Abstract:
Joint fixation systems and methods, enabling: drilling one or more major bores in a joint; drilling one or more minor bores in the joint, wherein the one or more minor bores are disposed about a periphery of and partially overlap the major bore(s); and disposing an implant in the major bore(s) and the one or more minor bores, wherein a cross-sectional shape of the implant substantially conforms to a collective cross-sectional shape of the major bore(s) and the one or more minor bores. Prior to drilling the major bore(s) or the one or more minor bores, a portal tube is disposed adjacent to the joint, thereby providing access to and stabilizing the joint. A drill guide tube is disposed concentrically within the portal tube, and a drill guide is disposed concentrically within the drill guide tube. Subsequent to drilling the major bore(s) and the one or more minor bores, an implant guide tube is disposed concentrically within the portal tube.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present patent application/patent claims the benefit of priority of co-pending U.S. Provisional Patent Application No. 62/095,120, filed on Dec. 22, 2014, and entitled “SACROILIAC JOINT FUSION SYSTEMS AND METHODS,” and U.S. Provisional Patent Application No. 61/118,759, filed on Feb. 20, 2015, and entitled “SACROILIAC JOINT FUSION SYSTEMS AND METHODS,” the contents of both of which are incorporated in full by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to sacroiliac and other joint fusion systems and methods. More specifically, the present invention relates to a portal tube, a drill guide tube, a drill guide, an implant guide tube, an implant, and related instrumentation for fusing or otherwise securing a sacroiliac or other joint via a minimally-invasive or open surgical procedure. 
       BACKGROUND OF THE INVENTION 
       [0003]    The sacroiliac joint is the joint between the sacrum and the ilium of the pelvis. The sacrum and the ilium are joined by ligaments. The sacrum supports the spine and is supported, in turn, by the ilium on each side. The sacroiliac joint is a synovial joint, with articular cartilage and irregular elevations and depressions that produce interlocking of the sacrum and the ilium. 
         [0004]    Pain associated with the sacroiliac joint can be caused by traumatic fracture, dislocation of the pelvis, degenerative arthritis, sacroiliitis, a degenerative condition or inflamation of the sacroiliac joint, osteitis condensans ilii, or the like. Sacroiliac joint fusion is often indicated as a surgical treatment for such conditions. Sacroiliac joint fusion can be performed via an anterior approach, a posterior approach, or a lateral approach, and typically involves the placement of a fixation assembly, an implant, and/or one or more screws. Significant problems exist, especially when sacroiliac joint fusion is performed via an open surgical procedure, for example. 
         [0005]    Open surgical procedures require general anesthesia and can involve considerable operative time, recovery time, hospitalization, and pain due to significant soft tissue damage. Damage to blood vessels and nerves is also possible. Specifically, the placement of a fixation assembly, an implant, and/or one or more screws can cause damage to the lumbosacral neurovascular elements and/or delayed union of the sacroiliac joint. In a worst case scenario, this can require revision or removal surgery. 
         [0006]    Minimally-invasive surgical procedures are technically more difficult and require multiplanar fluoroscopy/radiography of the articular surfaces of the sacroiliac joint, for example. Again, the placement of a fixation assembly, an implant, and/or one or more screws can cause damage to the lumbosacral neurovascular elements and/or delayed union of the sacroiliac joint. Further, sacral anomalies can lead to mal-placement of the implant, leading to damage to the surrounding structures. 
         [0007]    In both open and minimally-invasive surgical procedures, insufficient amounts of the articular surfaces and/or the cortical surfaces of the sacroiliac joint may be removed to relieve pain in the sacroiliac joint. Likewise, insufficient amounts of the articular surfaces and/or the cortical surfaces of the sacroiliac joint may be engaged by the fixation assembly, the implant, and/or the one or more screws to ensure adequate stabilization and/or fusion. The failure to adequately stabilize and/or fuse the sacroiliac joint can result in a failure to relieve the condition being treated. Mal-alignment of the sacroiliac joint is a similar problem and can lead to increased pain. 
