Abstract:
An inserter for implanting an intervertebral spacer into a spinal disc space is disclosed. The inserter comprises a jaw assembly connected to a shaft assembly that is connected to a handle assembly. The user operates the handle assembly to open and close the jaw assembly to thereby connect to and release from the intervertebral spacer. Furthermore, the handle assembly is operable to lock and unlock rotation of the jaw assembly while still connected thereto to permit angulation of the jaw assembly relative to the shaft assembly without losing hold of the intervertebral spacer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 60/933,538 entitled “Inserter for intervertebral spacer” filed on Jun. 7, 2007 which is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    The present invention generally relates to medical devices, and in particular, the present invention relates to a surgical instrument for introducing implants related to the spine. 
       BACKGROUND 
       [0003]    Deterioration or dislocation of a spinal disc located between two adjacent vertebral bodies often results in the two adjacent vertebral bodies coming closer together. The reduced disc space height typically results in instability of the spine, decreased mobility and pain and discomfort for the patient. A common treatment is to surgically restore the proper disc space height to thereby alleviate the neurologic impact of the collapsed disc space. Typically, most surgical corrections of a disc space include at least a partial discectomy which is followed by restoration of normal disc space height and, in some instances, fusion of the adjacent vertebral bodies. Restoration of normal disc space height generally involves the implantation of a spacer and fusion typically involves inclusion of bone graft or bone graft substitute material into the intervertebral disc space to create bony fusion. Fusion rods may also be employed. Some implants further provide artificial dynamics to the spine. Such techniques for achieving interbody fusion or for providing artificial disc functions are well-known in the art. 
         [0004]    One problem, among others, with inserting an implant, for example, is associated with patient anatomy. Inserting and positioning the implant in the space between adjacent vertebrae can be difficult or time consuming if the bony portions are spaced too close together, or if the adjacent tissue, nerves or vasculature impedes access to or placement of the implant in the space between the bony portions. Furthermore, maintenance of distraction of the space during insertion of the implant requires additional instruments in the operative space which can make the procedure more invasive and impede access and visibility during implant insertion and thereby make the procedure more difficult. 
         [0005]    Another difficulty of implant insertion is related to the point of access to the damaged disc space which may be accomplished from several approaches to the spine with each approach having different associated difficulties. One approach is to gain access to the anterior portion of the spine through a patient&#39;s abdomen. For an anterior approach, extensive vessel retraction is often required and many vertebral levels are not readily accessible from this approach. Another approach is a posterior approach. This approach typically requires that both sides of the disc space on either side of the spinal cord be surgically exposed, which may require a substantial incision or multiple access locations, as well as extensive retraction of the spinal cord. Yet another approach is a postero-lateral approach to the disc space. The posterior-lateral approach is employed in a posterior lumbar interbody fusion (PLIF) or transforaminal lumber interbody fusion (TLIF) procedure which may be performed as an open technique which requires making a larger incision along the middle of the back. Through this incision, the surgeon then cuts away, or retracts, spinal muscles and tissue to access the vertebrae and disc space. The TLIF procedure may also be performed as a minimally invasive or as an extreme lateral interbody fusion (XLIF) procedure that involves a retroperitoneal transpoas approach to the lumbar spine as an alternative to “open” fusion surgery. In the minimally invasive procedure, the surgeon employs much smaller incisions, avoids disrupting major muscles and tissues in the back and reduces the amount of muscle and tissue that is cut or retracted. As a result, blood loss is dramatically reduced and these minimally invasive benefits also lead to shorter hospital stays and quicker patient recovery times. The aforementioned and various other difficulties associated with the point of access to the damaged disc space and the need to navigate an implant insertion instrument through the point of access further place demands on the implant insertion instrument design. 
         [0006]    Therefore, there remains a need for improved insertion instruments, implants and techniques for use in any one or more types of approaches to the disc space that facilitate and provide for effective insertion while saving time, minimizing the degree of invasiveness for the patient and complementing surgeon skill demands. 
