Abstract:
An inserter for implanting a spinal implant such as 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 implant. 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 implant.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 60/937,384 entitled “Inserter for intervertebral spacer” filed on Jun. 27, 2007 which is incorporated herein by reference in its entirety. This application also claims priority to and is a continuation-in-part of U.S. patent application Ser. No. 12/157,647 entitled “Inserter for a spinal implant” filed on Jun. 11, 2008 which claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 60/934,104 filed on Jun. 11, 2007. This application also claims priority to and is a continuation-in-part of U.S. patent application Ser. No. 12/156,857 entitled “Inserter for a spinal implant” filed on Jun. 4, 2008 which claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 60/933,538 filed on Jun. 7, 2007, all of which are hereby incorporated by reference in their entireties. 
     
    
     FIELD 
       [0002]    The present invention generally relates to medical devices, and in particular, the present invention relates to a surgical instrument for introducing spinal implants such as an intervertebral spacer into a disc space between adjacent vertebral bodies. 
       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 a 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 on aspect of the invention, an inserter for implanting a spinal implant is provided. The inserter includes a jaw assembly configured to attach to the spinal implant. The inserter also includes a shaft assembly connected to the jaw assembly. The shaft assembly includes a shaft connected to a gear wheel. The inserter further includes a handle assembly connected to the gear wheel and the shaft assembly such that the handle assembly is operable to open and close the jaw assembly to thereby connect to and release the spinal implant and operable to lock and unlock rotation of the gear wheel to permit angulation of the jaw assembly relative to the shaft assembly. The gear wheel includes a wedge-shaped shaft receiving portion with the shaft disposed therein; the wedge-shaped shaft receiving portion limiting the degree of rotation of the gear wheel with respect to the shaft and thereby limiting the degree of angulation of an attached spinal implant with respect to the shaft assembly. The gear wheel is rotatable with respect to the handle assembly to angulate a spinal implant attached to the jaw assembly with respect to the shaft. A trigger is provided and configured to engage the gear wheel to lock the angulation in place and configured to release the gear wheel to permit angulation. In one variation, the trigger is configured such that it is movable distally by the user to release the gear wheel to permit angulation. In one variation, a slap hammer surface is provided at the proximal end of the inserter. The shaft includes a right shaft and left shaft. The proximal end of the right shaft is connected to the gear wheel at a distance offset from the center of the gear wheel. The proximal end of the left shaft is connected to the gear wheel at a distance offset from the center of the gear wheel. In one variation, the shaft assembly includes an angled portion such that the distal working end of the inserter is displaced from the proximal handle end by a distance such that the distal working end of the inserter is substantially unobstructed by the inserter&#39;s proximal end. 
         [0008]    According to another aspect of the invention, an inserter for implanting a spinal implant is disclosed. The inserter includes a jaw assembly configured to attach to a spinal implant. The inserter includes a shaft assembly connected to the jaw assembly. The shaft assembly includes an inner shaft comprising a right inner shaft and a left inner shaft, an outer shaft, and a gear wheel. The inner shaft has a distal end configured to connect with the jaw assembly. The outer shaft has a distal end configured to connect with the jaw assembly. The inner shaft is located in the outer shaft such that the inner shaft is movable with respect to the outer shaft. The proximal end of the right inner shaft is connected to the gear wheel. The proximal end of the left inner shaft is connected to the gear wheel. The inserter includes a handle assembly. The handle assembly includes a first portion connected to the gear wheel such that the gear wheel is rotatable with respect to the first portion. The handle assembly further includes a second portion connected to the first portion. The second portion is connected to the proximal end of the outer shaft such that the outer shaft is movable with respect to the second portion. The handle assembly includes a trigger connected to the first portion such that it is movable with respect to the first portion to unlock rotation of the gear wheel to permit angulation of the jaw assembly and lock rotation of the gear wheel to arrest angulation of the jaw assembly. 
