Abstract:
An orthopedic implant system includes an intervertebral implant. The implant includes a body having an upper surface extending generally in a first plane. The upper surface has a first plurality of longitudinal grooves and a second plurality of transverse grooves extending therealong. Portions of the upper surface extend between adjacent longitudinal grooves and transverse grooves form individual peaks. A lower surface extends generally in a second plane, parallel to the first plane. The lower surface has a third plurality of longitudinal grooves and a fourth plurality of transverse grooves extending therealong. Portions of the lower surface extend between adjacent longitudinal grooves and transverse grooves form individual peaks.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority from U.S. Provisional Patent Application Ser. No. 61/715,891, filed on Oct. 19, 2012, which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to an orthopedic systems for treatment of the spine specifically intervertebral implants, containing mechanism to rigidly attach to the vertebrae and systems for full lot control traceability. 
       BACKGROUND OF THE INVENTION 
       [0003]    Anterior intervertebral interbody fusion is a common technique for treating degenerative disc disease and major deformity. The anterior approach is common for both the cervical (ACIF) and lumbar (ALIF) spine. The approach allows full visibility of the disc and fusion site, while minimizing disruptions to the branch nerves of the spinal column as well as major trauma to the posterior musculature. Typical intervertebral fusion consists of an interbody spacer and a fixation means, such as anterior plate or posterior pedicle screws. An objective of the interbody spacer is to maintain the height of the intervertebral space, but allow for bone to grow through the interbody spacer to form a fused mass between vertebrae. 
         [0004]    Typically the interbody spacers are constructed from inert biocompatible material such as titanium or polyether-ether-ketone (PEEK). Titanium is typically used in orthopedic systems due to its strength and osteoconductive properties. However, in intervertebral spacers, titanium is not the preferred choice due to its high stiffness compared with bone. The large stiffness differential between bone and titanium has caused a high incidence of subsidence of the implant into the vertebral body. This has led the way for other biomaterials being selected for the spacer&#39;s body material. PEEK is a common interbody material selected because the Young&#39;s Modulus is extremely similar to bone and the material is extremely inert. However, PEEK is not an osteoconductive material and a large central oval cavity is the only space designed for bone through growth, thus the spacers remove a larger percentage of the fusion area. 
         [0005]    Current orthopedic systems used to treat conditions in the anterior spine have started to incorporate plate fixation directly to the interbody (see, for example, US2009/0182430). These systems typically utilize specifically designed plates to interbody connections and do not give a large amount of flexibility in the operating room for the end user to interoperatively switch between a standalone interbody and an isolated interbody. In addition, the interbodies used in the standalone assemblies are constructed of the same inert material and do not allow for bone ingrowth to occur. The lack of fusion area increases the strength of the fixation required to maintain the construct rigidity during healing. 
         [0006]    In July 2012, the United States (US) Food and Drug Administration (FDA) announced it was in the process of enacting rules to meet the congressional mandate for every medical device to contain a Unique Device Identification (UDI), such as lot number and part numbers. The US mandate requires every permanently implantable medical device to contain full traceability from manufacturer through distribution. This includes small devices that lack sufficient surface area to contain a distinguishable UDI. Typically, only sterile products have the ability to include a traceability sticker or manual lot recording is required for non-sterile products. 
       BRIEF SUMMARY OF INVENTION 
       [0007]    In accordance with one exemplary embodiment of invention, an intervertebral implant includes an upper surface generally conforming to a plane and lower surface generally conforming to a plane. A series of longitudinal grooves located on both upper and lower planes and a series of transverse grooves form a peak. A generally centrally located cavity pierces the upper and lower planes and surfaces. The implant further contains the means to contain a permanent osteoconductive material on all peaks on both the upper and lower planes. 
         [0008]    In a second exemplary embodiment of the invention, an intervertebral implant includes an upper surface generally conforming to a plane and lower surface generally conforming to a plane. A centrally located threaded aperture for adaption to an insertion instrument. A second centrally located recess is configured in a rectangular shape to prevent rotation of mating mechanisms. 
         [0009]    In a third exemplary embodiment of the invention, an insertion instrument includes a handle attached a hollow cylindrical tube attached to an engagement end. The engagement end contains a fastener for securing to an implant which can be activated by activating a cam. The engagement end containing a positive stop for controlling the depth and distance of the implant. 
         [0010]    In a fourth exemplary embodiment of the invention, an implant includes a plate designed to cooperatively attach to the intervertebral implant with an engagement mechanism. The engagement mechanism having a generally rectangular shape is located on the posterior plane of the implant and extending from the plane. A locking screw is designed to cooperatively attach to the plate implant and secure the intervertebral implant to a fixed position. 
