Patent Publication Number: US-2020289270-A1

Title: Spinal spacing implant, spinal spacer assembly, expander and insertion instrument, kit and methods of assembly and use

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/592,732 filed May 11, 2017 which will issue as U.S. Pat. No. 10,667,915 on Jun. 2, 2020; which claimed priority benefit to PCT Application No. PCT/US2015/060420 filed on Nov. 12, 2015, which claimed priority to U.S. provisional application Nos. 62/078,837 filed Nov. 12, 2014 and 62/180,981 filed Jun. 17, 2015, which all of these applications are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to general surgery, orthopaedic and neurosurgical implants used for insertion within a space between hard and soft tissue structures, and more specifically, but not exclusively, concerns spinal spacing implants and surgical instruments for implanting devices within a bone to replace a resected, fractured or diseased portion and to maintain or reestablish proper spacing between the bone fragments. 
     SUMMARY 
     The present invention is directed toward implants, assemblies, instruments, kits and methods of assembling and using the implants, assemblies, instruments, kits. 
     In one aspect, provided herein is a spinal implant replacement instrument kit, including a distraction instrument and a spinal implant. 
     In another aspect, provided herein is a distraction instrument including a first inserter member, a second inserter member, a first arm coupled to the first inserter member, a second arm coupled to the second inserter member, a distraction system coupled to the first arm and second arm, a first handle coupled to the first arm and the distraction system, and a second handle coupled to the second arm and the distraction system. 
     In yet another aspect, provided herein is a method for inserting a vertebral body replacement device, including obtaining the vertebral body replacement device and a distraction instrument. The method may also include attaching a first member and a second member of the vertebral body replacement to the distraction instrument and moving the distraction instrument to separate the first member and the second member. The method may further include coupling a spacer to a spacer inserter and moving the coupled spacer and spacer inserter through the distraction instrument into position between the first member and the second member. Finally, the method may include disengaging the spacer inserter from the spacer and removing the spacer inserter from the distraction instrument and disengaging the distraction instrument from the first member and second member of the vertebral body replacement device. 
     These, and other objects, features and advantages of this invention will become apparent from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the detailed description herein, serve to explain the principles of the invention. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. The foregoing and other objects, features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a perspective view of a distraction instrument of a vertebral body replacement instrument in an open position, in accordance with an aspect of the present invention; 
         FIG. 2  is a rear, perspective view of the distraction instrument of  FIG. 1 , in accordance with an aspect of the present invention; 
         FIG. 3  is a side view of the distraction instrument of  FIG. 1 , in accordance with an aspect of the present invention; 
         FIG. 4  is a front, perspective view of the distraction instrument of  FIG. 1 , in accordance with an aspect of the present invention; 
         FIG. 5  is a side view of a portion of the distraction instrument of  FIG. 1  showing the expansion system, in accordance with an aspect of the present invention; 
         FIG. 6  is a side view of a portion of the distraction instrument of  FIG. 1  with a transparent cover to show the ratcheting system, in accordance with an aspect of the present invention; 
         FIG. 7  is a top view of a connector portion of the distraction instrument of  FIG. 1 , in accordance with an aspect of the present invention; 
         FIG. 8  is a side view of a portion of the distraction instrument of  FIG. 1  engaging a first member and second member of a vertebral body implant, in accordance with an aspect of the present invention; 
         FIG. 9  is a top view of the distraction instrument and first member of  FIG. 8 , in accordance with an aspect of the present invention; 
         FIG. 10  is a side view of another embodiment of the distraction instrument of  FIG. 1  engaging a first member of a vertebral body implant, in accordance with an aspect of the present invention; 
         FIG. 11  is a top view of an elongate connector member of the distraction instrument of  FIG. 10 , in accordance with an aspect of the present invention; 
         FIG. 12  is a locking mechanism for coupling to the distraction instrument of  FIG. 1 , in accordance with an aspect of the present invention; 
         FIG. 13  is a key for the locking mechanism of  FIG. 12 , in accordance with an aspect of the present invention; 
         FIG. 14  is a side view of the distraction instrument of  FIG. 1  with an expander mechanism inserted into the distraction instrument, in accordance with an aspect of the present invention; 
         FIG. 15  is a detailed side view of the measurement mechanism shown as  190  in  FIG. 14 , in accordance with an aspect of the present invention; 
         FIG. 16  is a perspective view of an expander mechanism, in accordance with an aspect of the present invention; 
         FIG. 17  is a side view of the expander mechanism of  FIG. 16 , in accordance with an aspect of the present invention; 
         FIG. 18  is a front perspective view of the expander mechanism of  FIG. 16 , in accordance with an aspect of the present invention; 
         FIG. 19  is an exploded side view of the expander mechanism of  FIG. 16 , in accordance with an aspect of the present invention; 
         FIG. 20  is an exploded perspective view of the expander mechanism of  FIG. 16 , in accordance with an aspect of the present invention; 
         FIG. 21  is a perspective view of the distraction instrument of  FIG. 1  in an expanded position and coupled to first and second members of an implant, in accordance with an aspect of the present invention; 
         FIG. 22  is a side perspective view of the distraction instrument and first and second members of  FIG. 21 , in accordance with an aspect of the present invention; 
         FIG. 23  is a side perspective view of a spacer inserter, in accordance with an aspect of the present invention; 
         FIG. 24  is a top perspective view of the spacer inserter of  FIG. 23  with a spacer coupled to the proximal end, in accordance with an aspect of the present invention; 
         FIG. 25  is a detailed view of the proximal end of the spacer inserter of  FIG. 24  with the coupled spacer, in accordance with an aspect of the present invention; 
         FIG. 26  is a front perspective view of the spacer of  FIG. 24 , in accordance with an aspect of the present invention; 
         FIG. 27  is a side perspective view of the spacer of  FIG. 26 , in accordance with an aspect of the present invention; 
         FIG. 28  is another side perspective view of the spacer of  FIG. 26 , in accordance with an aspect of the present invention; 
         FIG. 29  is a front view of another embodiment spacer, in accordance with an aspect of the present invention; 
         FIG. 30  is a side perspective view of the distraction instrument of  FIG. 22  with the spacer inserter of  FIG. 23  inserting the spacer of  FIG. 25  between the first and second members of the implant, in accordance with an aspect of the present invention; 
         FIG. 31  is a detailed view of the proximal end of the system of  FIG. 30 , in accordance with an aspect of the present invention; 
         FIG. 32  is a side perspective view of the spacer of  FIG. 30 , in accordance with an aspect of the present invention; 
         FIG. 33  is a perspective view of one embodiment of an expansion mechanism, in accordance with an aspect of the present invention; 
         FIG. 34  is a perspective view of the distraction instrument of  FIG. 1  after insertion of the implant and the expansion mechanism of  FIG. 33 , in accordance with an aspect of the present invention; 
         FIG. 35  is a detailed view of the proximal end of the system of  FIG. 34 , in accordance with an aspect of the present invention; 
         FIG. 36  is a perspective view of the system of  FIG. 30  illustrating an alternative embodiment of an expansion mechanism positioned on the spacer inserter of  FIG. 23 , in accordance with an aspect of the present invention; 
         FIG. 37  is a perspective view of a first adjustment mechanism from a first end, in accordance with an aspect of the present invention; 
         FIG. 38  is a perspective view of the first adjustment mechanism of  FIG. 37  from a second end, in accordance with an aspect of the present invention; 
         FIG. 39  is a perspective view of a second adjustment mechanism from a first end, in accordance with an aspect of the present invention; 
         FIG. 40  is a perspective view of the second adjustment mechanism of  FIG. 39  from a second end, in accordance with an aspect of the present invention; 
         FIG. 41  is an exploded, front perspective view of a vertebral body implant, in accordance with an aspect of the present invention; 
         FIG. 42  is a front perspective view of the vertebral body implant of  FIG. 41 , in accordance with an aspect of the present invention; 
         FIG. 43  is a front view of the vertebral body implant of  FIG. 41 , in accordance with an aspect of the present invention; 
         FIG. 44  is a back view of the vertebral body implant of  FIG. 41 , in accordance with an aspect of the present invention; 
         FIG. 45  is a side view of the vertebral body implant of  FIG. 41 , in accordance with an aspect of the present invention; 
         FIG. 46  is a top view of the vertebral body implant of  FIG. 41 , in accordance with an aspect of the present invention; 
         FIG. 47  is a cross sectional view of the vertebral body implant of  FIG. 41  taken along line  47 - 47  in  FIG. 46 , in accordance with an aspect of the present invention; 
         FIG. 48  is a first front perspective view of a distraction instrument of a vertebral body replacement system in an open position, in accordance with an aspect of the present invention; 
         FIG. 49  is a second front perspective view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 50  is a first side view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 51  is a second side view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 52  is a top view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 53  is a partially exploded front perspective view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 54  is a partially exploded back perspective view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 55  is a perspective view of the inserter members of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 56  is a cross-sectional view of the distraction instrument of  FIG. 48  taken along line  56 - 56  in  FIG. 52 , in accordance with an aspect of the present invention; 
         FIG. 57  is a partially exploded perspective view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 58  is an exploded view of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 59  is a detailed side view of the first end of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 60  is a detailed bottom perspective view of the first end of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 61  is a cross-sectional view of a first arm of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 62  is a side view of the distraction instrument of  FIG. 48  engaging a portion of a spinal implant in an insertion position, in accordance with an aspect of the present invention; 
