Abstract:
An apparatus, method and system for the treatment and management of spinal defects and inserting a spinal implant into an implantation space is described. The system may include a slotted implant, a distractor and an inserter and be employed in posterior lumbar or thoracic surgery.

Description:
[0001]    This application is a continuation of U.S. patent application Ser. No. 11/405,633, filed on Apr. 18, 2006 which claims the priority benefit under 35 U.S.C. 119 of U.S. provisional application No. 60/672,544 filed Apr. 19, 2005 the disclosure of which are hereby incorporated by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to apparatus, method and system for the treatment and management of spinal defects. 
       BACKGROUND OF THE INVENTION 
       [0003]    The treatment and management of spinal defects remains one of the most challenging aspects of medicine. Spinal defects occur in a wide variety of clinical situations. They may result from spondylosis, tumor or even trauma. Preserving natural spinal motion and dynamics remains a considerable challenge. Maintaining or improving spinal sagittal balance should in theory allow the spine to be repaired at the level of correction and prevent adjacent level disease. Therefore, preserving spinal anatomy and stability are even more difficult in any surgical procedure in which a portion or complete section of disc space, vertebrae or several vertebrae is removed. 
         [0004]    Restoring natural anatomical length and shape of any bone with spondylosis is problematic. Additionally, whenever a vertebra, part of a vertebra or disc space has to be removed, it is necessary to insert a vertebral spacer to restore the natural length and curvature of the spine as well as to either maintain or restore natural spinal dynamics or promote bony fusion. A posterior artificial disc that allows for restoration of sagittal balance is one method of restoring natural spinal dynamics. Restoring spinal anatomy and stability and promoting spinal dynamics or bone fusion are even more difficult in any surgical procedure in which a portion or complete section of a vertebrae one or portion or complete section of a vertebral body or disc space. 
         [0005]    Often times inserts are impacted posteriorly into the implantation space with force enough to fracture the adjacent vertebral bodies or cause the implant to be placed partially into the vertebral body. The limiting factor often times is the posterior height of the disc space and wedging an insert through this part of the disc space may create longitudinal grooves within the vertebral bodies to allow for migration of the spinal insert back towards the neurologic tissue with subsequent neurologic injury or cause the surgeon to undersize the implant since he or she is gauging the posterior height of the disc space and not allowing the implant to directly interface with the cortical bony surface thereby causing a pseudoarthorosis or bony non union. 
         [0006]    Thus, there is a need for an improved implantation system for use in posterior lumbar surgery to create an interbody implantation space while achieving or maintaining natural spinal lordosis and providing for natural spinal dynamics or bony fusion while facilitating insertion and removal. 
       SUMMARY OF THE INVENTION 
       [0007]    An apparatus, method and system for the treatment and management of spinal defects are described. A surface of an apparatus has at least one slot to receive a surgical instrument such as a distractor to facilitate implantation of the apparatus in a spine. In at least one exemplary embodiment the device may be inserted into the posterior of the spine using a distractor and an insertion device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Advantages of embodiments the present invention will be apparent from the following detailed description of the preferred embodiments thereof, which description should be considered in conjunction with the accompanying drawings in which: 
           [0009]      FIG. 1  is a rear perspective view of a lumbar segment of a spine with the dural sac retracted to the left showing a partial discectomy and the guard with the blades of the distractor and distal end of the inserter holding an implant approaching the disc space between the adjacent vertebral bodies; 
           [0010]      FIG. 2   a  illustrates a top down view of an exemplary embodiment of an insert; 
           [0011]      FIG. 2   b  illustrates a top down view of an exemplary embodiment of an insert; 
           [0012]      FIG. 2   c  illustrates a top down view of an exemplary embodiment of an insert; 
           [0013]      FIG. 3   a  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0014]      FIG. 3   b  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0015]      FIG. 3   c  illustrates a rotated side view of an exemplary embodiment of an insert 
           [0016]      FIG. 4   a  illustrates a rear view of an exemplary embodiment of an insert; 
           [0017]      FIG. 4   b  illustrates a rear view of an exemplary embodiment of an insert; 
           [0018]      FIG. 4   c  illustrates a rear view of an exemplary embodiment of an insert; 
           [0019]      FIG. 5   a  illustrates a top down view of an exemplary embodiment of an insert; 
           [0020]      FIG. 5   b  illustrates a top down view of an exemplary embodiment of an insert; 
           [0021]      FIG. 5   c  illustrates a top down view of an exemplary embodiment of an insert; 
           [0022]      FIG. 6   a  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0023]      FIG. 6   b  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0024]      FIG. 6   c  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0025]      FIG. 7   a  illustrates a rear side view of an exemplary embodiment of an insert; 
           [0026]      FIG. 7   b  illustrates a rear side view of an exemplary embodiment of an insert; 
           [0027]      FIG. 7   c  illustrates a rear side view of an exemplary embodiment of an insert; 
           [0028]      FIG. 8  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0029]      FIG. 9  illustrates a rear view of an exemplary embodiment of an insert; 
           [0030]      FIG. 10  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0031]      FIG. 11  illustrates an enlarged fragmentary rotated side view of an exemplary embodiment of the knurls or teeth on an insert; 
           [0032]      FIG. 12  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0033]      FIG. 13  illustrates a rear view of an exemplary embodiment of an insert; 
           [0034]      FIG. 14  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0035]      FIG. 15  illustrates a perspective view of an exemplary embodiment of the knurls or teeth of the insert; 
           [0036]      FIG. 16  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0037]      FIG. 17  illustrates a rotated side view of an exemplary embodiment of an insert; 
           [0038]      FIG. 18  illustrates an enlarged fragmentary rotated side view of an exemplary embodiment of the knurls or teeth on an insert; 
           [0039]      FIG. 19  illustrates a rear view of an exemplary embodiment of an insert; 
           [0040]      FIG. 20  illustrates a top down view of an exemplary embodiment of an insert; 
           [0041]      FIG. 21  illustrates a partial cross-sectional view showing an exemplary embodiment of an implant, inserter and distractor inserting an implant into the disc space; 
           [0042]      FIG. 22  illustrates a partial cross-sectional view showing an exemplary embodiment of an implant, inserter and distractor inserting an implant across the disc space; 
           [0043]      FIG. 23  illustrates a side view of an exemplary embodiment of an implant, a partial side view of an inserter and partial side view of a distractor; 
           [0044]      FIG. 24  illustrates a side view of an exemplary embodiment of a distractor; 
           [0045]      FIG. 25  illustrates a side view of an exemplary embodiment of a portion of the distractor; 
           [0046]      FIG. 26  illustrates a side view of an exemplary embodiment of a handle of the distractor; 
           [0047]      FIG. 27   a  illustrates a partial cross-sectional view showing an exemplary embodiment of a distractor spreading a disc space apart; 
           [0048]      FIG. 27   b  illustrates a partial cross-sectional view showing a disc space; 
           [0049]      FIG. 28  is a partial cross-sectional view of an exemplary embodiment of a distractor spreading apart a disc space and sliding an insert along the slots into a disc space; 
           [0050]      FIG. 29  is a partial cross-sectional view of an exemplary embodiment of a distractor sliding away from an implanted insert into a disc space; 
           [0051]      FIG. 30  is a partial cross-sectional view of a disc space with an exemplary embodiment of a tapered insert in a disc space; 
           [0052]      FIG. 31  is a partial cross-sectional view of a disc space with an exemplary embodiment of an arched insert in a disc space. 