         [0011]    In a fifth exemplary embodiment of the invention, an implant includes a plate, adaptable to an intervertebral implant, and bone screws, where the bone screws contain cantilever segments. The cantilever segments deform during insertion of the bone screws into a recess. The recess generally containing a cylindrical section, an undercut and a round seat, with the undercut preventing the cantilever segments from backing out after insertion. 
         [0012]    In a sixth exemplary embodiment of the invention, a removable implant body extension contains descriptive information regarding the implant. The descriptive information contains lot number and/or serial number of the connected implant, allowing removal of the body extension to aid in tracing the implant. The removable body extension is adaptable for single cycle sterilization or multiple cycle sterilization. 
         [0013]    In a seventh exemplary embodiment of the invention, a bone screw contains a distal thread and a proximal thread connected by a shaft. Where the distal thread contains a distal pitch and the proximal screw contains a proximal pitch with the distal pitch being greater than the proximal pitch. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Other aspects, features, and advantages of the present invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings in which like reference numerals identify similar or identical elements. 
           [0015]      FIG. 1  is a perspective view of an intervertebral implant in accordance with one exemplary embodiment of the invention; 
           [0016]      FIG. 2  is a top view of the implant of  FIG. 1 ; 
           [0017]      FIG. 3  is a front view of the implant of  FIG. 1 ; 
           [0018]      FIG. 4  is a side view of the implant of  FIG. 1 ; 
           [0019]      FIG. 5  is a rear view of the implant of  FIG. 1 ; 
           [0020]      FIG. 6  is a cross section view of the intervertebral implant of  FIG. 1 , showing a hole configuration; 
           [0021]      FIG. 7  is a side view of the implant of  FIG. 1  with a first alternative exemplary type of surface; 
           [0022]      FIG. 8  is a side view of the implant of  FIG. 1  with a second alternative exemplary type of surface; 
           [0023]      FIG. 9  is a micrograph showing distribution of titanium on a PEEK substrate, providing an illustrative exemplary composition of the invention; 
           [0024]      FIG. 10  is a perspective view of an alternative exemplary embodiment view of an insertion instrument; 
           [0025]      FIG. 11  is an enlarged perspective view of an insertion instrument of  FIG. 10 , engagement end; 
           [0026]      FIG. 12(   a ) is a cross section view of the insertion instrument of  FIG. 10 , showing the attachment mechanism; 
           [0027]      FIG. 12(   b ) is an enlarged truncated cross section view of the insertion instrument implant attachment of  FIG. 10 ; 
           [0028]      FIG. 13  is an enlarged axial view of the insertion instrument of  FIG. 10 , showing visualization of the alignment features; 
           [0029]      FIG. 14  is a top of view of the insertion instrument of  FIG. 10 ; 
           [0030]      FIG. 15  is a perspective view of a plate for attachment to an intervertebral implant of  FIG. 1 , in accordance with one exemplary embodiment of the invention; 
           [0031]      FIG. 16  is a side view of the implant of  FIG. 15 ; 
           [0032]      FIG. 17  is a perspective view of a plate&#39;s posterior side showing rectangular connection of the plate shown in  FIG. 15 ; 
           [0033]      FIG. 18  is a perspective view of the plate shown in  FIG. 15 , attached to intervertebral implant of  FIG. 1 , with attachment mechanism; 
           [0034]      FIG. 19  is a side cross section view of the plate and intervertebral implant assembly of  FIG. 18 , showing connection means; 
           [0035]      FIG. 20  is a top cross section view of the plate and intervertebral implant assembly of  FIG. 18 , showing connection means; 
           [0036]      FIG. 21  is a perspective view of a fully configured plate and intervertebral implant, shown in  FIG. 18 , with bone screws, in accordance with another exemplary embodiment of the invention; 
           [0037]      FIG. 22  is a side view of the fully configured plate and intervertebral implant assembly of  FIG. 21 ; 
           [0038]      FIG. 23  is a perspective view of a fifth exemplary embodiment, showing a bone screw with cantilever segments; 
           [0039]      FIG. 24  is a truncated cross section view of the bone screw shown in  FIG. 23 , inserted into the plate shown in  FIG. 15 , in a non-locked state; 
           [0040]      FIG. 25  is a truncated cross section view of the bone screw of  FIG. 23 , inserted into the plate shown in  FIG. 15 , in a locked state; 
           [0041]      FIG. 26  is a perspective view of a sixth exemplary embodiment, showing a bone screw with removable body extension; 
           [0042]      FIG. 27(   a ) is a side view of a bone screw with removal body extension shown in  FIG. 26 , showing descriptive information; 
           [0043]      FIG. 27(   b ) is a further rotated side view of a bone screw with removal body extension shown in  FIG. 26 , showing descriptive information; 
           [0044]      FIG. 28  is a cross section view of bone screw with removal body extension shown in  FIG. 26 ; 