         FIG. 63  is a perspective view of the distraction instrument and spinal implant of  FIG. 62 , in accordance with an aspect of the present invention; 
         FIG. 64  is a perspective view of the distraction instrument and spinal implant of  FIG. 62  in an expanded position, in accordance with an aspect of the present invention; 
         FIG. 65  is a partially exploded perspective view of a spinal spacer assembly including the distraction instrument and spinal implant of  FIG. 62  and a spacer inserter and spinal implant spacer, in accordance with an aspect of the present invention; 
         FIG. 66  is a detailed perspective view of the first end of the spinal spacer assembly of  FIG. 65 , in accordance with an aspect of the present invention; 
         FIG. 67  is a perspective view of the spinal spacer assembly of  FIG. 65  with the distraction instrument of  FIG. 48  in an expanded position and the spacer inserter and spacer positioned in the spinal implant, in accordance with an aspect of the present invention; 
         FIG. 68  is a perspective view of the distraction instrument of  FIG. 48  in an expanded position and engaging the assembled spinal spacer implant, in accordance with an aspect of the present invention; 
         FIG. 69  is a top view of an inserter member for the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 70  is an exploded rear, perspective view of the inserter member of  FIG. 69 , in accordance with an aspect of the present invention; 
         FIG. 71  is a top view of a handle member of the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 72  is a top view of an alternative handle member for the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 73  is a top view of another handle member for the distraction instrument of  FIG. 48 , in accordance with an aspect of the present invention; 
         FIG. 74  is a side view of the distraction instrument of  FIG. 48  with an alternative stop member, in accordance with an aspect of the present invention; 
         FIG. 75  is a detailed side view of the stop member of  FIG. 74 , in accordance with an aspect of the present invention; 
         FIG. 76  is a perspective view of a locking driver instrument for locking the spacer in position between the first and second portions of the spinal implant, in accordance with an aspect of the present invention; 
         FIG. 77  is a perspective view of a first end of the locking driver instrument of  FIG. 76 , in accordance with an aspect of the present invention; 
         FIG. 78  is a perspective view of a threaded rod driver instrument for securing the threaded rods of the distraction instrument of  FIG. 48  to the spinal implant, in accordance with an aspect of the present invention; 
         FIG. 79  is a perspective view of a first end of the threaded rod driver instrument of  FIG. 78 , in accordance with an aspect of the present invention; 
         FIG. 80  is a partially exploded perspective view of a vertebral body replacement system including the distraction instrument, the spinal implant, and the spacer inserter of  FIG. 67 , the locking driver instrument of  FIG. 76 , and the threaded rod driver instrument of  FIG. 78 , in accordance with an aspect of the present invention; 
         FIG. 81  is a detailed perspective view of the first end of the vertebral body replacement system of  FIG. 80 , in accordance with an aspect of the present invention; 
         FIG. 82  is a first front perspective view of another distraction instrument of a vertebral body replacement system in an open position, in accordance with an aspect of the present invention; 
         FIG. 83  is a second front perspective view of the distraction instrument of  FIG. 82 , in accordance with an aspect of the present invention; 
         FIG. 84  is a side view of the distraction instrument of  FIG. 82 , in accordance with an aspect of the present invention; 
         FIG. 85  is a top view of the distraction instrument of  FIG. 82 , in accordance with an aspect of the present invention; and 
         FIG. 86  is an exploded view of the distraction instrument of  FIG. 82 , in accordance with an aspect of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Generally stated, disclosed herein are spinal spacing implants, spinal spacing instruments, and a spinal spacer assembly. Further, disclosed herein are an expander and insertion replacement instrument kit and methods for using the spinal spacing replacement instruments. 
     In this detailed description and the following claims, the words proximal, distal, anterior, posterior, medial, lateral, superior and inferior are defined by their standard usage for indicating a particular part of a bone, prosthesis or surgical instrument according to the relative disposition of the surgical instrument or directional terms of reference. For example, “proximal” means the portion of an instrument positioned nearest the torso, while “distal” indicates the part of the instrument farthest from the torso. As for directional terms, “anterior” is a direction towards the front side of the body, “posterior” means a direction towards the back side of the body, “medial” means towards the midline of the body, “lateral” is a direction towards the sides or away from the midline of the body, “superior” means a direction above and “inferior” means a direction below another object or structure. Also, the terms “implant” and “device” may be used interchangeably and have the same meaning herein. 
     Referring to the drawings, wherein like reference numerals are used to indicate like or analogous components throughout the several views, there is illustrated a spinal spacer assembly or vertebral body replacement instrument assembly. The assembly includes a distraction instrument  100 , as shown in  FIGS. 1-11 and 14-16 , an expander mechanism  200 , as shown in  FIGS. 17-21 , a spacer inserter  300 , as shown in  FIGS. 23-25 , a first adjustment mechanism  160 , as shown in  FIGS. 37-28 , and a second adjustment mechanism  180 , as shown in  FIGS. 39-40 . 
     The distraction instrument  100 , as shown in  FIGS. 1-11, 14-16, 22, 30-31, and 34-36 , may include a body  102 , a first elongate member  110 , a second elongate member  120 , a distraction system  130 , a movement system  140 , a handle  104 , and a trigger  106 . The first elongate member  110  may be coupled to a first end of the body  102  at a second end and include an engagement portion  112  at the first end. The distraction system  130  may movably couple the second elongate member  120  to the first elongate member  110 . The first and second elongate members  110 ,  120  may be positioned, for example, generally parallel to each other. The second elongate member  120  may be coupled to the distraction system  130  at a second end and include an engagement portion  122  at the first end. 
     The distraction system  130  may include two first links  132  and two second links  134 . One first link  132  and one second link  134  may be pivotally coupled together and pivotally attached to the first and second elongate members  110 ,  120  on a first side. The other first link  132  and the other second link  134  may be pivotally coupled together and pivotally attached to the first and second elongate members  110 ,  120  on a second side. The first links  132  may be attached to the first elongate member  110  at a first end and slidingly coupled to the channel  124  in the second elongate member  120  at a second end. The second links  134  may be attached to the second elongate member  120  at a first end and slidingly coupled to the channel  114  in the first elongate member  110  at a second end. The first and second links  132 ,  134  may be coupled to each other and the elongate members  110 ,  120  by at least one fastener  136 . The fasteners  136  may be, for example, screws, rivets, pins, or the like that allow for the links  132 ,  134  to be pivotally coupled to each other and the elongate members  110 ,  120 . 
     With continued reference to  FIGS. 1-11, 14-16, 22, 30-31, and 34-36 , the handle  104  and trigger  106  may be secured to a bottom side of the body  102  at a second end. The movement system  140  may be coupled to a top side of the body  102  at the second end. The movement system  140  may include a cover  142  positioned over a drive mechanism  144  and at least one locking mechanism  146 , as shown in  FIGS. 6 and 14 . The drive mechanism  144  may be coupled to the trigger  106  to allow for movement of the trigger  106  to actuate the drive mechanism  144 . As the drive mechanism  144  is actuated, the drive mechanism  144  may move the distraction system  130  to expand the space between the first and second elongate members  110 ,  120 . The movement system  140  may also include a spring  148  that engages the trigger  106  to move the trigger  106  back to a resting or starting position after release by a user. The movement system  140  may further include a translating member  150 . The translating member  150  may be positioned within the body  102  and moveably engage the drive mechanism  144  to move the first elongate member  110 . The translating member  150  may include teeth  152  along at least a portion of the translating member  150 . As the drive mechanism  144  is activated, the drive mechanism  144  engages the teeth  152  of the translating member  150  to move the translating member  150  toward a proximal end of the distraction instrument  100 . The translating member  150  may also include a slide mechanism  154  coupled to a first end of the translating member  150 , such that as the translating member  150  is moved forward by the drive mechanism  144  the slide mechanism  154  also move forward. The slide mechanism  154  may be positioned within the channel  114  and engage the links  132 ,  134  of the distraction system  130  to move the links  132 ,  134  proximally to separate the first and second elongate members  110 ,  120 . 
     Referring now to  FIGS. 7-9 , the second elongate member  120  may, for example, include an opening  123  extending from the first end into a portion of the elongate member  120  toward the second end. The engagement portion  122  of the second elongate member  120  may include protrusions  126  extending out from the lateral edges of the elongate member  120  to couple to an exterior surface of an implant  400 . The engagement portion  122  may also include gripping members  128  extending out from a center portion of the elongate member  120  between the protrusions  126 . The gripping members  128  may each include a tooth or other like protrusion or pin  129  extending toward each other. The gripping members  128  may be positioned on either side of the opening  123 . The opening  123  may be, for example, generally triangularly shaped to allow for movement of the gripping members  128  of the engagement portion  122 . As shown in  FIG. 9 , the gripping members  128  may each be inserted into an opening  472  in the coupling portion  470  of one embodiment of the first member  430  of implant  400 . The protrusions  126  of the engagement portion  122  may be positioned on the sides of the coupling portion  470  to provide additional support to the first member  430  during distraction of a patient&#39;s vertebrae. 
     An alternative engagement portion  122  of the second elongate member  120  is shown in  FIGS. 10 and 11 . The alternative engagement portion  122  may include the protrusions  126  extending out from the lateral edges of the elongate member  120  and a tooth  129  extending out from each protrusion  126  toward a midline along the longitudinal axis of the second elongate member  120 . The teeth  129  are positioned to engage an exterior surface of a first member  430  of an implant  400 . The protrusions  126  may be sized to provide additional stability to the first member  430  during insertion into the patient. 
