Abstract:
An expandable stabilizing cage includes a body having a fixed cage section, an expandable cage section, formed as a number of elongate blocks, and a relief between the fixed and expandable cage sections. An orifice, which through the expandable cage section decreases in diameter with increased distance along the central axis of the body away from the fixed cage section, is provided through the body. The expandable stabilizing cage also includes a wafer, which, when inserted into the orifice through the body, causes outward flaring of the elongate bars for fixing the expandable stabilizing cage securely in place in the intervertebral disc space between two adjacent vertebral bodies. Upper elongate blocks have substantially planar upper surfaces. Lower elongate blocks have substantially planar lower surfaces. The surfaces may be provided with surface irregularities for facilitating stable engagement with adjacent vertebral bodies, exemplary irregularities including denticles, dimples, scores, grooves or small protuberances.

Description:
RELATED APPLICATION 
     This present application claims all available benefit, under 35 U.S.C. §119(e), to U.S. provisional patent application Ser. No. 60/728,228 filed Oct. 19, 2005. By this reference, the full disclosure, including the drawings, of U.S. provisional patent application Ser. No. 60/728,228 is incorporated herein as though now set forth in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to medical devices. More particularly, the invention relates to an expandable stabilizing cage for replacement of a patient&#39;s intervertebral disc and fusion therethrough of the immediately superior and immediately inferior vertebral bodies, the expandable stabilizing cage being particularly adapted for either anterior or posterior insertion into the intervertebral space and for enhanced post-insertion stability. 
     BACKGROUND OF THE INVENTION 
     Patients suffering injury or deterioration of an intervertebral disc often require surgical intervention, which in some cases results in removal of the natural intervertebral disc and fusing of the adjacent superior and inferior vertebral bodies. In order to allow fusion with normal lordosis of the spine, however, it is necessary to mechanically stabilize the adjacent superior and inferior vertebral bodies in a desired relationship one to the other and, thereafter, to maintain the effected spatial relationship. As a consequence, medical technologists have developed a wide array of medical devices to this end. Unfortunately, the known devices are generally subject to inadvertent displacement during or following the fusion process due to ambulation of the patient and therefore generally require fairly invasive interventions to secure the devices in position in the intervertebral disc space. In particular, the known devices generally require the use of pedicle plates and pedicle screws or the like for maintenance of stable placement. 
     It is therefore an overriding object of the present invention to improve over the prior art by providing an expandable lordosis stabilizing cage that is inherently stable upon insertion into the intervertebral disc space of a patient under treatment. Additionally, it is an object of the present invention to provide such an expandable lordosis stabilizing cage that may be inserted into the patient&#39;s intervertebral disc space through either anterior or posterior surgical intervention. 
     SUMMARY OF THE INVENTION 
     In accordance with the foregoing objects, the present invention—an expandable stabilizing cage for insertion into the intervertebral disc space of a patient for establishing and maintaining a desired lordosis—generally comprises a body having a fixed cage section, an expandable cage section and a relief between the fixed cage section and the expandable cage section. The expandable cage section comprises a plurality of elongate blocks which are preferably connected to the fixed cage section by only a portion the end of each of the elongate blocks and which project longitudinally away from the fixed cage section. An orifice is provided through the body coaxial with a central longitudinal axis through the fixed cage section and the expandable cage section. The orifice through the expandable cage section decreases in diameter with increased distance along the central axis away from the fixed cage section. In at least one preferred embodiment of the present invention, the expandable stabilizing cage comprises a wafer, which, when inserted into the orifice through the body, causes outward flaring of the elongate bars for fixing the expandable stabilizing cage securely in place in the intervertebral disc space between two adjacent vertebral bodies. 
     Upper elongate blocks comprise a substantially planar upper surface and lower elongate blocks comprise a substantially planar lower surface. While still keeping with the critical requirement for substantially planar upper and lower surfaces, however, the surfaces may nonetheless be desirably provided surface irregularities for facilitating stable engagement of the elongate blocks with adjacent vertebral bodies. In particular (by way of example rather than limitation) the surface irregularities may comprise denticles, dimples, scores, grooves, small protuberances or the like. 