       
    
    
     DETAILED DESCRIPTION 
       [0053]    In an exemplary embodiment shown in  FIG. 1 , a system and method for spinal inserts is shown. In this figure a posterior view is shown with a dural sac retracted to the left, showing that a partial discectomy has been performed. In this exemplary embodiment, distractor  100  may fit around spinal insert  102  and, when inserted into a spinal column, act to separate two vertebrae by opening in a parallel fashion, allowing for the insertion of spinal insert  102 . Rod or inserter  103  may be inserted into spinal insert  102 . Insert  102  may have, for example, a threaded hole that accepts threading disposed on a distal end of rod  103 . Rod  103  may act to hold insert  102  in place prior to its insertion in a spinal column and may also act to help position and orient insert  102  during its placing. Distractor  100  may then be positioned such that it is in line with disc space  106  in spinal column  104 . Disc space  106  may be a hole formed between two vertebrae of a in a human spinal cord or thecal sac. In a further embodiment, distractor  100  may be used to implant insert  102  into hole  106  by opening the disc space in a parallel fashion. Distractor  100  may then release insert  102  and retract from hole  106  of spinal column  104  without disturbing the location, positioning or orientation of insert  102 . 
         [0054]    In another exemplary embodiment shown in  FIG. 2 , a spinal insert is shown. The spinal insert may be of any shape, for example configured in such a manner as to restore the natural height of the disc space which may have been lost due to a degenerative process. A top-down view of one side of exemplary inserts is shown in  FIGS. 2   a - c.  For example, in  FIG. 2   a , insert  200  may be tapered with respect to a longitudinal axis  201 . Here, rounded top leading portion  202  may have a width wider than bottom portion  204 . Additionally, teeth or knurls  206  may be disposed on each side of insert  200 . Teeth  206  may be coupled with a non-arcuate contour of a spinal insert, thus helping prevent migration or dislodging of the spinal insert. In one exemplary embodiment, teeth  206  may be angled towards bottom portion  204 . In other embodiments, teeth or knurls  206  may be angled towards rounded top portion  202  or may project straight out of insert  200 . Teeth  206  may act to prevent movement of insert  200  once insert  200  is inserted into, for example, the spine of a person. Additionally, insert  200 , as well as any other inserts described herein, may be made out of any of a variety of materials, for example titanium, PEEK, ceramics or bone. 
         [0055]    In  FIG. 2   b , another exemplary insert is shown having a longitudinal axis  215 . Insert  214  may have a rounded top portion  216  that is substantially the same width as bottom portion  218 . Middle portion  220 , however, may be wider than top portion  216  or bottom portion  218 , giving insert  214  an arched structure. Insert  214  may also have teeth  222  disposed on each side of insert  214 . Teeth or knurls  222  may project directly out of insert  214  or may be angled towards top portion  216  or bottom portion  218 . 
         [0056]    In  FIG. 2   c , an exemplary straight insert  226  is shown having a longitudinal axis  227 . In this embodiment, each side of insert  226  may be substantially straight. Insert  226  may also have rounded top portion  228  and substantially straight bottom portion  230 . Additionally, teeth  232  may be disposed on either side of insert  226 . Teeth or knurls  224  may project substantially straight out of insert  226 , or may be angled towards either rounded top portion  228  or bottom portion  230 . 
         [0057]      FIG. 3  shows a further exemplary embodiment with a rotated top-down view of a spinal insert. In the exemplary embodiment of  FIG. 3   a , rounded top portion  202  is shown as being substantially curved. Additionally, insert  200  may have slot  208 . Slot  208  may extend from rounded top portion  202  to bottom portion  204 . Additionally, another slot (not shown) may be disposed on an opposite side of insert  200  and may be disposed substantially opposite to slot  208 . In one exemplary embodiment, the slot extends substantially axially and is positioned offset from the longitudinal axis, as shown in  FIGS. 3   a ,  3   b ,  3   c ,  6   a ,  6   b  and  6   c . Further, in another exemplary embodiment the slot may be dispose diagonally across the insert  200  as is shown in  FIG. 6   c . The slots disposed on either side of insert  200  may have a width and a length substantially longer than the width to allow for a device, such as a distractor, to have prong blades inserted through the slots of insert  200 . When the prongs of a device are inserted into the slots, insert  200  may be positioned in any of a variety of fashions. Additionally, after insert  200  is inserted, for example into the spine of a person, the device inserted into the slots of insert  200  may be withdrawn without disturbing the location of insert  200  or any of the surrounding parts of the person. 
         [0058]      FIGS. 3   b  and  3   c  show additional exemplary embodiments of inserts  214  and  226 , respectively. In  FIG. 3   b , insert  214  is shown with rounded top portion  216  being substantially curved. Also the leading edge may be beveled or tapered to allow a little more ease of insertion. Additionally, insert  214  may have insertion slot  224 , which may extend from rounded top portion  216  to bottom portion  218 . There may also be an insertion slot (not shown) disposed substantially opposite slot  224 , similar to that in  FIG. 3   a . In  FIG. 3   c , insert  226  is shown with rounded top portion  228  being substantially curved. Additionally, insert  226  may have insertion slot  234 , which may extend from rounded top portion  228  to bottom portion  230 . There may also be an insertion slot (not shown) disposed substantially opposite slot  234 , similar to that in  FIG. 3   a . Further, in another exemplary embodiment the slot may be dispose diagonally across the insert  200  as is shown in  FIG. 6   c , allowing enough room for the insert to pass by the slot  234 . 