     Referring now to  FIGS. 12 and 13 , an optional locking mechanism  500  is shown. The locking mechanism  500  may be, for example, an external locking mechanism or an internal locking mechanism. The external locking mechanism (not shown) may be positioned by sliding the locking mechanism (not shown) over the exterior surfaces of the elongate members  110 ,  120  of the distraction instrument  100  to prevent the first elongate member  110  from separating from the second elongate member  120 . Alternatively, as shown in  FIG. 12 , the locking mechanism  500  may include a first portion  502  with a first internal groove  504  and a second portion  506  with a second internal groove  508 . The first internal groove  504  may be formed in the interior surface of the first elongate member  110  and the second internal groove  508  may be formed in the interior surface of the second elongate member  120 . A key member  510 , as shown in  FIG. 13 , may include a base  512  with a first end  514  shaped to correspond to the first internal groove  504  and a second end  516  shaped to correspond to the second internal groove  508 . The key member  510  may be inserted into the locking mechanism  500  to secure the first and second elongate members  110 ,  130  and prevent the elongate members  110 ,  130  from separating and distracting the attached implant components before distraction is desired. 
     The distraction instrument  100  may also include a measurement mechanism  190  with an indicator line  192 , as shown in  FIGS. 14-15 . The measurement mechanism  190  may be positioned on the body  102 . The indicator line  192  may be positioned on the translating member  150  and may be, for example, a groove inset into the translating member  150 . The body may include an opening  103  to enable the user to view the indicator line  192 . The measurement mechanism  190  may be coupled to the movement system  140  to measure the translation of the movement system  140  which in turn provides the amount of distraction or separation performed on the first and second members  430 ,  450 . 
     The expander mechanism  200 , as shown in  FIGS. 14 and 16-20 , may include a rod  202 , a first track member  210 , a second track member  230 , a first link member  222 , a second link member  242 , a sliding member  250 , a movement member  260 , and a locator  270 . The rod  202  has a first end including an attachment portion  204  and a second end with a handle  208 . The rod  202  may also include a protrusion  206  which may include, for example, a groove on either side of the protrusion  206 . The proximal end of the rod  202  extends through an opening (not shown) in the second end of the second track member  230 . The proximal end of the rod  202  is coupled to the sliding member  250  within an interior portion  238  in the second track member  230 . The second track member  230  may also include a channel  232 , a first edge protrusion  234 , a second edge protrusion  236 , and an interior portion  238 . The second track member  230  may fit within the interior portion of the first elongate member  110  and the first and second edge protrusions  234 ,  236  may sit on the top of the first elongate member  110 . The first track member  210  may include a channel  212 , a first edge protrusion  214 , a second edge protrusion  216 , and an interior portion  218 . The first track member  210  may fit within the interior portion of the second elongate member  120  and the first and second edge protrusions  214 ,  216  may sit on the bottom of the second elongate member  120 . 
     The first link member  222  may include a first opening  224  secured to the second track member  230  through opening  240  with a fastener  280 . The first link member  222  may also include a second opening  228  that may be used to secure the first link member  222  to the second link member  242  through a second opening  248  with a fastener  280 . In addition, the first link member  222  may include a third opening  226  for receiving a fastener  280  to movably couple the first link member  222  to the channel  212  of the first track member  210 . The second link member  242  also include a first opening  244  for securing the second link member  242  to the first track member  210  through opening  220  with a fastener  280 . The second link member  242  may further include a third opening  246  for receiving a fastener  280  to movably couple the second link member  242  to the channel  232  of the second track member  230 . The second link member  242  may also be secured to the sliding member  250  by inserting a fastener  280  through the channel  232  on a first side of the second track member  230 , the third opening  246  of the second link member  242 , the opening  252  in the sliding member  250 , and the channel  232  on a second side of the second track member  230 . The sliding member  250  is positioned to move the second track member  230  as force is applied to the movement member  260 . The movement member  260  may have, for example, a first portion coupled to a second portion to receive the protrusion  206 . The movement member  260  may include an opening  262  for the body  202  to extend through the movement member  260  and an extension member  264  for engaging the slide mechanism  154 . The locator  270  may include an opening  272  for being positioned on the body  202  of the expander mechanism  200 . The locator  270  provides a visual positioning marker for the user. The locator  270  may also be used as a stopper to mark how far the expander mechanism  200  should be inserted into the distraction instrument  100 . 
     As shown in  FIG. 14 , the expander mechanism  200  may be inserted into the distraction instrument  100  and positioned near a proximal end of the distraction instrument  100  prior to expansion. The expander mechanism  200  may be positioned near the proximal end to provide uniform expansion between the first and second elongate members  110 ,  120 . By positioning the expander mechanism  200  near the proximal end of the distraction instrument  100  it may assist in preventing deflection of the engagement portions  112 ,  122 . After distraction is performed with the expander mechanism  200 , as shown in  FIG. 14 , the expander mechanism  200  may then be removed from the distraction instrument  100  leaving the distraction instrument  100  and the first and second members  430 ,  450  in an expanded position, as shown in  FIGS. 21 and 22 . Also shown in  FIGS. 21  and  22  is a first member  430  coupled to the second elongate member  120  and a second member  450  coupled to the first elongate member  110 . 
     Referring now to  FIGS. 23-25 , the spacer inserter  300  may include a handle  302  with an actuation mechanism  304 . The actuation mechanism  304  is configured to enable the engagement shaft  306  to be secured in a first position wherein an implant spacer member  410  is secured to the proximal end  308  of the engagement shaft  306  for insertion into a patient. Then upon actuation of the actuation mechanism  304 , the handle  302  is released and free to move in a longitudinal direction along the shaft  306 . Once the handle  302  is released, the surgeon may use the handle  302  as a slide or slap hammer to facilitate tapping of the spacer member  410  through the tracks  434 ,  454  in the first and second members  430 ,  450 . The spacer inserter  300  may also include an alignment head  310  for alignment of the intermediate spacer member  410  on the spacer inserter  300  for insertion into the patient. The spacer inserter  300  may further include a movable housing  312  coupled to a tab  314  to assist in the alignment and insertion of the intermediate spacer member  410  between the first and second elongate members  110 ,  120  of the distraction mechanism  100 . The spacer inserter  300  may also include an engagement member  316  positioned on the housing  312 . The housing  312  may be actuated by the tab  314  to engage the spacer  410 . As the tab  314  is moved forward the housing  312  slides forward and causes the arms of the alignment head  310  to move closer together to engage the spacer  410 . The arms of the alignment head  310  clamp onto the spacer  410  during insertion. Once the spacer  410  is inserted between the first and second members  430 ,  450  of the implant  400 , the tab  314  may be moved in a rearward direction towards the handle  302  moving the housing  312  towards the handle  302  and releasing the arms of the alignment head  310 . After the arms of the alignment head  310  disengage from the spacer  410 , the spacer inserter  300  may be removed from the patient. 
     The engagement member  316  may be used to assist with moving the spacer  410  into position between the first and second members  430 ,  450  of the implant  400 . The engagement member  316  may engage the extensions  111  of the distraction mechanism  100  to assist with moving the spacer  410  into position. The engagement member  316  may act as a stopper for holding the spacer inserter  300  in position while additional force is applied to the spacer  410  using the handle  302  and threads  318 . The spacer inserter  300  may further include a threaded portion  318  positioned between the housing  312  and the handle  302 . The threaded portion  318  may be used to provide additional leverage for the user when moving the implant  400  into position. To use the threaded portion  318 , the actuation mechanism  304  may be depressed and the handle  302  moved proximally to engage the threaded portion  318 . Then, the handle  302  may be screwed onto the threaded portion  318  to push the spacer  410  into position between the first and second members  430 ,  450  of the implant  400 . 
     Referring now to  FIGS. 24-29 and 32 , the intermediate spacer  410  is shown. The intermediate spacer  410  may include a first end and a second end. The intermediate spacer  410  may include a coupling mechanism  416  for engaging the first member  430  on the first end and a coupling mechanism  418  for engaging the second member  450  on the second end. The coupling mechanisms  416 ,  418  may be, for example, the male portions of a dovetail mechanism. The intermediate spacer  410  may also include at least one instrument coupling mechanism  412  on a side of the exterior surface of the intermediate spacer  410 . In the depicted embodiment, the intermediate spacer  410  includes an instrument coupling mechanism  412  on each side of the exterior surface, as shown in  FIGS. 26 and 29 . The instrument coupling mechanisms  412  may be, for example, grooves or channels on the exterior side surfaces of the spacer  410 . The grooves  412  are sized and shaped to engage the alignment head  310  of the spacer inserter  300 . 
     The intermediate spacer  410  may further include a tapered portion  414  positioned between the groove  412  and the coupling mechanism  416  on each side of the spacer  410  near the first end. The tapered portion  414  may taper from the front side to the back side of the intermediate spacer  410 . The tapered portion  414  may be sized to expand the protrusions  126  of the engagement portion  122  as the intermediate spacer  410  is inserted between the first and second members  430 ,  450 . As the protrusions  126  expand, the elongate members  110 ,  120  of the distraction mechanism  100  are released from the first and second members  430 ,  450 , as shown in  FIG. 30 , and the distraction mechanism  100  may be removed from the implant  400 . As shown in  FIG. 31 , the spacer inserter  300  may optionally be removed from the spacer  410  prior to removing the disengaged distraction mechanism  100  from the first and second members  430 ,  450 . The spacer  410  may further include a fastener hole  420  on the front for receiving a fastener (not shown). The fastener hole  420  may be used to assist with insertion of the spacer  410  into the patient by coupling the spacer  410  to the inserter  300  during insertion. The fastener hole  420  may also receive a fastener (not shown) to secure the spacer  410  to the first and second members  430 ,  450 . In addition, the spacer  410  may include a gap or channel  422  on the back of the spacer  410  to allow for slight deflection of the spacer  410  during insertion between the first and second members  430 ,  450 . 
