;s anatomy. 
       FIG.  31    is a front view of the alternative frame and spacer system of  FIG.  30   . From this view, one can see a front or anterior view of the frame  650 . The frame  650  includes a distinct upper surface  660  that is advantageously designed to be low profile. In particular, the upper surface  660  comprises an arched portion  664  positioned between two adjacent slanted portions  662   a ,  662   b . The slanted portions  662   a ,  662   b  have a height that is reduced relative to the arched portion  664 , thereby enhancing the low profile of the frame  650 . In some embodiments, the frame  650  can also include a lower surface of a similar shape to the upper surface  660  to thereby reduce the overall profile of the frame and spacer system  610 . 
       FIG.  32    is a side view of the alternative frame and spacer system of  FIG.  30   . From the side view, one can see the first fixation member  632  that is angled upwardly and the third fixation member  636  which is angled downwardly. 
       FIG.  33    is a top view of the alternative frame and spacer system of  FIG.  30    without fixation members, while  FIG.  34    is a top view of the alternative frame and spacer system with fixation members. As shown in the figure, the frame  650  comprises a first side  652 , a second side  654 , a third side  656  and a fourth side  658 . The frame  650  advantageously encompasses a spacer  680  having a first side  682 , a second side  684  and a third side  686 . As shown in  FIG.  33   , in some embodiments, the frame  650  and the spacer  680  include a distinct shape and form that provides a better anatomical fit with certain patients. With respect to the frame  650 , the first side  652  and the second side  654  comprise convexly curved surfaces, while the third side  656  comprises a concave surface. The spacer  680 , which follows the contour of the frame  650 , also has a first side  682  and second side  684  that comprise convexly curved surfaces and a third side  686  that comprises a concavely curved surface. 
       FIG.  35    is a top perspective view of the alternative frame and spacer system of  FIG.  30    with alternative fixation members, while  FIG.  36    is a side view of the same system. The frame and spacer system  610  comprises a frame  650  and a spacer  680  with non-threaded blades or shims  732 ,  734 ,  736  received through the frame  650 . 
       FIG.  37    is a top view of a spacer and plug in accordance with some embodiments. The spacer  680  and plug  690  can advantageously be used with any of the frames (such as frame  650 ) shown above. In some embodiments, the spacer  680  is formed of PEEK or allograft. In the present embodiment, the spacer  680  is formed of allograft bone and is formed of multiple members assembled together (as shown in  FIG.  38   ). In some embodiments, the plug  690  is formed of a natural material, such as bone (e.g., cancellous bone). The advantage of providing such a plug  690  is that it helps to promote enhanced fusion. 
       FIG.  38    is an exploded view of the spacer and plug of  FIG.  37   . As shown in the figure, the spacer  680  is formed of a first member  682 , a second member  684  and a third member  686  held together via pins  688   a ,  688   b ,  688   c ,  688   d . In some embodiments, the pins  688   a ,  688   b ,  688   c ,  688   d  are also formed of bone. A first pair of pins  688   a ,  688   b  is received through the interface between the members  682 ,  686 , while a second pair of pins  688   c ,  688   d  is received through the interface between the members  684 ,  686 . 
     The systems described above can be used with a number of different surgical implants. Among the surgical implants include stabilization implants, including plates, screws (e.g., pedicle screws) and rods. In addition, more than one frame and spacer system can be applied, such as to different levels of the spine. In addition, the frame and spacer systems described above can be used with different prosthetic devices, such as facet devices. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Moreover, the frame and spacer systems described above need not feature all of the objects, advantages, features and aspects discussed above. Thus, for example, those skilled in the art will recognize that the invention can be embodied or carried out in a manner that achieves or optimizes one advantage or a group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. In addition, while a number of variations of the invention have been shown and described in detail, other modifications and methods of use, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is contemplated that various combinations or subcombinations of these specific features and aspects of embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the discussed bone screw assemblies. Thus, it is intended that the present invention cover the modifications and variations of this invention provided that they come within the scope of the appended claims or their equivalents.