         [0009]    According to another aspect of the invention, a method for implanting a spinal implant is provided. The method includes the step of providing an instrument. The instrument includes a jaw configured to attach to a spinal implant, a shaft connected to the jaw, and a handle connected to the shaft. The jaw is operable via the handle to open and close to connect to the spinal implant and also operable via the handle to angulate an attached spinal implant with respect to the shaft and further operable to lock and unlock such angulation. A spinal implant configured to attach to the instrument and sized for frictional engagement between spinal anatomy is provided. The jaw of the instrument is opened. The spinal impant is placed in juxtaposition to the jaw. The jaw is closed and the spinal implant is connected to the instrument. An incision in a patient targeting spinal anatomy is created and the instrument with the attached spinal implant is inserted into the incision. The spinal implant is positioned between spinal anatomy such that the spinal anatomy exerts a frictional force on the spinal implant holding it substantially in place. The instrument is unlocked such that angulation of the implant relative to the shaft is permitted. The attached implant is angulated relative to the shaft while the implant is connected to the instrument. The instrument is locked such that angulation of the implant relative to the shaft is arrested. The spinal implant is re-positioned between the spinal anatomy. The jaw is opened. The instrument is removed from the incision and spinal implant is left located in position between the spinal anatomy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    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. Some dimensions of the various features are arbitrarily expanded or reduced for clarity. 
           [0011]      FIG. 1   a  illustrates a perspective view of an inserter according to the present invention. 
           [0012]      FIG. 1   b  illustrates a top view of the inserter of  FIG. 1  according to the present invention. 
           [0013]      FIG. 1   c  illustrates a side view of the inserter of  FIG. 1  according to the present invention. 
           [0014]      FIG. 1   d  illustrates a cross-sectional view of the inserter of  FIG. 1  according to the present invention. 
           [0015]      FIG. 2   a  illustrates a perspective view of a right jaw of the jaw assembly of the inserter according to the present invention. 
           [0016]      FIG. 2   b  illustrates a perspective view of a left jaw of the jaw assembly of the inserter according to the present invention. 
           [0017]      FIG. 3  illustrates a perspective view of an outer shaft of the shaft assembly of the inserter according to the present invention. 
           [0018]      FIG. 4  illustrates a top view of an inner shaft assembly connected to a jaw assembly of the inserter according to the present invention. 
           [0019]      FIG. 4   a  illustrates top and side views of a right inner shaft of the inner shaft assembly of the inserter according to the present invention. 
           [0020]      FIG. 4   b  illustrates top and side views of a left inner shaft of the inner shaft assembly of the inserter according to the present invention. 
           [0021]      FIG. 4   c  illustrates a side and cross-sectional view taken along line A-A of a gear wheel of the inner shaft assembly of the inserter according to the present invention. 
           [0022]      FIG. 5  illustrates a perspective view of the handle of the handle assembly of the inserter according to the present invention. 
           [0023]      FIG. 6  illustrates a cross-sectional view of a trigger of the handle assembly of the inserter according to the present invention. 
           [0024]      FIG. 7  illustrates a perspective view of a spring of the handle assembly of the inserter according to the present invention. 
           [0025]      FIG. 8  illustrates a knob of the handle assembly of the inserter according to the present invention. 
           [0026]      FIG. 9   a  illustrates a top and detail view of a spacer in juxtaposition with the inserter according to the present invention. 
           [0027]      FIG. 9   b  illustrates a top and detail view of a spacer connected to the inserter according to the present invention. 
           [0028]      FIG. 9   c  illustrates a top and detail view of a spacer connected to the inserter and angulated in one direction according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    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. 
         [0030]    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. 
         [0031]    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 segment” 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. 
         [0032]    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. 
         [0033]    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. 
         [0034]    Referring now to  FIGS. 1   a - 1   d,  there is shown a perspective view, a top view, a side view, and a cross-sectional view, respectively, of an inserter  10  for inserting a spinal implant into a patient such as an intervertebral spacer into a disc space between two adjacent vertebral bodies. With particular reference to  FIG. 1   d,  the inserter  10  includes a jaw assembly  12 , a shaft assembly  14  and a handle assembly  16 . 
         [0035]    The jaw assembly  12  will now be discussed in reference to  FIGS. 2   a  and  2   b.  The jaw assembly  12  includes a jaw comprising two jaw pieces-a right jaw piece  18  and a left jaw piece  20 -two jaw pins  22  (not shown), and two shaft pins  24  (not shown). 