       SUMMARY 
       [0007]    According to one aspect of the invention, an inserter for implanting a spinal implant is disclosed. The inserter includes a jaw assembly configured to connect to the spinal implant. The inserter includes a shaft assembly connected to the jaw assembly. The jaw assembly is configured to angulate with respect to the shaft assembly. The inserter includes a handle assembly connected to the shaft assembly such that the handle assembly is operable by a user to (1) close and open the jaw assembly to thereby respectively connect the spinal implant to the jaw assembly and release the spinal implant from the jaw assembly; and (2) lock and unlock movement of the jaw assembly to permit angulation of the jaw assembly and thereby permit angulation of a connected spinal implant when angulation is unlocked; such angulation being relative to the shaft assembly while the spinal implant remains connected to the jaw assembly. The proximal end of the jaw assembly includes shaft engaging features and the distal end of the shaft assembly includes jaw assembly engaging features. The inserter is configured such that angulation of the jaw assembly is locked by engaging the jaw assembly engaging features of the shaft assembly to the shaft engaging features of the jaw assembly such that angulation of the jaw assembly is unlocked by disengaging the jaw assembly engaging features of the shaft assembly from the shaft engaging features of the jaw assembly. The shaft assembly is configured to move relative to the jaw assembly wherein movement of the shaft assembly closer to the jaw assembly engages the jaw assembly engaging features of the shaft assembly to the shaft engaging features of the jaw assembly and movement of the shaft assembly apart from the jaw assembly disengages the jaw assembly engaging features of the shaft assembly from the shaft engaging features of the jaw assembly. The handle assembly is configured to effect movement of the shaft assembly relative to the jaw assembly. In one variation, the shaft engaging features and the jaw assembly engaging features are teeth. 
         [0008]    According to another aspect of the present invention, an inserter for implanting a spinal implant is disclosed. The inserter includes a jaw configured to releasably connect to the spinal implant, a shaft connected to the jaw such that the jaw is movable with respect to the shaft and a handle connected to the shaft. The inserter is configured such that the angle of the spinal implant with respect to the shaft can be repeatedly changed and locked in position while the spinal implant is connected to the inserter. The inserter is operable to lock and unlock the attached spinal implant to permit angulation without disconnecting the inserter from the spinal implant. 
         [0009]    According to another aspect of the present invention, an inserter for implanting a spinal implant is disclosed. The inserter includes a jaw assembly configured to connect to the spinal implant. The jaw assembly includes a jaw having a first jaw piece and a second jaw piece and a jaw link connected to the first and second jaw pieces such that the first and second jaw pieces are movable with respect to the jaw link. The inserter further includes a shaft assembly connected to the jaw assembly. The shaft assembly includes an inner shaft connected to the jaw assembly, and an outer shaft having a central bore and located over the inner shaft. The shaft assembly further includes an angulation lock connected to the distal end of outer shaft. The inserter further includes a handle assembly connected to the shaft assembly. The handle assembly includes a handle connected to the inner shaft. The handle is operable to close and open the jaw to thereby attach and release the spinal implant to and from the jaw. The handle assembly further includes a knob connected to the outer shaft and movable with respect to the handle to engage and disengage the angulation lock to and from the jaw assembly so as to disable and enable angulation of the jaw assembly and hence of the attached spinal implant with respect to the shaft assembly. The handle is operable to close and open the jaw by moving the inner shaft proximally and distally with respect to the jaw. In another variation, the inserter further includes a middle shaft having a bore. The middle shaft is located over the inner shaft and inside the outer shaft. A pusher configured to engage the jaw link is provided and connected to the distal end of the middle shaft. The inserter is configured such that distal motion of the pusher by action of the handle engages the pusher to the jaw link to lock the jaw link relative to the shaft assembly. 
         [0010]    According to another aspect of the present invention, a method for implanting a spinal implant in a patient is provided. The method includes the steps of creating an incision in a patient and providing a spinal implant. An inserter that has a handle at the proximal end and a distal end that is configured to releasably connect to the spinal implant such that the spinal implant is capable of angulation with respect to the inserter is provided. The spinal implant is connected to the inserter at the distal end of the inserter. The spinal implant is locked relative to the inserter such that the spinal implant is not capable of angulation with respect to the inserter. The spinal implant is inserted into a location inside the patient. The spinal implant is unlocked relative to the inserter such that the spinal implant is capable of angulation with respect to the inserter while the spinal implant remains connected to the inserter. The spinal implant is angulated relative to the inserter while the implant is connected to the inserter. The spinal implant is disconnecting from the inserter and removed from the patient. The spinal implant is locked relative to the inserter such that the spinal implant is not capable of angulation with respect to the inserter after angulating the spinal implant relative to the inserter. The inserter with the spinal implant connected is moved to a second location inside the patient. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to-scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. 