           [0045]      FIG. 29  is a side view of a removal body extension showing descriptive information; 
           [0046]      FIG. 30  is a perspective view showing the removable body extension of  FIG. 29 , attached to the plate shown in  FIG. 15 ; 
           [0047]      FIG. 31  is a perspective view of a sixth exemplary embodiment, showing a bone screw; 
           [0048]      FIG. 32  is another perspective view of the bone screw shown in  FIG. 31 ; 
           [0049]      FIG. 33  is another side view of the showing a bone screw shown in  FIG. 31 ; 
           [0050]      FIG. 34  is a top view showing the bone screw of  FIG. 31 ; 
           [0051]      FIG. 35  is a cross sectional view showing the bone screw shown in  FIG. 31 ; 
           [0052]      FIG. 36  is an enlarged view of the proximal end of the bone screw shown in  FIG. 31 ; 
           [0053]      FIG. 37  is an enlarged view of the shaft of the bone screw shown in  FIG. 31 ; and 
           [0054]      FIG. 38  is an enlarged view of the distal end of the bone screw shown in  FIG. 31 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0055]    In the drawings, like numerals indicate like elements throughout. Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. For purposes of this description, the terms “anterior”, “posterior”, “superior” and “inferior” describe the position of surfaces or features relative to the anatomy. The term “anterior” refers to features having a relative position toward the front side of a spine, and “posterior” refers to features having a relative position toward the rear side of the spine. The term “superior” refers to features having a relative position above other features, in the cranial direction, and the term “inferior” refers to features having a relative position below other features in a caudal direction. The terminology includes the words specifically mentioned, derivatives thereof and words of similar import. 
         [0056]    The embodiments illustrated below are not intended to be exhaustive or to limit the invention to the precise form disclosed. These embodiments are chosen and described to best explain the principle of the invention and its application and practical use and to enable others skilled in the art to best utilize the invention. 
         [0057]    Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. The same applies to the term “implementation.” 
         [0058]    As used in this application, the word “exemplary” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion. 
         [0059]    Additionally, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. 
         [0060]    Applicant has observed a number of problems with the existing intervertebral spacers which use unsuitable materials, such as titanium or Polyether-ether ketone (PEEK). Interbody cages constructed from rigid materials such as titanium tend to have a large Young&#39;s modulus in the range of 105-130 GPa compared to bone, which has a relatively low modulus of 1.8 GPa. This makes titanium at least 58 times stiffer than bone and clinical studies have concluded this as the main cause of subsidence within the vertebral endplates. Subsidence is where the implant breaks through the vertebral endplates and intervertebral spacing is lost. Subsidence has been linked to pseudo-arthrosis, non-unions and re-operations of the fusion site. The high material stiffness may also enhance stress shielding of the central graft preventing or delaying bone through growth. However, the surface of titanium is well known for its osteoconductive properties. Osteoconductive materials encourage cell adhesion to the surface and can act like bone itself. This property can be used to increase the fusion area and allow bone growth directly on the implant. 
         [0061]    The other well utilized material for intervertebral spacers is PEEK. PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. In intervertebral fusion, intervertebral spacers constructed from PEEK have found a growing usage due to their relatively low stiffness, approximately 3.6 GPa compared to 1.8 GPa for bone. Clinical literature has reported lower occurrences of subsidence with PEEK intervertebral spacers, compared to a titanium spacer. However, PEEK is not an osteoconductive material and as such placement of a PEEK spacer within the intervertebral disc space can reduce the fusion area 60-70%, thus lowering the chances of a full fusion. 
         [0062]    The intervertebral spacers of the present invention improve upon prior approaches by addressing the subsidence and settling of the endplates, while maximizing the fusion area. The various embodiments of the present invention allow proper load distribution through the use of low stiffness material enabling the load to transfer through the bone graft material during implant settling, while increasing the fusion area and reducing the mitigation risks. To accomplish this, the embodiments include an osteoconductive material, such as titanium, applied on a substrate with similar properties to bone. The inferior and superior surfaces are configured to maximize the surface area through the use of a rectangular pyramid shaped tooth. The assembly also includes a mechanism which can engage both an insertion instrument and supplemental hardware, such as a plate and screw assembly. 