     As shown in  FIG. 29 , the spacer  410  may also optionally include a button  424  or button  426 . The button  424 ,  426  may be positioned to engage at least one of the teeth  129  on the second elongate member  120  shown in  FIGS. 10 and 11 . The button  424 ,  426  may be positioned, for example, on a top surface of the spacer  410 , as illustrated in  FIG. 29 . As the spacer  410  is inserted between the first and second members  430 ,  450  the button  424 ,  426  will engage at least one tooth  129  and push it out of an opening (not shown) in the side of the engagement portion  432  of the first member  430 . Once the tooth  129  is disengaged from the first member  430 , the distraction instrument  100  is free to be removed from engagement with the first and second members  430 ,  450 . It is also contemplated that the spacer  410  may include a button  424 ,  426  on the second end or alternatively, on both the first and second ends. 
       FIG. 33  illustrates an alternative expansion mechanism  194  for releasing the protrusions  126  of the elongate members  110 ,  120  from the first and second members  430 ,  450 . The expansion mechanism  194  may include a shaft portion  196  and a wedge portion  198 . The wedge portion  198  may be sized to engage the opening  123  and as the wedge portion  198  travels proximally within the opening  123  the protrusions  126  are released from the first and second members  430 ,  450  to allow for removal of the distraction mechanism  100 . The expansion mechanism  194  is shown in use with the distraction mechanism  100  in  FIGS. 34-35 . It is also contemplated that the expansion mechanism  194  may be used in an opening  113  in the first elongate member  110 . 
     Another alternative expansion mechanism  330  is shown in  FIG. 36 . The expansion mechanism  330  may be coupled to the housing  312  of the spacer inserter  300  near the proximal end  308 . As the spacer inserter  300  is moved proximally within the distraction mechanism  100  the expansion mechanism  330  will be positioned within at least one opening  113 ,  123  and the expansion mechanism  330  will expand the protrusions  126  away from each other to disengage the distraction mechanism  100  from the first and second members  430 ,  450 . 
       FIGS. 37 and 38  illustrate a first adjustment mechanism  160  which may be used to secure the first member  430  to the spacer  410  once a final position is achieved. The first adjustment mechanism  160  may include a shaft  162  with a drive mechanism  164  at a first end and a handle  166  at a second end. The first adjustment mechanism  160  may also include a first guide portion  168  and a second guide portion  170 . The first and second guide portions  168 ,  170  may be used to position the first adjustment mechanism  160  with respect to the second elongate member  120  and the first member  430  of the implant  400 . The first adjustment mechanism  160  is a separate instrument for use with the distraction mechanism  100 . It is also contemplated that a first adjustment mechanism could be integrated into the distraction mechanism  100  for securing the first member  430  in the desired position. 
       FIGS. 39 and 40  show a second adjustment mechanism  180  which may be used to secure the second member  450  to the spacer  410  once a final position is achieved. The second adjustment mechanism  180  may include a shaft  182  with a drive mechanism  184  at a first end and a handle  186  at a second end. The first adjustment mechanism  180  may also include a first guide portion  188  and a second guide portion  189 . The first and second guide portions  188 ,  189  may be used to position the second adjustment mechanism  180  with respect to the first elongate member  110  and the second member  450  of the implant  400 . The second adjustment mechanism  180  is a separate instrument for use with the distraction mechanism  100 . It is also contemplated that a second adjustment mechanism could be integrated into the distraction mechanism  100  for securing the second member  450  in the desired position. 
     A spinal implant  400  is shown in  FIGS. 41-47 . The implant  400  may include, for example, an intermediate spacer  410 , a first member  430 , a first end member  440 , a second member  450 , and a second end member  460 . Although not shown, it is also contemplated that the implant  400  may include, for example, the intermediate spacer  410 , the first member  430 , and the second member  450 . In the alternative embodiment, a first end of the first member  430  and a second end of the second member  450  may have a bone contacting surface with, for example, a coating or textured surface to allow for bone ingrowth or ongrowth. The intermediate spacer  410  is described in greater detail above with reference to  FIGS. 24-29 and 32 . The first member  430  may include an engagement portion or insertion instrument coupling portion  432  on the exterior surface of the first member  430 . The insertion instrument coupling portion  432  may optionally include an opening (not shown) extending into the first member  430 . The first member  430  may also include a coupling mechanism  434 , which may be, for example, a female portion of a dovetail mechanism. The first member  430  may further include an engagement portion  436  at a first end with at least one channel  438  for coupling the first end member  440 . The engagement portions  436  may, for example, engage the openings or pockets in the first end member  440  and may prohibit the first end member  440  from rotating along the long axis with respect to the first member  430  once assembled. The first end member  440  may include a coupling member  442  extending out from a bottom surface of the first end member  440  to engage an undercut on an inner diameter of the engagement portion  436  of the first member  430 . The tabs of the coupling member  442  may, for example, snap to engage the undercut of the first member  430  to prevent axial separation of the end member  440  from the first member  430 . The first end member  440  may also include a bone contacting surface  444  on the top end, which may include, for example, a coating, texture, or the like to assist with securing the implant  400  to the bone and allowing for bone ongrowth or ingrowth. 
     With continued reference to  FIGS. 41-47 , the second member  450  may include an engagement portion or insertion instrument coupling portion  452  on the exterior surface of the second member  450 . The insertion instrument coupling portion  452  may optionally include an opening (not shown) extending into the second member  450 . The second member  450  may also include a coupling mechanism  454 , which may be, for example, a female portion of a dovetail mechanism. The second member  450  may further include an engagement portion  456  at a first end with at least one channel  458  for coupling the second end member  460 . The engagement portions  456  may, for example, engage the openings or pockets in the second end member  460  and may prohibit the second end member  460  from rotating along the long axis with respect to the second member  450  once assembled. The second end member  460  may include a coupling member  462  extending out from a top surface of the second end member  460  to engage an undercut on an inner diameter of the engagement portion  456  of the second member  450 . The tabs of the coupling member  462  may, for example, snap to engage the undercut of the second member  450  to prevent axial separation of the end member  460  from the second member  450 . The second end member  460  may also include a bone contacting surface  464  on the bottom end, which may include, for example, a coating, texture, or the like to assist with securing the implant  400  to the bone and allowing for bone ongrowth or ingrowth. 
     A distraction instrument  1000  is shown in  FIGS. 48-61 . The distraction instrument  1000 , as shown in  FIGS. 48-54 and 56-58 , may include a first inserter member  1110  and second inserter member  1130  at a first end  1102 . The distraction instrument  1000  may also include a first arm  1150  coupled to the first inserter member  1110  and second arm  1160  coupled to the second inserter member  1130 . The distraction instrument  1000  may further include a distraction system  1180  engaging the first and second arms  1150 ,  1160 . In addition, the distraction instrument  1000  may include a first handle  1210  and a second handle  1230  at the second end  1104 . The first handle  1210  may be coupled to the second end of the first arm  1150  and the second member  1190  and the second handle  1230  may be coupled to the second end of the second arm  1160  and the first member  1182 . The distraction instrument  1000  may also include a stop member  1202  positioned to engage the first and second handles  1210 ,  1230  to hold the distraction instrument  1000  in the expanded position. 
     As shown in  FIGS. 55, 57, and 58 , the first inserter member  1110  may include a body  1112  with a first opening  1114  extending from a top surface through to a bottom surface. The first inserter member  1110  may also include engagement protrusions  1116  extending out from the first end of the body  1112  for engaging a portion of a spinal implant. The first inserter member  1110  may further include a hole  1118  extending from a side of the first inserter member  1110  through the opening  1114  and out the front of the inserter member  1110 . In addition, the first inserter member  1110  may include a coupling member  1120  extending out from the second end of the body  1112 . The coupling member  1120  may have a locking groove  1122  on a top surface of the coupling member  1120 . The coupling member  1120  may have, for example, a width and height that is smaller than the width and height of the body  1112 . The first inserter member  1110  may also include an insertion track  1124  for receiving a spinal implant spacer, as discussed in greater detail below with reference to  FIGS. 65-68 . The insertion track  1124  may be, for example, a groove set into a bottom surface of the body  1112  and extending from a first end out a side of the first inserter member  1110 . The insertion track  1124  may be, for example, a dovetail shaped groove to receive a correspondingly shaped spinal implant spacer. 