           [0012]      FIG. 1  illustrates a perspective view of an inserter according to the present invention. 
           [0013]      FIG. 2  illustrates an exploded perspective view of the inserter of  FIG. 1  according to the present invention. 
           [0014]      FIG. 3   a  illustrates a perspective view of a jaw assembly of the inserter according to the present invention. 
           [0015]      FIG. 3   b  illustrates an exploded perspective view of the jaw assembly of the inserter according to the present invention. 
           [0016]      FIG. 4   a  illustrates a perspective view of a shaft assembly of the inserter according to the present invention. 
           [0017]      FIG. 4   b  illustrates an exploded perspective view of the shaft assembly of the inserter according to the present invention. 
           [0018]      FIG. 4   c  illustrates a side view of an inner shaft of the shaft assembly of the inserter according to the present invention. 
           [0019]      FIG. 4   d  illustrates a perspective view of an angulation lock according to the present invention. 
           [0020]      FIG. 4   e  illustrates a top view of the angulation lock according to the present invention. 
           [0021]      FIG. 4   f  illustrates a side view of the angulation lock according to the present invention. 
           [0022]      FIG. 4   g  illustrates a perspective view of a pusher according to the present invention. 
           [0023]      FIG. 4   h  illustrates a cross-sectional view of a middle shaft according to the present invention. 
           [0024]      FIG. 4   i  illustrates a cross-sectional view of an outer shaft according to the present invention. 
           [0025]      FIG. 5  illustrates a cross-sectional view of a handle according to the present invention. 
           [0026]      FIG. 6   a  illustrates a perspective view of a spacer in juxtaposition with the inserter according to the present invention. 
           [0027]      FIG. 6   b  illustrates a perspective view of a spacer connected to the inserter according to the present invention. 
           [0028]      FIG. 6   c  illustrates a perspective view of a spacer connected to the inserter with the pusher advanced according to the present invention. 
           [0029]      FIG. 6   d  illustrates a top view of the spacer connected to the inserter in a first orientation according to the present invention. 
           [0030]      FIG. 6   e  illustrates a top view of the spacer connected to the inserter in a second orientation according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Before the subject devices, systems and methods are described, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims. 
         [0032]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. 
         [0033]    It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a spinal segrnent” may include a plurality of such spinal segments and reference to “the screw” includes reference to one or more screws and equivalents thereof known to those skilled in the art, and so forth. 
         [0034]    All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed. 
         [0035]    The present invention is described in the accompanying figures and text as understood by a person having ordinary skill in the field of spinal implants and related instrumentation. 
         [0036]    Referring now to  FIG. 1 , there is shown a perspective view of an inserter  10  for inserting an intervertebral spacer into a disc space between two adjacent vertebral bodies. An exploded perspective view of the inserter instrument  10  is shown in FIG.  2 . As seen in  FIG. 2 , the inserter  10  includes a jaw assembly  12 , a shaft assembly  14  and a handle assembly  16 . 
         [0037]    Turning now to  FIGS. 3   a  and  3   b , there are shown perspective and exploded perspective views, respectively, of the jaw assembly  12  according to the present invention. The jaw assembly  12  includes a jaw  18 , a jaw link  20 , a jaw pin  22 , and two fasteners  24  (only one shown in  FIG. 3   b ). 
         [0038]    Still referencing  FIGS. 3   a  and  3   b , the jaw  18  includes two jaw pieces  26 . Each jaw piece  26  includes a jaw pin receiving portion  28 , a bore  30  for receiving fastener  24  and spacer engaging features  32 . The spacer engaging features  32  are extending features configured to engage the interbody spacer (not shown). The features are projections configured to be inserted into complementarily shaped apertures in the interbody spacer. 