         [0059]    In other exemplary embodiments of the invention, slots  208 ,  224  and  234  may be angled in any manner or positioned diagonally, longitudinally or horizontally, or any other orientation that would still enable one having ordinary skill in the art to properly insert the device, for example, in the posterior of the human spine. For example, slots  208 ,  224  and  234  may be angled so that they only occupy a portion of inserts  200 ,  214  and  226 , respectively. 
         [0060]    An exemplary rear view of a spinal insert is shown in  FIG. 4 . In this exemplary view, it may be seen that rear portions  204 ,  218  and  230  of inserts  200 ,  214  and  226 , respectively, may appear substantially similar. In  FIG. 4   a , it is shown that insert  200  may have first and second insertion slots  208  and  210 , respectively. These slots may be used in a similar manner to that described with respect to  FIG. 3   a . Additionally, insert  200  may have inserter hole  212 . Inserter hole  212  may be used for a variety of purposes, for example, rod or inserter  103  may be inserted into the hole  212  to help guide the implant into position. Additionally, inserter hole  212  may be located in a central portion of insert  200 , or may optionally be located on any location of bottom portion  204 . Inserter hole  212  may also extend partially through insert  212 , for example about 1-10 mm. 
         [0061]    Similarly, in  FIGS. 4   b  and  4   c , it is shown that inserts  214  and  226  may also have first and second insertion slots. Insert  214  has first and second insertion slots  224  and  225 , respectively, and insert  226  has first and second insertion slots  234  and  236 , respectively. These slots may be used in a similar manner to that described with respect to  FIG. 3   a . Additionally, insert  214  may have inserter hole  223  and insert  226  may have inserter hole  238 . Inserter holes  223  and  238  may be used for a variety of purposes, similar to those described with respect to  FIG. 4   a . Additionally, inserter holes  223  and  238  may be located in a central portion of inserts  214  or  226 , respectively, or may optionally be located on any location of bottom portions  218  and  230 , respectively. Inserter holes  223  and  238  may also extend partially through inserts  214  and  226 , respectively, for example, about 1 to 10 mm. 
         [0062]      FIG. 5  shows another exemplary embodiment of an insert. In one exemplary embodiment shown in  FIG. 5   a , directional arrows are shown on either side of insert  200  to show an orientation of insert  200  when it can be inserted into the spine of a person. Additionally, holes  502  and  504  may drilled through insert  200  to allow one having ordinary skill in the art to evaluate bony fusion. For example the bone may not grow through these holes  502  and  504 , but rather the bone will grow from knurl to knurl and  502  and  504  allow to act like windows to evaluate the fusion. Holes  502  and  504  may be formed so as to allow for evaluation of bone growth into insert  200 . For example, after insert  200  is implanted in the spine of a person, vertebral bone growth maybe evaluated through holes  502  and  504 . Likewise, the holes  502  and  504  may facilitate location of bone growth in post operative x-ray or other evaluation tool known to one having ordinary skill in the art. Similarly in  FIG. 5   b , tapered insert  214  has direction arrows showing one orientation of insert  214  when it may be inserted into the spine of a person. Additionally, holes  506  and  508  may be drilled through insert  214 , and may provide a similar function as those discussed with respect to  FIG. 5   a . Further, in  FIGS. 5   c , straight insert  226  has direction arrows showing one orientation of insert  226  when it may be inserted into the spine of a person. Additionally, holes  510  and  512  may be drilled through insert  226 , and may provide a similar function as those discussed with respect to  FIG. 5   a . The holes  502 ,  506 , and  510  may optionally be used for any other purpose known to one having ordinary skill in the art. 
         [0063]      FIG. 6  shows additional exemplary embodiments of tapered insert  200 , arched insert  214  and straight insert  226 . The embodiments shown in  FIGS. 6   a - 6   c  may be similar to those shown in  FIGS. 3   a - c . Slots  208 ,  224  and  234  of  FIGS. 6   a ,  6   b  and  6   c , respectively, may be disposed at an angle as in  FIG. 6   c  to allow for the insertion of the distractor blades  2418   a  and  2418   b  (as shown in  FIG. 24 ) which may aid in placing and orienting the spinal inserts. Additionally, inserts  200 ,  214  and  226  may have holes  602 ,  604  and  606 , respectively, drilled into the inserts through the teeth or knurls  206 . Holes  602 ,  604  and  606  may be drilled partially through the inserts and may act to receive a prong of a surgical instrument facilitate placement of the inserts. The holes  602 ,  604  and  606  generally replace the functionality of the inserter or rod holes of, for example in  FIGS. 4   a - 4   c.  In another exemplary embodiment the holes  602 ,  604  and  606  may be drilled in the same plane as the inserter hole but instead of one inserter hole two or more inserter holes could be configured. Additionally, each of holes  602 ,  604  and  606  may have a hole drilled substantially on the opposite side of the insert. These holes,  603 ,  605  and  607 , respectively, are shown in  FIGS. 7   a -c. In one exemplary embodiment, holes  602  and  603  of insert  200  may each have a prong of a medical device inserted into them. The prongs of the medical device may be used in a similar manner as surgical pliers, acting to hold insert  200  in place, move insert  200 , or change the position or orientation of insert  200 . After insert  200  is inserted into a spine of a person, the medical instrument may be removed from holes  602  and  603 , and the medical instrument may be retracted or removed. Holes  604  and  605  of insert  214  and holes  606  and  607  of insert  226  may be used in a similar fashion as those described with respect to holes  602  and  603  of insert  200 . Further the holes  602 ,  604  and  606  may be used in any way to facilitate placement of the insert  200  known to one having ordinary skill in the art. 
         [0064]    Generally referring to  FIGS. 7   a -c and  19 - 20  show further exemplary embodiments in rear views of the inserts described with respect to  FIGS. 5 and 6 . In these exemplary embodiments, insert  200  is shown with hole  602  on a top portion of the insert, insert  214  is shown with hole  604  on a top portion of the insert and insert  226  is shown with hole  606  on a top portion of the insert. Additionally, in  FIG. 7   a , interior portion  703  and teeth  206  may be formed out of different materials. For example, interior portion  703  ( FIG. 7 ) or  1910  ( FIG. 19 ) may be formed out of polyethylene or another polymer while teeth  206  or  1908  ( FIG. 19 ) are formed of chrome molybdenum or another metallic substance. In other exemplary embodiments, interior portion  703  or  1910  may be polyurethane or polypropylene or poly ether ether keton (PEEK). Additionally, the teeth  206  or  1908  may be titanium or chromium molybdenum. Similarly, in  FIGS. 7   b  and  7   c , interior portions  705  and  707  may be formed out of polyethylene or another polymer while teeth  222  and  232  are formed of chrome molybdenum or another metallic substance. In other exemplary embodiments, interior portions  705  and  707  may be polyurethane, polypropylene or (poly ether ether ketone (PEEK). Additionally, the teeth  206  may be titanium or chromium cobalt. 