     Finally, many other features, objects and advantages of the present invention will be apparent to those of ordinary skill in the relevant arts, especially in light of the foregoing discussions and the following drawings, exemplary detailed description and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Although the scope of the present invention is much broader than any particular embodiment, a detailed description of the preferred embodiment follows together with illustrative figures, wherein like reference numerals refer to like components, and wherein: 
         FIG. 1  shows, in a partially exploded perspective view, a first preferred embodiment of the expandable lordosis stabilizing cage of the present invention; 
         FIG. 2  shows, in a second partially exploded perspective view, the expandable lordosis stabilizing cage of  FIG. 1 ; 
         FIG. 3  shows, in a posterior end elevational view, the expandable lordosis stabilizing cage of  FIG. 1 ; 
         FIG. 4  shows, in a right side elevational view, the expandable lordosis stabilizing cage of  FIG. 1 ; 
         FIG. 5  shows, in an anterior end elevational view, the expandable lordosis stabilizing cage of  FIG. 1 ; 
         FIG. 6  shows, in a cross sectional view taken through line  6 - 6  of  FIG. 4 , the expandable lordosis stabilizing cage of  FIG. 1 ; 
         FIG. 7  shows, in an end view, the preferred embodiment of the expansion wafer utilized in implementation of the present invention; 
         FIG. 8  shows, in a side view, the preferred embodiment of the expansion wafer of  FIG. 7 ; 
         FIG. 9  shows, in a posterior end view, the preferred embodiment of the end plug utilized in implementation of the present invention; 
         FIG. 10  shows, in a right side view, the end plug of  FIG. 9 ; 
         FIG. 11  shows, in a right side elevational view, the body of the expandable lordosis stabilizing cage of  FIG. 1  with the wafer of  FIGS. 7 and 8  inserted in preparation for a posterior insertion of the expandable lordosis stabilizing cage into the intervertebral disc space of a patient; 
         FIG. 12  shows, in a posterior elevational view, a section of assembled vertebrae, the view of  FIG. 12  particularly detailing an area “A” from which vertebral structures are surgically excised prior to posterior insertion of the expandable lordosis stabilizing cage of the present invention; 
         FIG. 13  shows, in a right side elevational view, the path of a posterior insertion of the expandable lordosis stabilizing cage of  FIG. 1  into the decompressed intervertebral disc space of a patient; 
         FIG. 14  shows, in a posterior elevational view of a section of assembled vertebrae, posterior placement of a pair of expandable lordosis stabilizing cages of  FIG. 1  into the decompressed intervertebral disc space of a patient; 
         FIG. 15  shows, in a right side elevational detail view taken in detail area B of  FIG. 13 , placement into the decompressed intervertebral disc space of a patient of the body of the expandable lordosis stabilizing cage of  FIG. 1  as prepared for posterior insertion according to  FIG. 11 ; 
         FIG. 16  shows, in a right side elevational detail view taken in detail area B of  FIG. 13 , expansion through operation of the expansion wafer of  FIGS. 7 and 8  of the expandable cage section of the body of the expandable lordosis stabilizing cage of  FIG. 1  after posterior insertion; 
         FIG. 17  shows, in a right side elevational detail view taken in detail area B of  FIG. 13 , final posterior insertion of the expandable lordosis stabilizing cage of  FIG. 1 ; 
         FIG. 18  shows, in a posterior elevational view of a section of assembled vertebrae, final posterior insertion of a pair of expandable lordosis stabilizing cages of  FIG. 1 ; 
         FIG. 19  shows, in a right side view, the body of the expandable lordosis stabilizing cage of  FIG. 1  with the wafer of  FIGS. 7 and 8  inserted in preparation for an anterior insertion of the expandable lordosis stabilizing cage into the intervertebral disc space of a patient; 
         FIG. 20  shows, in a right side view, the body of the expandable lordosis stabilizing cage of  FIG. 19  with the end plug of  FIGS. 9 and 10  inserted in further preparation for an anterior insertion of the expandable lordosis stabilizing cage into the intervertebral disc space of a patient; 
         FIG. 21  shows, the path of an anterior insertion of the expandable lordosis stabilizing cage of  FIG. 1  into the decompressed intervertebral disc space of a patient; 