         [0039]    Still referencing  FIGS. 3   a  and  3   b , the jaw link  20  includes jaw receiving portions  34  configured to receive each of the jaw pieces  26  and to be fastened together via fasteners  24  inserted through holes  35  such that the jaw pieces  26  are capable of movement with respect to the jaw link  20 . The jaw link  20  also includes a jaw pin receiving portion  36  configured to receive the jaw pin  22 . At the other end, the jaw link  20  includes a plurality of teeth  38  and a pusher engaging surface  40 . The jaw pieces  26  of the jaw  18  are inserted into the jaw receiving portions  34  of the jaw link  20 . The jaw pin  22  is disposed within the jaw pin receiving portion  28  of each jaw piece  26  and within the jaw pin receiving portion  36  of the jaw link  20 . Fasteners  24  are passed through holes  35  of the jaw link  20  and through bores  30  in the jaw pieces  26 , thereby, connecting the jaw  18  and the jaw link  20 . 
         [0040]    Turning now to  FIGS. 4   a  and  4   b , there are shown perspective and exploded perspective views, respectively, of the shaft assembly  14  according to the present invention. The shaft assembly  14  includes an inner shaft  42 , a middle shaft  44 , an outer shaft  46 , a pusher  48 , an angulation lock  50 , and a spring  52 . 
         [0041]    Turning now to  FIG. 4   c , there is shown a side view of the inner shaft  42 . The inner shaft  42  includes a threaded proximal end  54  and a slot  56  at the distal end. The slot  56  opens at the distal end and extends at least partially towards the proximal end of the inner shaft  42 . The distal end also includes a shoulder  58  and two aligned bores  57  formed to receive the jaw pin  22 . 
         [0042]    Turning now to  FIGS. 4   d ,  4   e , and  4   f , there are shown perspective, top planar, and side views, respectively, of the angulation lock  50  according to the present invention. The distal end of the angulation lock  50  includes a plurality of teeth  60  and a slot  62  opening at and extending from the distal end towards the proximal end of the angulation lock  50 . The slot  62  is configured to receive the pusher  48 . The angulation lock  50  further includes four prongs  64 . A pair of prongs  64  is located at the top side of the angulation lock  50  and a pair of prongs  64  is located at the bottom side of the angulation lock  50 . Each prong  64  extends from the distal end of the angulation lock  50  towards the proximal end of the angulation lock  50  such that the proximal end of each prong  64  is permitted to deflect inwardly. Upon inward deflection, the prongs  64  are configured such that they have the tendency to spring back. Also each prong  64  includes a barb  66 . 
         [0043]    Turning now to  FIG. 4   g , there is shown a pusher  48  according to the present invention. The pusher  48  includes a jaw link engaging portion  68  at the distal end of the pusher  48 . The jaw link engaging portion  68  is configured to engage the jaw link  20  of the jaw assembly  12 . The jaw link engaging portion  68  includes a surface that conforms to the pusher engaging surface  40  of the jaw link  20 . The pusher  48  further includes two prongs  70  that extend from the distal end towards the proximal end of the pusher. The prongs  70  are capable of inward deflection primarily at the proximal end of the prongs  70 . Each prong  70  also includes a barb  72  that protrudes outwardly from the prong  70 . Upon inward deflection, the prongs  70  are configured such that they have the tendency to spring back. 
         [0044]    Turning now to  FIG. 4   h , there is shown the middle shaft  44  according to the present invention. The middle shaft  44  includes a distal end  74  and a proximal end  76 . The middle shaft  44  is configured as a tube having a central bore  78  opening at and extending between the proximal and distal ends,  76 ,  74 . A circumferential inner groove  80  is formed in the inner surface of the bore  78  closer to the distal end  74 . The groove  80  is configured to engage the barbs  72  of the pusher  48  and as such, the groove  80  includes an angled surface  82  that corresponds to the angled surface of the barbs  72 . At least one window  84  is formed in the middle shaft  44 . The window  84  serves as an access point for releasing the barbs  72  from the inner shaft  44  via deflection of the prongs  70 . 