         [0065]    In another exemplary embodiment the insert may be engaged through the knurled surface with an pliers like inserter (not shown) as to prevent torsion while being inserted through the distractor, thereby demonstrating not only can the insert be engaged through the threaded slot but also through the sides with the knurl. 
         [0066]      FIG. 8  shows another exemplary embodiment of an insert. Here, insert  800  may be a straight insert, such as that described with respect to  FIG. 2   c . In this embodiment, insert  800  may have inserter hole  802  and slot  804 . Inserter  802  is shown as being disposed on a lower portion of insert  800 . Additionally, inserter hole  802  is shown as extending from the rear portion of insert  800  to cut out area  806 . Inserter hole  802  may also be threaded so as to receive a threaded insert, such as an inserter or rod  103 . Also, slot  804  may extend the length of insert  800  and may be used similarly to the slots described above with respect to  FIG. 3   a . The slot may, optionally, be positioned diagonally across the insert  800  as is showing in  FIG. 6   c  and provide a similar function. 
         [0067]    A rotated view of an exemplary insert is shown in  FIG. 9 . Insert  900  may have slots  902  and  904 . Slots  902  and  904  may allow for a device, such as a distractor  100 , to have prongs inserted through slots  902  and  904 . When the prongs of a device are inserted into slots  902  and  904 , insert  900  may be positioned in any of a variety of fashions. Additionally, after insert  900  is inserted, for example into the spine of a person, the device inserted into the slots of insert  900  may be withdrawn without disturbing the location of insert  900  or any of the surrounding parts of the patient or patient&#39;s spine. Further, in  FIG. 9 , inserter hole  906  is shown. Inserter hole  906  may be located centrally in insert  900  or may alternatively be offset to either side of insert  900 . Similar to insert hole  802  of  FIG. 8 , inserter hole  906  may extend part of the way through insert  900 . Inserter hole  906  may be threaded, allowing for the insertion of a rod having threading, which may aid in placing, locating or orienting insert  900 . Alternatively, any type of connection mechanism may used for the inserter hole  906  and the inserter or rod, such as using electromagnetism, magnets, clipping mechanism or tongue and groove type configuration or other surgical grade latching mechanism known to one having ordinary skill in the art. Further, teeth  908  may be disposed on either side of insert  900 . Teeth  908  may be oriented directly out of insert  900 , as shown in  FIG. 9 , or may be angled toward the top or bottom of insert  900 . Additionally, teeth  908  may be disposed on either side of insert  900  as well as above and below slots  902  and  904 . 
         [0068]    Another exemplary rotated view of an insert is shown in  FIG. 10 . In this cutout view, insert  1000  may have screw  1004  inserted into inserter hole  1002 . Screw  1004  may only penetrate insert  1000  a short distance, as shown in  FIG. 10 . In other exemplary embodiments, rod  1004  may penetrate insert  1000  to different depths. Additionally, teeth  1008  are shown as projecting straight out of insert  1000  in this exemplary embodiment. In other exemplary embodiments, teeth  1008  may be in any of a variety of different orientations. 
         [0069]      FIG. 11  shows an exemplary close up view of knurls or teeth  1102  of insert  1100 . In this embodiment, the knurls or teeth  1102  are substantially triangular. Teeth  1102  may act to grip a surrounding surface and prevent movement of insert  1100 . In other exemplary embodiments, teeth  1102  may be angled differently, such as towards the left or the right. Additionally teeth  1102  may be formed out of any other shape known to one having ordinary skill in that art that would provide adequate grip against any of a variety of surfaces, such as bone or tissue, so as to prevent the movement of insert  1100  after insert  1100  is inserted. 
         [0070]      FIG. 12  shows yet another exemplary embodiment of an insert. Here, insert  1200  may be a tapered insert, similar to that described in  FIG. 2   a . In this embodiment, insert  1200  may have inserter hole  1202  and slot  1204 . Inserter  1202  is shown as being disposed on a lower portion of insert  1200 . Additionally, inserter hole  1202  is shown as extending from the rear portion of insert  1200  to cut out area  1206 . Inserter hole  1202  may also be threaded so as to receive a threaded insert, such as a screw. Also, slot  1204  may extend the length of insert  1200  and may be used similarly to the slots described above with respect to  FIG. 3   a . Another slot may be disposed opposite to slot  1204  and provide a similar function. 
         [0071]    A rotated view of an exemplary insert is shown in  FIG. 13 . Insert  1300  may have slots  1302  and  1304 . Slots  1302  and  1304  may allow for a device, such as a distractor, to have prongs inserted through slots  1302  and  1304 . When the prongs of a device are inserted into slots  1302  and  1304 , insert  1300  may be positioned in any of a variety of fashions. Additionally, after insert  1300  is inserted, for example into the spine of a person, the device inserted into the slots of insert  1300  may be withdrawn without disturbing the location of insert  1300  or any of the surrounding parts of the person. Further, in  FIG. 13 , inserter hole  1306  is shown. Inserter hole  1306  may be located centrally in insert  1300  or may alternatively be offset to either side of insert  1300 . Similar to insert hole  1202  of  FIG. 12 , inserter hole  1306  may extend part of the way through insert  1300 . Further, teeth  1308  may be disposed on either side of insert  1300 . Teeth  1308  may be oriented directly out of insert  1300 , as shown in  FIG. 13 , or may be angled toward the top or bottom of insert  1300 . Additionally, teeth  1308  may be disposed on either side of insert  1300  as well as above and below slots  1302  and  1304 . Additionally, it may be noted that insert  1300  is shown as wider than insert  900  of  FIG. 9 . These inserts may be formed in any of a variety of sizes and shapes known to one having ordinary skill in the art. Additionally, the sizes and widths of the inserts may be varied or tailored to suit a particular need. For example, larger inserts may be utilized in situations where there are larger gaps between vertebrae or where greater separation between vertebrae is desired. Similarly, smaller inserts may be used where smaller gaps exist or where smaller separation is desired or may be achieved. 
         [0072]    Another exemplary rotated view of an insert is shown in  FIG. 14 . In this cutout view, insert  1400  may have screw  1404  inserted into threaded inserter hole  1402 . Screw  1404  may only penetrate insert  1400  a short distance, as shown in  FIG. 14 . In other exemplary embodiments, screw  1404  may penetrate insert  1400  to different depths. Additionally, teeth  1408  are shown as projecting towards the left portion of insert  1400  in this exemplary embodiment. In other exemplary embodiments, teeth  1408  may be in any of a variety of different orientations, such as projecting at different angles or projecting straight out of insert  1400 . 