         FIG. 22  shows, in an anterior elevational view of a section of assembled vertebrae, anterior placement of a single expandable lordosis stabilizing cage of  FIG. 1  into the decompressed intervertebral disc space of a patient; 
         FIG. 23  shows, in an anterior elevational view of a section of assembled vertebrae, anterior placement of a pair of expandable lordosis stabilizing cages of  FIG. 1  into the decompressed intervertebral disc space of a patient; 
         FIG. 24  shows, in a right side elevational detail view taken in detail area C of  FIG. 21 , placement into the decompressed intervertebral disc space of a patient of the body of the expandable lordosis stabilizing cage of  FIG. 1  as prepared for posterior insertion according to  FIG. 20 ; 
         FIG. 25  shows, in a right side elevational detail view taken in detail area C of  FIG. 21 , expansion through operation of the expansion wafer of  FIGS. 7 and 8  of the expandable cage section of the body of the expandable lordosis stabilizing cage of  FIG. 1  after anterior insertion, the depicted placement being the final anterior insertion of the expandable lordosis stabilizing cage; 
         FIG. 26  shows, in an anterior elevational view of a section of assembled vertebrae, final anterior insertion of a single expandable lordosis stabilizing cage of  FIG. 1 ; 
         FIG. 27  shows, in an anterior elevational view of a section of assembled vertebrae, final anterior insertion of a pair of expandable lordosis stabilizing cages of  FIG. 1 ; 
         FIG. 28  shows, in a partially exploded perspective view, a second preferred embodiment of the expandable lordosis stabilizing cage of the present invention; 
         FIG. 29  shows, in a second partially exploded perspective view, the expandable lordosis stabilizing cage of  FIG. 28 ; 
         FIG. 30  shows, in a right side elevational view, the expandable lordosis stabilizing cage of  FIG. 28 ; 
         FIG. 31  shows, in a cross sectional view taken through line  31 - 31  of  FIG. 30 , the expandable lordosis stabilizing cage of  FIG. 28 ; 
         FIG. 32  shows, in a posterior end elevational view, the expandable lordosis stabilizing cage of  FIG. 28 ; 
         FIG. 33  shows, in a cross sectional view taken through line  33 - 33  of  FIG. 32 , the expandable lordosis stabilizing cage of  FIG. 28 ; 
         FIG. 34  shows, in an anterior end elevational view, the expandable lordosis stabilizing cage of  FIG. 28 ; 
         FIG. 35  shows, in a perspective view, the expandable lordosis stabilizing cage of  FIG. 1  showing an alternative embodiment for implementation of irregularities on the upper surfaces of the upper pair of elongate blocks and the lower surfaces of the lower pair of elongate blocks of the expandable lordosis stabilizing cages of  FIG. 1  or  FIG. 28 ; 
         FIG. 36  shows, in a perspective view, the expandable lordosis stabilizing cage of  FIG. 1  showing a second alternative embodiment for implementation of irregularities on the upper surfaces of the upper pair of elongate blocks and the lower surfaces of the lower pair of elongate blocks of the expandable lordosis stabilizing cages of  FIG. 1  or  FIG. 28 ; and 
         FIG. 37  shows, in a perspective view, the expandable lordosis stabilizing cage of  FIG. 1  showing a third alternative embodiment for implementation of irregularities on the upper surfaces of the upper pair of elongate blocks and the lower surfaces of the lower pair of elongate blocks of the expandable lordosis stabilizing cages of  FIG. 1  or  FIG. 28 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Although those of ordinary skill in the art will readily recognize many alternative embodiments, especially in light of the illustrations provided herein, this detailed description is exemplary of the preferred embodiment of the present invention, the scope of which is limited only by the claims appended hereto. 
     Referring now to the figures, and to  FIGS. 1 and 2  in particular, the lordosis stabilizing cage  50  of the present invention is shown to generally comprise a body  51  and an expansion wafer  81 . As shown the figures, the body  51  comprises a generally rectilinear expandable cage section  52  and a fixed cage section  71  arranged adjacent one to the other along a central axis  80  running longitudinally through the body  51 . As shown in  FIGS. 1 through 6 , the expandable cage section  52  comprises a plurality of elongate blocks  54  extending from their proximal ends  55  from the fixed cage section  71 . As shown in the figures, the elongate blocks  54  are generally defined by the provision of slots  53  in the horizontal and vertical planes running through the central axis  80 . 