         [0063]    Referring now to  FIG. 1 , an interbody spacer  100  in accordance with one exemplary embodiment of the invention is shown. Interbody assemblies in accordance with the present invention may include a variety of body and teeth configurations. Interbody spacer  100  includes a rigid body  111  and a plurality of peaks, or teeth,  112  which form rigid body  111 . 
         [0064]    Rigid body  111  has an anterior surface  113  and a posterior surface  114  that is generally parallel to the anterior surface. Anterior surface  113  has a larger external surface area than posterior surface  114 . Anterior and posterior surfaces  113 ,  114 , respectively, are joined by a pair of lateral side surfaces  115  that extend generally radially to one another. A superior end surface  116  extends generally in a first plane and an inferior end surface  117  extends generally in a second plane obliquely, in a non-parallel manner, to the first plane between anterior side surface  113  and posterior side surface  114 . Superior and inferior end surfaces  116 ,  117 , respectively, taper or converge toward one another as end surfaces  116 ,  117  extend toward posterior side surface  114 , forming a wedge-shaped structure. The anterior, posterior and lateral side surfaces,  113 ,  114 , and  115 , respectively, surround a generally centrally located cavity  118  that forms a space for fusion material, such as a bone graft or bone graft substitute. 
         [0065]    Interbody spacer  100  includes a recess  120  extending through anterior surface  113  inwardly toward cavity  118  and generally centered between the superior  116  and inferior  117  surfaces. Recess  120  allows for the alignment of a congruent extension  1012  from either an instrument such as an insertion instrument  1000 , shown in  FIG. 10 , or an implant assembly such as plate assembly  1500 , shown in  FIG. 15 . An aperture  119  is centrally located within the recess  120  between the anterior surface  113  and the cavity  118 . The aperture  119  may be configured in either a threaded configuration, interference configuration or any means to secure the interbody spacer  100  to a separate device. 
         [0066]      FIG. 2  illustrates a top view of the interbody spacer  100  having a generally oval shape. This shape is generated by rounding the anterior  113 , posterior  114 , and lateral surfaces  115 , as well as the corner surfaces  211 . The central opening  118  can be constructed by creating a uniform offset of the outer perimeter  213 . The interbody spacer  100  benefits from a uniform geometry allowing the interbody to more evenly distribute the load distribution on the vertebral endplates. The center line A-P is defined by a line passing from the anterior surface  113  to the posterior surface  114 . The L-L line is defined by a line passing from the lateral surface  115  to the other lateral surface  115 . The teeth  112  are formed by adjacent ones of a plurality of anterior grooves  311  (shown in  FIG. 3 ) traversing longitudinally along the A-P direction and a plurality of lateral grooves  411  (shown in  FIG. 4 ) traversing transversely along the L-L direction. The intersection of anterior groove  311  and lateral groove  411  create a four sided pyramid-like tooth that maximize the surface area of superior surface  116  and inferior surface  117 . While a four sided tooth is shown, those skilled in the art will recognize that tooth (not shown) can have more or less than four sides. The teeth  112  are used to grip the superior and inferior endplate of the vertebral body (not shown). 
         [0067]      FIG. 3  illustrates the interbody spacer  100  from the anterior direction and shows the recess  120  and aperture  119 . The recess  120  is defined by parallel edge  312 , which forms a line segment and can be used to block rotation of congruent extension  1012  during insertion of the interbody spacer  100  into a patient (not shown). The teeth  112  are defined by the “V” shaped anterior groove  311 , however this groove can be a “U” shaped groove, “L” shape groove, “O” shape groove or any other configuration of groove which is create by a low peak (or trough)  314 , a high peak  315 , and peak width  316 . 
         [0068]      FIG. 4  illustrated a side profile of an interbody spacer  100 , which is shown as having a non-symmetric shape  400 . The implant superior surface  116 ′ and inferior surface  117 ′ cannot be mirrored about the A-P axis, thus defining the non-symmetric shape. The superior surface  117 ′ is defined by a superior convex dome  412  in an anterior-posterior direction, which is used to match the inferior vertebral endplate, not shown. The teeth  112  viewed from a lateral direction are constructed from an “L” shape groove  413  in the L-L direction. In order to maintain equal distance between peaks  315  on a domed surface, the teeth  112  must repeat at a crest angle (α), where crest angle α is greater than 0 degrees. Exemplary values for crest angle α may be between about 0 degrees and about 90 degrees. In an exemplary embodiment, crest angle α is about 10 degrees. The surfaces of adjacent peaks that define angle α extend generally perpendicular to the domed surface. The inferior surface  117 ′ teeth  112  are parallel to the A-P line and crest angle α is approximately 0 degrees between high peaks  315 . 