         [0073]      FIG. 15  shows an exemplary close up view of teeth  1502  of insert  1500 . In this embodiment, teeth  1502  are substantially triangular. Teeth  1502  may act to grip a surrounding surface and prevent movement of insert  1500 . In other exemplary embodiments, teeth  1502  may be angled differently, such as towards the left or the right. Additionally teeth  1502  may be formed out of any other shape known to one having ordinary skill in that art that would provide adequate grip against any of a variety of surfaces, such as bone or tissue, so as to prevent the movement of insert  1500  after insert  1500  is inserted. 
         [0074]    Another exemplary rotated and cutout view of an insert is shown in  FIG. 16 . In this cutout view, insert  1600  may be formed having an arched shape, similar to that described with respect to  FIG. 2   b . This insert would be ideal for a spine configuration as is shown, for example, in  FIG. 33 . Where the width of end points x, y, of the spine are substantially equal. The center portion z may be substantially wider than x and y. Likewise, insert  1600  may have end points x, y, that are equal where the center point z is substantially wider to accommodate the space  3304  in the cross-sectional spine shown in  FIG. 34 . With further progression of spondylosis a scalloped appearance may occur in the disc space relative to the adjacent vertebral bodies. In order to promote bony fusion or maintain spinal dynamics utmost anatomical contact between the knurled surfaces of the implant is imperative in order to overcome this spinal defect. Thus, in this exemplary embodiment, the center portion of insert  1600  may be substantially wider than either distal end of insert  1600 . This may provide a better fit between the vertebrae of some subjects. Additionally, insert  1600  may have screw  1604  inserted into threaded inserter hole  1602 . Screw  1604  may only penetrate insert  1600  a short distance, as shown in  FIG. 16 . In other exemplary embodiments, screw  1604  may penetrate insert  1600  to different depths. Additionally, teeth  1608  are shown as projecting straight out of insert  1600  in this exemplary embodiment. In other exemplary embodiments, teeth  1608  may be in any of a variety of different orientations. 
         [0075]    Yet another exemplary rotated and cutout view of an insert is shown in  FIG. 17 . In this cutout view, insert  1700  may be formed having a tapered shape, similar to that described with respect to  FIG. 2   a . Thus, in this exemplary embodiment, the one distal end of insert  1700  may be substantially wider than another distal end of insert  1700 . This may provide a better fit between the vertebrae of some subjects and provide different insertion characteristics than inserts having other shapes. This insert would be ideal for a spine configuration as is shown, for example, in  FIG. 32  where the width of end point y  3202  is substantially  2  times as wide as end point x  3204  in one embodiment. Also, insert  1700  may have screw  1704  inserted into threaded inserter hole  1702 . Screw  1704  may only penetrate insert  1700  a short distance, as shown in  FIG. 17 . In other exemplary embodiments, screw  1704  may penetrate insert  1700  to different depths. Additionally, teeth  1708  are shown as projecting towards the left portion of insert  1700  in this exemplary embodiment. In other exemplary embodiments, teeth  1708  may be in any of a variety of different orientations, such as projecting at different angles or projecting straight out of insert  1700 . With the progression of spondylosis or in post surgical patients, patients may lose their natural curvature of their spine. The loss of the lumbar lordosis leads to a poor sagittal balance. This implant is geared for not only to allow greater contact between implant and cortical bone, but also to restore sagittal balance in those patient who have lost it due to degenerative or post surgical reasons. 
         [0076]    Additionally, with respect to  FIGS. 10-17 , various sizes and shapes of inserts are shown. Each of the inserts, depending on its size or shape, as well as other properties, such as the orientation of the teeth projecting from the body of the insert, may be utilized in any of a variety of situations or circumstances. Some embodiments may provide better fitment in certain circumstances and other embodiments may provide for easier insertion or removal. Still other embodiments may better limit or prevent movement in certain circumstances. Therefore, any of the exemplary embodiments shown or described herein may be used in any of a variety of different circumstances. 
         [0077]      FIG. 18  shows an exemplary close up view of teeth  1802  of insert  1800 . In this embodiment, teeth  1802  are substantially triangular and are angled to the right. Teeth  1802  may act to grip a surrounding surface and prevent movement of insert  1800 . In other exemplary embodiments, teeth  1802  may be angled differently, such as towards the left or the right. Additionally teeth  1802  may be formed out of any other shape known to one having ordinary skill in that art that would provide adequate grip against any of a variety of surfaces, such as bone or tissue, so as to prevent the movement of insert  1800  after insert  1800  is inserted. 
         [0078]    A rotated view of an exemplary insert is shown in  FIG. 19 . Insert  1900  may have slots  1902  and  1904 . Slots  1902  and  1904  may allow for a device, such as a distractor  100 , to have prongs inserted through slots  1902  and  1904 . When the prongs of a device are inserted into slots  1902  and  1904 , insert  1900  may be positioned in any of a variety of fashions. Additionally, after insert  1900  is inserted, for example into the spine of a person, the device inserted into the slots of insert  1900  may be withdrawn without disturbing the location of insert  1900  or any of the surrounding parts of the person. Further, in  FIG. 19 , inserter hole  1906  is shown. Inserter hole  1906  may be located centrally in insert  1900  or may alternatively be offset to either side of insert  1900 . Also, inserter hole  1906  may be located at either a top or a bottom portion of insert  1900 . Further, similar to inserter holes  1602  or  1702  of  FIGS. 16 and 17 , respectively, inserter hole  1906  may extend part of the way through insert  1900 . Further, teeth  1908  may be disposed on either side of insert  1900 . Teeth  1908  may be oriented directly out of insert  1900 , as shown in  FIG. 19 , or may be angled toward the top or bottom of insert  1900 . Additionally, teeth  1908  may be disposed on either side of insert  1900  as well as above and below slots  1902  and  1904 . In order to maintain or restore natural spinal dynamics the goal centers on the ability to greatly on the dynamic insert to anatomically articulate with the cortical bone of the two adjacent vertebral bodies. If there is a loss of this contact, then with natural spinal motion or dynamics the implant may migrate and cause neurological injury. Therefore posterior artificial dynamic inserts will require a technique to overcome the smaller height of the posterior disc space and allow the surgeon to implant an insert which will not only restore sagittal balance but also to prevent migration of the implant. 