         [0036]    With particular reference to  FIG. 2   a,  the right jaw piece  18  includes a substantially flat portion with a curvate proximal end  28  connected to spacer engaging features  30 . Two shaft pin apertures  26  are formed in the substantially flat portion  28 . The spacer engaging features  30  are extending features configured to engage the interbody spacer (not shown). The features  30  are projections configured to be inserted into complementary shaped apertures in the spinal implant. 
         [0037]    With particular reference to  FIG. 2   b,  the left jaw piece  20  includes a right jaw receiving portion  32  formed between two substantially flat portions  34 -an upper flat portion and a lower flat portion. Each flat portion  34  includes a shaft pin aperture  36  and a jaw pin aperture  38 . The shaft pin aperture  36  of the upper flat portion is aligned with the shaft pin aperture  36  of the lower flat portion and the jaw pin aperture  38  of the upper flat portion is aligned with the jaw pin aperture  38  of the lower flat portion. The upper and lower flat portions  34  are connected to spacer engaging features  40 . The spacer engaging features  40  are extending features configured to engage the interbody spacer (not shown). The features are projections configured to be inserted into complementary shaped apertures in the spinal implant. 
         [0038]    Turning to  FIGS. 3 and 4 , the shaft assembly  14  according to the present invention will now be discussed. The shaft assembly includes an outer shaft  42  shown in  FIG. 3  and an inner shaft assembly  44  shown in  FIG. 4 . The outer shaft  42  is connected to the inner shaft  44 . 
         [0039]    With particular reference to  FIG. 3 , there is shown a perspective view of the outer shaft  42 . The outer shaft  42  has a solid proximal end  58  and splits into two prongs towards the distal end  60 . The split portion of the outer shaft  42  forms a jaw assembly receiving portion  46  and an inner shaft assembly receiving portion  48  between the prongs. A shoulder  50  for abutment against the handle assembly  16  is also formed. The proximal end  58  includes a threaded portion  52 . The outer shaft  42  includes a plurality of connecting apertures  54  aligned in the upper and lower prongs for connected to the inner shaft assembly  44 . The distal end  60  includes jaw pin apertures  56  aligned in the upper and lower prongs for receiving jaw pins  22  (not shown) for connecting the outer shaft  42  to the jaw assembly  12 . In one variation, the outer shaft  42  includes an angled portion  62  imparting the outer shaft  42  with a bayonet-like appearance. The bayonet shape permits the working distal end  60  to be displaced from the proximal handling end  58 . The displacement of the working distal end  60  from the proximal handling end  58  by a distance eases installation of the implant and helps keep the working distal end  60  substantially unobstructed by the instrument&#39;s proximal end when viewed from the proximal end  58  along the longitudinal axis of the distal end  60 . In another variation, the outer shaft  42  is not angled and is a substantially straight tube. 
         [0040]    With particular reference to  FIG. 4 , there is shown a top view of the inner shaft assembly  44  connected to the jaw assembly  12 . The inner shaft assembly  44  includes a right inner shaft  66  and a left inner shaft  68  both connected to a gear wheel  70  at the proximal end. 
         [0041]    With particular reference to  FIG. 4   a,  the right inner shaft  66  includes a pronged distal end  72  that includes aligned upper and lower shaft pin apertures  74  for receiving shaft pins  24  and connecting to the right jaw piece  18 . The body of the right inner shaft  66  includes elongated notches  76  substantially aligned with the connecting apertures  54  of the outer shaft  42 . The proximal end of the right inner shaft  66  includes a gear pin aperture for receiving a gear pin and connecting to the gear wheel  70 . In one variation, the right inner shaft  66  includes an angled portion  78  that conforms substantially to the angled portion  62  of the outer shaft  42 . 
         [0042]    With particular reference to  FIG. 4   b,  the left inner shaft  68  includes a pronged distal end  80  that includes aligned upper and lower shaft pin apertures  82  for receiving shaft pins  24  and connecting to the left jaw piece  20 . The body of the left inner shaft  68  includes elongated notches  84  substantially aligned with the connecting apertures  54  of the outer shaft  42  and elongated notches  76  of the right inner shaft  66 . The proximal end of the left inner shaft  68  includes a gear pin aperture for receiving a gear pin and connecting to the gear wheel  70 . In one variation, the left inner shaft  68  includes an angled portion  86  that conforms substantially to the angled portion  62  of the outer shaft  42  and the angled portion  78  of the right inner shaft  66 . 