         [0069]      FIG. 5  shows a posterior view of the interbody spacer  400 , which shows the overall wedge shaped. In an exemplary embodiment, the posterior surface  114  is a wedge shape to aid in the insertion of the interbody spacer  100  into the vertebral disc space. 
         [0070]      FIG. 6  shows the cross-sectional view of the interbody spacer  100  as well as the recess  120 , aperture  119  and a marker bore  612 . The recess  120  extends sufficiently into the interbody rigid body  111  enough to create a parallel edge  312 . The aperture  119  extends from the recess  312  into the central opening  118 . Marker bore  612  generally is a cylindrical in shape, however this can be rectangular, triangular, or other suitable shape. Marker bore  612  is used to insert marker  1251  (shown in  FIG. 12   b ), which can be constructed from any radiopaque material, such as stainless steel, titanium, tantalum, etc. Generally there are a total of three marker bores  612  and corresponding markers  1251  spaced along the perimeter of interbody spacer  100 . The markers  1251 , when viewed from an anterior direction, show the interbody spacer&#39;s  100  width, which is defined from lateral surface  115  to opposing surface lateral surface  115 . The markers  1251  when viewed from the lateral position show the depth of the implant. The depth is defined as the distance between the anterior surface  113  and the posterior surface  114 . 
         [0071]      FIGS. 7 and 8  show side views of an alternative embodiment of curved symmetric interbody spacer  700  and straight symmetric interbody spacer  800 , respectively, where the superior surface  116  and inferior surface  117  are symmetric about the A-P line. In certain regions of the spine, such as lumbar or thoracic regions symmetrical interbody spacers  700  and  800  may mate with the opposing vertebral endplates better than a non-symmetric interbody spacer  400 . The symmetric interbodies  700  and  800  are defined when the superior dome  412  or superior surface  116  can be mirrored about the A-P centerline to be equivalent to the inferior dome  711  or inferior surface  117 . Another feature that can aid the insertion of the symmetric interbody spacer  700  and  800  in between the vertebral endplates is the width of rear crest  714 . The width of rear crest  714  is generally larger than the width of mid crest  716 , which allows for the interbody spacers  400 ,  700  and  800  to wedge itself between the vertebral endplates. The rear crest  714  can be aided by aligning the superior  116  and inferior  117  surfaces at an angle  812  from the A-P centerline. In an exemplary embodiment, angle  812  can be between about 0 degrees and about 90 degrees. In addition, the angle  812  can be used to match the spine curvature, such as Kyphosis or Lordosis angles. 
         [0072]      FIG. 9  is a micrograph of a cross sectional cut of a substrate  910  and porous coating  912  on the surface of an interbody spacer  100 , including at least one side of each of the teeth  112 . In an exemplary embodiment, the thickness of porous coating  912  can be between about 25 μm and about 800 μm thick. The substrate  910  can be any polymeric material, such as PEEK, Polymethyl Methacrylate (PMMA), or any other biocompatible polymer with a Young&#39;s modulus between about 0.1 GPa and about 50 GPa, which may be used as the interbody spacer  100 . The porous coating  912  is constructed from an osteoconductive material, such as titanium, nickel titanium, or any other material which may encourage bone in growth. The porous coating  912  is rigidly bounded to substrate  910  through a bonded layer  911 , such as by a plasma spray, vapor deposition, or another other surface additive method. The pores substrate  912  contains small to large size cavities  914 , which encourage bone in-growth and attachment. In an exemplary embodiment, the porosity of the pores substrate  912  can be between about 5 percent and about 80 percent porous. The interbody spacer  100  superior dome  412  and superior surface  116  are coated with the porous coating  912 , as is the inferior dome  711  and inferior surfaces  117 . The coating allows the interbody spacer rigid body  111  to maintain the low stiffness, which can be constructed from PEEK or low stiffness polymer, while gaining the porous coating  912  with osteoconductive properties. 
         [0073]    Optionally, a hydroxyapatite coating can be applied on surfaces  113 ,  114 ,  115  and on the walls of cavity  118  to enhance for visualization of implant  100  after implementation. 