         [0008]    Thus, what are still needed in the art are improved sacroiliac joint fusion systems and methods that provide adequate visualization of and access to the sacroiliac joint, provide very predictable and consistent results easily and efficiently, provide adequate stabilization and/or fusion of the sacroiliac joint, as well as optional distraction and/or translation, if desired, and minimize surgical time, thereby eliminating the problems described above. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    In various exemplary embodiments, the present invention provides a portal tube, a drill guide tube, a drill guide, and implant guide tube, an implant, and related instrumentation for fusing or otherwise securing a sacroiliac or other joint via a minimally-invasive or open surgical procedure, with direct and/or indirect (i.e. fluoroscopy/radiography) visualization. These sacroiliac joint fusion systems and methods provide superior visualization of and access to the sacroiliac joint, provide very predictable and consistent results easily and efficiently, provide superior stabilization and/or fusion of the sacroiliac joint, as well as optional distraction and/or translation, if desired, and minimize surgical time, thereby eliminating the problems described above. 
         [0010]    In one exemplary embodiment, the present invention provides a joint fixation system, including: a portal tube disposed adjacent to a joint (and optionally partially into the joint), thereby providing access to and stabilization of the joint; a drill guide tube selectively disposed concentrically within the portal tube through which: one or more major bores are drilled in the joint; and one or more minor bores are drilled in the joint, wherein the one or more minor bores are disposed about a periphery of and partially overlap the major bore(s); and an implant guide tube selectively disposed concentrically within the portal tube through which an implant is selectively disposed in the major bore(s) and the one or more minor bores, wherein a cross-sectional shape of the implant substantially conforms to a collective cross-sectional shape of the major bore(s) and the one or more minor bores. The portal tube is secured to one of the bony structures forming the joint using a guide pin. The system also includes a drill guide selectively disposed concentrically within the drill guide tube. The implant guide tube defines an internal channel that has a cross-sectional shape that substantially conforms to the cross-sectional shape of the implant, wherein the implant is disposed in the major bore(s) and the one or more minor bores through the internal channel of the implant guide tube. The implant is disposed in the major bore(s) and the one or more minor bores through the implant guide tube using an elongate impaction tool that has a cross-sectional shape that substantially conforms to the cross-sectional shape of the internal channel of the implant guide tube. Optionally, the implant includes one or more recesses configured to hold a bone graft material. Optionally, the joint is a sacroiliac joint. It should be noted that the major bore(s) and the minor bore(s) can have the same relative size, or can be different sizes, although the major bore(s) are typically drilled first. The major bore(s) and the minor bore(s) can also overlap, or they can simply be drilled adjacent to one another, provided that they remove a bulk of the bony material in a predetermined area that roughly corresponds to the shape of the implant that is eventually inserted into this area by press fitting. 
         [0011]    In another exemplary embodiment, the present invention provides a joint fixation method, including: drilling one or more major bores in a joint; drilling one or more minor bores in the joint, wherein the one or more minor bores are disposed about a periphery of and partially overlap the major bore(s); and disposing an implant in the major bore(s) and the one or more minor bores, wherein a cross-sectional shape of the implant substantially conforms to a collective cross-sectional shape of the major bore(s) and the one or more minor bores. The method also includes, prior to drilling the major bore(s) or the one or more minor bores, disposing a portal tube adjacent to the joint (and optionally partially into the joint), thereby providing access to and stabilizing the joint. The method further includes securing the portal tube to one of the bony structures forming the joint using a guide pin. The method still further includes, prior to drilling the major bore(s) or the one or more minor bores, disposing a drill guide tube concentrically within the portal tube. The method still further includes drilling the major bore(s) through the drill guide tube and drilling the one or more minor bores through the drill guide tube. The method still further includes, prior to drilling the one or more minor bores, disposing a drill guide concentrically within the drill guide tube. The method still further includes, subsequent to drilling the major bore(s) and the one or more minor bores, disposing an implant guide tube concentrically within the portal tube. The implant guide tube defines an internal channel that has a cross-sectional shape that substantially conforms to the cross-sectional shape of the implant, wherein the implant is disposed in the major bore(s) and the one or more minor bores through the internal channel of the implant guide tube. The implant is disposed in the major bore(s) and the one or more minor bores through the implant guide tube using an elongate impaction tool that has a cross-sectional shape that substantially conforms to the cross-sectional shape of the internal channel of the implant guide tube. Optionally, the implant includes one or more recesses configured to hold a bone graft material. Optionally, the joint is a sacroiliac joint. Again, it should be noted that the major bore(s) and the minor bore(s) can have the same relative size, or can be different sizes, although the major bore(s) are typically drilled first. The major bore(s) and the minor bore(s) can also overlap, or they can simply be drilled adjacent to one another, provided that they remove a bulk of the bony material in a predetermined area that roughly corresponds to the shape of the implant that is eventually inserted into this area by press fitting. 