     As shown in the figures, the elongate blocks  54  preferably comprise an upper pair  60  of elongate blocks  54  and lower pair  67  of elongate blocks  54 . In order to promote stability of the lordosis stabilizing cage  50  after insertion into the intervertebral disc space  102  of a patient (as will be better understood further herein), it is critical to the present invention that each elongate block  54  of the upper pair  60  comprises a substantially planar upper surface  61 . Likewise, it is critical to the present invention that each elongate block  54  of the lower pair  67  comprises a substantially planar lower surface  68 . In this manner, expansion radially from the central axis  80  of the distal end  57  of each elongate block  54  (as will also be better understood further herein) results in engagement of a maximum surface area of the expandable cage section  52  of the lordosis stabilizing cage  50  with the adjacent superior vertebral body  95  and inferior vertebral body  100 . 
     As shown in  FIGS. 1 through 6 , the fixed cage section  71  of the body  51  of the lordosis stabilizing cage  50  may comprise a nut  72 , which although not critical to the present invention is preferably rectilinear in shape to facilitate manufacture of the lordosis stabilizing cage  50 . In any case, the body  51  of the lordosis stabilizing cage  50  of the present invention comprises an orifice  74  arranged coaxially with the central axis  80  through the fixed cage  71 . The orifice  74  through the fixed cage section  71  is cylindrical in shape and terminates into an orifice  69  through the expandable cage section  52 . The orifice  69  through the expandable cage section  52 , however, is shaped as a frustum of a cone, which frustum decreases in diameter with increased distance along the central axis  80  from the fixed cage section  71 . 
     As a result of the described arrangement of orifice  74  and orifice  69  through the fixed cage section  71  and the expandable cage section  52 , respectively, insertion of the expansion wafer  81  into and through the orifice  74  of the fixed cage section  71  and into and through the orifice  69  of the expandable cage section  52  results in the radially outward flaring of the distal ends  57  of the elongate blocks  54 . In order to facilitate the desired flaring of the distal ends  57  of the elongate blocks  54 , a relief  77  is provide in the body  51  of the lordosis stabilizing cage  50  in the area of intersection between the expandable cage section  52  and the fixed cage section  71 . As shown in  FIGS. 1 through 6 , a suitable relief  77  may be implemented by providing an annulus  78  in the fixed cage section  71  at the location where the fixed cage section  71  interconnects with the expandable cage section  52 . In this case, only a fractional, radially interior portion  56  of each of the proximal ends  55  of the elongate blocks  54  interconnect with the fixed cage section  71 . 
     To facilitate generation of the radial force required for flaring of the distal ends  57  of the elongate blocks  54  during insertion of the expansion wafer  81 , the orifice  69  through the expandable cage section  52  is preferably provided with interior threading  70 . Likewise, the orifice  74  through the fixed cage section  71  is also provided with interior threading  76 . As will be understood by those of ordinary skill in the art, the interior threading  76  of the orifice  74  through the fixed cage section  71  is tapped cylindrically through the orifice  74  to the portion interior  79  of the annulus  78 . The interior threading  70  of the orifice  69  though the expandable cage section  52 , however, is tapped as a frustum of a cone. In this implementation of the body  51  of the lordosis stabilizing cage  50 , the expansion wafer  81  preferably comprises a set screw  82  or substantially equivalent structure having provided thereon circumferential threading  83  sized to mate with the interior threading  70 , 76  of the orifices  69 ,  74 , respectively. Additionally, the set screw  82 , or substantially equivalent structure, is provided at the central portion of one face  84  thereof with an Allen (hexagonal) socket  85  or any substantially equivalent drive such as, for example, a driver slot. In this manner, the surgeon may utilize the leverage of the threading  83  of the set screw  82  interplaying with the threading  70  of the orifice  69  through the expandable cage section  52  for generation of the outward radial force required to flare the distal ends  57  of the elongate blocks  54 . 
     In order to prevent inadvertent driving of the expansion wafer  81  entirely through the orifice  69  of the expandable cage section  52 , wafer stops  58  are preferably provided at the distal ends  57  of the elongate blocks  54 . In one implementation of the present invention, shoulders  59  are provided at the termination of the interior threading  70  of the orifice  69  through the expandable cage section  52 . 
     In at least one embodiment of the present invention, the lordosis stabilizing cage  50  comprises an end plug  86  for insertion into and closure of the orifice  74  of the fixed cage section  71  at the front face  73  of the fixed cage section  71 . The end plug  86  is preferably implemented comprising a head  87  and a circumferentially threaded section  90 . An Allen (hexagonal) socket  89  or any substantially equivalent drive such as, for example, a driver slot, is provided at or across the central portion of the face  88  of the head  87  of the end plug  86 . The threading provided about the end plug  86  is, as will appreciated by those of ordinary skill in the art, sized to mate with the interior threading  76  of the orifice  74  through the fixed cage section  71 . In the preferred embodiment, however, the orifice  74  is provided with a shoulder  75  adjacent to the front face  73  of the fixed cage section  71  for flush acceptance into the orifice  74  of the head  87  of the end plug  86 . 