         [0079]      FIGS. 19 and 20  further show another exemplary embodiment of an insert. In these embodiment, a top-down, cutout version of a tapered insert, similar to that described with respect to  FIG. 17 , is shown. Here insert  2000  has a center portion  2002 . Additionally, in  FIGS. 19 and 20 , interior portion  1910  and  2004  teeth  1908  may be formed out of different materials. For example, interior portion  1910  or  1910  ( FIG. 19 ) may be formed out of polyethylene or another polymer while teeth  206  or  1908  ( FIG. 19 ) are formed of chrome molybdenum or another metallic substance. In other exemplary embodiments, interior portion  1910  or  2002  may be polyurethane or polypropylene to flex in a manner known to one having skill in the art that would be similar to a disk in a human spine. Additionally, the teeth  1908  may be titanium, chromium or molybdenum or any other surgical grade material known to one having ordinary skill in the art to prevent migration within the disc space. 
         [0080]    An exemplary embodiment of a spinal insert being inserted is shown in  FIG. 21 . In this embodiment, distractor  2102  is shown at an approximately  90  degree angle from spinal column  2104 . Additionally, rod  2103  is shown as holding insert  2106 . Rod  2103  may be engaged with insert  2106  in any of a variety of manners. In one exemplary embodiment, rod  2103  has threading at a distal end that may be inserted into a threaded hole in insert  2106 . Insert  2106  may be, for example, one of any of the different types of inserts discussed herein. Also, distractor  2102  is shown as utilizing slots disposed on either side of insert  2106 . These slots may be similar to those discussed with respect to  FIG. 3   a . After insert  2106  is placed, distractor  2102  and rod  2103  may be retracted and removed. 
         [0081]    Another exemplary embodiment of a spinal insert being inserted is shown in  FIG. 22 . Here, distractor  2202  is shown at an approximately 45 degree angle from spinal column  2204 . The distractor  2202  may optionally be placed in a 45 degree angle plane, another embodiment could be the distractor  2202  is still in the vertical plane like  FIG. 21  but the tips  2418   a,    2418   b  are angled 45 degrees. Since these tips could be made of titanium, steel, carbon graphite, ceramic, PEEK or any other material know to one having ordinary skill in the art and could be disposable to the point if there is a overt fracture or microfractures with in the tips then the whole distractor  2202  will not need to be replaced. In further embodiments, a distractor may be inserted into a spinal column at any angle that allows for the insertion of a spinal insert. Additionally, rod  2203  is shown as holding insert  2206 . Rod  2203  may be engaged with insert  2206  in any of a variety of manners. In one exemplary embodiment, rod  2203  has threading at a distal end that may be inserted into a threaded hole in insert  2206 . Also, in  FIG. 22 , insert  2206  may be, for example, one of any of the different types of inserts discussed herein. Also, distractor  2202  is shown as utilizing slots disposed on either side of insert  2206 . These slots may be similar to those discussed with respect to  FIG. 3   a . Similar to the exemplary embodiment shown in  FIG. 21 , both distractor  2202  and rod  2203  may be retracted and removed after insert  2206  is placed. 
         [0082]    Additionally, with respect to  FIGS. 21 and 22 , distractor  2102 / 2202  may be hinged. As shown in  FIG. 22 , a hinge  2210  may be disposed on distractor  2202 . Hinge  2210  can allow for a user of distractor  2202  to move a portion of distractor  2202  out of a line of sight. Hinge  2210  may also be two hinges, for example, a first hinge disposed on a first jaw of a distractor and a second hinge disposed on a second jaw of a distractor. For example, if a user has inserted distractor  2202  into spinal column  2204 , distractor  2202  may be oriented in such as fashion that it may block some or all of a user&#39;s view of insert  2206 . The use of hinge  2210  may therefore allow a user to move a portion of distractor  2202  out of the line of sight and therefore aid in the positioning and orienting of insert  2206 . Hinge  2210  may be disposed in any of a variety of different locations on distractor  2202 , depending on the different size of distractor being used, as well as depending on where a user would desire to hinge a distractor for a specific use or operation. 
         [0083]    An exemplary view of a distractor is shown in  FIG. 23 . In this embodiment, distractor  2302  may have a variety of parts and components. Arm  2304  may have an angled portion that terminates in a pair of blades. The slope of arm  2304  may be such that it allows a user to better position distractor  2302  for disc insertion and removal, for example. Additionally, the blades of arm  2304  may be configured to clasp and hold a spinal insert, such as spinal insert  2308 . Arm  2304  may be formed in any of a variety of manners and out of any of a variety of materials known to one having ordinary skill in the art, such as steel or other materials as described above or known to one having ordinary skill in the art. Additionally, arm  2304  may be formed in different sizes and shapes so as to be able to grasp, clasp or hold any of a variety of different sized spinal inserts. Distractor  2302  may utilize rod  2306 . Rod  2306  may be formed and made in any manner known to one having ordinary skill in the art. Additionally  2306  may have a threaded distal end that may be inserted into spinal insert  2308 . Thus, rod  2306  may be securely screwed into insert  2308  and may also be unscrewed and removed from insert  2308 . Further, rod  2306  may be used for any of a variety of functions, such as positioning insert  2308 , securing insert  2308  or stabilizing distractor  2302 . In a further embodiment, distractor  2302  may hold insert  2308  and be positioned in any of a variety of manners and at any angle so as to allow a user to insert a spinal insert between vertebrae. 
         [0084]      FIG. 24  shows an exemplary embodiment of a distractor. Distractor  2400  may have a pair of handles  2402   a  and  2402   b,  which may be movable with respect to each other to actuate a pair of jaws  2404   a  and  24044   b  coupled thereto. Distractor  2400  may be used for a variety of procedures, for example spinal disc distraction and spinal implant or insert insertion. Distractor  2400  may therefore be configured such that actuation of handles  12  ( 12   a,    12   b ) moves jaws  14  ( 14   a,    14   b ) apart substantially parallel along a distraction axis to a working position corresponding to the desired resulting relative position of the endplates. For example, the blades may be moved to a substantially parallel position to separate adjacent vertebrae to be treated. 
         [0085]    Generally referring to  FIGS. 25 and 26 , another attendant advantage is the ability to grasp the handle  2402  to prevent the distractor from moving down towards the ground if, for example a surgeon&#39;s latex glove was to slip cause neurologic injury. The distractor handle  2502 ,  2402  has a hand placement area which acts as a safety mechanism to prevent sudden motions when applying the distraction force. Further the distractor may have a bend  2602  and a distal connection point allowing hinged movement. Likewise the connection point  2504  facilitates hinged movement. The connection points  2504 ,  2602  and  2604  may be any kind of connection that allows in hinged movement that is known to one having ordinary skill in the art. 