         [0012]    In a further exemplary embodiment, the present invention provides a joint fixation method, including: drilling a plurality of bores in a joint, wherein the plurality of bores collectively approximate a predetermined cross-sectional shape; and press fitting an implant having the predetermined cross-sectional shape in the plurality of bores drilled in the joint. The method also includes, prior to drilling the plurality of bores, disposing a portal tube adjacent to the joint, thereby providing access to and stabilizing the joint. The method further includes securing the portal tube to the joint using a guide pin. The method still further includes, prior to drilling the plurality of bores, disposing a drill guide tube concentrically within the portal tube and drilling the plurality of bores through the drill guide tube. Optionally, the method still further includes, prior to drilling at least some of the plurality of bores, disposing a drill guide concentrically within the drill guide tube. Optionally, the method still further includes, subsequent to drilling the plurality of bores, disposing an implant guide tube concentrically within the portal tube. The implant guide tube defines an internal channel that has a cross-sectional shape that substantially conforms to the predetermined cross-sectional shape of the implant, wherein the implant is disposed in the plurality of bores through the internal channel of the implant guide tube. Optionally, the implant is disposed in the plurality of bores through the implant guide tube using an elongate impaction tool that has a cross-sectional shape that substantially conforms to the cross-sectional shape of the internal channel of the implant guide tube. Optionally, the implant includes one or more recesses configured to hold a bone graft material. Optionally, the joint is a sacroiliac joint. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like system components/method steps, as appropriate, and in which: 
           [0014]      FIG. 1  is a series of perspective views of one exemplary embodiment of the portal tube of the present invention; 
           [0015]      FIG. 2  is a series of perspective views of one exemplary embodiment of the drill guide tube of the present invention; 
           [0016]      FIG. 3  is a perspective view of one exemplary embodiment of the portal tube and the drill guide tube of the present invention in an assembled configuration; 
           [0017]      FIG. 4  is a series of perspective views of one exemplary embodiment of the drill guide of the present invention; 
           [0018]      FIG. 5  is a perspective view and a top planar view of one exemplary embodiment of the portal tube, the drill guide tube, and the drill guide of the present invention in an assembled configuration; 
           [0019]      FIG. 6  is a series of schematic diagrams of exemplary drilling patterns that can be utilized in conjunction with/provided by the present invention; 
           [0020]      FIG. 7  is a series of schematic diagrams of another exemplary drilling pattern that can be utilized in conjunction with/provided by the present invention; 
           [0021]      FIG. 8  is a schematic diagram of a further exemplary drilling pattern that can be utilized in conjunction with/provided by the present invention; 
           [0022]      FIG. 9  is a series of perspective views of one exemplary embodiment of the implant guide tube of the present invention; 
           [0023]      FIG. 10  is a perspective view of one exemplary embodiment of the portal tube and the implant guide tube of the present invention in an assembled configuration; 
           [0024]      FIG. 11  is a planar view of one exemplary embodiment of the implant of the present invention; and 
           [0025]      FIG. 12  is a series of perspective views of one exemplary embodiment of the implant insertion tool of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Again, in various exemplary embodiments, the present invention provides a portal tube, a drill guide tube, a drill guide, and implant guide tube, an implant, and related instrumentation for fusing or otherwise securing a sacroiliac or other joint via a minimally-invasive or open surgical procedure. These sacroiliac joint fusion systems and methods provide superior visualization of and access to the sacroiliac joint, provide very predictable and consistent results easily and efficiently, provide superior stabilization and/or fusion of the sacroiliac joint, as well as distraction and/or translation, if desired, and minimize surgical time, thereby eliminating the problems described above. 