         [0045]    Turning now to  FIG. 4   i , there is shown the outer shaft  46  according to the present invention. The outer shaft  46  includes a distal end  86  and a proximal end  88 . The outer shaft  46  is configured as a tube having a central bore  90  opening at and extending between the distal and proximal ends,  86 ,  88 . A circumferential inner groove  92  is formed in the inner surface of the bore  90  closer to the distal end  86 . The groove  92  is configured to engage the barbs  66  of the angulation lock  50  and as such, the groove  92  includes an angled surface  94  that corresponds to the angled surface of the barbs  66 . At least one window  96  is formed in the outer shaft  46 . The window  96  serves as an access point for releasing the barbs  66  from the outer shaft  46  via deflection of the prongs  64 . Another window  98  is formed closer to the proximal end  88  and is configured for connection to a portion of the hand assembly  16 . 
         [0046]    The assembly of the shaft assembly  14  will now be discussed. The angulation lock  50  is inserted into the slot  56  of the inner shaft  42  and the pusher  48  is inserted into the slot  62  of the angulation lock  50 . The distal end  74  of the middle shaft  44  is passed over the inner shaft  42  from the proximal end of the inner shaft  42 . As it passes over the inner shaft  42 , the middle shaft  44  engages the pusher  48  and deflects the prongs  70  of the pusher  48  until the barbs  72  of the prongs  70  spring into the groove  80  locking the pusher  48  to the middle shaft  44 . The pusher  48  is releasable from the middle shaft  44  by deflecting the prongs  70  inwardly via the window  84  and pulling the pusher  48  free of the middle shaft  44 . The distal end  86  of the outer shaft  46  is passed over the middle shaft  44  beginning at the proximal end  76  of the middle shaft  44 . As it passes over the middle shaft  44 , the outer shaft  46  engages the angulation lock  50  and deflects the prongs  64  of the angulation lock  50  until the barbs  66  of the prongs  64  spring into the groove  92  locking the angulation lock  50  to the outer shaft  46 . The angulation lock  50  is releasable from the outer shaft  46  by deflecting the prongs  64  inwardly via the window  96  and pulling the angulation lock  50  free of the outer shaft  46 . The spring  52  is passed over the proximal end of the inner shaft  42  until it slides up against the proximal end  88  of the outer shaft  46  which is shorter in length than the middle shaft  44  which is shorter than the inner shaft  42 . 
         [0047]    Referring back to  FIG. 2 , the handle assembly  16  includes a knob  100 , a handle  102  and fasteners  104 . The knob  100  includes finger engaging portions  106  and a bore  108  opening at and extending between the proximal end  110  and the distal end  112 . The bore  108  is configured to receive the outer shaft  46  therein. 
         [0048]    Turning now to  FIG. 5 , there is shown a cross-sectional view of the handle  102  having a proximal end  116  and a distal end  118 . The handle  102  includes a central bore  114  opening at and extending between the proximal end  116  and the distal end  118 . The bore  114  includes a threaded portion  120 , a middle shaft ledge  122 , and a spring ledge  124 . 
         [0049]    The assembly of the jaw, shaft and handle assemblies  12 ,  14 ,  16  of the instrument  10  will now be discussed. The jaw assembly  12  is inserted into the slot  56  of the inner shaft  42  such that the jaw pin receiving portion  28  is aligned with bores  57  of the inner shaft  42 . The jaw pin  22  of the jaw assembly  12  is then passed through the bores  57  and the jaw pin receiving portion  28  in a press-fit engagement thereby connecting the jaw assembly  12  to the shaft assembly  14  such that the jaw assembly  12  is capable of movement with respect to the shaft assembly  14  about the jaw pin  22 . The knob  100  of the handle assembly  16  is passed over the proximal end of the inner shaft  42 , middles shaft  44  and outer shaft  46  until it is aligned with windows  98  of the outer shaft  46 . Fasteners  104  are passed into the knob  100  and into windows  98 , connecting the knob  100  to the outer shaft  46 . The distal end  118  of the handle  102  is passed over the proximal end of the inner shaft  42  such that the inner shaft  42  is inserted into the bore  114  of the handle  102  until the threaded proximal end  54  of the inner shaft  42  engages the threaded portion  120  of the handle  102 . The inner shaft  42  is threaded to the handle  102 . Threaded advancement of the shaft assembly  14  inside the bore  114  is arrested by the middle shaft ledge  122  which contacts the proximal end  76  of the middle shaft  44 . The spring  52  is disposed and is compressible between the spring ledge  124  and the proximal end  88  of the outer shaft  46 . 