         [0086]    Further, as shown in  FIG. 24 , handles  2402  and jaws  2404  may be configured to move jaws  2404  apart along a distraction axis a sufficient amount to adequately separate adjacent vertebrae to be treated (for example 5 mm-33 mm, or typically 13 mm-15 mm) yet to occupy a minimal amount of space within the insertion region during the procedure. Thus, handles  2402  and jaws  2404  may be pivotally coupled together in a scissors configuration such that movement of handles  2404   a  and  2404   b  together causes jaws  2404   a  and  2404   b  to move apart and effect insertion or distraction of object or organic material between which jaws  2404  are positioned. Thus, proximal ends  2408   a  and  2408   b  of handles  2402  may be configured to facilitate gripping. 
         [0087]    In addition, distractor  2400  may have biasing element  2410 , such as a pair of leaf springs, which may maintain handles  2402   a  and  2402   b  in a spaced-apart configuration such that jaws  2404   a  and  2404   b  may be close together, ready for insertion through a small incision and narrow passage through the patient in the neutral configuration of  FIG. 24 . 
         [0088]    Further, distractor mechanism  2411  may be provided such that movement of handles  2402  to actuate distractor mechanism  2411  can cause jaws  2404  to move apart to effect distraction of adjacent elements such as vertebrae. Distractor mechanism  2411  may have a scissor-type configuration such that handle  2402   a  and jaw  2404   a  are at opposite ends of a first lever arm and handle  2402   b  and jaw  2404   b  are on opposite ends of a second lever arm pivotally coupled to the first lever arm. Additionally, distractor mechanism  2411  may be in the form of a triple-acting scissor configuration having greater than one pivot point, for example three pivot points, thus reducing the amount of space required along a distraction axis and laterally away from a distractor mechanism longitudinal axis to effectuate distraction. Also, in order to form a triple-acting scissor configuration, handles  2402  and jaws  2404  can be provided on separate lever arms which are pivotally coupled together. In particular, handle  2404   a  can be formed at a proximal end of proximal lever arm  2413  a, handle  2402   b  is formed at a proximal end of lever arm  2413   b,  jaw  2404   a  is formed at a distal end of distal lever arm  2412   a,  and jaw  2404   b  is formed at a distal end of distal lever arm  2413   b.  Distal end  2414   a  of proximal lever arm  2413   a  is pivotally coupled to proximal end of distal lever arm  2412   a  and distal end  2414   b  of proximal lever arm  2413   b  is pivotally coupled to a proximal end of distal lever arm  2412   b.  In order to actuate the triple-acting mechanism to effectuate distraction and hence movement of jaws  2404   a  and  2404   b  apart upon movement of handles  2402   a  and  2402   b  together, one set of lever arms can be laterally pivotally coupled together and the other set of lever arms is crosswise pivotally coupled together. Further, with distractor mechanism  2411 , the triple-acting configuration can break the pivoting action into three components, reducing the total movement of distractor mechanism  2411  required along a distraction axis. 
         [0089]    An additional feature of distractor  2411  which can facilitate use thereof during distraction is the relative offset positions of jaws  2404   a  and  2404   b,  handles  2402   a  and  2402   b,  and distractor mechanism  2411  with respect to one another, as may be appreciated in the side elevational view of  FIG. 26 . In a further embodiment, distal jaw ends  2416   a  and  2416   b  may be positioned to properly distract adjacent vertebrae and distractor mechanism  2411  and handles  2402   a  and  2402   b  may be offset relative to distal jaw ends  2416   a  and  2416   b  to permit optimal visualization of distal jaw ends  2416   a  and  2416   b  from the proximal end of distractor  2400  (outside the patient&#39;s body) during distraction. For example, a distal bend may be provided immediately proximal of distal jaw ends  2416   a  and  2416   b,  as may be appreciated with reference to  FIG. 26 . Thus, the remainder of distractor  2400  (i.e., the proximal portions of distractor  2400  such as distractor mechanism  2411  and handles  2402   a  and  2402   b ) may be in a different plane from the plane of distal jaw ends  2416   a  and  2416   b  and the distraction site. With such an offset, visualization of the distraction site and of insertion of the implant or insert therein is enhanced. Also, such offset of portions of distractor  2400 , such as distractor mechanism  2411  and handles  2402   a  and  2402   b,  from the distal jaw ends  2416  accommodate an implant holder for insertion of the implant to permit a substantially straight insertion of the implant holder. The bend proximate distal jaw ends  2416  may be between 0 degrees and 30 degrees, for example 10 degrees, to achieve improved visualization and increased area for the implant holder. 
         [0090]    In one exemplary embodiment the sharp edges  2426   a,    2426   b  may be configured to be blade guides to start an insert  102  or those shown in  FIGS. 2   a - 2   c,  to be guided smoothly into a distracted disc space to facilitate placement of an insert, for example, in in posterior lumbar surgery. 
         [0091]    A distractor  2400  provided in accordance with the principles of the present invention is configured to distract adjacent vertebrae so that an implant may be inserted therebetween. Preferably, each jaw of a distractor formed in accordance with the principles of the present invention is provided with a blade, such as blades  2418   a  and  2418   b,  shaped and configured to contact a vertebral endplate and also to permit insertion of an implant there between via a parallel opening movement of the blades  2418   a  and  2418   b  which provides optimal space between the disc space. The parallel opening movement of the blades  2418   a  and  2418   b  may provide an optimal opening for a surgeon to safely and efficiently insert an implant. The parallel opening mechanism may decrease risk of injury and make posterior spinal surgery more efficient and safe to both patient and surgeon. Once the implant is properly positioned between the vertebral endplates, the distractor, along with its blades, may be removed from the distraction site in the patient. 
         [0092]    As shown in  FIG. 24 , blades  2418   a  and  2418   b  are provided on jaws  2404   a  and  2404   b,  respectively, to engage the vertebrae to be distracted. In a preferred embodiment, blades  2418   a  and  2418   b  may be configured and shaped to correspond to a slot in an insert, such as those discussed in earlier embodiments. Thus, as the selected implant is moved toward the treatment site with a desired insertion tool, insert contacting surfaces of blades  2418   a  and  2418   b  contact respective slots in the inserts. Additionally, the insert contacting surfaces of blades  2418   a  and  2418   b  may be closer together than the point of connection of blades  2418   a  and  2418   b  to respective jaws  2404   a  and  2404   b.  Thus, jaws  2404   a  and  2404   b  may be sufficiently spaced apart to permit insertion of the thickest dimension of the implant therebetween, yet blades  2418   a  and  2418   b  can be closer together to account for the narrower dimension of the implant in the region of slots on an insert and thereby to securely grasp the implant via the slots. 