         [0027]    Referring now specifically to  FIG. 1 , in one exemplary embodiment, the portal tube  10  includes a cannulated access tube  12  and a handle  14  coupled to the proximal end of the access tube  12 . The handle  14  is used to manipulate the access tube  12 , as well as to secure other components inside the access tube  12 . All components can be keyed accordingly. The distal end of the access tube  12  includes an angled end  16 , optionally including a cut away  18 , that is configured and shaped to engage the sacroiliac joint, or another joint, such that the access tube  12  is held in proper alignment, without penetrating too deeply. Preferably, the access tube  12  is made of a surgically compatible metal or plastic, and has a length of between about 120 and about 150 mm, an external diameter of between about 20 and about 25 mm, and an internal diameter of between about 15 and about 20 mm. The handle  14  is a generally paddle shaped component and may include a recess  20 , finger contours, etc. The handle  14  includes a first port  22  through which a guide pin  24  is inserted. The access tube  12  includes a corresponding cannulated channel  26  through which the guide pin  24  passes. Preferably, the guide pin  24  includes a shoulder stop (not illustrated) at its proximal end, such that penetration of the guide pin  24  through the channel  26  is limited, and protrudes a predetermined distance beyond the distal end of the channel  26 . This protruding portion of the guide pin  24  includes a drill bit or is threaded such that it can penetrate into the bony structure on one side of the joint, thereby securing the access tube  12  to the joint in the proper alignment. The handle  14  also includes a second port  28  that is configured to receive a corresponding pin associated with other components secured inside the access tube  12 , thereby preventing the relative rotation of these components with respect to the access tube  12 . Finally, the access tube  12  or handle  14  includes one or more guide pins  30  that are operable for visualizing the alignment of the access tube  12  with respect to the joint in an open or minimally-invasive surgical procedure, optionally under fluoroscopy/radiography. Specifically, these guide pins  30  can be aligned with the joint between the sacrum and the ilium, for example. In general, the access tube  12  acts as a guide relative to the joint in an open surgical procedure or a portal to the joint in a minimally-invasive surgical procedure. 
         [0028]    Referring now specifically to  FIG. 2 , in one exemplary embodiment, the drill guide tube  40  includes a cannulated drill tube  42  and a handle  44  coupled to the proximal end of the drill tube  42 . In this exemplary embodiment, the drill tube  42  defines a central drill bore  32  with a plurality of smaller corner drill bores  34  disposed about the periphery of the central drill bore  32  in a generally square configuration. This and other exemplary configurations are described in greater detail below. However, all of the drill bores are configured to receive elongate drill bits (not illustrated) through the drill tube  42  such that a predetermined hole pattern can be drilled into and across the bony structures of the joint, providing a tailored void for receiving an implant, also described in greater detail below. The handle  44  is used to manipulate the drill tube  42 , as well as to secure the drill tube  42  inside the access tube  12  ( FIG. 1 ). The distal end of the drill tube  42  includes an angled end  46  defining one or more points, optionally including a cut away  48 , that is configured and shaped to engage the sacroiliac joint, or another joint, such that the drill tube  42  is held in proper alignment, without penetrating too deeply. The angled end  46 /cut away  48  of the drill tube  42  is preferably conformal with the angled end  16  (FIG.  1 )/cut away  18  ( FIG. 1 ) of the access tube  12  when the drill tube  42  is inserted into the access tube  12 . Preferably, the drill tube  42  is made of a surgically compatible metal or plastic, and has a length of between about 120 and about 150 mm, an external diameter of between about 15 and about 20 mm, and an internal diameter of between about 3 and about 10 mm. The handle  44  is a generally paddle shaped component and may include a recess, finger contours, etc. The handle  44  includes a first port  52  that is configured to receive the shoulder stop of the guide pin  24  ( FIG. 1 ). The handle  44  also includes pin  58  that is configured to engage the corresponding second port  28  ( FIG. 1 ) of the handle  14  ( FIG. 1 ) of the access tube  12  when the drill tube  42  is inserted into the access tube  12 , thereby preventing the relative rotation of the drill tube  42  with respect to the access tube  12 . In general, the drill tube  42  acts as a drill guide relative to the joint in an open surgical procedure or a minimally-invasive surgical procedure. 
         [0029]      FIG. 3  illustrates the portal tube  10  and the drill guide tube  40  in an assembled configuration, highlighting that the angled end  46 /cut away  48  of the drill guide tube  40  is conformal with the angled end  16 /cut away  18  of the portal tube  10  when the drill guide tube  40  is inserted into the portal tube  10 . The orientation of the handles  14  and  44  is also coincident. 