         [0043]    With particular reference to  FIG. 4   c,  the gear wheel  70  of the inner shaft assembly is substantially circular in shape and includes a toothed periphery  88 . The gear wheel  70  includes a central bore  90  and gear pin apertures  92  for receiving gear pins and connecting to the right and left inner shafts  66 ,  68 . The gear wheel  70  includes an inner shaft assembly receiving portion  94  (also seen in  FIG. 1   d ) for receiving the proximal end of the inner shaft assembly  44  inside the gear wheel  70 . The inner shaft assembly receiving portion  94  is substantially wedge-shaped for limiting rotation of the wheel  70  about the inner shaft assembly  44  within this wedge as well as defining the span of angulation of the jaw assembly  12 . 
         [0044]    The assembly of the inner shaft assembly  44  will now be described in reference to  FIG. 4 . The proximal ends of the right inner shaft  66  and left inner shaft  68  are connected to the gear wheel  70  by passing gear pins (not shown) into gear pin apertures of the right and left inner shafts  66 ,  68  and into gear pin apertures  92  on the gear wheel  70  such that the gear wheel  70  is capable of relative movement with respect to the right and left inner shafts  66 ,  68 . The angled portions  78  and  86  of the right and left inner shafts  66 ,  68  are aligned as are the elongated notches  76  and  84 . 
         [0045]    The assembly of the inner shaft assembly  44  to the jaw assembly  12  will now be described in reference to  FIG. 4 . The distal end of the right inner shaft  66  is connected to the right jaw piece  18  by disposing the right jaw piece  18  into the pronged distal end  72  of the right inner shaft  66  and passing a shaft pin into the shaft pin apertures  74  of the right inner shaft  66  and into the shaft pin aperture  26  of the right jaw piece  18  such that the right inner shaft  66  is capable of relative movement with respect to the right jaw piece  18 . The distal end of the left inner shaft  68  is connected to the left jaw piece  20  by disposing the pronged distal end  80  into the left jaw piece  20  (in particular, disposing the pronged distal end  80  into the right jaw receiving portion  32  of the left jaw piece  20 ) and passing a shaft pin into the shaft pin apertures  82  of the left inner shaft  68  and into the shaft pin apertures  36  of the left jaw piece  20  such that the left inner shaft  68  is capable of relative movement with respect to left jaw piece  20 . 
         [0046]    The assembly of the inner shaft assembly  44  to the outer shaft  42  will, now be discussed. The inner shaft assembly  44  is inserted into the inner shaft assembly receiving portion  48  of the outer shaft  42 . A first jaw pin is passed into the upper jaw pin aperture  56  of the outer shaft  42  and into the upper jaw pin aperture  38  of the left jaw piece  20  and a second jaw pin is passed into the lower jaw pin aperture  56  of the outer shaft  42  and into the lower jaw pin aperture  38  of the left jaw piece  20  securing the left jaw piece  20  to the outer shaft  42  such that relative movement of the left jaw piece  20  and outer shaft  42  is permitted. Fasteners are passed through the connecting apertures  54  of the outer shaft  42  and into the apertures created by the conjunction of notches  76  and  84  of the adjacent right and left inner shafts  66 ,  68  to connect the inner shaft assembly  44  to the outer shaft  42  such that the right and left inner shafts  66 ,  68  are capable of relative movement with respect to the outer shaft  42 . 
         [0047]    The handle assembly  16  will now be described in reference to  FIGS. 5-8 . The handle assembly  16  includes a handle  96 , a trigger  98 , a knob  100 , spring  102  and a number of fasteners for connecting the elements together. 