         [0000]    Another embodiment of the invention is the insertion instrument  1000  illustrated in  FIGS. 10-14 , which is used to insert interbody  100  into the spine. The insertion instrument  1000  must capture the interbody spacer  100 , position the interbody spacer  100 , and deploy the interbody spacer  100  in between two adjacent vertebral bodies (not shown). The insertion instrument  1000  has a handle  1010  used to grip the instrument and rear end  1020  that can cooperate with an impact device (not shown). The hollow shaft  1016  is of a smaller diameter than the handle and has enough length to maneuver around soft tissue. Located between the shaft  1016  and handle  1010  has a cam  1018  used to engage and disengage a drive shaft  1252  from the aperture  119  in the interbody spacer  100 . A fastener portion, or engagement end  1014 , is located at the opposite end from the rear end  1020 . 
         [0074]    The engagement end  1014  is illustrated in  FIGS. 11-12   b  and is designed to releasably engage the interbody spacer  100 . The engagement end  1014  contains an engagement extension  1112 , which is located at the end of the drive shaft  1252 . The engagement extension  1112  is centrally located within the congruent extension  1012 , which is defined by two parallel edges  1120 . The congruent extension  1012  must contain at least one parallel edge  1114  but can be in a circular, rectangular, hexagonal, triangular or oblong. The engagement end  1014  may also have depth stop  1115 , which is used to control the placement of the interbody spacer  100  within the intervertebral disc space. The height of the depth stops  1115  must be greater than the highest interbody spacer  100 . 
         [0075]      FIGS. 12-14  illustrate the attachment of the interbody spacer  100  to the insertion instrument  1000 . The interbody spacer  100  is positioned at the engagement end  1014  of the insertion instrument  1000 . The engagement extension  1112  is coaxially aligned with and inserted into the implant aperture  119  in the recess  120  and the cam  1018  is rotated. The cam  1018  translates rotational motion through the drive shaft  1252  and extends engagement extension  1112 , until engagement is achieved. In this example, the engagement extension  1112  and aperture  119  have matching threads, however engagement may also be completed by an interference fit or other suitable engagement means. The rotation of the cam  1018  draws the interbody spacer  100  until contact is achieved with depth stops  1115 . The interbody spacer  100  is then placed into position by using an impaction device (not shown), such as, for example, a mallet, a hammer, a slap hammer, or other such device, on the rear end  1020  until the depth stops  1114  are flush with the surface of the vertebral bodies (not shown). The cam  1018  is then rotated in the reverse (unlocking) direction to retract engagement extension  1112  inwardly into shaft  1016  in the direction of arrow “A” in  FIG. 12   a , and the engagement extension  1112  is then removed from interbody spacer  100 . In the case of the non-symmetric interbody spacer, alignments to the proper direction of the spine is important, as shown in  FIG. 13 . In this case, indicator arrows  613  point towards the superior surface  116  and superior dome  412 . During insertion, the surgeon needs to visualize these indicator arrows  613  and the insertion instrument  1000  depth stop  1115  must have a width  1310  small enough to visualize the arrows  613 . 
         [0076]    Another embodiment of the invention is a plate assembly  1500  illustrated in  FIGS. 15-22 . The plate assembly  1500  contains a rigid body  1508 , which is defined by anterior surface  1510 , posterior surface  1512 , and an external perimeter  1518 . The plate has a generally “dog bone” shape but can have a rectangular, square or triangular shape. In an exemplary embodiment, the plate  1500  includes at least two screw recesses  1520 . Located in the center of the plate is a generally frusto-conical countersunk surface  1542  and attachment aperture  1540 . The attachment aperture  1540  is designed to align coaxially with the interbody spacer  100  aperture  119  and has an equal or larger diameter than aperture  119 . The countersunk surface  1542  and attachment aperture  1540  are coaxially aligned with the congruent extension  1012 . The attachment aperture  1540  is shown with a circular configuration but could be an oblong or oval shape to allow linear translation of a locking screw  1810  (shown in  FIG. 18 ) relative to the plate  1500 . 
         [0077]      FIGS. 16-17  show a side view and bottom view of a congruent extension  1012 , respectively. The congruent extension  1012  is located on the posterior side  1512  of the plate assembly  1500  and is designed to engage with a recess  120 , such as the one contained on the interbody spacer  100 . The interbody spacer  100  is designed to sit in the center of plate assembly  1500 . As such, the interbody  100  may be recessed beneath the vertebral walls. Therefore, the congruent extension  1012  sits on a congruent extension shelf  1720 . The mating side of the congruent extension shelf  1720  matches the surface of the implant, such as the anterior surface  113  of the interbody spacer  100 . In order to block rotation of the plate  1500 , the congruent extension  1012  contains at least one straight portion  1722  that engages parallel edge  312 , which may be incorporated into a circle, square, rectangle, triangle or oblong shape. 