     The second inserter member  1130  may include a body  1132  with a first opening  1134  extending from a top surface through to a bottom surface, as shown in  FIGS. 55, 57, and 58 . The second inserter member  1130  may also include engagement protrusions  1136  extending out from the first end of the body  1132  for engaging a portion of a spinal implant. The second inserter member  1130  may further include a hole  1138  extending from a side of the second inserter member  1130  through the opening  1134  and out the front of the inserter member  1130 . In addition, the second inserter member  1130  may include a coupling member  1140  extending out from the second end of the body  1132 . The coupling member  1140  may have a locking groove  1142  on a bottom surface of the coupling member  1140 . The coupling member  1140  may have, for example, a width and height that is smaller than the width and height of the body  1132 . The second inserter member  1130  may also include an insertion track  1144  for receiving a spinal implant spacer, as discussed in greater detail below with reference to  FIGS. 65-68 . The insertion track  1144  may be, for example, a groove set into a top surface of the body  1132  and extending from a first end out a side of the second inserter member  1130 . The insertion track  1144  may be, for example, a dovetail shaped groove to receive a correspondingly shaped spinal implant spacer. 
     As shown in  FIGS. 69-70 , the inserter members  1110 ,  1130  may be angled from the longitudinal axis at an angle α. The angle α may, for example, range from approximately 0° to approximately 60° and more particularly may be 0°, 30°, 45°, 60°. The angle α may be selected to provide visualization of the patient&#39;s spine and for ease of insertion of the spinal implant. 
     The first arm  1150  of the distraction instrument  1000 , as shown in  FIGS. 57, 58, and 61 , may include a lever opening  1152  positioned near the first end of the first arm  1150  on a top surface. The lever opening  1152  may be sized and shaped to receive a lever  1170 . The first arm  1150  may also include an inserter member hole  1154  for receiving the coupling member  1120  of the first inserter member  1110 . In addition, the first arm  1150  may include a groove  1156  extending through the side of the first arm  1150  for coupling to a first end  1184  of the first member  1182 . The groove  1156  may be positioned, for example, near a center point of the first arm  1150 . The first arm  1150  may further include an opening  1158  near the second end of the first arm  1150  for coupling to the second end  1194  of the second member  1190  and the first handle  1210 . 
     The second arm  1160  of the distraction instrument  1000 , as shown in  FIGS. 57 and 58 , and the reverse of first arm  1150  in  FIG. 61 , may include a lever opening  1162  positioned near the first end of the second arm  1160  on a bottom surface. The lever opening  1162  may be sized and shaped to receive a lever  1170 . The second arm  1160  may also include an inserter member hole  1164  for receiving the coupling member  1140  of the second inserter member  1130 . In addition, the second arm  1160  may include a groove  1166  extending through the side of the second arm  1160  for coupling to a first end  1192  of the second member  1190 . The groove  1166  may be positioned, for example, near a center point of the second arm  1160 . The second arm  1160  may further include an opening  1168  near the second end for coupling to the second end  1186  of the first member  1182  and the second handle  1230 . 
     As shown in  FIGS. 49, 51, 53, 54, 57, and 58 , the distraction system  1180  of the distraction instrument  1000  may include the first member  1182 , the second member  1190 , and a center hinge pin  1200 . The first member  1182  may include a first end  1184 , a second end  1186 , and a center opening  1188 . The first end  1184  may include an opening for receiving a hinge pin  1198  for moveably coupling the first end  1184  of the first member  1182  to the groove  1156  of the first arm  1150 . The second end  1186  may include an opening for receiving a hinge pin  1198  for rotatably coupling the first member  1182  to the second end of the second arm  1160  and the first end of the second handle  1230 . The second member  1190  may include a first end  1192 , a second end  1194 , and a center opening  1196 . The first end  1192  may include an opening for receiving a hinge pin  1198  for moveably coupling the first end  1192  of the second member  1190  to the groove  1166  of the second arm  1160 . The second end  1194  may include an opening for receiving a hinge pin  1198  for rotatably coupling the second member  1190  to the second end of the first arm  1150  and the first end of the first handle  1210 . The center opening  1188  of the first member  1182  may be aligned with the center opening  1196  of the second member  1190  and the center hinge pin  1200  may rotatably couple the first member  1182  to the second member  1190 . 
     As shown in  FIGS. 48-54 and 56-58 , the first handle  1210  may include a body  1222  removeably coupled to a handle portion  1220 . The body  1222  may include an opening  1212  at a first end, a stop member channel  1214  near the first end, a lever opening  1216  near the second end, and a hinge member  1218  positioned near a center point of the body  1222 . As shown in  FIG. 54 , the body  1222  may also include an inserter member hole  1224  at the second end. The inserter member hole  1224  may extend into the lever opening  1216 . The handle portion  1220  may include a coupling member  1226  extending away from the first end of the handle portion  1220 . The coupling member  1226  may include a locking groove  1228  on a top surface. The coupling member  1226  may be inserted into the inserter member hole  1224  and extend into the lever opening  1216 . A lever  1250  may be coupled to the lever opening  1216  to secure the coupling member  1226  of the handle portion  1220  to the body  1222 . The lever  1250  may have a locking protrusion  1252  at a first end, a button  1254  at a second end, and a hinge member  1256  positioned near a center point of the lever  1250 . The locking protrusion  1252  may engage the locking groove  1228  of the coupling member  1226  to secure the handle portion  1220  to the body  1222 . The handle portion  1220  may be released from the body  1222  by depressing the button  1254 . 
     As shown in  FIGS. 48-54 and 56-58 , the second handle  1230  may include a body  1242  removeably coupled to a handle portion  1240 . As shown in  FIGS. 56 and 58 , the body  1242  may include an opening  1232  at a first end, a stop member channel  1234  near the first end, a lever opening  1236  near the second end, and a hinge member  1238  positioned near a center point of the body  1242 . As shown in  FIG. 54 , the body  1242  may also include an inserter member hole  1244  at the second end. The inserter member hole  1244  may extend into the lever opening  1236 . The handle portion  1240  may include a coupling member  1246  extending away from the first end of the handle portion  1240 . The coupling member  1246  may include a locking groove  1248  on a bottom surface. The coupling member  1246  may be inserted into the inserter member hole  1244  and extend into the lever opening  1236 . A lever  1250  may be coupled to the lever opening  1236  to secure the coupling member  1246  of the handle portion  1240  to the body  1242 . The lever  1250  may have a locking protrusion  1252  at a first end, a button  1254  at a second end, and a hinge member  1256  positioned near a center point of the lever  1250 . The locking protrusion  1252  may engage the locking groove  1248  of the coupling member  1246  to secure the handle portion  1240  to the body  1242 . The handle portion  1240  may be released from the body  1242  by depressing the button  1254 . 
     Alternative first and second handle portions  1220 ,  1240  are also contemplated. For example, as shown in  FIGS. 71-73 , the handle portions  1220 ,  1240  may come in multiple sizes with varying widths and heights. In addition, the handle portions  1220 ,  1240  may be, for example, angled along the longitudinal axis, as shown in  FIG. 73 . The handle portions  1220 ,  1240  may be, for example, angled in a range of approximately 0° to 90°. The handle portions  1220 ,  1240  may also come in multiple lengths, widths, and shapes. 
     As shown in  FIGS. 48-52 and 56 , the distraction instrument  1000  may be assembled by attaching the first body  1222  to the second body  1242  with a pin  1206 . The coupling portion  1204  of the stop member  1202  may be secured in the stop member channel  1234  and the stop member  1202  may extend through the stop member channel  1214 . The opening  1212  of the first body  1222  may be aligned with the opening  1158  of the first arm  1150  and the opening in the second end  1194  of the second member  1190 . A pin  1198  may be inserted through the openings to attach the first body  1222 , the first arm  1150 , and the second member  1190 . In addition, the opening  1232  of the second body  1242  may be aligned with the opening  1168  of the second arm  1160  and the opening in the second end  1186  of the first member  1182 . A pin  1198  may be inserted through the openings to attach the second body  1242 , the second arm  1160 , and the first member  1182 . The center opening  1188  of the first member  1182  is aligned with the center opening  1196  of the second member  1190 . Then, a center hinge pin  1200  is inserted into the openings  1188 ,  1196  to moveably couple the first member  1182  to the second member  1196 . 
     Next, with continued reference to  FIGS. 48-52 and 56 , the opening in the first end  1184  of the first member  1182  is aligned with the groove  1156  of the first arm  1150  and a pin  1198  may be used to moveably secure the first member  1182  to the first arm  1150 . The pin  1198  may translate within the groove  1156  to allow for the distraction instrument  1000  to expand. The opening in the first end  1192  of the second member  1190  is aligned with the groove  1166  of the second arm  1160  and a pin  1198  may be used to moveably secure the second member  1190  to the second arm  1160 . The pin  1198  may translate within the groove  1166  to allow for the distraction instrument  1000  to expand. In addition, a lever  1170  may be inserted into the lever opening  1152  in the first arm  1150  and a lever  1170  may be inserted into the lever opening  1162  in the second arm  1160 . In addition, a lever  1250  may be inserted into the lever opening  1216  in the first body  1222  and a lever  1250  may be inserted into the lever opening  1236  in the second body  1242 . The levers  1170 ,  1250  may be secured in the lever openings  1152 ,  1162 ,  1216 ,  1236  using pins, screws, rivets, or the like that allows the levers  1170 ,  1250  to move with respect to the lever openings  1152 ,  1162 ,  1216 ,  1316 . 