         [0048]    With reference first to  FIG. 5 , the handle  96  of the handle assembly  16  will now be described. The handle  96  has a proximal end  104  and a distal end  106 . The handle  96  includes a bore  108  opening at and extending between the proximal end  104  and the distal end  106 . A pair of oppositely disposed side windows  110  and at least one aperture  112  are also formed in the handle  96 . A pair of oppositely disposed apertures  112  is employed for receiving fasteners to secure the gear wheel  70  to the handle  96 . 
         [0049]    Referring now to  FIG. 6 , the trigger  98  of the handle assembly  16  will now be described. The trigger  98  includes an aperture  114 , an engaging portion  116 , a lever portion  118  and a spring receiving portion  120 . The aperture  114  forms a pivot point for the trigger  98  once connected via a pin to the handle  96 . The engaging portion  116  includes a toothed surface for contacting the toothed gear wheel  70  in a complementary fashion such that the toothed engaging portion  116  interlocks with the toothed periphery  88  of the gear wheel  70  for arresting rotation of the gear wheel  70 . The lever portion  118  is configured with respect to the handle  96  for conveniently releasing the trigger  98 . The spring receiving portion  120  is configured to receive a spring  102  of the like shown in  FIG. 7 . 
         [0050]    Referring now to  FIG. 7 , there is shown a spring  102  for biasing the trigger  98  with respect to the handle  96 . The spring  102  includes two legs  121  configured to be disposed inside the handle  96  and inside the spring receiving portion  120  such that actuation of the trigger  98  results in an opposed spring force biasing the trigger  98  towards the gear wheel  70 . 
         [0051]    Turning now to  FIG. 8 , there is shown a knob  100  of the handle assembly  16 . The knob  100  includes a threaded bore  122  configured to receive the threaded portion  52  of the outer shaft  42 . 
         [0052]    The assembly of the handle assembly  16  and of the shaft assembly  14  to the handle assembly  16  will now be discussed. The proximal ends of the right and left inner shafts  66 ,  68  of the inner shaft assembly  44  are inserted at the distal end  106  into the bore  108  of the handle  96 . The gear wheel  70  is inserted into the side window  110  of the handle  96  and the proximal ends of the right and left inner shafts  66 ,  68  are connected to the wheel  70  by inserting the right and left inner shafts  66 ,  68  into the inner shaft assembly receiving portion  94  of the gear wheel  70  and passing gear pins (not shown) into gear pin apertures of the right and left inner shafts  66 ,  68  and into gear pin apertures  92  on the gear wheel  70  such that the gear wheel  70  is capable of relative movement with respect to the right and left inner shafts  66 ,  68  within the constraints of the wedged-shaped inner shaft receiving portion  94 . The gear wheel  70  is connected to the handle  96  by passing a fastener into the gear wheel apertures  112  in the handle  96  and the central bore  90  of the gear wheel  70 . The trigger  98  and spring  102  are disposed inside the handle  96  and gear wheel  70  such that the spring  102  exerts a spring force against the trigger  98  forcing the toothed engaging portion  116  of the trigger  98  to contact the toothed gear wheel  70 . A pin secures the trigger  98  to the handle  96  such that the trigger  98  is allowed to pivot about the pin with respect to the handle  96 . The proximal end  58  of the outer shaft  42  extends from the bore  108  and beyond the proximal end  104  of the handle  96 . The knob  100  is threadingly connected to the threaded portion  52  of the outer shaft  42 . The distal end of the knob  100  is disposed inside the bore  108  of the handle  96  and secured thereto via pins passing through the handle and into a recess formed around the knob  100 . In one variation, an impaction knob  124  (shown in  FIG. 1   d ) is attached to the proximal end  58  of the outer shaft  42  and serves as an impaction surface for hammering the inserter  10  into position. 
         [0053]    Operation of the inserter instrument  10  will now be discussed with initial reference to  FIGS. 9   a,    9   b  and  9   c.  Referring firstly to  FIG. 9   a,  an interbody spacer  126  having engaging apertures (not shown) is shown in juxtaposition with the distal end of the inserter  10  with the jaw assembly  12  in an open position in which the jaws  18 ,  20  are spread apart and unlocked. 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. The bearing surfaces include grooves or texturing formed to facilitate engagement with the vertebral endplates and resist the spacer from migrating within the disc space. The implant 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 wall. The overall shape provides a banana or kidney type shape for the spacer. 