         [0078]    The congruent extension  1012  cooperatively engages the recess  112  of the interbody spacer  100 , as illustrated in  FIGS. 18-20 . Once the congruent extension  1012  is seated in the recess  120  of interbody spacer  100 , locking screw  1810  can be used to secure the plate assembly  1500  to the interbody  100 . The locking screw  1810  generally has instrument recess  1812  on the head  1912  and threads on the shaft  1910 . The instrument recess  1812  is shown with a hexagonal connection but those skilled in the art will recognize that the connection can be a Torx, Philips, Square or any other torque transmitting connection. The locking screw  1810  has sufficient length for the trailing end  1914  to remain slightly recessed or extend in the central opening  118 . In the example shown, the shaft  1910  is threaded into the aperture  119  in the interbody spacer  100 ; however this can be an interference fit or any other fit in which the locking screw  1810  cannot disengage from the interbody spacer  100 . 
         [0079]      FIGS. 21 and 22  illustrate the attachment of bone screw  2100  to the plate assembly  1500  and interbody spacer  100 . As shown in the Figures, when the plate  1500  is coupled to the intervertebral implant  100 , a first plurality of the recesses  1520  extends above the upper surface of implant  100  and a second plurality of recesses  1512  extends below the lower surface of the implant  100 . The combination of the bone screws  2100  in the plate assembly  1500  and interbody spacer  100  is to prevent motion post-operatively to enable the vertebral bodies to fuse to the porous coating  912  of interbody spacer  100  and achieve bone growth through the central opening  118 . Referring to  FIG. 23 , the bone screws  2100  have a bulbous head  2110  and a head recess  2116  designed for engaging a mechanical translating instrument, such as a screw driver. The shaft  2118  is composed of a plurality of bone threads  2114  and terminate at a distal end  2112 . The distal end  2112  is configured to self-drill and tap into the bone with the use of minimal instrumentation. 
         [0080]    The plate assembly  1500  screw recess  1520  is designed with a spherical seat  2412  (shown in  FIG. 24 ) to allow the bulbous head  2110  to seat in a variety of angular positions based of on an angle  2212  (shown in  FIG. 22 ) from the center axis  2214  of the plate assembly  1500 . The angle  2212  allows for the surgeon to customize the position of the bone screw  2100  intraoperatively. The spherical like shape of the bulbous head  2110  allows for the bone screws  1500  to adapt as the vertebral endplates settle on the superior surface  116  and inferior surface  117  of the interbody spacer  100 . This plate configuration is known as semi-constrained; however the bone screw recess  1520  could be slotted to allow for linear dynamic transition of the bulbous head  2110 . 
         [0081]    Another embodiment of the invention is the locking head  2300  of bone screw  2100  further illustrated in  FIG. 23 . The locking head  2300  is composed of a plurality of cantilever segments  2310  extending around the head  2300  that are created when a circular groove  2314  is segmented by a plurality of gaps  2312  at equal distance from each other. In order for the cantilever segments  2310  to deform, at least one gap  2312  must be created between them. The groove  2314  is created circumferentially around the axis  2320  of bone screw  2100  and extends outwards from the head recess  2116 . 
         [0082]      FIGS. 24 and 25  show the bone screw  2100  inserted into a rigid plate body  1508  in an unlocked and locked position, respectively. The rigid body  1508  screw recess  1520  is designed to have a spherical seat  2412 , an undercut ledge  2520 , and a cylindrical section  2522  extending inwardly from the ledge  2520 . The spherical seat  2412  is designed to cooperatively engage the bone screws bulbous head  2110  while allowing translation about the bone screw bore center axis  2214 . The cantilever segments  2310  are designed to deflect, or bias, inwardly during insertion of the bone screw  2100  in the screw recess  1520  by contacting the cylindrical section  2522  and deflecting towards the bone screw axis  2320 . The deflection is great enough to allow the bulbous head  2110  to pass, but not enough to plastically deform the cantilever segments  2310 . Once the bulbous head  2110  has passed the cylindrical section  2522  the cantilever segments  2310  elastically spring back, or bias outwardly beneath cylindrical section  2522 . The undercut ledge  2520  prevents the bone screws  2100  from disengaging from the plate  1508 . The undercut ledge  2520  also blocks excessive rotation of the bulbous head  2110  but contacts the top of the cantilever segment  2310 . 