         [0093]    Blades  2418  may converge directly towards each other in a distal direction before actuation of distractor mechanism  2411  as may be appreciated with reference to  FIG. 24 . Thus, upon actuation of distractor mechanism  2411  and pivoting apart of jaws  2404 , blades  2418 , and particularly the outwardly facing distracting surfaces of the blades (positioned to contact the endplates in the treatment site), may be moved into an orientation appropriate for the vertebral region being treated. For example, actuation of distractor mechanism  2411  may move the distracting surfaces of blades  2418  into a parallel orientation with respect to each other (i.e. moving blades  2418  apart while maintaining a 180 degree angle between blades  2418   a  and  2418   b ) to securely engage endplates which are parallel with respect to each other. 
         [0094]      FIGS. 25 and 26  show further exemplary embodiments of a distractor. Specifically,  FIGS. 25 and 26  show separated components of distractor  2400 . 
         [0095]      FIG. 27  shows an exemplary embodiment of a distractor being used. In this embodiment, distractor  2400  is shown as inserted into vertebra  2702 . Handles  2402  may be used to actuate jaws  2404 , thus separating blades  2418   a  and  2418   b.  The contact portions of blades  2418   a  and  2418   b  contact upper vertebra portion  2702   a  and lower vertebra portion  2702   b,  respectively, and can act to separate upper and lower vertebra  2702   a  and  2702   b.  This separation may allow for the insertion of a spinal insert or implant. 
         [0096]      FIG. 28  shows another exemplary embodiment of a distractor being used. Similar to  FIG. 27 , distractor  2400  is shown as inserted into vertebra  2702 , providing separation between upper vertebra portion  2702   a  and  2702   b.  Additionally, in this embodiment, insert  2802  is shown as being used with distractor  2400 . Insert  2802  may be any type of insert, for example any type of insert described herein. Distractor  2400  may hold insert  2802  between jaws  2404   a  and  2404   b  until there is sufficient separation between upper vertebra portion  2702   a  and  2702   b  so as to insert spinal insert  2802  between upper vertebra portion  2702   a  and lower vertebra portion  2702   b.  Insert  2802  may have hole that accepts a rod as an insert, allowing for insert  2802  to be placed between upper vertebra portion  2702   a  and lower vertebra portion  2702   b  and aiding with the withdrawal of distractor  2400  there from. 
         [0097]      FIG. 28  further shows the benefits of the parallel opening movement of the blades  2418   a,    2418   b  which moves the vertebral bones  2702   a  and  2702   b  apart so that no grooves or canals are formed in the bone near the distractor blades  2418   a,    2418   b  when inserting the device which greatly reduces the chances of migration once the insert  2802  is implanted and the distractor  2400  removed. This technique is safer for the surgeon and will create superior results for the patient. For example, this parallel distraction technique and system of implanting an insert reduces the chance of a surgeon pushing the insert into the bone of a patient with soft vertebrae because the space created with the parallel distraction technique made available by the distractor  2400  opens the disc space optimally for insertion of an insert such as the tapered cage  2802 . Likewise, this technique facilitates trials during surgery by reducing the surgical impact in the vertebrae  2702   a  and  2702   b  with less scratching and scarring of the bone surface. For example, during surgery, many different types of implants, tapered  200 , arched or curved  216  or straight  228  may be inserted into the disc space and an x-ray taken to determine which insert will provide optimal results for the patient based on the space between the patient&#39;s vertebrae. For example, some patient&#39;s disc space may be contoured as in  FIG. 33  which would require an arched insert  216 . Likewise others as shown, for example, in  FIG. 32  would benefit from a tapered insert  200 . 
         [0098]      FIG. 29  shows a further embodiment of a distractor being used. In this embodiment, insert  2802  has been placed between upper vertebra portion  2702   a  and lower vertebra portion  2702   b.  Blades  2418   a  and  2418   b  have been partially retracted from upper vertebra portion  2702   a  and lower vertebra portion  2702   b  and the lower contact portion of blades  2418   a  and  2418   b  are no long in contact with insert  2802 . Additionally, if a rod is used to help position and insert spinal insert  2802 , it may also be retracted after insert  2802  is placed between upper vertebra portion  2702   a  and lower vertebra portion  2702   b.    
         [0099]      FIGS. 30 and 31  show exemplary embodiments of spinal inserts that may be inserted into a spinal column. In  FIG. 30 , tapered insert  3002  has been inserted between upper vertebra portion  2702   a  and lower vertebra portion  2702   b.  In  FIG. 31 , arched or curved insert  3102  has been inserted between upper vertebra portion  2702   a  and lower vertebra portion  2702   b.  Each of these inserts may be placed with the assistance of distractor  2400  in a manner similar to that described above with respect to  FIGS. 27 and 28 . Additionally, each insert  3002  and  3102  may provide different advantages when inserted. For example, tapered insert  3002  may be placed in such a manner where a non-tapered insert would not fit. Additionally, tapered insert  3002  or arched insert  3102  may be used in situations where the vertebra are shaped in such a manner that would not otherwise accept an insert, or where tapered insert  3002  or arched insert  3102  may provide an improved fit. 
         [0100]    Curved Cage  3102  with further progression of spondylosis a scalloped appearance may occur in the disc space relative to the adjacent vertebral bodies. In order to promote bony fusion or maintain spinal dynamics utmost anatomical contact between the knurled surfaces of the implant  3102  in at least one exemplary embodiment may assist to overcome this spinal defect. 
         [0101]    Tapered Cage  3002  with the progression of spondylosis or in post surgical patients, patients may lose their natural curvature of their spine. The loss of the lumbar lordosis leads to a poor sagittal balance. The tapered cage  3002  is geared for not only to allow greater contact between implant  3002  and cortical bone, but also to restore sagittal balance in those patient who have lost it due to degenerative or post surgical. 
         [0102]    The foregoing description and accompanying drawings illustrate the principles, preferred embodiments and modes of operation of the invention. However, the invention should not be construed as being limited to the particular embodiments discussed above. Additional variations of the embodiments discussed above will be appreciated by those skilled in the art. 
         [0103]    Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive. Accordingly, it should be appreciated that variations to those embodiments can be made by those skilled in the art without departing from the scope of the invention as defined by the following claims.