     Then, as shown in  FIGS. 57-58 and 69-70 , a spring  1128  may be inserted into the opening  1114  in the first inserter member  1110  and a threaded rod  1126  may be inserted through the hole  1118  and the spring  1128 . In addition, a spring  1148  may be inserted into the opening  1134  in the second inserter member  1130  and a threaded rod  1146  may be inserted through the hole  1138  and the spring  1148 . The threaded rods  1126 ,  1146  may engage a portion of a spinal implant, as shown in  FIGS. 62-68 . The springs  1128 ,  1148  may preload the threaded rods  1126 ,  1146  to enable the threaded rods  1126 ,  1146  to disengage from the spinal implants. Thus, once the threaded rods  1126 ,  1146  disengage from the spinal implants, the springs  1128 ,  1148  will cause the threaded rods  1126 ,  1146  to retract into the inserter members  1110 ,  1130  to fully disengage from the spinal implants. Referring now to  FIGS. 48-52 and 56 , the first inserter member  1110  may be coupled to the first arm  1150  by inserting the coupling member  1120  into the inserter member hole  1154 . The locking protrusion  1172  may engage the locking groove  1122  to secure the first inserter member  1110  to the first arm  1150 . The second inserter member  1130  may be coupled to the second arm  1160  by inserting the coupling member  1140  into the inserter member hole  1164 . The locking protrusion  1172  may engage the locking groove  1142  to secure the second inserter member  1130  to the second arm  1160 . The first handle portion  1220  may be coupled to the first body  1222  by inserting the coupling member  1226  into the inserter member hole  1224 . The locking protrusion  1252  may engage the locking groove  1228  to secure the handle portion  1220  to the first body  1222 . The second handle portion  1240  may be coupled to the second body  1242  by inserting the coupling member  1246  into the inserter member hole  1244 . The locking protrusion  1252  may engage the locking groove  1248  to secure the handle portion  1240  to the second body  1242 . 
     An alternative stop member  1202  is shown in  FIGS. 74-75 . The alternative stop member  1202  may be a ratcheting mechanism  1260 . The ratcheting mechanism  1260  may include, for example, a lever arm  1262 , a tooth member  1264  for engaging the lever arm  1262 , and a toothed clutch  1266  to assist with maintaining the position of the inserter members  1110 ,  1130  after expansion and distraction of the patient&#39;s spine. 
     Referring now to  FIGS. 76 and 77 , a locking driver instrument  1400  for locking the spacer  1350  in position between the first and second portions  1320 ,  1340  of the spinal implant  1300  is shown. The locking driver instrument  1400  may include a shaft  1402  with a handle  1410  at a first end  1404  and a driver tip  1412  at a second end  1406 . The shaft  1402  may have, for example, a length to enable insertion of the spacer  1350  through the distraction instrument  1000  and into position between the first and second portions  1320 ,  1340  of the spinal implant  1300 . The driver tip  1412  may be shaped to engage the locking member  1380 , as shown in  FIG. 68 , in the spacer  1350 . The driver tip  1412  may have a cross-section with, for example, a hexagonal shape, a polygonal shape, or other shape that corresponds to the shape of the opening in the locking member  1380 . After the driver tip  1412  is inserted into the locking member  1380 , the handle  1410  of the locking driver instrument  1400  may be rotated to secure the spacer  1350  in position between the first and second portions  1320 ,  1340 . Alternatively, the handle  1410  of the locking driver instrument  1400  may be rotated in the opposite direction to disengage the locking member  1380  and release the spacer  1350  from the first and second portions  1320 ,  1340 , for example, to replace the spacer  1350  or the entire spinal implant  1300 . 
     A threaded rod driver instrument  1420  is shown in  FIGS. 78 and 79 . The threaded rod driver instrument  1420  may be used to secure the threaded rods  1126 ,  1146  of the distraction instrument  1000  to the spinal implant  1300 , as shown in  FIGS. 66 and 68 . The threaded rod driver instrument  1420  may include a shaft  1422  with a handle  1430  at a first end  1424  and a driver tip  1432  at a second end  1426 . The shaft  1422  may have, for example, a length to enable insertion into the patient during surgery to disengage the threaded rods  1126 ,  1146  from the first and second portions  1320 ,  1340  of the spinal implant  1300 . The driver tip  1432  may be shaped to engage the head of the threaded rods  1126 ,  1146 . The driver tip  1432  may have a cross-section with, for example, a hexagonal shape, a polygonal shape, or other shape that corresponds to the shape of the opening in the head of the threaded rods  1126 ,  1146 . The driver tip  1432  may also have a curved or rounded end to, for example, allow for insertion into the head of the threaded rods  1126 ,  1146  at multiple angles. The driver tip  1432  may be inserted into the heads of the threaded rods  1126 ,  1146  and the handle  1430  rotated in a first direction to engage the first and second portions  1320 ,  1340  of the spinal implant  1300  to secure the first and second portions  1320 ,  1340  to the distraction instrument  1000 . Once the spinal implant  1300  is inserted between the patient&#39;s vertebrae, the driver tip  1432  of the threaded rod driver instrument  1420  may be inserted into each of the heads of the threaded rods  1126 ,  1146 . The handle  1430  of the driver instrument  1420  may then be rotated in a second direction to disengage the threaded end of the threaded rods  1126 ,  1146  from the first and second portions  1320 ,  1340  of the spinal implant  1300 . 
     Referring now to  FIGS. 80 and 81 , a vertebral body replacement system  1500  including the distraction instrument  1000 , the spinal implant  1300 , the spacer inserter  1360 , the locking driver instrument  1400 , and the threaded rod driver instrument  1420  is shown. The distraction instrument  1000 , the spinal implant  1300 , the spacer inserter  1360 , the locking driver instrument  1400 , and the threaded rod driver instrument  1420  are as described above with reference to  FIGS. 48-79 . 
     Referring now to  FIGS. 62-68 , a method of inserting a spinal implant  1300  is shown. The spinal implant  1300  may include a first end plate  1310 , a first portion  1320 , a second end plate  1330 , a second portion  1340 , and a spacer  1350 . Although not shown, it is also contemplated that the implant  1300  may include, for example, the first portion  1320 , the second portion  1340 , and the spacer  1350 . In the alternative embodiment, a first end of the first portion  1320  and a second end of the second portion  1340  may have a bone contacting surface with, for example, a coating or textured surface to allow for bone ingrowth or ongrowth. The first end plate  1310  may couple to the first portion  1320  and the second end plate  1330  may couple to the second portion  1340 . The distraction instrument  1000  may engage the first and second portions  1320 ,  1340  of the spinal implant  1300 . The first portion  1320  may include grooves (not shown) to engage the protrusions  1116  of the first inserter member  1110  for insertion of the spinal implant. Once the first portion  1320  engages the protrusions  1116 , the threaded rod  1126  may be inserted into the first portion  1320  with the threaded rod driver instrument  1420 . The second portion  1340  may also include grooves (not shown) to engage the protrusions  1136  of the second inserter member  1130  for insertion of the spinal implant. Once the second portion  1340  engages the protrusions  1136 , the threaded rod  1146  may be inserted into the second portion  1340  with the threaded rod driver instrument  1420 . After the first and second portions  1320 ,  1340  are coupled to the distraction instrument  1000 , the spinal implant  1300  may be inserted into a patient&#39;s spine. When the spinal implant  1300  is positioned in the desired position, the spinal implant  1300  may be expanded to realign the patient&#39;s spine. The inserter members  1110 ,  1130  may be expanded by squeezing the handle portions  1220 ,  1240 . As the handle portions  1220 ,  1240  are squeezed the inserter members  1110 ,  1130  expand away from each other, separating the first and second portions  1320 ,  1340  of the spinal implant  1300 , as shown in  FIGS. 64-66 . The stop member  1202  maintains the expanded position of the inserter members  1110 ,  1130  and the first and second portions  1320 ,  1340  while the spacer  1350  is inserted between the first and second portions  1320 ,  1340 . 
     After the first and second portions  1320 ,  1340  are in the desired position, the size of the space between the first and second portions  1320 ,  1340  may be measured and a spacer  1350  may be selected. The spacer  1350  may be coupled to a spacer inserter  1360 , as shown in  FIGS. 65-67 . The spacer inserter  1360  may include a handle  1362  with an actuation mechanism (not shown). The actuation mechanism may be configured to enable the engagement shaft  1364  to be secured in a first position wherein an implant spacer member  1350  is secured to the proximal end  1366  of the engagement shaft  1364  for insertion into a patient. Then upon actuation of the actuation mechanism (not shown), the handle  1362  is released and free to move in a longitudinal direction along the shaft  1364 . Once the handle  1362  is released, the surgeon may use the handle  1362  as a slide or slap hammer to facilitate tapping of the spacer member  1350  through the tracks  1124 ,  1144  in the first and second members  1320 ,  1340 . Once in the desired position, the spacer inserter  1360  may be removed leaving an intermediate spacer member  1350  of the implant  1300  in the patient. The spacer inserter  1360  may also include an alignment head  1368  for alignment of the intermediate spacer member  1350  on the spacer inserter  1360  for insertion into the patient. The spacer inserter  1360  may further include a movable housing  1370  with a coupled tab  1372  to assist in the alignment and insertion of the intermediate spacer member  1350  between the first and second inserter members  1110 ,  1130  of the distraction mechanism  1000 . The spacer inserter  1360  may also include an engagement member  1374  positioned on the housing  1370 . The tab  1372  may be axially translated toward the center spacer  1350 . The housing  1370  may be actuated by the tab  1372  to engage the spacer  1350 . As the tab  1372  is moved forward the housing  1370  slides forward and causes the arms of the alignment head  1368  to move closer together to engage the spacer  1350 . The arms of the alignment head  1368  clamp onto the spacer  1350  during insertion. Once the spacer  1350  is inserted between the first and second members  1320 ,  1340  of the implant  1300 , the tab  1372  may be moved in a rearward direction towards the handle  1362  moving the housing  1370  towards the handle  1362  and releasing the arms of the alignment head  1368 . After the arms of the alignment head  1368  disengage from the spacer  1350 , the spacer inserter  1360  may be removed from the patient. The engagement member  1374  remains static as the tab  1372  is translated and assists with preventing the tab  1372  and the housing  1370  from rotating. In addition, the engagement member  1374  may act as a positive stop for the handle  1362  when translated to assist with the insertion of the center spacer  1350 . The handle  1362  may translate on the engagement shaft  1364  when the button  304 , such as shown in  FIGS. 23-24 , is depressed, to move the center spacer  1350  through the insertion tracks  1124 ,  1144 . If there is excessive friction between the center spacer  1350  and the insertion tracks  1124 ,  1144  which makes it difficult to push the center spacer  1350  by hand, then the handle  1362  may be tamped by, for example, a slap hammer (not shown) to overcome the friction and move the center spacer  1350  into position between the first and second portions  1320 ,  1340 . The spacer inserter  1360  may further include an end portion  1376  coupled to the engagement shaft  1364 , which may be the point of contact when tamping is necessary. 