     As shown in  FIGS. 1 through 6 , the first preferred embodiment of the lordosis stabilizing cage  50  of the present invention comprises a body  51  having a generally square cross section as pointed out in the figures by reference  91 . Additionally, however, a second preferred embodiment comprises a generally rectangular cross section as denoted in the figures by reference  92  and particularly shown in  FIGS. 28 through 34 . The particular utility of each of these preferred embodiments will be detailed further herein. 
     Referring now to  FIGS. 28 ,  29  and  37  through  39 , it is noted that the present invention contemplates that the substantially planar upper surfaces  61  of the upper pair  60  of elongate blocks  54  and the substantially planar lower surfaces  68  of the lower pair  67  of elongate blocks  54  may be provided with surface irregularities  62 . These surface irregularities  62  are provided to enhance secure engagement of the upper surfaces  61  and the lower surfaces  68  with the immediately superior vertebral body  95  and immediately inferior vertebral body  100  and should be limited to structures that enhance or facilitate maintenance of the position in the patient&#39;s intervertebral disc space  102  of the lordosis stabilizing cage  50 . As shown in the figures, surface irregularities  62  meeting these requirements may comprise denticles  63 , dimples  64 , grooves or scores  65 , bumps, nodules or other protuberances  66  or any substantially equivalent structure. In the case of irregularities  62  such as the denticles  63 , it is noted that such structures are preferably transversely oriented such that maximum benefit of the irregularity  62  is directed towards maintenance of the anterior-posterior position of the inserted lordosis stabilizing cage  50  and also such that the irregularities  62  do not prevent or unduly hinder transverse spreading of the upper pair  60  or lower pair  67  of elongate blocks  54  during the expansion or flaring of the expandable cage section  52 . 
     Referring now to  FIGS. 11 through 18 , the procedure for posterior insertion of the lordosis stabilizing cage  50  of the present invention into the decompressed intervertebral disc space  102  between a superior vertebra  94  and an inferior vertebra  99  of a section of assembled vertebrae  93  is described. As shown in  FIG. 11 , the body  51  of the lordosis stabilizing cage  50  is first prepared for posterior insertion by inserting the expansion wafer  81  (with the socket  85  of the expansion wafer  81  facing outward) into the orifice  74  of the nut  72  forming the fixed cage section  71 . The expansion wafer  81  is threaded into the orifice  74  and positioned adjacent to the proximal end of the orifice  69  of the expandable cage section  52 . 
     With the body  51  of the lordosis stabilizing cage  50  prepared for insertion, the patient is prepared by surgically excising portions of the spinous process  96 , the inferior articular process  97  and the lamina  98  of the superior vertebra  94  and portions of the lamina  101  of the inferior vertebra  99  falling generally within the area depicted with reference A in  FIG. 12 . Additionally, the superior vertebra  94  and inferior vertebra  99  are decompressed by surgical removal of the affected intervertebral disc  103 . 
     As shown in  FIGS. 13 and 14 , the prepared body  51  is then inserted (expandable cage section  52  first) into the decompressed intervertebral disc space  102 . As particularly shown in  FIG. 14 , the posterior insertion of the lordosis stabilizing cage  50  will generally require the insertion of a pair of the generally square cross section stabilizing cages  91  in side-by-side position in order to avoid dangerous interaction with the spinal cord (not shown). In any case, with the previously prepared bodies  51  inserted into the intervertebral disc space  102  as depicted in  FIG. 15 , the surgeon then operates the expansion wafer  81  to translate the expansion wafer  81  through the orifice  69  of the expandable cage section  52  into position at the distal ends  57  of the elongate blocks  54 , thereby causing radially outward flaring of the distal ends  57 . The outward flaring of the distal ends  57  of the elongate blocks  54  in turn results in the wedging of the substantially planar surfaces  61  of the upper pair  60  of elongate blocks  54  and the substantially planar lower surfaces  68  of the lower pair  67  of elongate blocks  54  firmly between the superior vertebra  94  and inferior vertebra  99  bounding the intervertebral disc space  102 . 