         [0054]    The spacer  126  includes spacer engaging apertures (not shown) configured to be aligned with the spacer engaging features  30 ,  40  of the jaw assembly  12 . The knob  100  of the handle assembly  16  is rotated such that the threaded engagement with the outer shaft  42  draws the outer shaft  42  into the bore  108  of the handle  96  and moves the jaw pin  22  along with it, thereby angulating the jaws  18 ,  20  towards each other into a closed position. In the closed or locked position, the spacer engaging features  30 ,  40  are securely clamped to the spacer  126  as shown in  FIG. 9   b.  The spacer  126  is unclamped from the inserter  10  by rotating the knob  100  in the opposite direction. 
         [0055]    Releasing the trigger  98  unlocks the gear wheel  70  which is then rotated with respect to the handle  96  by the user to articulate the jaws  18 ,  20 . Rotation of the gear wheel  70  in one direction moves one of the right or left inner shafts  66 ,  68  proximally and moves the other of the right or left inner shafts  66 ,  68  distally, thereby, angulating the jaw assembly  12  as shown in  FIG. 9   c.    FIG. 9   c  depicts the right inner shaft  66  moved distally and the left inner shaft  68  moved proximally and, as a result, the jaw assembly  12  angled with respect to the outer shaft  42  towards the left inner shaft  68  with relative rotation of the gear wheel  70 . The gear wheel  70  rotation is permitted while the spring-biased trigger  98  is released from being locked onto the gear wheel  70 . The gear wheel  70  is rotatable in an opposite direction, while the trigger  98  is unlocked from the gear wheel  70 , to bring the jaw assembly  12  into a normal position or angulated beyond the normal and towards the right inner shaft  66  opposite of that shown in  FIG. 9   c.  Any number of angular positions within the range permitted by the wedge-shaped inner shaft assembly receiving portion  94  of the gear wheel  70 . The jaw assembly  12  can be locked at any point along its range of angulation by releasing the trigger  98  such that it engages the gear wheel  70  to lock it in place. Hence, 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. 9   b  to a second orientation such as that shown in  FIG. 9   c  or any other position within its span of angulation. With the trigger  98  engaged by the user to thereby release the trigger  98  and free rotation of the gear wheel  70 , angulation is achieved by the user turning the gear wheel  70  directly. Alternatively, angulation is achieved by the user taking advantage of the friction force on the implant  126  when placed between two vertebral bodies to hold the implant  126  in place while the entire instrument  10  is angulated with respect to the substantially stationary implant  126 . For example, a spinal implant  126  is first connected to the inserter  10  as described above. The inserter  10  and attached implant  126  is then inserted into a patient through an incision and placed in between tissue or bony anatomy. If the implant is destined for placement between vertebral bodies, a measurement is typically made beforehand to determine the size of the implant most suitable for the particular patient anatomy. With the appropriately sized implant attached to the inserter and inserted in the target disc space, the vertebral bodies adjacent to the disc space will exert some force on the implant and hold it substantially in place, that is, there will be some resistance on the implant when inserted between the vertebral bodies or other areas of tight tissue. This resistance is employed by the surgeon user to hold the implant in place. With the implant held in place by friction from the patient anatomy, the gear wheel  70  is freed to rotate by moving the trigger and then angulating the entire inserter  10  relative to the implant  126  to achieve angulation. The desired angulation can then be locked and the surgeon user may then re-position the spacer  126  along another axis of insertion. Another axis or angle of insertion may be desirable for generating more insertive force, navigating the implant into position or for simply pinpointing placement of the spacer in the perfect location. Such angulation makes the instrument  10  useful for easing and facilitating insertion, positioning and implantation of the spacer  126  inside the patient. Advantageously, the trigger  98  may be repeatedly disengaged and re-engaged and the gear wheel rotated in one direction or another direction relative to the handle  96  as needed by the surgeon in situ, in either or both of the two methods described above to conveniently orientate the spacer without losing hold of the intervertebral spacer. The spacer  126  can be released from the inserter  10  at any angle by rotating the knob  100  and the instrument removed from the patient. 
         [0056]    The preceding merely illustrates the principles of the invention. 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.