     The intermediate spacer  1350  may be of the type described above with reference to implant  400 . The intermediate spacer  1350  may include a first end and a second end. The intermediate spacer  1350  may include a coupling mechanism  1352  for engaging the first member  1320  on the first end and a coupling mechanism  1354  for engaging the second member  1340  on the second end. The coupling mechanisms  1352 ,  1354  may be, for example, the male portions of a dovetail mechanism. The intermediate spacer  1350  may also include at least one instrument coupling mechanism (not shown) on a side of the exterior surface of the intermediate spacer  1350 . The instrument coupling mechanisms  1356  may be, for example, grooves or channels on the exterior side surfaces of the spacer  1350 . The grooves  1356  are sized and shaped to engage the alignment head  1368  of the spacer inserter  1360 . 
     The spacer  1350  may further include a locking member  1380 , as shown in  FIG. 68 , on the front for securing the spacer  1350  within the spinal implant  1300 . The locking member  1380  may have, for example, a permanently integral member (not shown) or alternatively, a removable member (not shown). The locking member  1380  may be used to secure or lock the spacer  1350  to the first and second members  1320 ,  1340 , once the spacer  1350  is fully inserted between the first and second members  1320 ,  1340 . In addition, the spacer  1350  may include a gap or channel  1358  on the back of the spacer  1350  to allow for slight deflection of the spacer  1350  during insertion between the first and second members  1320 ,  1340 . 
     After the spacer  1350  is selected and coupled to the spacer inserter  1360 , the coupling mechanism  1352  may be aligned with the spacer insertion track  1124  and the coupling mechanism  1354  may be aligned with the spacer insertion track  1144 . The spacer  1350  may be slid along the tracks  1124 ,  1144  and into engagement with the first and second members  1320 ,  1340 , as shown in  FIGS. 67-68 . Once the spacer  1350  is positioned between the first and second members  1320 ,  1340 , the locking driver instrument  1400  may be inserted through the center cannulation of the spacer inserter  1360  to engage the locking member  1380  in the spacer  1350 , as shown in  FIG. 80 . The locking member  1380  may then be rotated to expand the locking member  1380 , for example, a wedge piece, and engage the spacer  1350  causing the gap  1358  to expand or increase. As the locking member  1380  expands the gap  1358 , the spacer  1350  is mechanically locked to the first and second members  1320 ,  1340  by increasing the friction between the coupling mechanisms  1352 ,  1354  of the spacer  1350  and the tracks  1124 ,  1144  of the first and second members  1320 ,  1340 . A locking mechanism, for example, a fastener (not shown), a button such as button  424 ,  426  as described in greater detail above, or the like, may be activated to secure the spacer  1350  to the first and second members  1320 ,  1340 . Next, the threaded rods  1126 ,  1146  may be disengaged from the first and second implant members  1320 ,  1340  using the threaded rod driver instrument  1420  and the distraction instrument  1000  may be removed from the patient. Finally, the patient&#39;s incision may be closed. 
     Referring now to  FIGS. 82-86 , another distraction instrument  2000  is shown. The distraction instrument  2000  may include a first inserter member  2110  and second inserter member  2130  at a first end  2102 . The distraction instrument  2000  may also include a first arm  2150  coupled to the first inserter member  2110  and second arm  2160  coupled to the second inserter member  2130 . The distraction instrument  2000  may further include a distraction system  2180  engaging the first and second arms  2150 ,  2160 . In addition, the distraction instrument  2000  may include a first handle  2210  and a second handle  2230  at the second end  2104 . The first handle  2210  may be coupled to the second end of the first arm  2150  and the second member  2190  and the second handle  2230  may be coupled to the second end of the second arm  2160  and the first member  2182 . The distraction instrument  2000  may also include a ratcheting mechanism  2300  positioned to engage the first and second handles  2210 ,  2230  to hold the distraction instrument  2000  in the expanded position. 
     As shown in  FIG. 86 , the first inserter member  2110  may be of the type described above with reference to the first inserter member  1110 . The first inserter member  2110  may include a body  2112  with a first opening  2114 , engagement protrusions  2116 , a hole  2118 , a coupling member  2120  with a locking groove  2122 , and an insertion track  2124 , which may be of the type described above with reference to the body  2112  with the first opening  2114 , the engagement protrusions  2116 , the hole  2118 , the coupling member  2120  with the locking groove  2122 , and the insertion track  2124  and which will not be described again here for brevity sake. 
     The second inserter member  2130  may be of the type described above with reference to the second inserter member  1130 . The second inserter member  2130  may include a body  2132  with a first opening  2134 , engagement protrusions  2136 , a hole  2138 , a coupling member  2140  with a locking groove  2142 , and an insertion track  2144 , which may be of the type described above with reference to the body  2132  with the first opening  2134 , the engagement protrusions  2136 , the hole  2138 , the coupling member  2140  with the locking groove  2142 , and the insertion track  2144  and which will not be described again here for brevity sake. 
     The first arm  2150  of the distraction instrument  2000 , as shown in  FIGS. 83, 84, and 86 , may include an opening  2152  positioned near the first end of the first arm  2150  extending into a top surface. The opening  2152  may be sized and shaped to receive a securement member  2170 . The first arm  2150  may also include an inserter member hole  2154  for receiving the coupling member  2120  of the first inserter member  2110 . In addition, the first arm  2150  may include a groove  2156  extending through the side of the first arm  2150  for coupling to a first end  2184  of the first member  2182 . The groove  2156  may be positioned, for example, near the first end of the first arm  2150 . The first arm  2150  may further include an opening  2158  near the second end of the first arm  2150  for coupling to the second end  2194  of the second member  2190  and the first handle  2210 . 
     The second arm  2160  of the distraction instrument  2000 , as shown in  FIGS. 83, 84, and 86 , may include an opening  2162  positioned near the first end of the second arm  2160  extending into a bottom surface. The opening  2162  may be sized and shaped to receive a securement member  2170 . The second arm  2160  may also include an inserter member hole  2164  for receiving the coupling member  2140  of the second inserter member  2130 . In addition, the second arm  2160  may include a groove  2166  extending through the side of the second arm  2160  for coupling to a first end  2192  of the second member  2190 . The groove  2166  may be positioned, for example, near the first end of the second arm  2160 . The second arm  2160  may further include an opening  2168  near the second end for coupling to the second end  2186  of the first member  2182  and the second handle  2230 . 
     As shown in  FIG. 86 , the distraction system  2180  of the distraction instrument  2000  may include the first member  2182  and the second member  2190 . The first member  2182  may include a first end  2184 , a second end  2186 , and a center opening  2188 . The first end  2184  may include an opening for receiving a hinge pin  2198  for moveably coupling the first end  2184  of the first member  2182  to the groove  2156  of the first arm  2150 . The second end  2186  may include an opening for receiving a hinge pin  2198  for rotatably coupling the first member  2182  to the second end of the second arm  2160  and the first end of the second handle  2230 . The second member  2190  may include a first end  2192 , a second end  2194 , and a center opening  2196 . The first end  2192  may include an opening for receiving a hinge pin  2198  for moveably coupling the first end  2192  of the second member  2190  to the groove  2166  of the second arm  2160 . The second end  2194  may include an opening for receiving a hinge pin  2198  for rotatably coupling the second member  2190  to the second end of the first arm  2150  and the first end of the first handle  2210 . The center opening  2188  of the first member  2182  may be aligned with the center opening  2196  of the second member  2190  and the center hinge pin  2200  may rotatably couple the first member  2182  to the second member  2190 . 
     As shown in  FIG. 86 , the first handle  2210  may include a body  2222  removeably coupled to a handle portion  2220 . The body  2222  may include an opening  2212  at a first end, a ratchet member opening  2214  near the second end, an opening  2216  at a second end, and a hinge member  2218  positioned between the first end and the second end of the body  2222 . The body  2222  may also include an inserter member hole  2224  at the second end. The inserter member hole  2224  may extend into the opening  2216 . The handle portion  2220  may include a coupling member  2226  extending away from the first end of the handle portion  2220 . The coupling member  2226  may include a locking groove  2228  on a top surface. The coupling member  2226  may be inserted into the inserter member hole  2224  and extend into the opening  2216 . A securement member  2250  may be coupled to the opening  2216  to secure the coupling member  2226  of the handle portion  2220  to the body  2222 . The securement member  2250  may have a locking protrusion  2252 . The locking protrusion  2252  may engage the locking groove  2228  of the coupling member  2226  to secure the handle portion  2220  to the body  2222 . The handle portion  2220  may be released from the body  2222  by releasing the securement member  2250 . 