     As shown in  FIG. 17 , the surgeon then may insert the end plug  86  in place in the front face  73  of the fixed cage section  71 . (Although not discussed in detail, it should be noted and understood by those of ordinary skill in the art that the surgeon will of course perform other steps during the conduct of the described procedures including, for example, packing of the lordosis stabilizing cage  50  and other areas in or about the intervertebral disc space  102  with bone, bone growth factors or the like.) Finally, as shown in  FIG. 18 , upon final placement of the lordosis stabilizing cages  50  of the present invention, the superior vertebra  94  and the inferior vertebra  99  will obtain and securely and stably maintain normal lordosis. 
     Referring now to  FIGS. 19 through 27 , the procedure for anterior insertion of the lordosis stabilizing cage  50  of the present invention into decompressed intervertebral disc space  102  between a superior vertebra  94  and an inferior vertebra  99  of a section of assembled vertebrae  93  is described. As shown in  FIG. 19 , the body of the lordosis stabilizing cage  50  is first prepared for anterior insertion by inserting the expansion wafer  81  (with the socket  85  of the expansion wafer  81  facing inward) into the orifice  74  of the nut  72  forming the fixed cage section  71 . The expansion wafer  81  is threaded into the orifice  74  in position adjacent to the proximal end of the orifice  69  of the expandable cage section  52 . As shown in  FIG. 20 , the end plug  86  is then inserted in place in the front face  73  of the fixed cage section  71 . 
     With the body  51  of the lordosis stabilizing cage  50  prepared for insertion, the patient is prepared by surgically excising the affected intervertebral disc  103 . It will be appreciated by those of ordinary skill in the art, anterior insertion of the lordosis stabilizing cage  50  of the present invention does not require surgical excision of the posterior bone structures as previously described with respect to posterior insertion. It is noted, however, that unlike a posterior insertion an anterior insertion carries the associated risk of surgery about delicate structures such as, for example, the patient&#39;s vena cava. 
     As shown in  FIGS. 21 through 24 , the prepared body  51  or a pair of prepared bodies  51  is then inserted (fixed cage section  71  first) into the decompressed intervertebral disc space  102 . As particularly shown in  FIGS. 22 and 23 , the anterior insertion of the lordosis stabilizing cage  50  may be performed with a single generally square cross section stabilizing cage  91 , a pair of the generally square cross section stabilizing cages  91  in side-by-side position or by insertion of a single generally rectangular cross section stabilizing cage  92 , as has been described in detail with respect to  FIGS. 28 through 34 . 
     In any case, with the previously prepared bodies  51  inserted into the intervertebral disc space  102  as depicted in  FIG. 24 , the surgeon then operates the expansion wafer  81  to translate the expansion wafer  81  through the orifice  69  of the expandable cage section  52  into position at the distal ends  57  of the elongate blocks  54 , thereby radially outward flaring of the distal ends  57 . Because in the anterior insertion of the lordosis stabilizing cage  50  it is necessary to draw the expansion wafer  81  toward the surgeon, the provision of threading in the orifices and about the expansion wafer  81  as previously described is particularly desirable for this procedure. In any case, the outward flaring of the distal ends  57  of the elongate blocks  54  in turn results in the wedging of the substantially planar surfaces  61  of the upper pair  60  of elongate blocks  54  and the substantially planar lower surfaces  68  of the lower pair  67  of elongate blocks  54  firmly between the superior vertebra  94  and the inferior vertebra  99  bounding the intervertebral disc space  102 , as depicted in  FIG. 25 . As shown in  FIGS. 25 through 27 , upon final placement of the lordosis stabilizing cage or cages  50  of the present invention, the superior vertebra  94  and the inferior vertebra  99  will obtain and securely and stably maintain normal lordosis. 
     While the foregoing description is exemplary of the preferred embodiment of the present invention, those of ordinary skill in the relevant arts will recognize the many variations, alterations, modifications, substitutions and the like as are readily possible, especially in light of this description, the accompanying drawings and claims drawn thereto. For example, although poly-ether-ether-ketone is the presently preferred choice of material for construction of the expandable lordosis stabilizing cage of the present invention, those of ordinary skill in the art will recognize that other materials such as carbon fiber or titanium or any substantially equivalent material may also be utilized. In any case, because the scope of the present invention is much broader than any particular embodiment, the foregoing detailed description should not be construed as a limitation of the scope of the present invention, which is limited only by the claims appended hereto.