         [0030]    Referring now specifically to  FIG. 4 , in one exemplary embodiment, the drill guide  60  includes an elongate shaft  62  defining a plurality of drill bit receiving channels  64  disposed around the periphery and along the major axis thereof. The elongate shaft  62  is disposed within the drill guide tube  40  ( FIGS. 2 and 3 ), which is disposed within the portal tube  10  ( FIGS. 1 and 3 ). A key feature  66  protrudes from the proximal end of the elongate shaft  62  and is configured to engage a corresponding recess (not illustrated) manufactured into the handle  14  or  44  of either the portal tube  10  or the drill guide tube  40  or the proximal end of portal tube  10  or the drill guide tube  40 , thereby preventing rotation of the drill elongate shaft  62  within the drill guide tube  40 . In the exemplary embodiment illustrated, the elongate shaft  62  defines four drill bit receiving channels  64  disposed evenly around the periphery and along the major axis of the elongate shaft. Preferably, the drill guide  60  is made of a surgically compatible metal or plastic, and has a length of between about 120 and about 150 mm and an external diameter of between about 15 and about 20 mm. Each of the drill bit receiving channels  64  has a diameter of between about 2.5 and about 5 mm. Optionally, the distal end of the drill guide  60  includes an angled end  68  that is conformal with the angled end  16  ( FIGS. 1 and 3 )/cut away  18  ( FIGS. 1 and 3 ) of the access tube  12  ( FIG. 1 ) and the angled end  46  ( FIGS. 2 and 3 )/cut away  48  ( FIGS. 2 and 3 ) of the drill tube  42  ( FIG. 2 ) when the drill tube  42  is inserted into the access tube  12 . 
         [0031]      FIG. 5  illustrates the portal tube  10 , the drill guide tube  40 , and the drill guide  60  in an assembled configuration. 
         [0032]      FIG. 6  illustrates exemplary drilling patterns that can be utilized in conjunction with/provided by the present invention. The commonality among these drilling patterns is that they each include a major bore  70  that is drilled into/across the joint and one or more minor bores  72  that are drilled into/across the joint overlapping the major bore  70 . In practice, the minor bores  72  can be drilled first with the drill guide  60  ( FIGS. 4 and 5 ) inserted into the drill guide tube  40  ( FIGS. 2, 3, and 5 ) inserted into the portal tube  10  ( FIGS. 1, 3, and 5 ), with the major bore  70  drilled second with the drill guide  60  removed. Alternatively, the major bore  70  can be drilled first without the drill guide  60  inserted into the drill guide tube  40 , with the minor bores  72  drilled second with the drill guide  60  inserted into the drill guide tube  40  inserted into the portal tube  10 . Multiple major bores  70  can also be utilized, with the appropriate drill guide tube  40  and/or adjustment of the position of the portal tube  10  and/or drill guide tube  40  between the drilling of each major bore  70  and/or the minor bores  72 . The resulting drilling pattern can thus for a rough square recess (illustrated), a rough diamond recess (illustrated), a rough H recess (illustrated), a rough rectangle recess (illustrated), etc. into which a corresponding implant can subsequently be impacted and press fit, as described below. It will be readily apparent to those of ordinary skill in the art that, using a variety of sizes and locations of drilled holes, a wide array of implant receiving holes can be created in terms of size and shape. 
         [0033]      FIG. 7  is a series of schematic diagrams of another exemplary drilling pattern that can be utilized in conjunction with/provided by the present invention, highlighting that the major/minor bores  70  and  72  can be drilled in any order to form the predetermined void shape that is suitable for receiving the implant (not illustrated). 
         [0034]      FIG. 8  is a schematic diagram of a further exemplary drilling pattern that can be utilized in conjunction with/provided by the present invention, highlighting that the major/minor bores  70  and  72  may all be similarly sized to form the predetermined void shape that is suitable for receiving the implant (not illustrated). 