     The second handle  2230  may include a body  2242  removeably coupled to a handle portion  2240 . As shown in  FIG. 86 , the body  2242  may include an opening  2232  at a first end, a ratchet member opening  2234  near the second end, an opening  2236  at a second end, and a hinge member  2238  positioned between the first end and the second end of the body  2242 . The body  2242  may also include an inserter member hole  2244  at the second end. The inserter member hole  2244  may extend into the opening  2236 . The handle portion  2240  may include a coupling member  2246  extending away from the first end of the handle portion  2240 . The coupling member  2246  may include a locking groove  2248  on a bottom surface. The coupling member  2246  may be inserted into the inserter member hole  2244  and extend into the opening  2236 . A securement member  2250  may be coupled to the opening  2236  to secure the coupling member  2246  of the handle portion  2240  to the body  2242 . The securement member  2250  may have a locking protrusion  2252 . The locking protrusion  2252  may engage the locking groove  2248  of the coupling member  2246  to secure the handle portion  2240  to the body  2242 . The handle portion  2240  may be released from the body  2242  by releasing the securement member  2250 . 
     Although the first and second handle portions  2220 ,  2240  are shown as curved handle portions  2220 ,  2240 , alternative first and second handle portions  2220 ,  2240  are also contemplated. For example, as shown in  FIGS. 58 and 71-73 , the handle portions  2220 ,  2240  may come in multiple sizes with varying widths and heights. In addition, the handle portions  2220 ,  2240  may be, for example, angled along the longitudinal axis, as shown in  FIG. 73 . The handle portions  2220 ,  2240  may be, for example, angled in a range of approximately 0° to 90°. The handle portions  2220 ,  2240  may also come in multiple lengths, widths, and shapes. 
     With continued reference to  FIGS. 82-86 , the distraction instrument  2000  may also include a ratcheting mechanism  2300 . The ratcheting mechanism  2300  may include, for example, a ratcheting bar  2302  and a lever member  2310 . The ratcheting bar  2302  may include, for example, a coupling end  2304  for attachment to the second handle  2230  and teeth  2306  along at least one side of the ratcheting bar  2302  for engaging the lever member  2310 . The ratcheting bar  2302  may be, for example, a curved or straight bar. The ratcheting bar  2302  may be secured to the second handle  2230  by, for example, pins  2308 . 
     As shown in  FIG. 86 , the lever member  2310  may include, for example, a base  2312  and an engagement portion  2320 . The base  2312  and engagement portion  2320  may be, for example, integral or separate components. The base  2312  may include, for example, a handle member  2314  for advancing the engagement portion  2320  along the teeth  2306  of the ratcheting bar  2302 . The lever member  2310  may also include a spring member  2316  to, for example, retain the ratcheting mechanism  2300  in the desired position along the ratcheting bar  2302 . The engagement portion  2320  may include at least one tooth  2322  on at least one side of the engagement portion  2320 . The at least one tooth  2322  may be sized and shaped to engage the plurality of teeth  2306  of the ratcheting bar  2302 . The lever member  2310  may be moveably coupled to the first handle  2210  by, for example, pins  2324 . The lever member  2310  may be positioned, for example, within the ratchet member opening  2214 . 
     The locking driver instrument  1400 , as shown in  FIGS. 76 and 77  and discussed above, may be used with the distraction instrument  2000  for locking the spacer  1350  in position between the first and second portions  1320 ,  1340  of the spinal implant  1300 . The threaded rod driver instrument  1420 , as shown in  FIGS. 78 and 79  and described in greater detail above, may also be used with the distraction instrument  2000  to secure the threaded rods  2126 ,  2146  of the distraction instrument  2000  to the spinal implant  1300 . 
     As shown in  FIGS. 82-85 , the distraction instrument  2000  may be assembled by attaching the first body  2222  to the second body  2242  with a pin  2206 . A spring member  2208  may be positioned, for example, around the pin  2206  and positioned to engage the first and second bodies  2222 ,  2242 . The lever member  2310  may be coupled to the body  2222  of the first handle  2210  and the ratcheting bar  2302  may be coupled to the body  2242  of the second handle  2230 . The opening  2212  of the body  2222  may be aligned with the opening  2158  of the first arm  2150  and the opening in the second end  2194  of the second member  2190 . A pin  2198  may be inserted through the opening  2212 , opening  2158 , and the opening in the second end  2194  to attach the first body  2222 , the first arm  2150 , and the second member  2190 . In addition, the opening  2232  of the second body  2242  may be aligned with the opening  2168  of the second arm  2160  and the opening in the second end  2186  of the first member  2182 . A pin  2198  may be inserted through the opening  2232 , the opening  2168  and the opening in the second end  2186  to attach the second body  2242 , the second arm  2160 , and the first member  2182 . The center opening  2188  of the first member  2182  may be aligned with the center opening  2196  of the second member  2190 . Then, a center hinge pin  2200  is inserted into the openings  2188 ,  2196  to moveably couple the first member  2182  to the second member  2196 . 
     Next, with continued reference to  FIGS. 82-85 , the opening in the first end  2184  of the first member  2182  is aligned with the groove  2156  of the first arm  2150  and a pin  2198  may be used to moveably secure the first member  2182  to the first arm  2150 . The pin  2198  may translate within the groove  2156  to allow for the distraction instrument  2000  to expand. The opening in the first end  2192  of the second member  2190  may be aligned with the groove  2166  of the second arm  2160  and a pin  2198  may be used to moveably secure the second member  2190  to the second arm  2160 . The pin  2198  may translate within the groove  2166  to allow for the distraction instrument  2000  to expand. In addition, a securement member  2170  may be inserted into the opening  2152  in the first arm  2150  and a securement member  2170  may be inserted into the opening  2162  in the second arm  2160 . In addition, a securement member  2250  may be inserted into the opening  2216  in the first body  2222  and a securement member  2250  may be inserted into the opening  2236  in the second body  2242 . The securement members  2170 ,  2250  may be secured in the openings  2152 ,  2162 ,  2216 ,  2236  using fasteners  2174 ,  2254 , for example, pins, screws, rivets, or the like, that allows the securement members  2170 ,  2250  to move with respect to the openings  2152 ,  2162 ,  2216 ,  2316 . 
     Then, as discussed in greater detail above with reference to distraction instrument  1000 , which will not be described again here for brevity sake, the spring  2128  and the threaded rod  2126  may be inserted into the opening  2114  in the first inserter member  2110  and the spring  2148  and threaded rod  2146  may be inserted into the opening  2134  in the second inserter member  2130 . The springs  2128 ,  2148  and threaded rods  2126 ,  2146  may be of the type described above with reference to springs  1128 ,  1148  and threaded rods  1126 ,  1146 , respectively. The threaded rods  2126 ,  2146  may engage a portion of a spinal implant, such as implant  400 ,  1300 . 
     The first inserter member  2110  may be coupled to the first arm  2150  by inserting the coupling member  2120  into the inserter member hole  2154 . The locking protrusion  2172  may engage the locking groove  2122  to secure the first inserter member  2110  to the first arm  2150 . The second inserter member  2130  may be coupled to the second arm  2160  by inserting the coupling member  2140  into the inserter member hole  2164 . The locking protrusion  2172  may engage the locking groove  2142  to secure the second inserter member  2130  to the second arm  2160 . The first handle portion  2220  may be coupled to the first body  2222  by inserting the coupling member  2226  into the inserter member hole  2224 . The locking protrusion  2252  may engage the locking groove  2228  to secure the handle portion  2220  to the first body  2222 . The second handle portion  2240  may be coupled to the second body  2242  by inserting the coupling member  2246  into the inserter member hole  2244 . The locking protrusion  2252  may engage the locking groove  2248  to secure the handle portion  2240  to the second body  2242 . 
     The distraction instrument  2000  may be used in place of distraction instrument  1000  for inserting a spinal implant  1300  as described in reference to the method of use described in greater detail above with reference to  FIGS. 62-68 . When the distraction instrument  2000  is used, the ratcheting mechanism  2300  maintains the expanded position of the inserter members  2110 ,  2130  and the first and second portions  1320 ,  1340  while the spacer  1350  is inserted between the first and second portions  1320 ,  1340 . 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has”, and “having”), “include” (and any form of include, such as “includes” and “including”), and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method or device that “comprises,” “has,” “includes,” or “contains” one or more steps or elements possesses those one or more steps or elements, but is not limited to possessing only those one or more steps or elements. Likewise, a step of a method or an element of a device that “comprises,” “has,” “includes,” or “contains” one or more features possesses those one or more features, but is not limited to possessing only those one or more features. Furthermore, a device or structure that is configured in a certain way is configured in at least that way, but may also be configured in ways that are not listed. 
     The invention has been depicted and described with reference to example embodiments. It will be understood that the architectural and operational embodiments described herein are exemplary of a plurality of possible arrangements to provide the same general features, characteristics, and general system operation. Modifications, substitutions, and alterations will occur to others upon a reading and understanding of the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations and therefore these changes be considered to be within the scope of the following claims.