         [0050]    Operation of the inserter instrument  10  will now be discussed with initial reference to  FIGS. 6   a ,  6   b  and  6   c . Referring firstly to  FIG. 6   a , an interbody spacer  126  having engaging apertures  128  is shown in juxtaposition with the inserter  10  with the jaw assembly  12  in an open position in which the jaws  18  are spread apart. The typical spacer  126  includes a body formed by a wall extending about a central cavity. The cavity extends between and opens at an upper bearing surface and a lower bearing surface. The upper and lower bearing surfaces contact the adjacent vertebral endplates to support the adjacent vertebrae when the spacer is implanted into the spinal disc space. Surfaces include grooves formed to facilitate engagement with the vertebral endplates and resist the spacer from migrating within the disc space. The spacer includes a convexly curved anterior wall and an opposite concavely curved posterior wall. These wall portions are connected by a convexly curved leading end wall and a convexly curved trailing end. The overall shape provides a banana or kidney type shape for the spacer. 
         [0051]    The spacer  126  includes spacer engaging apertures  128  that are shown in  FIG. 6   a  to be aligned with the spacer engaging features  32  of the jaw assembly  12 . The handle  102  is rotated such that the threaded engagement with the inner shaft  42  draws the inner shaft  42  into the bore  114  of the handle  102  and moves the jaw pin  22  along with it, thereby angulating the jaws  18  about pins  22 ,  24  into a closed position. In the closed position, the spacer engaging features  32  are clamped to the spacer  126  as shown in  FIG. 6b . Rotating, or screwing of the handle  102  brings the middle shaft  44  against the middle shaft ledge  122  inside the bore  114  of the handle  102 . With the middle shaft  44  abutted against the middle shaft ledge  122 , continued advancement, screwing of the handle  102 , pushes the middle shaft  44  forward relative to the handle  102  and since the middle shaft  44  is attached to the pusher  48 , the pusher  48  moves forward (distally) and contacts the pusher engaging surface  40  of the jaw link  20  biasing it against the jaw  18  to further lock the spacer  126  to the instrument  10  as shown in  FIG. 6   c . Such advancement also biases the spring  52  between the inside spring ledge  124  and the proximal end  88  of the outer shaft  46 . The spring bias pushes the outer shaft  46  forward and because the outer shaft  46  is connected to the angulation lock  50 , the teeth  60  of the angulation lock  50  engage the teeth  38  of the jaw link  20  which prevents rotation of the jaw assembly  12  relative to the rest of the instrument  10 . 
         [0052]    Pulling on the knob  100  compresses the spring  52  and because the knob  100  is connected to the outer shaft  46  which in turn is connected to the angulation lock  50 , the angulation lock  50  is thereby disengaged from the jaw assembly  12 , in particular, the teeth  60  of the angulation lock  50  are disengaged from the teeth  38  of the jaw link  20  and the jaw assembly  12  is free to rotate about the jaw pin  22 . With the angulation lock  50  thereby disengaged from the jaw link  20 , the surgeon is able to angulate the spacer  126  relative to the instrument from, for example, a first orientation such as that shown in  FIG. 6   d  to a second orientation such as that shown in  FIG. 6   e . Such angulation makes the instrument  10  useful for easing and facilitating insertion, positioning and implantation of the spacer  126  inside the patient. When the knob  100  is released, the spring  52  forces the knob  100  and outer shaft  46  together with the angulation lock  50  forward distally and the teeth  60  of the angulation lock  50  re-engage the teeth of the jaw link  20  thereby locking the two from relative motion. The angulation lock  50  may be repeatedly disengaged and re-engaged as needed by the surgeon to conveniently orientate the spacer advantageously without losing hold of the intervertebral spacer. 
         [0053]    The preceding merely illustrates the principles of the invention. Although the description is with respect to the implantation of an intervertebral body spacer, the invention is readily adapted for any spinal implant, including but not limited to spinal implants such as interspinous process spacers, intervertebral body spacers, rods, screws, bone anchors and connectors. It will be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents and equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. The scope of the present invention, therefore, is not intended to be limited to the exemplary embodiments shown and described herein. Rather, the scope and spirit of present invention is embodied by the appended claims.