         [0083]    Another exemplary embodiment of the invention is a removable body extension assembly  2600  as illustrated in  FIGS. 26-30 . The removable body extension assembly  2600  is a cylindrical shaped extension, which can be attached to a headless bone screw  2610 , bone screw  2100 , plate  1500 , or any other implantable implant requiring UDI tracking. The removable body extension assembly  2600  allows for indicia, or descriptive information  2710 , such as the part number  2714  and or serial/lot number  2716 , to be contained with the implant, specifically, when the surface area, like the shaft  2616  of screw  2610 , is not large enough to contain the descriptive information  2710 . 
         [0084]    The removable body extension assembly  2600  has an engagement end  2810  specifically designed to interface with an implant. In the example shown in  FIG. 28 , the engagement extension  2810  is threaded to engage recess  3212  in the proximal head  2630  of a headless compression bone screw  2610 . The engagement extension  2810  can be press fit or have an interference fit engagement recess  3212  or head recess  3210  of the implant. The engagement extension  2810  may also be manufactured directly as part of the implant in a monolithic configuration and disengage through breaking connection located at the engagement extension end  2810 . 
         [0085]    In the case of the headless compression screw  2610 , one issue during surgery is removing the headless compression screw  2610  from a screw holder because of the sharp proximal threads  2614  located on the proximal head  2630 . The proximal end  2910  of the removable body extension  2600  can be smooth or knurled to allow a grip zone  2912 . Prior to inserting headless compression screw  2610 , the removable body extension  2900  is used to remove the screw from a screw caddie (not shown). The removable body extension  2900  is then removed by unscrewing the engagement section  2810  from the engagement recess  3212  of screw  2610 . Screw  2610  is then inserted into the patient. The removable body extension  2900  is left outside of the patient and the descriptive information  2710  is recorded. 
         [0086]    In addition to headless bone screws,  FIG. 30  shows an example of a plate  1500  with the removable body extension  2900  attached via the engagement extension  2810 . The removable body extension  2900  can be attached to a number of implants, such as the interbody spacer  100 , plate  1500 , headless compression screw  2610 , bone staple (not shown), suture anchor (not shown), or any other implant which is too small to physically laser mark descriptive information  2710 . 
         [0087]    In another embodiment shown in  FIGS. 31-38 , headless compression screw  2610  is shown in more detail. The headless compression screw  2610  is defined by proximal head  2630  and a distal end  2640  joined by a shaft  2616 . The distal end  2640  has distal threads  2612  with a distal pitch  3310  and the proximal head  2630  has proximal threads  2614  with a proximal thread pitch  3312 , where the proximal thread pitch  3312  is less than distal thread pitch  3310 . The difference in proximal thread pitch  3312  and distal thread pitch  3310  causes a compressive force to generate between segments. The proximal head  2630  has an engagement recess  3210  which can be a Torx, Hexagonal, Square, or Phillips in shape. 
         [0088]      FIGS. 36-38  specifically show the self-cutting features of the headless bone screw  2620 . The proximal head  2630  has a groove  3620 , which removes material as the proximal head  2630  and the proximal threads  2614  begin to engage a substrate, such as bone. 
         [0089]      FIG. 37  illustrates a reverse cutting groove  3720  positioned on the distal end  2640  and engages the distal threads  2612  near the shaft  2616 . The reverse cutting groove  3720  removes material, such as bone, as the headless bone screw  2610  is removed. 
         [0090]      FIG. 38  illustrates the tip of the distal end  2640 , which includes distal threads  2612  and self drilling groove  3820 . The length of self-drilling groove  3820  is greater than the distal thread pitch  3310  and is used as the headless bone screw  2610  is inserted into a substrate such as bone. 
         [0091]    Optionally, each device described above that is to be implanted (i.e., interbody, screws, plate, etc.) can be coated with an antimicrobial agent, such as, for example, silver oxide. The anti-microbial coating can be in the form of a nano coating or other type of coating. Such an antimicrobial coating can be used to reduce or eliminate infections within the patient. 
         [0092]    It should also be understood that this invention is not limited to the disclosed features and other similar method and system may be utilized without departing from the spirit and the scope of the invention. 
         [0093]    While the invention has been described with reference to the preferred embodiment and alternative embodiments, which embodiments have been set forth in considerable detail for the purposes of making a complete disclosure of the invention, such embodiments are merely exemplary and are not intended to be limiting or represent an exhaustive enumeration of all aspects of the invention. The scope of the invention, therefore, shall be defined solely by the claims. Further, it will be apparent to those of skill in the art that numerous changes may be made in such details without departing from the spirit and the principles of the invention. It should be appreciated that the invention is capable of being embodied in other forms without departing from its essential characteristics.