         [0035]    Referring now specifically to  FIG. 9 , in one exemplary embodiment, the implant guide tube  80  includes a cannulated implant tube  82  and a handle  84  coupled to the proximal end of the implant tube  82 . In this exemplary embodiment, the implant tube  82  defines an implant bore  83  having a generally square shape through which a corresponding generally square implant is disposed in a generally square implant receiving hole formed as described above. It will be readily apparent to those of ordinary skill in the art that other shapes could be used equally. The handle  84  is used to manipulate the implant tube  82 , as well as to secure the implant tube  82  inside the access tube  12  ( FIG. 1 ) after the drill tube  42  ( FIG. 2 ) is removed subsequent to drilling, for example. The distal end of the implant tube  82  includes an angled end  86 , optionally including a cut away  88 , that is configured and shaped to engage the sacroiliac joint, or another joint, such that the implant tube  82  is held in proper alignment, without penetrating too deeply. The angled end  86 /cut away  88  of the implant tube  82  is preferably conformal with the angled end  16  ( FIGS. 1 and 3 )/cut away  18  ( FIGS. 1 and 3 ) of the access tube  12  when the implant tube  82  is inserted into the access tube  12 . 
         [0036]    Preferably, the implant tube  82  is made of a surgically compatible metal or plastic, and has a length of between about 120 and about 150 mm, an external diameter of between about 15 and about 20 mm, and an internal width of between about 7 and about 12 mm. The handle  84  is a generally paddle shaped component and may include a recess, finger contours, etc. The handle  84  includes a first port  92  that is configured to receive the shoulder stop of the guide pin  24  ( FIG. 1 ). The handle  84  also includes pin  98  that is configured to engage the corresponding second port  28  ( FIG. 1 ) of the handle  14  ( FIGS. 1 and 3 ) of the access tube  12  when the implant tube  82  is inserted into the access tube  12 , thereby preventing the relative rotation of the implant tube  82  with respect to the access tube  12 . In general, the implant tube  82  acts as an implant alignment and insertion guide relative to the joint in an open surgical procedure or a minimally-invasive surgical procedure. 
         [0037]      FIG. 10  illustrates the portal tube  10  and the implant guide tube  80  in an assembled configuration. 
         [0038]    Referring now specifically to  FIG. 11 , in one exemplary embodiment, the implant  100  of the present invention includes a body portion  102  and, optionally, a tapered tip portion  104 . The tapered tip portion  104  aides in translating the implant into and through the implant guide tube  80  and press fitting the implant  100  into the hole prepared by the drilling techniques described above. Once placed, the body portion  102  promotes stabilization/fusion of the sacroiliac or other joint, and may also optionally provide or secure a desired degree of translation and/or distraction of the joint. Accordingly, it is desirable that the implant  100  have roughly the same shape perpendicular to its primary axis as the hole prepared by the drilling techniques described above. The implant may be made of a surgically compatible metal or plastic, bone allograft material, or the like. Typically, the implant  100  has a length of between about 17 and about 25 mm and a width or thickness of between about 7 and about 15 mm. Optionally, the body portion  102  defines one or more internal or external voids or channels  106  that is/are configured to receive bone graft material, thereby promoting bony fusion of the joint. Optionally, the body portion  102  also defines one or more internal or external voids or channels  105  that is/are configured to receive a placement/impaction tool, such as that described below. Finally, the body portion  102  may include one or more external fins, friction structures, or the like for preventing the implant  100  from backing out of the hole prepared by the drilling techniques described above. In practice, the implant  100  may be “over-impacted” into the hole prepared by the drilling techniques described above such that a bone “cap” of bone fusion promoting material or the like can be disposed on top of the implant  100 . It should be noted that, in this regard, bone fusion promoting material can be placed in the hole before and/or after the implant  100  is impacted into the hole. 
         [0039]    Referring now specifically to  FIG. 12 , in one exemplary embodiment, the implant impaction tool  110  of the present invention includes an elongate body portion  112  that substantially conforms to the internal shape of the implant guide tube  80  ( FIGS. 9 and 10 ) and a handle portion  114 . The implant impaction tool  110  is used to translate the implant  100  ( FIG. 11 ) through the implant guide tube  80  and press fit the implant  100  into the hole prepared by the drilling techniques described above. Accordingly, the elongate body portion  112  has a length of between about  135  and about  150  mm and the handle portion or a separate shoulder stop may act as a penetration depth limiter. 
         [0040]    Although the present invention is illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention, are contemplated thereby, and are intended to be covered by the following non-limiting claims.